In October 2009, the MoD was heavily criticized for withdrawing the bi-annual non-operational training £20m budget for the volunteer Territorial Army (TA), ending all non-operational training for 6 months until April 2010. The government eventually backed down and restored the funding. The TA provides a small percentage of the UK's operational troops. Its members train on weekly evenings and monthly weekends, as well as two-week exercises generally annually and occasionally bi-annually for troops doing other courses. The cuts would have meant a significant loss of personnel and would have had adverse effects on recruitment.

When was the TA budget withdrawn?

October 2009

How much money was allocated to the volunteer Territorial Army?

When was the training for the TA supposed to resume?

April 2010

How much of the UK's troops are provided by the TA?

a small percentage

How often do the TA troops regularly train?

weekly evenings and monthly weekends

What was the Territorial Army criticized for removing from the MoD?

I'm not sure.

What did the Territorial Army removing the MoD budget end up causing?

I'm not sure.

What was eventually restored by the TA?

I'm not sure.

What percentage of the troops take part in other courses?

I'm not sure.

How often did the MoD members train in 2009?

I'm not sure.


In 2013 it was found that the Ministry of Defence had overspent on its equipment budget by £6.5bn on orders that could take up to 39 years to fulfil. The Ministry of Defence has been criticised in the past for poor management and financial control, investing in projects that have taken up to 10 and even as much as 15 years to be delivered.

By how much did the MoD go over its equipment budget?

When was the overbudget amount discovered?

What are some of the criticisms that have been directed at the MoD?

poor management and financial control

What is a long-range estimate on fulfillment of some of the equipment orders made by the MoD?

up to 39 years

Past projects ordered by the MoD have taken what type of time frame to fulfill?

up to 10 and even as much as 15 years

For how long did the MoD go over its equipment budget?

I'm not sure.

How long has the MoD existed?

I'm not sure.

How long has the MoD been poorly managed?

I'm not sure.

What has the government had for 10 to 15 years?

I'm not sure.

What was the Mod's equipment budget in 2013?

I'm not sure.


The term high definition once described a series of television systems originating from August 1936; however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30 lines of resolution. The ongoing competition between companies and nations to create true "HDTV" spanned the entire 20th century, as each new system became more HD than the last.In the beginning of the 21st century, this race has continued with 4k, 5k and current 8K systems.

The term "high definition" originally described televisions systems from what year?

Earlier television systems were based on what?

mechanical systems with as few as 30 lines of resolution

During which entire century were companies and nations trying to achieve true HDTV?

In what century were 4k, 5k, and 8k systems introduced?

What is the most current HDTV system development?

What came out in 1935?

I'm not sure.

The term "high definition" originally described vcrs from what year?

I'm not sure.

Earlier television systems were not based on what?

I'm not sure.

During which entire century were companies and nations trying to achieve true SDTV?

I'm not sure.

In what century were 10k systems introduced?

I'm not sure.


The British high-definition TV service started trials in August 1936 and a regular service on 2 November 1936 using both the (mechanical) Baird 240 line sequential scan (later to be inaccurately rechristened 'progressive') and the (electronic) Marconi-EMI 405 line interlaced systems. The Baird system was discontinued in February 1937. In 1938 France followed with their own 441-line system, variants of which were also used by a number of other countries. The US NTSC 525-line system joined in 1941. In 1949 France introduced an even higher-resolution standard at 819 lines, a system that should have been high definition even by today's standards, but was monochrome only and the technical limitations of the time prevented it from achieving the definition of which it should have been capable. All of these systems used interlacing and a 4:3 aspect ratio except the 240-line system which was progressive (actually described at the time by the technically correct term "sequential") and the 405-line system which started as 5:4 and later changed to 4:3. The 405-line system adopted the (at that time) revolutionary idea of interlaced scanning to overcome the flicker problem of the 240-line with its 25 Hz frame rate. The 240-line system could have doubled its frame rate but this would have meant that the transmitted signal would have doubled in bandwidth, an unacceptable option as the video baseband bandwidth was required to be not more than 3 MHz.

Who started trials in August 1936?

The British high-definition TV service

When was the Baird system discontinued?

February 1937

Which country developed the 441-line system?

France

What prevented France's 819-line system from achieving the definition it was capable of?

the technical limitations of the time

Which system used interlaced scanning to correct the flicker problem of the 240-line?

405-line system

Who started trials in September 1936?

I'm not sure.

When was the Baird system created?

I'm not sure.

Which country developed the 941-line system?

I'm not sure.

What prevented France's 919-line system from achieving the definition it was capable of?

I'm not sure.

Which system used interlaced scanning to correct the flicker problem of the 940-line?

I'm not sure.


Colour broadcasts started at similarly higher resolutions, first with the US NTSC color system in 1953, which was compatible with the earlier monochrome systems and therefore had the same 525 lines of resolution. European standards did not follow until the 1960s, when the PAL and SECAM color systems were added to the monochrome 625 line broadcasts.

What year did color broadcasts start in the US?

How many lines of resolution did the US NTSC color system have in 1953?

When did Europe begin color broadcasts?

The PAL and SECAM were color systems where?

Europe

How many lines of resolution were the European monochrome broadcasts?

What year did black and white broadcasts start in the US?

I'm not sure.

How many lines of resolution did the UK NTSC color system have in 1953?

I'm not sure.

When did Asia begin color broadcasts?

I'm not sure.

The PAL and SECAM were black and white systems where?

I'm not sure.

How many lines of resolution were the European color broadcasts?

I'm not sure.


The Nippon Hōsō Kyōkai (NHK, the Japan Broadcasting Corporation) began conducting research to "unlock the fundamental mechanism of video and sound interactions with the five human senses" in 1964, after the Tokyo Olympics. NHK set out to create an HDTV system that ended up scoring much higher in subjective tests than NTSC's previously dubbed "HDTV". This new system, NHK Color, created in 1972, included 1125 lines, a 5:3 aspect ratio and 60 Hz refresh rate. The Society of Motion Picture and Television Engineers (SMPTE), headed by Charles Ginsburg, became the testing and study authority for HDTV technology in the international theater. SMPTE would test HDTV systems from different companies from every conceivable perspective, but the problem of combining the different formats plagued the technology for many years.

What is the Japan Broadcasting Corporation called?

Nippon Hōsō Kyōkai

What does NHK stand for in Japan?

Nippon Hōsō Kyōkai

What year was NHK Color created?

What was the aspect ratio of the NHK Color?

What organization became the authority on testing and studying international HDTV technology?

The Society of Motion Picture and Television Engineers (SMPTE)

What is the Chinese Broadcasting Corporation called?

I'm not sure.

What does NHK stand for in China?

I'm not sure.

What year was NHK Black and White created?

I'm not sure.

What was the aspect ratio of the NHK black and white?

I'm not sure.

What organization became the authority on testing and studying international SDTV technology?

I'm not sure.


There were four major HDTV systems tested by SMPTE in the late 1970s, and in 1979 an SMPTE study group released A Study of High Definition Television Systems:

How many major HDTV systems were tested by SMPTE in the late 70's?

four

Who tested the four major HDTV systems in the late 1970's?

SMPTE

Who released A Study of High Definition Television Systems?

an SMPTE study group

In what year was A Study of High Definition Television Systems released?

What was released by an SMPTE study group in 1979?

A Study of High Definition Television Systems

How many major SDTV systems were tested by SMPTE in the late 70's?

I'm not sure.

Who tested the three major HDTV systems in the late 1970's?

I'm not sure.

Who released A Study of Standard Definition Television Systems?

I'm not sure.

In what year was A Study of Standard Definition Television Systems released?

I'm not sure.

What was released by an SMPTE study group in 1989?

I'm not sure.


Since the formal adoption of digital video broadcasting's (DVB) widescreen HDTV transmission modes in the early 2000s; the 525-line NTSC (and PAL-M) systems, as well as the European 625-line PAL and SECAM systems, are now regarded as standard definition television systems.

When was widescreen HDTV transmission modes formally adopted?

early 2000s

In addition to the 625-line PAL system, what European system is considered a standard definition television system?

SECAM systems

In addition to the NTSC system, what 525-line system is considered a standard definition television system?

PAL-M

525 and 625-line systems are now considered what?

standard definition television systems

What does DVD stand for?

I'm not sure.

When was widescreen SDTV transmission modes formally adopted?

I'm not sure.

In addition to the 625-line PAL system, what Asian system is considered a standard definition television system?

I'm not sure.

In addition to the NTSC system, what 525-line system is considered a high definition television system?

I'm not sure.

525 and 625-line systems are not considered what?

I'm not sure.


In 1949, France started its transmissions with an 819 lines system (with 737 active lines). The system was monochrome only, and was used only on VHF for the first French TV channel. It was discontinued in 1983.

In what year did France start transmissions using and 819 line system?

What country started transmissions using and 819 line system in 1949?

France

What did France start transmissions with in 1949?

an 819 lines system

Was France's 819 line system in color?

monochrome only

When was France's 819 line system discontinued?

In what year did England start transmissions using and 819 line system?

I'm not sure.

What country started transmissions using and 819 line system in 1959?

I'm not sure.

What did France start transmissions with in 1939?

I'm not sure.

Was Englands 819 line system in color?

I'm not sure.

When was France's 811 line system discontinued?

I'm not sure.


In 1958, the Soviet Union developed Тransformator (Russian: Трансформатор, meaning Transformer), the first high-resolution (definition) television system capable of producing an image composed of 1,125 lines of resolution aimed at providing teleconferencing for military command. It was a research project and the system was never deployed by either the military or consumer broadcasting.

In the end what was the Soviet Union's Transformator system used for?

a research project

When did the Soviet Union develop Transformator?

Who developed Transformator in 1958?

the Soviet Union

How many lines of resolution could an image using the Transformator system have?

What was the goal of the Transformator system?

providing teleconferencing for military command

In the end what was the Non-Soviet Union's Transformator system used for?

I'm not sure.

When did the Soviet Union not develop Transformator?

I'm not sure.

Who developed Transformator in 1988?

