reforest

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(rē-fôr'ĭst, -fŏr'ĭst) pronunciation
tr.v., -est·ed, -est·ing, -ests.
To replant (an area) with forest cover.

reforestation re'for·es·ta'tion n.

The reestablishment of forest cover either naturally or artificially. Given enough time, natural regeneration will usually occur in areas where temperatures and rainfall are adequate and when grazing and wildfires are not too frequent.

Reforestation occurs on land where trees have been recently removed due to harvesting or to natural disasters such as a fire, landslide, flooding, or volcanic eruption. When abandoned cropland, pastureland, or grasslands are converted to tree cover, the practice is termed afforestation (where no forest has existed in recent memory). Afforestation is common in countries such as Australia, South Africa, Brazil, India, and New Zealand. Although natural regeneration can occur on abandoned cropland, planting trees will decrease the length of time required until the first harvest of wood. Planting also has an advantage in that both tree spacing and tree species can be prescribed. The selection of tree species can be very important since it affects both wood quality and growth rates. Direct seeding is also used for both afforestation and reforestation, although it often is less successful and requires more seed than tree planting. Unprotected seed are often eaten by birds and rodents, and weeds can suppress growth of newly germinated seed. For these reasons, direct seeding accounts for only about 5% and 1% of artificial reforestation in Canada and the United States, respectively.


Replanting a previously wooded area that has been felled. Trees may be planted in order to replicate the previous ecosystem; the implicit assumption is that the restoration will succeed reforestation.

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Tropical tree nursery at Planeta Verde Reforestación S.A.'s plantation in Vichada, Colombia.
A 15-year-old reforested plot of land.
A 21-year-old plantation of red pine in Southern Ontario.

Reforestation is the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation.[1] Reforestation can be used to improve the quality of human life by soaking up pollution and dust from the air, rebuild natural habitats and ecosystems, mitigate global warming since forests facilitate biosequestration of atmospheric carbon dioxide, and harvest for resources, particularly timber.

The term reforestation is similar to afforestation, the process of restoring and recreating areas of woodlands or forests that may have existed long ago but were deforested or otherwise removed at some point in the past. Sometimes the term re-afforestation is used to distinguish between the original forest cover and the later re-growth of forest to an area. Special tools, e.g. tree planting bar, are used to make planting of trees easier and faster.

Contents

Management

Reforestation of large areas can be done through the use of measuring rope (for accurate plant spacing) and ribbeds, (or wheeled augers for planting the larger trees) for making the hole in which a seedling or plant can be inserted. Indigenous soil inoculants (e.g., Zaccaria bi color) can optionally be used to increase survival rates in hardy environments.[citation needed]

A debatable issue in managed reforestation is whether or not the succeeding forest will have the same biodiversity as the original forest. If the forest is replaced with only one species of tree and all other vegetation is prevented from growing back, a monoculture forest similar to agricultural crops would be the result. However, most reforestation involves the planting of different feedlots of seedlings taken from the area often of multiple species. Another important factor is the natural regeneration of a wide variety of plant and animal species that can occur on a clear cut. In some areas the suppression of forest fires for hundreds of years has resulted in large single aged and single species forest stands. The logging of small clear cuts and or prescribed burning, actually increases the biodiversity in these areas by creating a greater variety of tree stand ages and species.[citation needed]

For harvesting

Reforestation need not be only used for recovery of accidentally destroyed forests. In some countries, such as Finland, the forests are managed by the wood products and pulp and paper industry. In such an arrangement, like other crops, trees are replanted wherever they are cut. In such circumstances, the industry can cut the trees in a way to allow easier reforestation. The wood products industry systematically replaces many of the trees it cuts, employing large numbers of summer workers for tree planting work. For example, in 2010, Weyerhaeuser reported planting 50 million seedlings.[2]

In just 20 years, a teak plantation in Costa Rica can produce up to about 400 m of wood per hectare. As the natural teak forests of Asia become more scarce or difficult to obtain, the prices commanded by plantation-grown teak grow higher every year. Other species such as mahogany grow slower than teak in Tropical America but are also extremely valuable. Faster growers include pine, eucalyptus, and Gmelina.[citation needed]

Reforestation, if several native species are used, can provide other benefits in addition to financial returns, including restoration of the soil, rejuvenation of local flora and fauna, and the capturing and sequestering of 38 tons of carbon dioxide per hectare per year.[citation needed]

