Old-growth forest - Knowledge

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definition does not provide an explanation of forest function. It just gives a useful number to measure. So, some forests may be excluded from being categorized as old-growth even if they have old-growth attributes just because they are too young. Also, older forests can lack some old-growth attributes and be categorized as old-growth just because they are so old. The idea of using age is also problematic, because human activities can influence the forest in varied ways. For example, after the logging of 30% of the trees, less time is needed for old-growth to come back than after removal of 80% of the trees. Although depending on the species logged, the forest that comes back after a 30% harvest may consist of proportionately fewer hardwood trees than a forest logged at 80% in which the light competition by less important tree species does not inhibit the regrowth of vital hardwoods.

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Thus, each understory tree grows at a different rate. The differences in establishment timing and in growth rate create a population of understory trees that is variable in size. Eventually, some understory trees grow to become as tall as the main canopy trees, thereby filling the gap. This perpetuation process is typical for the old-growth stage. This, however, does not mean that the forest will be old-growth forever. Generally, three futures for old-growth stage forest are possible: 1) The forest will be hit by a disturbance and most of the trees will die, 2) Unfavorable conditions for new trees to regenerate will occur. In this case, the old trees will die and smaller plants will create

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in terms of the species supported. Therefore, for most people, the physical size of the trees is the most recognized hallmark of old-growth forests, even though the ecologically productive areas that support such large trees often comprise only a very small portion of the total area that has been mapped as old-growth forest. (In high-altitude, harsh climates, trees grow very slowly and thus remain at a small size. Such trees also qualify as old growth in terms of how they are mapped, but are rarely recognized by the general public as such.)

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reinitiation stage. Using the stand dynamics definition, old-growth can be easily evaluated using structural attributes. However, in some forest ecosystems, this can lead to decisions regarding the preservation of unique stands or attributes that will disappear over the next few decades because of natural succession processes. Consequently, using stand dynamics to define old-growth forests is more accurate in forests where the species that constitute old-growth have long lifespans and succession is slow.

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amount of carbon stored in the soil, but other research suggests older forests that have trees of many ages, multiple layers, and little disturbance have the highest capacities for carbon storage. As trees grow, they remove carbon from the atmosphere, and protecting these pools of carbon prevents emissions into the atmosphere. Proponents of harvesting the forest argue the carbon stored in wood is available for use as

4320: 641:, and 3) The regenerating understory trees are different species from the main canopy trees. In this case, the forest will switch back to stem-exclusion stage, but with shade-tolerant tree species. 4) The forest in an old-growth stage can be stable for centuries, but the length of this stage depends on the forest's tree composition and the climate of the area. For example, frequent natural fires do not allow 4390: 489: 1051:(RFA) was originally designed to protect much of this natural wealth, many of the RFA old-growth forests protected in Tasmania consist of trees of little use to the timber industry. RFA old-growth and high conservation value forests that contain species highly desirable to the forestry industry have been poorly preserved. Only 22% of Tasmania's original tall-eucalypt forests managed by 1036:. From certain forestry perspectives, fully maintaining an old-growth forest is seen as extremely economically unproductive, as timber can only be collected from falling trees, and also potentially damaging to nearby managed groves by creating environments conducive to root rot. It may be more productive to cut the old growth down and replace the forest with a younger one. 870:, they are not protected by international treaties, because it is generally thought that aging forests cease to accumulate carbon. However, in forests between 15 and 800 years of age, net ecosystem productivity (the net carbon balance of the forest including soils) is usually positive; old-growth forests accumulate carbon for centuries and contain large quantities of it. 123:(2.7 billion acres) of primary forest remaining. Combined, three countries (Brazil, Canada, and Russia) host more than half (61 percent) of the world's primary forest. The area of primary forest has decreased by 81 million ha (200 million acres) since 1990, but the rate of loss more than halved in 2010–2020 compared with the previous decade. 225:, catastrophic disturbances like wildfires minimize opportunities for major accumulations of dead and downed woody material and other structural legacies associated with old growth conditions. Typical characteristics of old-growth forest include the presence of older trees, minimal signs of human disturbance, mixed-age stands, presence of 2018: 1992: 1117:. This coarse filter approach to biodiversity conservation recognizes ecological processes and provides for a dynamic distribution of old growth across the landscape. And all seral stages—young, medium and, old—support forest biodiversity. Plants and animals rely on different forest ecosystem stages to meet their habitat needs. 621:, thus competing for the light with neighbors; light competition mortality kills slow-growing trees and reduces forest density, which allows surviving trees to increase in size. Eventually, the canopies of neighboring trees touch each other and drastically lower the amount of light that reaches lower layers. Due to that, the 717:

deterioration through root rot or insect infestation, and they occupied land that could be used for more productive second-growth stands. In some regions, old growth is not the most commercially viable timber—in British Columbia, Canada, harvesting in the coastal region is moving to younger second-growth stands.