I'm not sure.

How many lines of resolution could an image using the Transformator never system have?

I'm not sure.

What was the goal of the non-Transformator system?

I'm not sure.


In 1979, the Japanese state broadcaster NHK first developed consumer high-definition television with a 5:3 display aspect ratio. The system, known as Hi-Vision or MUSE after its Multiple sub-Nyquist sampling encoding for encoding the signal, required about twice the bandwidth of the existing NTSC system but provided about four times the resolution (1080i/1125 lines). Satellite test broadcasts started in 1989, with regular testing starting in 1991 and regular broadcasting of BS-9ch commencing on November 25, 1994, which featured commercial and NHK programming.

In what year did NHK first develop consumer HD television with a 5:3 aspect ratio?

Who first developed consumer HD television with a 5:3 aspect ratio?

the Japanese state broadcaster NHK

When did satellite test broadcasts of Hi-Vision start?

When did regular broadcasting of BS-9ch start?

November 25, 1994

When did regular testing of Hi-Vision start?

In what year did NHK first develop consumer SD television with a 5:3 aspect ratio?

I'm not sure.

Who first developed consumer HD television with a 1:3 aspect ratio?

I'm not sure.

When did satellite test broadcasts of lo-Vision start?

I'm not sure.

When did regular broadcasting of BS-8ch start?

I'm not sure.

When did regular testing of Lo-Vision start?

I'm not sure.


In 1981, the MUSE system was demonstrated for the first time in the United States, using the same 5:3 aspect ratio as the Japanese system. Upon visiting a demonstration of MUSE in Washington, US President Ronald Reagan was impressed and officially declared it "a matter of national interest" to introduce HDTV to the US.

When was the MUSE system demonstrated in the US first?

What aspect ratio did the MUSE system use when demonstrated in 1981?

Which president declared it "a matter of national interest" to introduce HDTV to the US?

President Ronald Reagan

Which system was demonstrated in the US for the first time in 1981?

MUSE

Which system was demonstrated in Washington to President Ronald Reagan?

MUSE

When was the MUSE system demonstrated in the UK first?

I'm not sure.

What aspect ratio did the MUSE system use when demonstrated in 1988?

I'm not sure.

Which president declared it "a matter of national interest" to introduce SDTV to the US?

I'm not sure.

Which system was demonstrated in the UK for the first time in 1981?

I'm not sure.

Which system was demonstrated in Washington to President Bush?

I'm not sure.


Several systems were proposed as the new standard for the US, including the Japanese MUSE system, but all were rejected by the FCC because of their higher bandwidth requirements. At this time, the number of television channels was growing rapidly and bandwidth was already a problem. A new standard had to be more efficient, needing less bandwidth for HDTV than the existing NTSC.

Why did the FCC reject systems such as MUSE?

their higher bandwidth requirements

What was increasing and consuming a lot of bandwidth?

television channels

Who rejected systems such as MUSE as the new standard for the US?

the FCC

What was one of the requirements for a new standard system in the US?

had to be more efficient, needing less bandwidth

What was the existing system at the time?

NTSC

Why did the ECC reject systems such as MUSE?

I'm not sure.

What was decreasing and consuming a lot of bandwidth?

I'm not sure.

Who rejected systems such as MUSE as the old standard for the US?

I'm not sure.

What was one of the requirements for an old standard system in the US?

I'm not sure.

What wasn't the existing system at the time?

I'm not sure.


The limited standardization of analog HDTV in the 1990s did not lead to global HDTV adoption as technical and economic constraints at the time did not permit HDTV to use bandwidths greater than normal television.

What constraints kept HDTV from being widely adopted in the 90's?

technical and economic

What was HDTV not permitted to do in the 90's?

use bandwidths greater than normal television

What constraints kept SDTV from being widely adopted in the 90's?

I'm not sure.

What was SDTV not permitted to do in the 90's?

I'm not sure.


Early HDTV commercial experiments, such as NHK's MUSE, required over four times the bandwidth of a standard-definition broadcast. Despite efforts made to reduce analog HDTV to about twice the bandwidth of SDTV, these television formats were still distributable only by satellite.

How much more bandwith was required from early HDTV commercial experiments than an SD broadcast?

over four times

Efforts were made to reduce analog HDTV to how much of the bandwith of SDTV?

about twice

Despite the reduced bandwith, HDTV format still had to be distributed how?

by satellite

What kind of experiments required over four times the bandwith of a SDTV broadcast?

Early HDTV commercial experiments

How much more bandwith was required from early SDTV commercial experiments than an SD broadcast?

I'm not sure.

Efforts were made to reduce analog SDTV to how much of the bandwith of SDTV?

I'm not sure.

Despite the reduced bandwith, SDTV format still had to be distributed how?

I'm not sure.

What kind of experiments required over five times the bandwith of a SDTV broadcast?

I'm not sure.


In addition, recording and reproducing an HDTV signal was a significant technical challenge in the early years of HDTV (Sony HDVS). Japan remained the only country with successful public broadcasting of analog HDTV, with seven broadcasters sharing a single channel.

How many broadcasters did Japan have sharing a single channel?

seven

Which country had successful public analog HDTV broadcasting?

Japan

What was particularly challenging in the early years of HDTV?

recording and reproducing an HDTV signal

What accomplishment in early HDTV did Japan have?

the only country with successful public broadcasting of analog HDTV

How many broadcasters did Japan have sharing a multi channel?

I'm not sure.

Which country had successful public analog SDTV broadcasting?

I'm not sure.

What was particularly challenging in the early years of SDTV?

I'm not sure.

What accomplishment in early SDTV did Japan have?

I'm not sure.


Since 1972, International Telecommunication Union's radio telecommunications sector (ITU-R) had been working on creating a global recommendation for Analog HDTV. These recommendations, however, did not fit in the broadcasting bands which could reach home users. The standardization of MPEG-1 in 1993 also led to the acceptance of recommendations ITU-R BT.709. In anticipation of these standards the Digital Video Broadcasting (DVB) organisation was formed, an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies. The DVB develops and agrees upon specifications which are formally standardised by ETSI.

What does ITU-R stand for?

International Telecommunication Union's radio telecommunications sector

What does DVB stand for?

Digital Video Broadcasting

What is the DVB?

an alliance of broadcasters, consumer electronics manufacturers and regulatory bodies

What is the DVB's role?

develops and agrees upon specifications

Who standardizes HDTV specifications?

ETSI

What does ETU-R stand for?

I'm not sure.

What is the DVD?

I'm not sure.

What is the DVD's role?

I'm not sure.

Who standardizes SDTV specifications?

I'm not sure.


DVB created first the standard for DVB-S digital satellite TV, DVB-C digital cable TV and DVB-T digital terrestrial TV. These broadcasting systems can be used for both SDTV and HDTV. In the US the Grand Alliance proposed ATSC as the new standard for SDTV and HDTV. Both ATSC and DVB were based on the MPEG-2 standard, although DVB systems may also be used to transmit video using the newer and more efficient H.264/MPEG-4 AVC compression standards. Common for all DVB standards is the use of highly efficient modulation techniques for further reducing bandwidth, and foremost for reducing receiver-hardware and antenna requirements.

What did the Grand Alliance propose as the new standard for SDTV and HDTV?

ATSC

Which standard were ATSC and DVB based on?

Who created the standard for DVB-2, DVB-C, and DVB-T?

DVB

Who proposed ATSC as the new standard for SDTV and HDTV?

the Grand Alliance


In 1983, the International Telecommunication Union's radio telecommunications sector (ITU-R) set up a working party (IWP11/6) with the aim of setting a single international HDTV standard. One of the thornier issues concerned a suitable frame/field refresh rate, the world already having split into two camps, 25/50 Hz and 30/60 Hz, largely due to the differences in mains frequency. The IWP11/6 working party considered many views and throughout the 1980s served to encourage development in a number of video digital processing areas, not least conversion between the two main frame/field rates using motion vectors, which led to further developments in other areas. While a comprehensive HDTV standard was not in the end established, agreement on the aspect ratio was achieved.

When did ITU-R start trying to work towards setting a single international HDTV standard?

What did ITU-R start trying to do in 1983?

setting a single international HDTV standard

What was one of the issues with setting a single HDTV standard?

a suitable frame/field refresh rate

What was used as a conversion between the two main frame/field rates?

motion vectors

How many frame/field rates were primarily being used in 1983?

two

When did ITU-R start trying to work towards setting a single international DVD standard?

I'm not sure.

What did ITU-R start trying to do in 1981?

I'm not sure.

What was one of the issues with setting a single DVD standard?

I'm not sure.

What was used as a conversion between the three main frame/field rates?

I'm not sure.

How many frame/field rates were primarily being used in 1981?

I'm not sure.


Initially the existing 5:3 aspect ratio had been the main candidate but, due to the influence of widescreen cinema, the aspect ratio 16:9 (1.78) eventually emerged as being a reasonable compromise between 5:3 (1.67) and the common 1.85 widescreen cinema format. An aspect ratio of 16:9 was duly agreed upon at the first meeting of the IWP11/6 working party at the BBC's Research and Development establishment in Kingswood Warren. The resulting ITU-R Recommendation ITU-R BT.709-2 ("Rec. 709") includes the 16:9 aspect ratio, a specified colorimetry, and the scan modes 1080i (1,080 actively interlaced lines of resolution) and 1080p (1,080 progressively scanned lines). The British Freeview HD trials used MBAFF, which contains both progressive and interlaced content in the same encoding.

What aspect ratio was agreed upon due to the influence of widescreen cinema?

Who agreed upon the 16:9 aspect ratio?

the IWP11/6 working party

What was a leading factor in the 16:9 aspect ratio being chosen?

widescreen cinema

Which encoding contains both progressive and interlaced content?

MBAFF

Which aspect ratio was the early favorite?

What aspect ratio was agreed upon due to the influence of full screen cinema?

I'm not sure.

Who agreed upon the 11:9 aspect ratio?

I'm not sure.

What was a leading factor in the 11:9 aspect ratio being chosen?