The reestablishment of forests is not just simple tree planting. Forests are made up of a diversity of species and they build dead organic matter into soils over time. A major tree-planting program in a place like this would enhance the local climate and reduce the demands of burning large amounts of fossil fuels for cooling in the summer.[3]

For climate change mitigation

Forests are an important part of the global carbon cycle because trees and plants absorb carbon dioxide through photosynthesis. By removing this greenhouse gas from the air, forests function as terrestrial carbon sinks, meaning they store large amounts of carbon. At any time, forests account for as much as double the amount of carbon in the atmosphere.[4]:1456 Even as more anthropogenic carbon is produced, forests remove around three billion tons of anthropogenic carbon every year. This amounts to about 30% of all carbon dioxide emissions from fossil fuels. Therefore, an increase in the overall forest cover around the world would tend to mitigate global warming.

There are four major strategies available to mitigate carbon emissions through forestry activities: increase the amount of forested land through a reforestation process; increase the carbon density of existing forests at a stand and landscape scale; expand the use of forest products that will sustainably replace fossil-fuel emissions; and reduce carbon emissions that are caused from deforestation and degradation.[4]:1456

Achieving the first strategy would require enormous and wide-ranging efforts. However, there are many organizations around the world that encourage tree-planting as a way to offset carbon emissions for the express purpose of fighting climate change. For example, in China, the Jane Goodall Institute, through their Shanghai Roots & Shoots division, launched the Million Tree Project in Kulun Qi, Inner Mongolia to plant one million trees to stop desertification and help curb climate change.[5][6] China has used 24 billion metres squared of new forest plantation and natural forest regrowth to offset 21% of Chinese fossil fuel emissions in 2000[4]:1456. In Java, Indonesia each newlywed couple is to give whoever is sermonizing their wedding 5 seedlings to combat global warming. Each couple that wishes to have a divorce has to give 25 seedlings to whoever divorces them.[7]

The second stategy has to do with selecting species for tree-planting. In theory, planting any kind of tree to produce more forest cover would absorb more carbon dioxide from the atmosphere. On the other hand, a genetically modified tree specimen might grow much faster than any other regular tree.[8]:93 Some of these trees are already being developed in the lumber and biofuel industries. These fast-growing trees would not only be planted for those industries but they can also be planted to help absorb carbon dioxide faster than slow-growing trees.[8]:93

Extensive forest resources placed anywhere in the world will not always have a the same impact. For example, large reforestation programs in boreal or subarctic regions have a limited impact on climate mitigation. This is because it substitutes a bright snow-dominated region that reflects the sunlight with dark forest canopies. A study from the National Center for Atmospheric Research in Boulder, Colorado, USA, found that trees in temperate latitudes have a net warming effect on the atmosphere. The heat that dark leaves release without absorbing outweighs the carbon they sequester.[9] On the other hand, a positive example would be reforestation projects in tropical regions, which would lead to a positive biophysical change such as the formation of clouds. These clouds would then reflect the sunlight, creating a positive impact on climate mitigation.[4]:1457

There is an advantage to planting trees in tropical climates with wet seasons. In such a setting, trees have a quicker growth rate because they can grow year-round. Trees in tropical climates have, on average, larger, brighter, and more abundant leaves than non-tropical climates. A study of the girth of 70,000 trees across Africa has shown that tropical forests are soaking up more carbon dioxide pollution than previously realized. The research suggests almost one fifth of fossil fuel emissions are absorbed by forests across Africa, Amazonia and Asia. Simon Lewis, a climate expert at the University of Leeds, who led the study, said: "Tropical forest trees are absorbing about 18% of the carbon dioxide added to the atmosphere each year from burning fossil fuels, substantially buffering the rate of change."[10]

It is also important to deal with the rate of deforestation. At this point, there are 13 billion metres squared of tropical regions that are deforested every year. There is potential for these regions to reduce rates of deforestation by 50% by 2050, which would be a huge contribution to stabilize the global climate.[4]:1456