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where forests are relatively productive, trees live a long time, decomposition is relatively slow, and fires are infrequent. The differences between forests must, therefore, be taken into consideration when determining how they should be managed to store carbon. A 2019 study projected that old-growth

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Stand age can also be used to categorize a forest as old-growth. For any given geographical area, the average time since disturbance until a forest reaches the old growth stage can be determined. This method is useful, because it allows quick and objective determination of forest stage. However, this

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pattern for this stage. New trees regenerate at different times from each other, because each of them has a different spatial location relative to the main canopy, hence each one receives a different amount of light. The mixed age of the forest is an important criterion in ensuring that the forest is

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defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. One-third (34 percent) of the world's forests are primary forests. Old-growth features include

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Tree species succession may change tree species' composition once the old-growth stage has been achieved. For example, an old boreal forest may contain some large aspen trees, which may die and be replaced by smaller balsam fir or black spruce. Consequently, the forest will switch back to understory

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Old-growth forests are often perceived to be in equilibrium or in a state of decay. However, evidence from analysis of carbon stored above ground and in the soil has shown old-growth forests are more productive at storing carbon than younger forests. Forest harvesting has little or no effect on the

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Additionally, in mountainous, temperate landscapes (such as Western North America), and specifically in areas of high-quality soil and a moist, relatively mild climate, some old-growth trees have attained notable height and girth (DBH: diameter at breast height), accompanied by notable biodiversity

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that may be far more important to society than their use as a source of raw materials. These services include making breathable air, making pure water, carbon storage, regeneration of nutrients, maintenance of soils, pest control by insectivorous bats and insects, micro- and macro-climate control,

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A 2001 scientific symposium in Canada found that defining old growth in a scientifically meaningful, yet policy-relevant, manner presents some basic difficulties, especially if a simple, unambiguous, and rigorous scientific definition is sought. Symposium participants identified some attributes of

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In logging terms, old-growth stands are past the economic optimum for harvesting—usually between 80 and 150 years, depending on the species. Old-growth forests were often given harvesting priority because they had the most commercially valuable timber, they were considered to be at greater risk of

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Old-growth: Main canopy trees become older and more of them die, creating even more gaps. Since the gaps appear at different times, the understory trees are at different growth stages. Furthermore, the amount of light that reaches each understory tree depends on its position relative to the gap.

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may be higher or lower in old-growth forests compared to that in second-growth forests, depending on specific circumstances, environmental variables, and geographic variables. Logging in old-growth forests is a contentious issue in many parts of the world. Excessive logging reduces biodiversity,

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28% in North America, which harvests 10,000 km (3,900 sq mi) of ancient forests every year. Many of the fragmented forests of southern Canada and the United States lack adequate animal travel corridors and functioning ecosystems for large mammals. Most of the remaining old-growth

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Of importance is that while the stand switches from one tree community to another, the stand will not necessarily go through old-growth stage between those stages. Some tree species have a relatively open canopy. That allows more shade-tolerant tree species to establish below even before the

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have been reserved. Ten thousand hectares of tall-eucalypt RFA old-growth forest have been lost since 1996, predominantly as a result of industrial logging operations. In 2006, about 61,000 hectares of tall-eucalypt RFA old-growth forests remained unprotected. Recent logging attempts in the

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understory reinitiation stage. The shade-tolerant trees eventually outcompete the main canopy trees in stem-exclusion stage. Therefore, the dominant tree species will change, but the forest will still be in stem-exclusion stage until the shade-tolerant species reach old-growth stage.

424:. Because old-growth forest is structurally diverse, it provides higher-diversity habitat than forests in other stages. Thus, sometimes higher biological diversity can be sustained in old-growth forests, or at least a biodiversity that is different from other forest stages. 2867:

van der Sande, Masha T.; Arets, Eric J. M. M.; Peña-Claros, Marielos; de Avila, Angela Luciana; Roopsind, Anand; Mazzei, Lucas; Ascarrunz, Nataly; Finegan, Bryan; Alarcón, Alfredo (1 May 2016). "Old-growth Neotropical forests are shifting in species and trait composition".