I'm not sure.

Which encoding contains both not progressive and interlaced content?

I'm not sure.

Which aspect ratio was the late favorite?

I'm not sure.


It also includes the alternative 1440×1152 HDMAC scan format. (According to some reports, a mooted 750-line (720p) format (720 progressively scanned lines) was viewed by some at the ITU as an enhanced television format rather than a true HDTV format, and so was not included, although 1920×1080i and 1280×720p systems for a range of frame and field rates were defined by several US SMPTE standards.)

What scan format is also included in MBAFF?

1440×1152 HDMAC

What was viewed by some as enhanced television format and not true HDTV format?

a mooted 750-line

A mooted 750-line was seen by some at the ITU as what?

an enhanced television format

What were 1920x1080i and 1280x720p defined by?

US SMPTE standards

What scan format is never included in MBAFF?

I'm not sure.

What was viewed by some as enhanced television format and not true SDTV format?

I'm not sure.

A mooted 750-line was seen by some at the IEU as what?

I'm not sure.

What were 1920x1080i and 1280x720p not defined by?

I'm not sure.


HDTV technology was introduced in the United States in the late 1980s and made official in 1993 by the Digital HDTV Grand Alliance, a group of television, electronic equipment, communications companies consisting of AT&T Bell Labs, General Instrument, Philips, Sarnoff, Thomson, Zenith and the Massachusetts Institute of Technology. Field testing of HDTV at 199 sites in the United States was completed August 14, 1994. The first public HDTV broadcast in the United States occurred on July 23, 1996 when the Raleigh, North Carolina television station WRAL-HD began broadcasting from the existing tower of WRAL-TV southeast of Raleigh, winning a race to be first with the HD Model Station in Washington, D.C., which began broadcasting July 31, 1996 with the callsign WHD-TV, based out of the facilities of NBC owned and operated station WRC-TV. The American Advanced Television Systems Committee (ATSC) HDTV system had its public launch on October 29, 1998, during the live coverage of astronaut John Glenn's return mission to space on board the Space Shuttle Discovery. The signal was transmitted coast-to-coast, and was seen by the public in science centers, and other public theaters specially equipped to receive and display the broadcast.

When was HDTV introduced in the US?

late 1980s

Who made HDTV official in 1993?

the Digital HDTV Grand Alliance

AT&T, Philips, Zenith, and MIT, among others, made up what group in the 90's?

the Digital HDTV Grand Alliance

When did the first public HDTV broadcast happen in the US?

July 23, 1996

What does ATSC stand for?

Advanced Television Systems Committee

When was SDTV introduced in the US?

I'm not sure.

Who made SDTV official in 1993?

I'm not sure.

AT&T, Philips, Zenith, and MIT, among others, made up what group in the 50's?

I'm not sure.

When did the last public HDTV broadcast happen in the US?

I'm not sure.

What does STSC stand for?

I'm not sure.


The first HDTV transmissions in Europe, albeit not direct-to-home, began in 1990, when the Italian broadcaster RAI used the HD-MAC and MUSE HDTV technologies to broadcast the 1990 FIFA World Cup. The matches were shown in 8 cinemas in Italy and 2 in Spain. The connection with Spain was made via the Olympus satellite link from Rome to Barcelona and then with a fiber optic connection from Barcelona to Madrid. After some HDTV transmissions in Europe the standard was abandoned in the mid-1990s.

When did the first HDTV transmissions happen in Europe?

What event was the first HDTV broadcast in Europe?

FIFA World Cup

When did Europe abandon standard transmission?

Where was the FIFA World Cup able to be watched in HDTV?

8 cinemas in Italy and 2 in Spain

When did the first SDTV transmissions happen in Europe?

I'm not sure.

When did Europe not abandon standard transmission?

I'm not sure.

Where was the FIFA World Cup able to be watched in SDTV?

I'm not sure.


The first regular broadcasts started on January 1, 2004 when the Belgian company Euro1080 launched the HD1 channel with the traditional Vienna New Year's Concert. Test transmissions had been active since the IBC exhibition in September 2003, but the New Year's Day broadcast marked the official launch of the HD1 channel, and the official start of direct-to-home HDTV in Europe.

When did regular broadcasts start in Europe?

January 1, 2004

What event was first broadcasted on January 1, 2004?

Vienna New Year's Concert

The New Year's Day broadcast officially launched which channel?

When did test transmissions of HDTV begin in Europe?

September 2003

Which European company launched HD1?

When did non-regular broadcasts start in Europe?

I'm not sure.

What event was first broadcasted on March 1, 2004?

I'm not sure.

The New Year's Day broadcast officially did not launch which channel?

I'm not sure.

When did test transmissions of SDTV begin in Europe?

I'm not sure.

Which European company launched SD1?

I'm not sure.


Euro1080, a division of the former and now bankrupt Belgian TV services company Alfacam, broadcast HDTV channels to break the pan-European stalemate of "no HD broadcasts mean no HD TVs bought means no HD broadcasts ..." and kick-start HDTV interest in Europe. The HD1 channel was initially free-to-air and mainly comprised sporting, dramatic, musical and other cultural events broadcast with a multi-lingual soundtrack on a rolling schedule of 4 or 5 hours per day.

Euro1080 was a division of what former company?

Alfacam

What "chicken or the egg" stalemate prompted Euro1080 to broadcast HDTV channels?

"no HD broadcasts mean no HD TVs bought means no HD broadcasts ..."

What was Euro1080 hoping to kick-start by broadcasting HDTV channels?

HDTV interest in Europe

How much did viewers have to pay for the HD1 channel?

free-to-air

What was on HD1 for 4 or 5 hours per day?

a multi-lingual soundtrack on a rolling schedule

Euro180 was a division of what former company?

I'm not sure.

What "chicken or the egg" stalemate prompted Asia1080 to broadcast HDTV channels?

I'm not sure.

What was Euro1080 hoping to kick-start by broadcasting SDTV channels?

I'm not sure.

How much did viewers have to pay for the SD1 channel?

I'm not sure.

What was on SD1 for 4 or 5 hours per day?

I'm not sure.


These first European HDTV broadcasts used the 1080i format with MPEG-2 compression on a DVB-S signal from SES's Astra 1H satellite. Euro1080 transmissions later changed to MPEG-4/AVC compression on a DVB-S2 signal in line with subsequent broadcast channels in Europe.

What format did the first European HDTV broadcast use?

1080i format

What compression did the first European HDTV broadcast use?

What signal did the first European HDTV broadcast use?

DVB-S

What compression did Euro1080 later change to?

What signal did Euro1080 later change to?

What format did the first European SDTV broadcast use?

I'm not sure.

What compression did the first Asian HDTV broadcast use?

I'm not sure.

What signal did the first European SDTV broadcast use?

I'm not sure.

What compression did Euro1180 later change to?

I'm not sure.


Despite delays in some countries, the number of European HD channels and viewers has risen steadily since the first HDTV broadcasts, with SES's annual Satellite Monitor market survey for 2010 reporting more than 200 commercial channels broadcasting in HD from Astra satellites, 185 million HD capable TVs sold in Europe (£60 million in 2010 alone), and 20 million households (27% of all European digital satellite TV homes) watching HD satellite broadcasts (16 million via Astra satellites).

According to the 2010 Satellite Monitor market survey, how many HD capable TV's were sold in Europe?

185 million

According to the 2010 Satellite Monitor market survey, how many European households were watching HD broadcasts?

20 million

How many pounds were spent in Europe on HD capable TVs in 2010?

£60 million

What percentage of European digital satellite TV homes were watching HD broadcasts in 2010?

The number of European HD channels and viewers has done what since the first HDTV broadcasts?

risen steadily

According to the 2010 Satellite Monitor market survey, how many SD capable TV's were sold in Europe?

I'm not sure.

According to the 2010 Satellite Monitor market survey, how many European households were watching SD broadcasts?

I'm not sure.

How many pounds were spent in Europe on SD capable TVs in 2010?

I'm not sure.

What percentage of European digital satellite TV homes were watching SD broadcasts in 2010?

I'm not sure.

The number of European HD channels and viewers has done what since the first SDTV broadcasts?

I'm not sure.


In December 2009 the United Kingdom became the first European country to deploy high definition content using the new DVB-T2 transmission standard, as specified in the Digital TV Group (DTG) D-book, on digital terrestrial television.

Which European country first deployed HD content using the new DVB-T2 standard?

the United Kingdom

When did the UK deploy HD content using the new DVB-T2 transmission standard?

December 2009

What transmission standard did the UK start using in December 2009?

What does DTG stand for?

Digital TV Group

Which European country first deployed SD content using the new DVB-T2 standard?

I'm not sure.

When did the UK deploy SD content using the new DVB-T2 transmission standard?

I'm not sure.

What transmission standard did the US start using in December 2009?

I'm not sure.

What does DTD stand for?

I'm not sure.


The Freeview HD service currently contains 10 HD channels (as of December 2013[update]) and was rolled out region by region across the UK in accordance with the digital switchover process, finally being completed in October 2012. However, Freeview HD is not the first HDTV service over digital terrestrial television in Europe;

How many HD channels did the Freeview HD service contain as of December 2013?

When was the digital switchover process completed in the UK?

October 2012

Which service contains 10 HD channels and finished its roll out in October 2012?

Freeview HD

How was the Freeview HD service rolled out in the UK?

region by region

How many SD channels did the Freeview SD service contain as of December 2013?

I'm not sure.

When was the digital switchover process completed in the US?

I'm not sure.

Which service contains 10 HD channels and finished its roll out in October 2022?

I'm not sure.

How was the Freeview HD service rolled out in the US?

I'm not sure.


If all three parameters are used, they are specified in the following form: [frame size][scanning system][frame or field rate] or [frame size]/[frame or field rate][scanning system].[citation needed] Often, frame size or frame rate can be dropped if its value is implied from context. In this case, the remaining numeric parameter is specified first, followed by the scanning system.

What are the three HDTV parameters?