Incentives

Some incentives for reforestation can be as simple as a financial compensation. Streck and Scholz (2006) explain how a group of scientists from various institutions have developed a compensated reduction of deforestation approach which would reward developing countries that disrupt any further act of deforestation. Countries that participate and take the option to reduce their emissions from deforestation during a committed period of time would receive financial compensation for the carbon dioxide emissions that they avoided.[11]:875 To raise the payments, the host country would issue government bonds or negotiate some kind of loan with a financial institution that would want to take part in the compensation promised to the other country. The funds received by the country could be invested to help find alternatives to the extensive cutdown of forests. This whole process of cutting emissions would be voluntary, but once the country has agreed to lower their emissions they would be obligated to reduce their emissions. However, if a country was not able to meet their obligation, their target would get added to their next commitment period. The authors of these proposals see this as a solely government-to-government agreement; private entities would not participate in the compensation trades.[11]:876

Examples

Forest regrowth in Mount Baker-Snoqualmie National Forest, Washington state, USA

It is the stated goal of the US Forest Service to manage forest resources sustainably. This includes reforestation after timber harvest, among other programs.[12]

In Germany, reforestation is required as part of the federal forest law. 31% of Germany is forested, according to the second forest inventory of 2001–2003. The size of the forest area in Germany increased between the first and the second forest inventory due to forestation of degenerated bogs and agricultural areas.[13] In China, extensive replanting programs have existed since the 1970s. Programs have had overall success. The forest cover has increased from 12% of Chinas land area to 16%. However, specific programs have had limited success. The "Green Wall of China", an attempt to limit the expansion of the Gobi Desert has primarily failed, where 75% of new trees have failed. In Canada, overall forest cover is increasing over the last decades.

Criticisms

Reforestation competes with other land uses such as food production, livestock grazing, and living space for further economic growth.

There is also the risk that through a forest fire or insect outbreak much of the stored carbon in a reforested area could make its way back to the atmosphere.[4]:1456 Reduced harvesting rates and fire suppression have caused an increase in the forest biomass in the western United States over the past century. This causes an increase of about a factor of four in the frequency of fires due to longer and hotter dry seasons.[4]:1456

See also

References

  1. ^ "Reforestation - Definitions from Dictionary.com". dictionary.reference.com. http://dictionary.reference.com/browse/Reforestation. Retrieved 2008-04-27. 
  2. ^ "Sustainable Forest Management". Key Timberland Statistics. Weyerhaeuser. 10 June 2011. http://www.weyerhaeuser.com/Sustainability/Planet/SustainableForestManagement. Retrieved 7 January 2012. 
  3. ^ Wood well, G.M.; North, WJ (1988-12-16). "CO2 Reduction and Reforestation". Science (ALAS) 242 (4885): 1493–1494. DOI:10.1126/science.242.4885.1493-a. PMID 17788407. 
  4. ^ a b c d e f g Canadell, J.G.; M.R. Raupach (2008-06-13). "Managing Forests for Climate Change". Science (AAAS) 320 (5882): 1456–1457. DOI:10.1126/science.1155458. PMID 18556550. 
  5. ^ Shanghai Roots & Shoots
  6. ^ The Million Tree Project
  7. ^ "Five tree fee for a Java wedding". BBC News. 2007-12-03. http://news.bbc.co.uk/2/hi/asia-pacific/7124680.stm. Retrieved 2010-08-29. 
  8. ^ a b "A changing climate of opinion?". The Economist (The Economist Newspaper Limited) 387: 93–96. 2008. http://www.economist.com/help/DisplayHelp.cfm?folder=663377. Retrieved 2010-08-29. 
  9. ^ B.W., Time Magazine, 2007
  10. ^ Adam, David (2009-02-18). "Fifth of world carbon emissions soaked up by extra forest growth, scientists find". The Guardian (London). http://www.guardian.co.uk/environment/2009/feb/18/trees-tropics-climate-change. Retrieved 2010-05-22. 
  11. ^ a b Streck, C.; S.M. Scholz (2006). "The role of forests in global climate change: whence we come and where we go". International Affairs (The Royal Institute of International Affairs) 82 (5): 861–879. DOI:10.1111/j.1468-2346.2006.00575.x. 
  12. ^ "Forest Service Chief testifies before Senate appropriations committee on 2013 agency budget". US Forest Service. 18 April 2012. http://www.fs.fed.us/news/2012/releases/04/budget.shtml. Retrieved 29 April 2012. 
  13. ^ www.bundeswaldinventur.de

Further reading

  • Bonan, G. B. (2008). "Forests and climate change: Forcings, feedbacks, and the climate benefits of forests". Science 320 (5882): 1444–1449. DOI:10.1126/science.1155121. PMID 18556546. 

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