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that has not been subjected to significant disturbance by mankind, altering the appearance of the landscape and its ecosystems, has not been subjected to logging (or other types of development such as road networks or housing), and has inherently progressed per natural

566:. Different organisms may need certain well-defined soil horizons to live, while many trees need well-structured soils free of disturbance to thrive. Some herbaceous plants in northern hardwood forests must have thick duff layers (which are part of the soil profile). 925:: "In the long term, a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre, or energy from the forest, will generate the largest sustained mitigation benefit." 1732:"Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer (eds) Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA" 1243:

8% in Africa, which has lost most of its intact forest landscapes in the last 30 years. The timber industry and local governments are responsible for destroying huge areas of intact forest landscapes and continue to be the single largest threat to these

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Dai, Limin; Jia, Juan; Yu, Dapao; Lewis, Bernard J.; Zhou, Li; Zhou, Wangming; Zhao, Wei; Jiang, Linhai (15 July 2013). "Effects of climate change on biomass carbon sequestration in old-growth forest ecosystems on Changbai Mountain in Northeast China".

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Ryan, Michael G.; Harmon, Mark E.; Birdsey, Richard A.; Giardina, Christian P.; Heath, Linda S.; Houghton, Richard A.; Jackson, Robert B.; McKinley, Duncan C.; Morrison, James F.; Murray, Brian C.; Pataki, Diane E.; Skog, Kenneth E. (2010).

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A better understanding of natural systems has resulted in new ideas about forest management, such as managed natural disturbances should be designed to achieve the landscape patterns and habitat conditions that are normally maintained in

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representative examples of old-growth forests with their associated characteristics and values. Literature around old growth and its management is inconclusive about the best way to characterize the true essence of an old-growth stand.

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Understory reinitiation: Trees die from low-level mortality, such as windthrow and diseases. Individual canopy gaps start to appear and more light can reach the forest floor. Hence, shade-tolerant species can establish in the

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desire to harvest valuable timber from the forests, destroying the forests in the process, to generate short-term profits, while environmentalists seek to preserve the forests in their pristine state for benefits such as

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introduced a rule, according to which, logging is strongly limited in old growth forests, but permitted in "mature forests", representing a compromise between the logging industry and environmental activists.

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on the forest floor. The trees of old-growth forests develop distinctive attributes not seen in younger trees, such as more complex structures and deeply fissured bark that can harbor rare lichens and mosses.

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only become established in canopy openings, but persist beneath an understory. Openings are a result of tree death due to small impact disturbances such as wind, low-intensity fires, and tree diseases.

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The large trees in old-growth forests are economically valuable, and have been subject to aggressive logging throughout the world. This has led to many conflicts between logging companies and

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of defined "old-growth forests". This led to struggles over what constitutes "old growth". For example, in Western Australia, the timber industry tried to limit the area of old growth in the

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grow more substantial, the ability of old-growth forests to sequester carbon is affected. Climate change showed an impact on the mortality of some dominant tree species, as observed in the

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Less than 3% in Europe, where more than 150 km (58 sq mi) of intact forest landscapes are cleared every year and the last areas of the region's intact forest landscapes in

980:. Climate change also showed an effect on the composition of species when forests were surveyed over a 10- and 20-year period, which may disrupt the overall productivity of the forest. 1021:, as of January 2009, only 21% of the original old-growth forests that once existed on Earth are remaining. An estimated one-half of Western Europe's forests were cleared before the 3338: 2097: 1148:. A small proportion of old-growth forest also exists in South-West Australia, and is protected by federal laws from logging, which has not occurred there for more than 20 years. 194:

or 'regeneration' until enough time passes for the effects of the disturbance to be no longer evident. Depending on the forest, this may take from a century to several millennia.

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Common cultural definitions and common denominators regarding what comprises old-growth forest, and the variables that define, constitute and embody old-growth forests include:

1766: 3963: 202:, Canada, old growth is defined as 120 to 140 years of age in the interior of the province where fire is a frequent and natural occurrence. In British Columbia's coastal 1251:, where the Paradise Forests are being destroyed faster than any other forest on Earth. Much of the large, intact forest landscapes have already been cut down, 72% in 3026: 397:. Thus, uniformly aged stands are less stable ecosystems. Boreal forests are more uniformly aged, as they are normally subject to frequent stand-replacing wildfires. 2969: 726:

late-successional, temperate-zone, old-growth forest types that could be considered in developing an index of "old-growthness" and for defining old-growth forests:

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Old-growth forests often contain rich communities of plants and animals within the habitat due to the long period of forest stability. These varied and sometimes

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Old-growth forests serve as a reservoir for species, which cannot thrive or easily regenerate in younger forests, so they can be used as a baseline for research.

