Forest Definition and 25 Threads

A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. The Food and Agriculture Organization defines a forest as land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban land use. Using this definition FRA 2020 found that forests covered 4.06 billion hectares or approximately 31 percent of the global land area in 2020.Forests are the predominant terrestrial ecosystem of Earth, and are distributed around the globe. More than half of the world’s forests are found in only five countries (Brazil, Canada, China, Russian Federation and United States of America). The largest part of the forest (45 percent) is found in the tropical domain (Tropical forests), followed by the boreal, temperate and subtropical domains.Forests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass. Net primary production is estimated at 21.9 gigatonnes carbon per year for tropical forests, 8.1 for temperate forests, and 2.6 for boreal forests.Forests at different latitudes and elevations, and with different precipitation and evapotranspiration form distinctly different biomes: boreal forests around the North Pole, tropical moist forests and tropical dry forests around the Equator, and temperate forests at the middle latitudes. Higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition.
Almost half the forest area (49 percent) is relatively intact, while 9 percent is found in fragments with little or no connectivity. Tropical rainforests and boreal coniferous forests are the least fragmented, whereas subtropical dry forest and temperate oceanic forests are among the most fragmented. Roughly 80 percent of the world’s forest area is found in patches larger than 1 million hectares. The remaining 20 percent is located in more than 34 million patches across the world – the vast majority less than 1 000 hectares in size.Human society and forests influence each other in both positive and negative ways. Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect people's health. Human activities, including unsustainable use of forest resources, can negatively affect forest ecosystems.

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  1. pinball1970

    Earth's earliest forest discovered in SW England

    Paper here. https://www.lyellcollection.org/doi/abs/10.1144/jgs2023-204 Article here https://phys.org/news/2024-03-earth-earliest-forest-revealed-somerset.html "The record of fossil forests, where tree bases are preserved where they were living, so far dates back to those discovered in New...
  2. Astronuc

    US Forest Service, National Forests, and The Big Burn (1910)

    The Big Burn - In the summer of 1910, the largest fire in American history raged in the Northern Rockies. https://www.pbs.org/wgbh/americanexperience/films/burn/#part01 https://en.wikipedia.org/wiki/Great_Fire_of_1910 https://en.wikipedia.org/wiki/Ed_Pulaski Wallace, Idaho has an interesting...
  3. Y

    Does creating fire break lines work to control forest fires?

    I really don't want to get into politics, I am sick and tired of smelling and breathing the smoke from the forest fire in N Calif even I am living in the silicon valley. Trump said because Calif refuse to clear fire break lines, clear the debriefs, then once the fire started, there is no break...
  4. G

    Dark Forest Theory: Uncovering the Scary Answer to the Fermi Paradoxon

    Dark forest is the title of the second book of Three Body Problem, IMHO, a masterpiece of science fiction. Dark Forest theory is a really scary answer to the Fermi paradoxon. Cixin Liu's book has the following axioms: - life grows exponentially, but there is limited amount of matter in the...
  5. ORF

    Can a Forest Die? Timeframe to Recover After a Blaze

    Summary: If a forest is scorched, after a while it will regrow(wont it?); but if it is periodically burnt to ashes, could it eventually die? (as a ecosystem) What is the time-scales in order to recover a forest after a blaze? Hello, If a forest is scorched, after a while it will regrow (wont...
  6. F

    I Understanding Gunn-Peterson through the Reionization epoch

    Into an extra-galactic physics course, I don't understand well the "Gunn - Peterson" effect on the spectrum of high redshift quasars (z greater than 3 or 4, up to the current limit of z = 6-7 I think) The observed fact is that there is an almost total absorption for the photons of the blue part...
  7. E

    I Understanding the Ly-α Forest for EnSlavingBlair

    Hi, I'm currently trying to wrap my head around how the Ly-α forest works. This is what I have so far; A distant quasar produces these Ly-α photons, which occur when a hydrogen's electron drops from n=2 to n=1, and has a wavelength of around 121nm (depending on the exact transition). This...
  8. A

    A Lyman-alpha forest: why not Lyman-beta?

    Hello everyone! We observe the so-called Lyman-alpha forest in the spectrum of distant quasars and it is said that these multiple absorption lines are due to the presence of intergalactic HI clouds that absorb light at the wavelenght of 1216 A , the Lyman-alpha transition. My question is the...
  9. Kior

    What is the difference between a carbon sink and reservoir?

    I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sinkis a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And the...
  10. Kior

    What is the difference between carbon sink and reservoir?

    I am trying to figure out the difference between a carbon sink and a carbon reservoir. The definition for a carbon sink from wikipedia is that “carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. ” And...
  11. N

    How Did Nina Rediscover Her Love for Math?