[frame size][scanning system][frame or field rate]

Which two parameters can be dropped if its value is implied from context?

frame size or frame rate

When can the frame size or frame rate parameter specification be dropped?

if its value is implied from context

When a parameter is dropped, the remaining numeric parameter is specified first, followed by what?

the scanning system

What are the three SDTV parameters?

I'm not sure.

Which two parameters can't be dropped if its value is implied from context?

I'm not sure.

When can the frame size or frame rate parameter specification be not dropped?

I'm not sure.

When a parameter is dropped, the remaining numeric parameter is specified last, followed by what?

I'm not sure.


For example, 1920×1080p25 identifies progressive scanning format with 25 frames per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 1080i25 or 1080i50 notation identifies interlaced scanning format with 25 frames (50 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 1080i30 or 1080i60 notation identifies interlaced scanning format with 30 frames (60 fields) per second, each frame being 1,920 pixels wide and 1,080 pixels high. The 720p60 notation identifies progressive scanning format with 60 frames per second, each frame being 720 pixels high; 1,280 pixels horizontally are implied.

What size is each 1920x1080p25 frame?

1,920 pixels wide and 1,080 pixels high

The 1920x1080p25 notion identifies progressive scanning format with how many frames per second?

The 1080i25 or 1080i50 notion identifies interlaced scanning format with how many frames per second?

The 1080i30 or 1080i60 notion identifies interlaced scanning format with how many frames per second?

The 720p60 notion identifies progressive scanning format with how many frames per second?

What size is each 120x180p25 frame?

I'm not sure.

The 580i25 or 1380i50 notion identifies interlaced scanning format with how many frames per second?

I'm not sure.

The 1030i25 or 1480i50 notion identifies interlaced scanning format with how many frames per second?

I'm not sure.

The 1080i30 or 1080i60 notion identifies interlaced scanning format with how many frames per minute?

I'm not sure.

The 720p60 notion identifies progressive scanning format with how many frames per minute?

I'm not sure.


50 Hz systems support three scanning rates: 50i, 25p and 50p. 60 Hz systems support a much wider set of frame rates: 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p and 60p. In the days of standard definition television, the fractional rates were often rounded up to whole numbers, e.g. 23.976p was often called 24p, or 59.94i was often called 60i. 60 Hz high definition television supports both fractional and slightly different integer rates, therefore strict usage of notation is required to avoid ambiguity. Nevertheless, 29.97i/59.94i is almost universally called 60i, likewise 23.976p is called 24p.

What three scanning rates do 50 Hz systems support?

50i, 25p and 50p

Which system suports 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p, and 60p

60 Hz

SD television fractional rates were often rounded to what?

whole numbers

Strict notation is required with HD fractional rates to avoid what?

ambiguity


For the commercial naming of a product, the frame rate is often dropped and is implied from context (e.g., a 1080i television set). A frame rate can also be specified without a resolution. For example, 24p means 24 progressive scan frames per second, and 50i means 25 interlaced frames per second.

What is usually dropped for the commercial naming of an HDTV product?

the frame rate

What does 24p mean?

24 progressive scan frames per second

What does 50i mean?

25 interlaced frames per second

When naming a commercial HDTV product, a frame rate can be specified without what?

a resolution

What is usually dropped for the commercial naming of an SDTV product?

I'm not sure.

What does 54p mean?

I'm not sure.

What does 10i mean?

I'm not sure.

When naming a commercial SDTV product, a frame rate can be specified without what?

I'm not sure.


There is no single standard for HDTV color support. Colors are typically broadcast using a (10-bits per channel) YUV color space but, depending on the underlying image generating technologies of the receiver, are then subsequently converted to a RGB color space using standardized algorithms. When transmitted directly through the Internet, the colors are typically pre-converted to 8-bit RGB channels for additional storage savings with the assumption that it will only be viewed only on a (sRGB) computer screen. As an added benefit to the original broadcasters, the losses of the pre-conversion essentially make these files unsuitable for professional TV re-broadcasting.

Is there a single standard for HDTV color support?

no

Before being converted to RGB, colors are ususally broadcasted using what color space?

YUV

Colors are typically broadcast using YUV and then converted to what?

a RGB color space

When transmitted over the internet, colors are typically to what?

8-bit RGB channels

What assumption is made with colors being transmitted over the internet?

it will only be viewed only on a (sRGB) computer screen

Is there a single standard for SDTV color support?

I'm not sure.

Before being converted to RGB, colors are not usually broadcasted using what color space?

I'm not sure.

Colors are typically broadcast using UUV and then converted to what?

I'm not sure.

When transmitted over the internet,  black and white are typically to what?

I'm not sure.

What assumption is made with colors being transmitted not over the internet?

I'm not sure.


At a minimum, HDTV has twice the linear resolution of standard-definition television (SDTV), thus showing greater detail than either analog television or regular DVD. The technical standards for broadcasting HDTV also handle the 16:9 aspect ratio images without using letterboxing or anamorphic stretching, thus increasing the effective image resolution.

At least how many times more linear resolution does HDTV have over SDTV?

twice

HDTV increases the effective image resolution by not using what?

letterboxing or anamorphic stretching

What does SDTV stand for?

standard-definition television

HDTV handles what aspect ratio without using letterboxing or anamorphic stretching?

At least how many times more linear resolution does SDTV have?

I'm not sure.

HDTV increases the effective image resolution by using what?

I'm not sure.

What does HDTV stand for?

I'm not sure.

SDTV handles what aspect ratio without using letterboxing or anamorphic stretching?

I'm not sure.


A very high resolution source may require more bandwidth than available in order to be transmitted without loss of fidelity. The lossy compression that is used in all digital HDTV storage and transmission systems will distort the received picture, when compared to the uncompressed source.

If more bandwith is required than is available, a very high resolution source my not be able to transmitted without loss of what?

fidelity

The compression used in all HDTV storage and transmission systems will do what if resolution is too high?

distort the received picture

A very high resolution source may require more of what?

bandwidth

If more bandwidth is required than is available, a very low resolution source my not be able to transmitted without loss of what?

I'm not sure.

The compression used in all SDTV storage and transmission systems will do what if resolution is too high?

I'm not sure.

A very low resolution source may require more of what?

I'm not sure.


The optimum format for a broadcast depends upon the type of videographic recording medium used and the image's characteristics. For best fidelity to the source the transmitted field ratio, lines, and frame rate should match those of the source.

A broadcasts optimum format depends on what two things?

the type of videographic recording medium used and the image's characteristics

For best fidelity to the source, what three things should match the source?

transmitted field ratio, lines, and frame rate

For best fidelity to the source, the transmitted field ratio, lines, and frame rate should match what?

those of the source

The type of videographic recording medium used and the image's characteristics determine what?

The optimum format for a broadcast

A broadcasts optimum format depends on what three things?

I'm not sure.

For best fidelity to the source, what five things should match the source?

I'm not sure.

For best fidelity to the source, the transmitted field ratio, lines, and frame rate should not match what?

I'm not sure.

The type of videographic recording medium didn't use and the image's characteristics determine what?

I'm not sure.


PAL, SECAM and NTSC frame rates technically apply only to analogue standard definition television, not to digital or high definition broadcasts. However, with the roll out of digital broadcasting, and later HDTV broadcasting, countries retained their heritage systems. HDTV in former PAL and SECAM countries operates at a frame rate of 25/50 Hz, while HDTV in former NTSC countries operates at 30/60 Hz.

PAL, SECAM, and NTSC frame rates apply to what definition televisions?

analogue standard

PAL, SECAM, and NTSC frame rates do not apply to what broadcasts?

digital or high definition

In former PAL and SECAM countries, what frame rate does HDTV operate at?

25/50 Hz

In former NTSC countries, what frame rate does HDTV operate at?

30/60 Hz

PEL, CAM, and ETSC frame rates apply to what definition televisions?

I'm not sure.

PAL, SECAM, and NTSC frame rates do apply to what broadcasts?

I'm not sure.

In former PAL and SECAM countries, what frame rate does SDTV operate at?

I'm not sure.

In former NTSC countries, what frame rate does SDTV operate at?

I'm not sure.


Standard 35mm photographic film used for cinema projection has a much higher image resolution than HDTV systems, and is exposed and projected at a rate of 24 frames per second (frame/s). To be shown on standard television, in PAL-system countries, cinema film is scanned at the TV rate of 25 frame/s, causing a speedup of 4.1 percent, which is generally considered acceptable. In NTSC-system countries, the TV scan rate of 30 frame/s would cause a perceptible speedup if the same were attempted, and the necessary correction is performed by a technique called 3:2 Pulldown: Over each successive pair of film frames, one is held for three video fields (1/20 of a second) and the next is held for two video fields (1/30 of a second), giving a total time for the two frames of 1/12 of a second and thus achieving the correct average film frame rate.

At what rate is standard 35mm photographic film exposed and projected?

24 frames per second

To be shown on SDTV in PAL-system countries, at what rate is cinema film scanned?

25 frame/s

The technique in which with successive pair of film frames, one is held for three video fields, and the next is held for two, is called what?

3:2 Pulldown

The 3:2 Pulldown techniques gives what total time for two frames?

1/12 of a second

What is achieved by the 3:2 Pulldown technique producing a total time of 1/12 of a second for two frames?

the correct average film frame rate

At what rate is standard 50mm photographic film exposed and projected?

I'm not sure.

To be shown on SDTV in PAL-system countries, at what rate is cinema film not scanned?

I'm not sure.

The technique in which with successive pair of film frames, one is held for three video fields, and the next is held for two, isn't called what?

I'm not sure.

The 3:2 Pulldown techniques gives what total time for five frames?

I'm not sure.

What is achieved by the 3:2 Pulldown technique producing a total time of 1/15 of a second for two frames?

I'm not sure.


Non-cinematic HDTV video recordings intended for broadcast are typically recorded either in 720p or 1080i format as determined by the broadcaster. 720p is commonly used for Internet distribution of high-definition video, because most computer monitors operate in progressive-scan mode. 720p also imposes less strenuous storage and decoding requirements compared to both 1080i and 1080p. 1080p/24, 1080i/30, 1080i/25, and 720p/30 is most often used on Blu-ray Disc.