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layer that is able to nurture certain types of organisms. Mounds provide a place free of leaf inundation and saturation, where other types of organisms thrive.

92:. Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and 3734: 3268: 3319: 1175: 1104:

Increased understanding of forest dynamics in the late 20th century led the scientific community to identify a need to inventory, understand, manage, and

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Old-growth forests tend to have large trees and standing dead trees, multilayered canopies with gaps that result from the deaths of individual trees, and

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A long natural rotation for catastrophic or stand-replacing disturbance (e.g., a period greater than the maximum longevity of the dominant tree species)

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Long-lived, shade-tolerant tree species associations (e.g., sugar maple, American beech, yellow birch, red spruce, eastern hemlock, white pine)

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Estoque, Ronald C.; Ooba, Makoto; Avitabile, Valerio; Hijioka, Yasuaki; DasGupta, Rajarshi; Togawa, Takuya; Murayama, Yuji (23 April 2019).

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to old-growth forests may someday prove to be invaluable towards curing various human ailments, as has been realized in numerous plants in

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Brothers, Timothy S.; Spingarn, Arthur (1992). "Forest Fragmentation and Alien Plant Invasion of Central Indiana Old-Growth Forests".

3343: 2163: 1902: 945:, particulates, and other pollutants, in some cases at levels above those from traditional fuel sources such as coal or natural gas. 918: 3293: 761:

Average age of dominant species approaching half the maximum longevity for species (about 150+ years for most shade-tolerant trees)

452:) by the roots pulled out of the ground when trees fall due to natural causes, including being pushed over by animals. Pits expose 2296: 2149: 1319: 1085: 2221: 972:

Old-growth forests have the potential to impact climate change, but climate change is also impacting old-growth forests. As the

4487: 3298: 3073: 2406: 2189: 1867: 2318: 4482: 2063: 1773: 1652: 1625: 1579: 1539: 3744: 3287: 206:, old growth is defined as trees more than 250 years, with some trees reaching more than 1,000 years of age. In Australia, 3034: 1392: 2977: 472:

provide food sources and habitat for many types of organisms. In particular, many species of dead-wood predators, such as

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have sparked a series of protests and media attention over the arrests that have taken place in this area. Additionally,

858:). They collectively represent a very significant store of carbon. Destruction of these forests releases this carbon as 3435: 3393: 3303: 341: 306:

affecting not only the old-growth forest itself, but also indigenous species that rely upon old-growth forest habitat.

1673:"Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink" 416:

Old-growth forests are unique, usually having multiple horizontal layers of vegetation representing a variety of tree

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forest requires frequent surface fires to reduce the shade-tolerant species and regenerate the canopy species. In the

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A forest regenerated after a severe disturbance, such as wildfire, insect infestation, or harvesting, is often called

3667: 3647: 2150:"B.C. old-growth data 'misleading' public on remaining ancient forest: independent report, June 4, 2020, The Narwhal" 1851: 1807: 704:

The debate over old-growth definitions has been inextricably linked with a complex range of social perceptions about

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Intact soils harbor many life forms that rely on them. Intact soils generally have very well-defined horizons, or

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gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.

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is mainly located in Brazil, which clears a larger area of forest annually than any other country in the world.

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Each forest has a different potential to store carbon. For example, this potential is particularly high in the

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Paper Presented at the Eighth Biennial Southern Silvicultural Research Conference, Auburn, al, Nov. L-3, 1994

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of much old-growth forest consists of pits and mounds. Mounds are caused by decaying fallen trees, and pits (

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perspective, old-growth forest is in a stage that follows understory reinitiation stage. Those stages are:

3074:"Old-growth definitions and management: A literature review BC Journal of Ecosystems and Management P. 16" 2407:"Old-growth definitions and management: A literature review BC Journal of Ecosystems and Management P. 22" 2190:"Old-growth definitions and management: A literature review BC Journal of Ecosystems and Management P. 17" 2078:

Provincial Non-Spatial Old Growth Order. 2004. Integrated Land Management Bureau, British Columbia, Canada

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or be a net emitter of greenhouse gases based on deforestation scenarios over the subsequent decades.

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McGarvey, Jennifer; Thompson, Jonathan R.; Epstein, Howard E.; Shugart, Herman H. (1 February 2015).

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preservation, biodiversity, aesthetics, and spirituality, as well as economic or industrial values.