    Hello My name is Nina and I dropped out of high school bc of disease. Last year I "re-entered the game" by beginning studies with an HF. Oh yeah, and I live in Denmark - born and raised. An HF is a sort-of high school degree. I live with my parents and my younger brother near a giant forrest...
  12. T

    How to see the forest through the trees? (How not to miss the obvious?

    I just spent 5 minutes getting a problem wrong, only to stop for a second and try again to realize the problems answer was completely obvious, and very, very simple and I wanted to know what I could do to help prevent spending time on things that are obviously not wrong and see right off that...
  13. T

    Infinitely tall tree falling in a forest

    Homework Statement Suppose that there is a negligibly thin tree in the forest of infinite length that begun tipping over. Negating frictional effects from the pivoting, does the tree ever hit the ground? Homework Equations My approach was to solve the problem for a tree of length l and...
  14. C

    Work hardening and Forest Hardening

    Anyone know the difference¿¿¿¿¿¿¿¿
  15. C

    Wormwood Forest: A Natural History of Chernoby

    Hello everyone. I am the author of "Wormwood Forest: A Natural History of Chernobyl" and stumbled upon your very interesting forum when googling Genn Saji, a Japanese nuclear scientist who has been sending out daily email updates about Fukushima. I am fortunate enough to be on his list and...
  16. K

    Forest Fires Equation: Exploring Energy Conservation

    Hello ! I'm studying the forest fires, and I found an equation but there is something I don't understand. The equation is obtained thanks to energy conservation, and it is something like this : ρC dT/dt = h(T-T0) - Q Ys Aexp(-Ea/RTs) The first term is the volumic enthalpy, the second is due...
  17. G

    How Does the Lyman-Alpha Forest Inform Us About the Universe's Expansion?

    Homework Statement You are observing a high redshift (z ≥ 5) quasar. Suppose that there are n(z) = n_{0}(1+z)^3 damped Lyman-alpha (DLA) clouds per Mpc3 at redshift z, each with cross-sectional area a. Explain why we expect to see through n(z)al of them along a length l of the path towards...
  18. A

    Schools 1st Gen Minority College student, lost in a forest. Please HELP

    High school stats: 1860 Sat 87-88 GPA Top 33% No extra currics. I got into a nice state school but couldn't afford it (I got 20K but still came short by 10-15K). Now I am at a Community College. I am taking Bio 102/Pre Calc/Engl 101/Speech 101. I want to finish my 2 year Associates in...
  19. A

    Olbers Paradox and The Sherwood Forest

    1. Homework Statement Suppose that in sherwood forest, the average radius of a tree is equal to R= 1m and the average number of trees per unit area sigma = 0.005 m^-2 . If Robin Hood shoots an arrow in a random direction , how far , on average, will it travel before it strikes a tree? 2...
  20. M

    Does a Falling Tree Make a Sound if Unheard?

    I'm trying to put an end this age old question, but I want to translate it into form of an equation. SOME SAY: No, because "sound" is ears interpretation of those waves. I SAY: Yes, because it makes a "sound" (as defined by the vibrations). I'm going by textbook definition. It makes sound...
  21. Jonathan Scott

    Lyman alpha forest different for different objects?

    I was wondering how the distribution of Lyman alpha absorbers (as seen in the "forest" of absorption lines of a quasar spectrum) varies with red-shift (corresponding to evolution with the age of the universe). I've found various sources which mention in passing that the frequency of absorbers...
  22. S

    Calculating Distance of Robin Hood's Arrow in Sherwood Forest

    Homework Statement Suppose that in sherwood forest, the average radius of a tree is equal to R= 1m and the average number of trees per unit area sigma = 0.005 m^-2 . If Robin Hood shoots an arrow in a random direction , how far , on average, will it travel before it strikes a tree...
  23. Ivan Seeking

    Mysterious Red Carnivore Found in Borneo Forest

    http://www.newscientist.com/article.ns?id=dn8419
  24. Jonathan

    What new evidence has been discovered in the Rendlesham Forest UFO incident?

    I saw a show, UFO Invasion at Rendlesham at 9/8C on SciFi, and they came to these conclusions: -There were two landing sites. -the new one was out of the lighthouse's veiw, so the lighthouse theory is out. -The depressions on the ground were supposed to be exactly 12ft center to center...
  25. H

    Gunn-Peterson effect and the Lyman-alpha forest

    After the recombination epoch neutral hydrogen was formed in the universe. Since neutral hydrogen absorbs radiation in the Lyman-alpha transition, a dark epoch begun, which was finished with the reionization of hydrogen due to radiation sources. The electromagnetic spectrum from quasars...
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