What two formats are typically used to recorde non-cinematic HDTV video intended for broadcast?

720p or 1080i

Which format is typically used for internet distribution of HD video?

Most computer monitors operate in what mode?

progressive-scan

1080i, 1080p, and 720p are often used on what kind of disc.

Blu-ray

What two formats are typically used to record cinematic HDTV video intended for broadcast?

I'm not sure.

Which format is typically used for internet distribution of SD video?

I'm not sure.

No computer monitors operate in what mode?

I'm not sure.

1080i, 1080p, and 720p are never used on what kind of disc.

I'm not sure.


In the US, residents in the line of sight of television station broadcast antennas can receive free, over the air programming with a television set with an ATSC tuner (most sets sold since 2009 have this). This is achieved with a TV aerial, just as it has been since the 1940s except now the major network signals are broadcast in high definition (ABC, Fox, and Ion Television broadcast at 720p resolution; CBS, My Network TV, NBC, PBS, and The CW at 1080i). As their digital signals more efficiently use the broadcast channel, many broadcasters are adding multiple channels to their signals. Laws about antennas were updated before the change to digital terrestrial broadcasts. These new laws prohibit home owners' associations and city government from banning the installation of antennas.

In the US, what kind of tuner is needed for residents to receive free, over the air programming?

ATSC

Laws regarding antennas were upated before what?

the change to digital terrestrial broadcasts

Who do these laws prohibit from banning the installation of antennas?

home owners' associations and city government

Laws about antennas keep home owners' associations and city government from banning what?

the installation of antennas

Most television sets sold since what year have an ATSC tuner?

In the UK, what kind of tuner is needed for residents to receive free, over the air programming?

I'm not sure.

Laws regarding antennas weren't updated before what?

I'm not sure.

Who do these laws allow the installation of antennas?

I'm not sure.

Laws about antennas keep home owners' associations and city government from allowing what?

I'm not sure.


Additionally, cable-ready TV sets can display HD content without using an external box. They have a QAM tuner built-in and/or a card slot for inserting a CableCARD.

HD content can be displayed by cable-ready TVs without using what?

an external box

Without using an external box, cable-ready TVs can display what?

HD content

What features allow the cable-ready TVs to display HD content without an external box?

a QAM tuner built-in and/or a card slot for inserting a CableCARD

What kind of built-in tuner will allow a cable-ready TV to display HD content without an external box?

QAM

What kind of card will allow a cable-ready TV to display HD content without an external box?

CableCARD

SD content can be displayed by cable-ready TVs without using what?

I'm not sure.

Without using an internal box, cable-ready TVs can display what?

I'm not sure.

What features allow the cable-ready TVs to display HD content without an internal box?

I'm not sure.

What kind of built-in tuner will allow a cable-ready TV to display HD content without an intenal box?

I'm not sure.

What kind of card will allow a cable-ready TV to display HD content without an external box?

I'm not sure.


High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable, IPTV (including GoogleTV Roku boxes and AppleTV or built into "Smart Televisions"), Blu-ray video disc (BD), and internet downloads.

Roku and AppleTV are examples of what?

IPTV

Internet downloads, Blu-ray videos, and Apple TV are examples of what?

High-definition image sources

Terrestrial broadcast and direct broadcast satellite are examples of what?

High-definition image sources

Digital cable and Roku are examples of what?

High-definition image sources

Roku and AppleTV aren't examples of what?

I'm not sure.

Internet downloads, Blu-ray videos, and Apple TV aren't examples of what?

I'm not sure.

Digital cable and Roku aren't examples of what?

I'm not sure.


Sony's PlayStation 3 has extensive HD compatibility because of its built in Blu-ray disc based player, so does Microsoft's Xbox 360 with the addition of Netflix and Windows Media Center HTPC streaming capabilities, and the Zune marketplace where users can rent or purchase digital HD content. Recently, Nintendo released a next generation high definition gaming platform, The Wii U, which includes TV remote control features in addition to IPTV streaming features like Netflix. The HD capabilities of the consoles has influenced some developers to port games from past consoles onto the PS3, Xbox 360 and Wii U, often with remastered or upscaled graphics.

Why does the PlayStation 3 have extensive HD compatibility?

because of its built in Blu-ray disc based player

In addition to having a Blu-ray player the Xbox 360 also features what?

Netflix and Windows Media Center HTPC streaming capabilities, and the Zune marketplace

What high definition gaming platform did Nintendo recently release?

The Wii U

The HD capabilities of modern gaming systems has inspired developers to do what?

port games from past consoles onto the PS3, Xbox 360 and Wii U, often with remastered or upscaled graphics

Why does the PlayStation 3 have extensive SD compatibility?

I'm not sure.

In addition to having a Blu-ray player the Xbox One also features what?

I'm not sure.

What low definition gaming platform did Nintendo recently release?

I'm not sure.

The HD capabilities of modern gaming systems has not inspired developers to do what?

I'm not sure.


HDTV can be recorded to D-VHS (Digital-VHS or Data-VHS), W-VHS (analog only), to an HDTV-capable digital video recorder (for example DirecTV's high-definition Digital video recorder, Sky HD's set-top box, Dish Network's VIP 622 or VIP 722 high-definition Digital video recorder receivers, or TiVo's Series 3 or HD recorders), or an HDTV-ready HTPC. Some cable boxes are capable of receiving or recording two or more broadcasts at a time in HDTV format, and HDTV programming, some included in the monthly cable service subscription price, some for an additional fee, can be played back with the cable company's on-demand feature.

Sky HD's set-top box, TiVo's Series 3, and Dish Network's VIP 622 are examples of what?

an HDTV-capable digital video recorder

Some cable boxes are capable of doing what?

receiving or recording two or more broadcasts at a time in HDTV format

What restriction does W-VHS recordings have?

analog only

What does D-VHS stand for?

Digital-VHS or Data-VHS

Sky HD's set-top box, TiVo's Series 3, and Dish Network's VIP 622 aren't examples of what?

I'm not sure.

Some cable boxes can't be capable of doing what?

I'm not sure.

What restriction does W-VHS recordings not have?

I'm not sure.

What does DVD stand for?

I'm not sure.


The massive amount of data storage required to archive uncompressed streams meant that inexpensive uncompressed storage options were not available to the consumer. In 2008, the Hauppauge 1212 Personal Video Recorder was introduced. This device accepts HD content through component video inputs and stores the content in MPEG-2 format in a .ts file or in a Blu-ray compatible format .m2ts file on the hard drive or DVD burner of a computer connected to the PVR through a USB 2.0 interface. More recent systems are able to record a broadcast high definition program in its 'as broadcast' format or transcode to a format more compatible with Blu-ray.

When was the Hauppauge 1212 Personal Video Recorder introduced?

How does the Personal Video Recorder store content?

in MPEG-2 format in a .ts file or in a Blu-ray compatible format .m2ts file

Recent systems can record a broadcast HD program in what format?

'as broadcast' format or transcode to a format more compatible with Blu-ray

What uncompressed storage option was introduced in 2008?

the Hauppauge 1212 Personal Video Recorder

When was the Hauppauge 1212 NonPersonal Video Recorder introduced?

I'm not sure.

How doesn't the Personal Video Recorder store content?

I'm not sure.

Recent systems can record a broadcast SD program in what format?

I'm not sure.

What uncompressed storage option wasn't introduced in 2008?

I'm not sure.


Analog tape recorders with bandwidth capable of recording analog HD signals, such as W-VHS recorders, are no longer produced for the consumer market and are both expensive and scarce in the secondary market.

W-VHS recorders are capable of recording what kinds of signals?

analog HD

What kind of recorder is no longer produced for the consumer market?

Analog tape

In the secondary market, analog tape recorders are considered what?

expensive and scarce

W-VHS recorders aren't capable of recording what kinds of signals?

I'm not sure.

What kind of recorder is still produced for the consumer market?

I'm not sure.

In the secondary market, analog tape recorders arent considered what?

I'm not sure.


In the United States, as part of the FCC's plug and play agreement, cable companies are required to provide customers who rent HD set-top boxes with a set-top box with "functional" FireWire (IEEE 1394) on request. None of the direct broadcast satellite providers have offered this feature on any of their supported boxes, but some cable TV companies have. As of July 2004[update], boxes are not included in the FCC mandate. This content is protected by encryption known as 5C. This encryption can prevent duplication of content or simply limit the number of copies permitted, thus effectively denying most if not all fair use of the content.

Prior to 2004, what were US cable companies required to provide customers who rent HD set-top boxes?

a set-top box with "functional" FireWire (IEEE 1394) on request

When were boxes with "functional" FireWire no longer included in the FCC mandate?

July 2004

Content is now protected by what encryption?

What can 5c encryption prevent?

duplication of content or simply limit the number of copies permitted

Prior to 2006, what were US cable companies required to provide customers who rent HD set-top boxes?

I'm not sure.

When were boxes with "functional" FireWire included in the FCC mandate?

I'm not sure.

Content is not protected by what encryption?

I'm not sure.

What can 5c encryption not prevent?

I'm not sure.


It has been used for thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs.[citation needed] In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber.

In addition to being used to build things, what has wood been used for over thousands of years?

fuel

What kind of strong fibers are part of the composite of wood?

cellulose

What's the matrix in wood made up of?

lignin

What one word describes the function wood provides to a tree or plant?

support

What does wood convey to leaves, roots, and other tissues of a woody plant in addition to water?

nutrients


The Earth contains about 434 billion cubic meters of growing stock forest, 47% of which is commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991, approximately 3.5 cubic kilometers of wood were harvested. Dominant uses were for furniture and building construction.

How many cubic meters of growing stock forest are there on the planet?

434 billion

What percentage of the Earth's stock forest is commercial?

In addition to buildings, what is wood often used to make?

furniture

About how many cubic kilometers of the vast stock forest's wood were harvested in 1991?

In addition to being carbon neutral, what other adjective describes wood that makes it compelling as a renewable energy source?

abundant


A 2011 discovery in the Canadian province of New Brunswick uncovered the earliest known plants to have grown wood, approximately 395 to 400 million years ago. Wood can be dated by carbon dating and in some species by dendrochronology to make inferences about when a wooden object was created.

What year were the earliest plants that grew wood discovered?

In which Canadian province were the oldest woody plants found?

New Brunswick

If dendrochronology can't be used, what method would scientists employ to date wood?

carbon dating

How many millions of years old were the plants that were discovered in New Brunswick?

395 to 400


People have used wood for millennia for many purposes, primarily as a fuel or as a construction material for making houses, tools, weapons, furniture, packaging, artworks, and paper. The year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at that time.

What has been the primary purpose of wood for millennia other than fuel?

construction material

What is often made of wood that provides shelter to people?

houses

For clues about the climate of a place, we can look at variation in isotopic abundances or what other thing?

tree-ring widths

What could be made out of wood that could be used to fight off attackers?

weapons

What category of items often constructed from wood does a chair belong to?

furniture


Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, and roots. This process is known as secondary growth; it is the result of cell division in the vascular cambium, a lateral meristem, and subsequent expansion of the new cells. Where there are clear seasons, growth can occur in a discrete annual or seasonal pattern, leading to growth rings; these can usually be most clearly seen on the end of a log, but are also visible on the other surfaces. If these seasons are annual these growth rings are referred to as annual rings. Where there is no seasonal difference growth rings are likely to be indistinct or absent.

Where does wood come from?

trees

What forms in a tree to increase its diameter?

woody layers

What is the process of trees growing out to get bigger around called?

secondary growth

What do many places have four of that would cause growth rings in a tree?

seasons

If a place has annual seasons, what are the growth rings on the trees there called?

annual rings


If there are differences within a growth ring, then the part of a growth ring nearest the center of the tree, and formed early in the growing season when growth is rapid, is usually composed of wider elements. It is usually lighter in color than that near the outer portion of the ring, and is known as earlywood or springwood. The outer portion formed later in the season is then known as the latewood or summerwood. However, there are major differences, depending on the kind of wood (see below).

If a growth ring has differences over one season, would the part nearest the tree's center be narrower or wider?

wider

What name, besides springwood, is used for the part of a growth ring formed in the beginning of the growing season?

earlywood

If the opposite of springwood is summerwood, what's the opposite of earlywood?

latewood

Is earlywood usually lighter or darker than the part of the growth ring that forms later in the season?

lighter

Is summerwood the inner or outer portion of a growth ring?

outer


A knot is a particular type of imperfection in a piece of wood; it will affect the technical properties of the wood, usually reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a roughly circular "solid" (usually darker) piece of wood around which the grain of the rest of the wood "flows" (parts and rejoins). Within a knot, the direction of the wood (grain direction) is up to 90 degrees different from the grain direction of the regular wood.

What is the sort of circular imperfection in a piece of wood called?

knot

What property of wood does a knot usually reduce in the wood around it?

strength

In what direction is wood often sawn so that a knot appears as a solid circle that the grain flows around?

longitudinally

Are knots usually lighter or darker than the surrounding wood?

darker

The direction of grain in a knot can differ by as much as how many degrees from the regular wood?


In the tree a knot is either the base of a side branch or a dormant bud. A knot (when the base of a side branch) is conical in shape (hence the roughly circular cross-section) with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud.

Other than the base of a side branch, what tree feature causes a knot?

a dormant bud

What shape is the knot formed by a side branch's base?

conical

What measurement of a stem determines a knot's inner tip placement?

diameter

Because a knot's shape is conical, what shape does a cross-section of it have?

circular


During the development of a tree, the lower limbs often die, but may remain attached for a time, sometimes years. Subsequent layers of growth of the attaching stem are no longer intimately joined with the dead limb, but are grown around it. Hence, dead branches produce knots which are not attached, and likely to drop out after the tree has been sawn into boards.

What will the lower limbs of a tree usually do during development?

die

For what length of time can a dead lower limb stay attached to a tree?

years

Rather than being joined to the limb that died, where do subsequent layers grow?

around it

Are the knots that dead tree limbs form attached or not attached?

not attached

A detached knot will probably drop out of the wood when someone saws it into what?

boards


In grading lumber and structural timber, knots are classified according to their form, size, soundness, and the firmness with which they are held in place. This firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow.

What's the process in which knots are classified called?

grading

Along with firmness, soundness, and form, what property of a knot is classified?

size

What property of knots does the amount of time a branch stayed on a tree while the stem kept growing affect?

firmness


Knots do not necessarily influence the stiffness of structural timber, this will depend on the size and location. Stiffness and elastic strength are more dependent upon the sound wood than upon localized defects. The breaking strength is very susceptible to defects. Sound knots do not weaken wood when subject to compression parallel to the grain.

What is wood's breaking strength susceptible to?

defects

Depending on the placement and size of a knot, what property of structural timber can be affected?

stiffness

What do stiffness and elastic strength depend on more than defects?

sound wood

What direction of compression in relation to its grain won't weaken wood with sound knots in it?

parallel


In some decorative applications, wood with knots may be desirable to add visual interest. In applications where wood is painted, such as skirting boards, fascia boards, door frames and furniture, resins present in the timber may continue to 'bleed' through to the surface of a knot for months or even years after manufacture and show as a yellow or brownish stain. A knot primer paint or solution, correctly applied during preparation, may do much to reduce this problem but it is difficult to control completely, especially when using mass-produced kiln-dried timber stocks.

What positive visual component can knots sometimes add to decorative pieces?

interest

What term is used to describe what knots can do to affect the finish of things made from wood even when they've been painted?

bleed

Is bleed easy or difficult to control?

difficult

The stain from a knot bleeding is usually brownish or what other color?

yellow

In what stage of processing does knot primer need to be applied for maximum effectiveness?

preparation


Heartwood (or duramen) is wood that as a result of a naturally occurring chemical transformation has become more resistant to decay. Heartwood formation occurs spontaneously (it is a genetically programmed process). Once heartwood formation is complete, the heartwood is dead. Some uncertainty still exists as to whether heartwood is truly dead, as it can still chemically react to decay organisms, but only once.

What's another word for "duramen"?

Heartwood

What is heartwood naturally resistant to?

decay

How does heartwood formation occur due to its being genetically programmed?

spontaneously

What adjective describes fully formed heartwood?

dead

Despite being considered dead, what can heartwood have one chemical reaction to?

decay organisms


Heartwood is often visually distinct from the living sapwood, and can be distinguished in a cross-section where the boundary will tend to follow the growth rings. For example, it is sometimes much darker. However, other processes such as decay or insect invasion can also discolor wood, even in woody plants that do not form heartwood, which may lead to confusion.

In what part of a tree's cross-section is heartwood visible?

growth rings

What simple color distinction can heartwood have that makes it stand out from living wood in a tree?

darker

Along with insect infestation, what process can discolor wood and make it look like heartwood?

decay

What kind of plants never form heartwood?

woody

What is the living wood in a tree called?

sapwood


Sapwood (or alburnum) is the younger, outermost wood; in the growing tree it is living wood, and its principal functions are to conduct water from the roots to the leaves and to store up and give back according to the season the reserves prepared in the leaves. However, by the time they become competent to conduct water, all xylem tracheids and vessels have lost their cytoplasm and the cells are therefore functionally dead. All wood in a tree is first formed as sapwood. The more leaves a tree bears and the more vigorous its growth, the larger the volume of sapwood required. Hence trees making rapid growth in the open have thicker sapwood for their size than trees of the same species growing in dense forests. Sometimes trees (of species that do form heartwood) grown in the open may become of considerable size, 30 cm or more in diameter, before any heartwood begins to form, for example, in second-growth hickory, or open-grown pines.

What term is interchangeable with "sapwood"?

alburnum

Is sapwood the younger or older wood in a tree?

younger

What essential liquid is the sapwood tasked with carrying around a tree?

water

How much of the wood in a tree is sapwood at some point in its life?

All

Does a tree growing quickly out in the open have thinner or thicker sapwood for its size than the same kind of tree in a dense forest?

thicker


The term heartwood derives solely from its position and not from any vital importance to the tree. This is evidenced by the fact that a tree can thrive with its heart completely decayed. Some species begin to form heartwood very early in life, so having only a thin layer of live sapwood, while in others the change comes slowly. Thin sapwood is characteristic of such species as chestnut, black locust, mulberry, osage-orange, and sassafras, while in maple, ash, hickory, hackberry, beech, and pine, thick sapwood is the rule. Others never form heartwood.

If a tree starts forming heartwood right away, will its sapwood layer be thin or thick?

thin

What property of heartwood that has nothing to do with how important it is to trees got it its name?

position

Does a beech tree usually have thin or thick sapwood?

thick

Does a sassafras tree typically have a thin or thick sapwood layer?

Thin

Would a thin or a thick sapwood layer be found in a pine tree?

thick


No definite relation exists between the annual rings of growth and the amount of sapwood. Within the same species the cross-sectional area of the sapwood is very roughly proportional to the size of the crown of the tree. If the rings are narrow, more of them are required than where they are wide. As the tree gets larger, the sapwood must necessarily become thinner or increase materially in volume. Sapwood is thicker in the upper portion of the trunk of a tree than near the base, because the age and the diameter of the upper sections are less.

What part of a tree is the cross-sectional area of the sapwood approximately proportional to?

crown

Are more rings necessary if they're narrow or wide?

narrow

As a tree grows bigger, if the sapwood layer doesn't increase in volume, what will it become?

thinner

In what part of the tree trunk is the sapwood layer thinnest?

near the base

Along with the smaller diameter of the upper trunk, what factor leads to thinner sapwood higher up a tree?

age


When a tree is very young it is covered with limbs almost, if not entirely, to the ground, but as it grows older some or all of them will eventually die and are either broken off or fall off. Subsequent growth of wood may completely conceal the stubs which will however remain as knots. No matter how smooth and clear a log is on the outside, it is more or less knotty near the middle. Consequently, the sapwood of an old tree, and particularly of a forest-grown tree, will be freer from knots than the inner heartwood. Since in most uses of wood, knots are defects that weaken the timber and interfere with its ease of working and other properties, it follows that a given piece of sapwood, because of its position in the tree, may well be stronger than a piece of heartwood from the same tree.

What usually covers the whole trunk of a very young tree?

limbs

What evidence of the stubs of the limbs a tree loses can always be seen in the wood?

knots

In a very old tree, are you more likely to find a lot of knots in the heartwood or the sapwood?

heartwood

What hides the stubs of a tree's lost limbs from being visible later in its life?

Subsequent growth

Since knots are defects that weaken lumber, would the heartwood or the sapwood from the same tree be stronger?

sapwood


It is remarkable that the inner heartwood of old trees remains as sound as it usually does, since in many cases it is hundreds, and in a few instances thousands, of years old. Every broken limb or root, or deep wound from fire, insects, or falling timber, may afford an entrance for decay, which, once started, may penetrate to all parts of the trunk. The larvae of many insects bore into the trees and their tunnels remain indefinitely as sources of weakness. Whatever advantages, however, that sapwood may have in this connection are due solely to its relative age and position.

What do broken limbs and deep wounds open a door for in a tree?

decay

Decay can spread to all of what part of a tree?

the trunk

What growth stage of insects bore holes into trees?

larvae

What part of a tree often stays impressively sound even when hundreds or thousands of years old?

inner heartwood

What evidence do some insect larvae leave in a tree forever?

tunnels


If a tree grows all its life in the open and the conditions of soil and site remain unchanged, it will make its most rapid growth in youth, and gradually decline. The annual rings of growth are for many years quite wide, but later they become narrower and narrower. Since each succeeding ring is laid down on the outside of the wood previously formed, it follows that unless a tree materially increases its production of wood from year to year, the rings must necessarily become thinner as the trunk gets wider. As a tree reaches maturity its crown becomes more open and the annual wood production is lessened, thereby reducing still more the width of the growth rings. In the case of forest-grown trees so much depends upon the competition of the trees in their struggle for light and nourishment that periods of rapid and slow growth may alternate. Some trees, such as southern oaks, maintain the same width of ring for hundreds of years. Upon the whole, however, as a tree gets larger in diameter the width of the growth rings decreases.

In what stage of its life does a tree usually grow the fastest?

youth

As a tree ages, do its growth rings usually get wider or narrower?

narrower

What part of a tree opens and spreads out more as it matures?

crown

Is wood production of a tree lessened or increased as it ages?

lessened

Along with nutrients, what do trees growing in forests have to compete for?

light


Different pieces of wood cut from a large tree may differ decidedly, particularly if the tree is big and mature. In some trees, the wood laid on late in the life of a tree is softer, lighter, weaker, and more even-textured than that produced earlier, but in other trees, the reverse applies. This may or may not correspond to heartwood and sapwood. In a large log the sapwood, because of the time in the life of the tree when it was grown, may be inferior in hardness, strength, and toughness to equally sound heartwood from the same log. In a smaller tree, the reverse may be true.

When a big tree is cut up, will the pieces of wood differ or all be the same?

differ

In a large log, will the heartwood or sapwood usually be stronger and tougher?

heartwood

If you need really hard, strong wood from a small tree, would it likely be better to use the heartwood or sapwood?

sapwood

Besides big trees, what trees are more likely to have a range of different kinds of wood?

mature


In species which show a distinct difference between heartwood and sapwood the natural color of heartwood is usually darker than that of the sapwood, and very frequently the contrast is conspicuous (see section of yew log above). This is produced by deposits in the heartwood of chemical substances, so that a dramatic color difference does not mean a dramatic difference in the mechanical properties of heartwood and sapwood, although there may be a dramatic chemical difference.

When trees have a visible difference in color between sapwood and heartwood, which is darker?

heartwood

What is deposited naturally in heartwood that changes its color?

chemical substances

Is the color difference between heartwood and sapwood usually very subtle or conspicuous?

conspicuous

What type of properties of heartwood and sapwood is often the same even if their colors are very different?

mechanical

Although heartwood and sapwood might be similar mechanically, if their colors are very different, what other type of difference would they have?

chemical


Some experiments on very resinous Longleaf Pine specimens indicate an increase in strength, due to the resin which increases the strength when dry. Such resin-saturated heartwood is called "fat lighter". Structures built of fat lighter are almost impervious to rot and termites; however they are very flammable. Stumps of old longleaf pines are often dug, split into small pieces and sold as kindling for fires. Stumps thus dug may actually remain a century or more since being cut. Spruce impregnated with crude resin and dried is also greatly increased in strength thereby.

What type of tree has resin that makes it stronger when it dries?

Longleaf Pine

What's the funny name for resin-saturated heartwood?

fat lighter

What is fat lighter practically impervious to in addition to termites?

rot

If spruce is shot full of crude resin and dried, which of its properties is increased?

strength

Since it's highly flammable, what do people often use little pieces of longleaf pine tree stumps for?

kindling


Since the latewood of a growth ring is usually darker in color than the earlywood, this fact may be used in judging the density, and therefore the hardness and strength of the material. This is particularly the case with coniferous woods. In ring-porous woods the vessels of the early wood not infrequently appear on a finished surface as darker than the denser latewood, though on cross sections of heartwood the reverse is commonly true. Except in the manner just stated the color of wood is no indication of strength.

Which of the wood in a growth ring is usually darker?

latewood

Which property of a tree's wood that gives clues about its strength and hardness can be judged by it's color?

density

What category of trees show this difference greatly?

coniferous

What type of woods might sometimes appear to have darker earlywood on a finished surface?

ring-porous

With the exception of earlywood/latewood difference in some types of trees, how much of an indication of strength is a wood's color?

no indication


Abnormal discoloration of wood often denotes a diseased condition, indicating unsoundness. The black check in western hemlock is the result of insect attacks. The reddish-brown streaks so common in hickory and certain other woods are mostly the result of injury by birds. The discoloration is merely an indication of an injury, and in all probability does not of itself affect the properties of the wood. Certain rot-producing fungi impart to wood characteristic colors which thus become symptomatic of weakness; however an attractive effect known as spalting produced by this process is often considered a desirable characteristic. Ordinary sap-staining is due to fungal growth, but does not necessarily produce a weakening effect.

What condition does an abnormal color usually indicate in wood?

diseased

What other property can you assume of wood that is diseased?

unsoundness

What causes the black checked pattern in the wood of western hemlocks?

insect attacks

What animals cause the reddish-brown streaks of color in hickory wood?

birds

What's the name for the pretty coloring effect caused in some wood by rot-producing fungi?

spalting


In heartwood it occurs only in the first and last forms. Wood that is thoroughly air-dried retains 8–16% of the water in the cell walls, and none, or practically none, in the other forms. Even oven-dried wood retains a small percentage of moisture, but for all except chemical purposes, may be considered absolutely dry.

What does wood retain in its cell walls despite being air-dried?

water

Air-dried wood keeps up to what percentage of the water in its cell walls?

What kind of dried wood retains a small quantity of water but is considered absolutely dry?

oven-dried


The general effect of the water content upon the wood substance is to render it softer and more pliable. A similar effect of common observation is in the softening action of water on rawhide, paper, or cloth. Within certain limits, the greater the water content, the greater its softening effect.

Often the water in wood makes it more pliable and what else?

softer

What material sometimes used for dog chews reacts similarly to wood because of its water content?

rawhide

What material we use to write or print on, like wood, becomes softer and more pliable when wet?

paper

When water content increases within certain limits in wood, does is have a less or greater softening effect?

greater

What type of action does water create in cloth?

softening


Drying produces a decided increase in the strength of wood, particularly in small specimens. An extreme example is the case of a completely dry spruce block 5 cm in section, which will sustain a permanent load four times as great as a green (undried) block of the same size will.

What will drying often increase in wood?

strength

What color is also used interchangeably with "undried" for wood?

green

What type of wood can hold four times as much of a load when dried?

spruce


The greatest strength increase due to drying is in the ultimate crushing strength, and strength at elastic limit in endwise compression; these are followed by the modulus of rupture, and stress at elastic limit in cross-bending, while the modulus of elasticity is least affected.

What type of "ultimate" strength is one of the two types increased the most by drying wood?

crushing

What property of wood is least affected by drying?

elasticity

Is strength at elastic limit in endwise compression or stress at elastic limit in cross-bending increased more by drying wood?

strength at elastic limit in endwise compression

Is the strength of the modulus of rupture or elasticity increased more when wood is dried?

modulus of rupture


Wood is a heterogeneous, hygroscopic, cellular and anisotropic material. It consists of cells, and the cell walls are composed of micro-fibrils of cellulose (40% – 50%) and hemicellulose (15% – 25%) impregnated with lignin (15% – 30%).

Along with hygroscopic, cellular, and anisotropic, how is the material of wood described?

heterogeneous

What does wood consist of?

cells

What part of wood's cells are composed of cellulose and hemicellulose?

walls

What makes up 40-50% of the cell walls in wood?

cellulose

What substance is hemicellulose impregnated with?

lignin


In coniferous or softwood species the wood cells are mostly of one kind, tracheids, and as a result the material is much more uniform in structure than that of most hardwoods. There are no vessels ("pores") in coniferous wood such as one sees so prominently in oak and ash, for example.

What type of cells makes up most wood cells in coniferous trees?

tracheids

Are hardwood or softwood species more uniform in structure?

softwood

What are the visible vessels in hardwoods commonly called?

pores

What hardwood that starts with the letter "O" would have pores?

oak

Besides oak, what's an example of a hardwood with prominent pores?

ash


The structure of hardwoods is more complex. The water conducting capability is mostly taken care of by vessels: in some cases (oak, chestnut, ash) these are quite large and distinct, in others (buckeye, poplar, willow) too small to be seen without a hand lens. In discussing such woods it is customary to divide them into two large classes, ring-porous and diffuse-porous.

Is the structure of hardwood simple or complex?

complex

What handles most of the water conduction in hardwoods?

vessels

Are the vessels in chestnut wood large or small?

large

In wood from a willow tree, what would you need to use to see the tiny vessels?

a hand lens

Besides ring-porous, what's the other class hardwoods are often divided into?

diffuse-porous


In ring-porous species, such as ash, black locust, catalpa, chestnut, elm, hickory, mulberry, and oak, the larger vessels or pores (as cross sections of vessels are called) are localised in the part of the growth ring formed in spring, thus forming a region of more or less open and porous tissue. The rest of the ring, produced in summer, is made up of smaller vessels and a much greater proportion of wood fibers. These fibers are the elements which give strength and toughness to wood, while the vessels are a source of weakness.[citation needed]

What species of hardwood are hickory and mulberry trees?

ring-porous

In what season do the growth-rings of ring-porous species form with larger vessels localized?

spring

In what season does the part of the growth-ring with smaller vessels form in ring-porous species?

summer

What fibers does the summer's section of growth-ring have more of?

wood fibers

Along with strength, what property do wood fibers lend to wood?

toughness


In diffuse-porous woods the pores are evenly sized so that the water conducting capability is scattered throughout the growth ring instead of being collected in a band or row. Examples of this kind of wood are alder, basswood,[citation needed] birch, buckeye, maple, willow,and the Populus species such as aspen, cottonwood and poplar. Some species, such as walnut and cherry, are on the border between the two classes, forming an intermediate group.[citation needed]

What kind of woods have pores that are uniformly sized?

diffuse-porous

What species do aspen, cottonwood, and poplar trees belong to?

Populus

With walnut, what's another tree in the intermediate group?

cherry

What capability is spread through the growth ring in ring-porous species?

water conducting

Is maple wood diffuse-porous or ring-porous?

diffuse-porous


In temperate softwoods there often is a marked difference between latewood and earlywood. The latewood will be denser than that formed early in the season. When examined under a microscope the cells of dense latewood are seen to be very thick-walled and with very small cell cavities, while those formed first in the season have thin walls and large cell cavities. The strength is in the walls, not the cavities. Hence the greater the proportion of latewood the greater the density and strength. In choosing a piece of pine where strength or stiffness is the important consideration, the principal thing to observe is the comparative amounts of earlywood and latewood. The width of ring is not nearly so important as the proportion and nature of the latewood in the ring.

What kind of softwoods often have significant differences in their earlywood and latewood?

temperate

Is latewood denser or less dense than earlywood?

denser

Does strength come from the walls or cavities of wood cells?

walls

Are the cell walls of earlywood thick or thin?

thin

What general size are the cavities in the cells of very dense latewood?

very small


If a heavy piece of pine is compared with a lightweight piece it will be seen at once that the heavier one contains a larger proportion of latewood than the other, and is therefore showing more clearly demarcated growth rings. In white pines there is not much contrast between the different parts of the ring, and as a result the wood is very uniform in texture and is easy to work. In hard pines, on the other hand, the latewood is very dense and is deep-colored, presenting a very decided contrast to the soft, straw-colored earlywood.

Comparing a heavy and a lightweight piece of wood from a pine, which would have a greater proportion of latewood?

heavy

What feature of a piece of pine with more latewood would be more clear and pronounced?

growth rings

What type of tree has very little contrast between parts of its growth rings?

white pines

Is white pine easy or difficult to work with because of its texture?

easy

What kind of pines have very deep, darkly colored hardwood that stands out against the light earlywood?

hard pines


It is not only the proportion of latewood, but also its quality, that counts. In specimens that show a very large proportion of latewood it may be noticeably more porous and weigh considerably less than the latewood in pieces that contain but little. One can judge comparative density, and therefore to some extent strength, by visual inspection.

Having a high proportion of latewood isn't all that matters; what else is important?

quality

What can we judge in wood just by looking at it?

comparative density

What property of wood could we project some indication of by looking at its density?

strength

What could we call some specimens with a high proportion of latewood that explains why they weigh less than specimens with much less latewood?

porous


No satisfactory explanation can as yet be given for the exact mechanisms determining the formation of earlywood and latewood. Several factors may be involved. In conifers, at least, rate of growth alone does not determine the proportion of the two portions of the ring, for in some cases the wood of slow growth is very hard and heavy, while in others the opposite is true. The quality of the site where the tree grows undoubtedly affects the character of the wood formed, though it is not possible to formulate a rule governing it. In general, however, it may be said that where strength or ease of working is essential, woods of moderate to slow growth should be chosen.

What facet of wood is affected to some degree by the place where the tree grows?

character

If you want wood that's easy to work with, what kind of growth would you want the tree to have?

moderate to slow

What species of tree can be said to growth ring proportions that aren't determined just by their rate of growth?

conifers

What counterpart of earlywood are scientists still trying to explain the formation of?

latewood

While there is some relationship between where and how a tree grows, what can't anyone formulate to govern it?

a rule


In ring-porous woods each season's growth is always well defined, because the large pores formed early in the season abut on the denser tissue of the year before.

What kind of woods always have very clearly marked seasonal growth?

ring-porous

What size pores form early in ring-porous woods' growing season?

large

When does the denser tissue the new pores abut come from?

the year before


In the case of the ring-porous hardwoods there seems to exist a pretty definite relation between the rate of growth of timber and its properties. This may be briefly summed up in the general statement that the more rapid the growth or the wider the rings of growth, the heavier, harder, stronger, and stiffer the wood. This, it must be remembered, applies only to ring-porous woods such as oak, ash, hickory, and others of the same group, and is, of course, subject to some exceptions and limitations.

Ring-porous hardwoods have a clear relationship between their properties and what other factor?

rate of growth

Is harder, heavier wood indicated by narrower or wider growth rings?

wider

What kind of wood with a name that starts with "H" is a ring-porous hardwood?

hickory

If the growth rings are wider, was the growth of the tree slower or more rapid?

more rapid

What is the only kind of wood that will definitely be harder and stronger when it grows faster?

ring-porous


In ring-porous woods of good growth it is usually the latewood in which the thick-walled, strength-giving fibers are most abundant. As the breadth of ring diminishes, this latewood is reduced so that very slow growth produces comparatively light, porous wood composed of thin-walled vessels and wood parenchyma. In good oak these large vessels of the earlywood occupy from 6 to 10 percent of the volume of the log, while in inferior material they may make up 25% or more. The latewood of good oak is dark colored and firm, and consists mostly of thick-walled fibers which form one-half or more of the wood. In inferior oak, this latewood is much reduced both in quantity and quality. Such variation is very largely the result of rate of growth.

Which specific type of wood within ring-porous woods have more fibers to make it strong?

latewood

When there is less latewood, what is diminishing?

breadth of ring

Does slow or rapid growth make relatively porous, light wood?

slow

What kind of oak has just 6-10% volume of large vessels in the log?

good

What kind of fibers are in the latewood of good oak, making it very firm?

thick-walled


Wide-ringed wood is often called "second-growth", because the growth of the young timber in open stands after the old trees have been removed is more rapid than in trees in a closed forest, and in the manufacture of articles where strength is an important consideration such "second-growth" hardwood material is preferred. This is particularly the case in the choice of hickory for handles and spokes. Here not only strength, but toughness and resilience are important. The results of a series of tests on hickory by the U.S. Forest Service show that:

What term is sometimes used for wood with wide rings?

second-growth

Do young trees grow more quickly in open stands or in a closed forest?

open stands

What property is important to manufacturers who use "second-growth" hardwood?

strength

What specific kind of "second-growth" hardwood is often used to make handles and spokes?

hickory

What organization tested hickory to find out about its properties?

U.S. Forest Service


In the diffuse-porous woods, the demarcation between rings is not always so clear and in some cases is almost (if not entirely) invisible to the unaided eye. Conversely, when there is a clear demarcation there may not be a noticeable difference in structure within the growth ring.

What kind of wood often has ring divisions that can't even be seen by looking at it?

diffuse-porous

In diffuse-porous woods, if the demarcation between rings is obvious, what type of difference within the ring might not be?

structure

What adjective describes how our eyes function without a tool like a microscope to help?

unaided


In diffuse-porous woods, as has been stated, the vessels or pores are even-sized, so that the water conducting capability is scattered throughout the ring instead of collected in the earlywood. The effect of rate of growth is, therefore, not the same as in the ring-porous woods, approaching more nearly the conditions in the conifers. In general it may be stated that such woods of medium growth afford stronger material than when very rapidly or very slowly grown. In many uses of wood, total strength is not the main consideration. If ease of working is prized, wood should be chosen with regard to its uniformity of texture and straightness of grain, which will in most cases occur when there is little contrast between the latewood of one season's growth and the earlywood of the next.

What kind of wood has all similarly sized vessels?

diffuse-porous

What rate of growth in a tree will make the wood from it stronger than trees that grow very slowly or very quickly?

medium

The capability of diffuse-porous woods to carry what substance is spread out in the growth ring?

water

What division of trees are diffuse-porous woods more similar in growth rate to than ring-porous woods?

conifers

Does uniformity of the texture and grain of wood usually result from much or little contrast between earlywood and latewood?

little


Structural material that resembles ordinary, "dicot" or conifer wood in its gross handling characteristics is produced by a number of monocot plants, and these also are colloquially called wood. Of these, bamboo, botanically a member of the grass family, has considerable economic importance, larger culms being widely used as a building and construction material in their own right and, these days, in the manufacture of engineered flooring, panels and veneer. Another major plant group that produce material that often is called wood are the palms. Of much less importance are plants such as Pandanus, Dracaena and Cordyline. With all this material, the structure and composition of the structural material is quite different from ordinary wood.

What's another term used for "conifer" wood?

dicot

What type of plants produce material that is referred to as "wood" even though it is technically not?

monocot

What monocot plant produces "wood" by the same name that's often used for flooring and veneer?

bamboo

While we call bamboo "wood," what botanical family does it belong to?

grass

Along with bamboo, what's the other monocot that's a major source of so-called "wood"?

palms