542:, and creating microhabitats by creating relief on the forest floor. In some ecosystems such as the 4238: 3924: 3532: 3497: 1222: 1206: 1026: 330: 261:) and landscapes with a mix of old and younger forest types in the southern part of its range (the 233:, down wood in various stages of decay, standing snags (dead trees), multilayered canopies, intact 230: 3874: 4067: 3958: 3854: 3849: 2744: 1057: 334: 222: 198:

forests of the eastern United States can develop old-growth characteristics in 150–500 years. In

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Forest types have very different development patterns, natural disturbances and appearances. A

2705:"U.S. Forest Service A Synthesis of the Science on Forests and Carbon for U.S. Forests Page 4" 1284: – Forestry/logging practice in which most or all trees in an area are uniformly cut down 898: 4352: 4338: 4009: 3277: 1081: 674: 543: 394: 68: 3946: 1043:, just off the southeast coast of Australia, has the largest amount of temperate old-growth 500: 257:

primarily inhabits old-growth forests in the northern part of its range (Canada to southern

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The State of the World's Forests 2020. In brief – Forests, biodiversity and people

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Natural regeneration of dominant tree species within canopy gaps or on decaying logs

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BC Journal of Ecosystems Old growth definitions and management: A literature review

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The State of the World's Forests 2020. In brief – Forests, biodiversity and people

4305: 4163: 4148: 4004: 3951: 3934: 3637: 3605: 3575: 3527: 3512: 3487: 3360: 3323: 2853: 1327: – Harvest, transportation, purchase, or sale of timber in violation of laws 1324: 1263: 1160: 934: 604: 294: 1144:

Labor Government. Old-growth forests in this region have now been placed inside

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Stand-replacing: Disturbance hits the forest and kills most of the living trees.

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Some forests in the old-growth stage have a mix of tree ages, due to a distinct

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reserves in Australia with around 1,239,000 hectares in total. While the local

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and degrades within a relatively short time to result in a new cycle of forest

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Final stages of stand development before a relatively steady state is reached

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Natural Resources Canada Old-growth boreal forests: unraveling the mysteries

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Restoring old-growth characteristics to New England’s and New York’s forests

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Characterized by small-scale disturbances creating gaps in the forest canopy

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gaps are essential in creating and maintaining mixed-age stands. Also, some

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may depend on the unique environmental conditions created by these forests.

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Keith, Heather; Mackey, Brendan G.; Lindenmayer, David B. (14 July 2009).

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Uneven or multi-aged stand structure, or several identifiable age cohorts

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forests of the Southern Forests Region; this led to the creation of the

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Forest that has developed over a long period of time without disturbance

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Some old trees at close to their maximum longevity (ages of 300+ years)

705: 622: 473: 449: 445: 390: 203: 2889: 2019:"What does "Old-Growth" really mean? It depends. (Installment 1 of 6)" 1993:"What does "Old-Growth" really mean? It depends. (Installment 1 of 6)" 1697: 1672: 4153: 4131: 4032: 3974: 3590: 3456: 3365: 2866: 2645: 1571: 1531: 1376: 1352: 1252: 1121: 958: 551: 217:

stand may grow for centuries without disturbance while an old-growth

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Collection of Google map links of clear cuts in or around old growth

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Presence of standing dead and dying trees in various stages of decay

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Virgin forest about 2,500 m (8,200 ft) above sea level in

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Wirth, Christian; Gleixner, Gerd; Heimann, Martin (7 July 2009).

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rarely exceed 350 years of age due to frequent fire disturbance.

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they provide. This can be a point of contention when some in the

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Old-growth forests are valuable for economic reasons and for the

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are shrinking rapidly. In the United Kingdom, they are known as

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above and below the ground (either as humus, or in wet soils as

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Stand-initiation: A population of new trees becomes established.

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The tree species present have long continuity on the same site;

567: 523: 421: 258: 238: 64: 2483:"Old-Growth Forests Can Actually Contribute to Global Warming" 1670: 1419: – Habitat type defined by the World Wide Fund for Nature 480:

is well known for needing standing snags for nesting habitat.

80:

diverse tree-related structures that provide diverse wildlife

4389: 4109: 3269:

Provincial Old Growth regulations of British Columbia, Canada

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Global Forest Resources Assessment 2020 Key findings

1502:. Eighth Biennial Southern Silvicultural Research Conference 19:"Old growth" redirects here. For the Dead Meadow album, see 4168: 4143: 3817: 3371: 2765: 855: 535: 531: 234: 685:

The forest habitat possesses relatively mature, old trees;

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Nature's Temples: The Complex World of Old-Growth Forests

1025:, and 90% of the old-growth forests that existed in the 3290:– U.S. Geological Survey Biological Science Report (pdf) 673:

in northern California redwood forest: According to the

26:"Virgin forest" redirects here. For the 1985 movie, see 1427: