Forest restoration

In the 1980s, conservation organizations warned that, once destroyed, tropical forests could never be restored. Thirty years of restoration research now challenge this: a) This site in Doi Suthep-Pui National Park, N. Thailand was deforested, over-cultivated and then burnt. The black tree stump was one of the original forest trees. Local people teamed up with scientists to repair their watershed.
b) Fire prevention, nurturing natural regeneration and planting framework tree species resulted in trees growing above the weed canopy within a year.
c) After 12 years, the restored forest overwhelmed the black tree stump.

Forest restoration is defined as “actions to re-instate ecological processes, which accelerate recovery of forest structure, ecological functioning and biodiversity levels towards those typical of climax forest”[1] i.e. the end-stage of natural forest succession. Climax forests are relatively stable ecosystems that have developed the maximum biomass, structural complexity and species diversity that are possible within the limits imposed by climate and soil and without continued disturbance from humans (more explanation here). Climax forest is therefore the target ecosystem, which defines the ultimate aim of forest restoration. Since climate is a major factor that determines climax forest composition, global climate change may result in changing restoration aims.[2]

Forest restoration is a specialized form of reforestation, but it differs from conventional tree plantations in that its primary goals are biodiversity recovery and environmental protection.[3][4]

Scope

Forest restoration may include simply protecting remnant vegetation (fire prevention, cattle exclusion etc.) or more active interventions to accelerate natural regeneration,[5] as well as tree planting and/or sowing seeds (direct seeding) of species characteristic of the target ecosystem. Tree species planted (or encouraged to establish) are those that are typical of, or provide a critical ecological function in, the target ecosystem. However, wherever people live in or near restoration sites, restoration projects often include economic species amongst the planted trees, to yield subsistence or cash-generating products.

Forest restoration is an inclusive process, which depends on collaboration among a wide range of stakeholders including local communities, government officials, non-government organizations, scientists and funding agencies. Its ecological success is measured in terms of increased biological diversity, biomass, primary productivity, soil organic matter and water-holding capacity, as well as the return of rare and keystone species, characteristic of the target ecosystem. Economic indices of success include the value of forest products and ecological services generated (e.g. watershed protection, carbon storage etc.), which ultimately contribute towards poverty reduction. Payments for such ecological services (PES) and forest products can provide strong incentives for local people to implement restoration projects.

Opportunities for forest restoration

Demonstration forest restoration plot, SUNY-ESF, Syracuse, NY

Forest restoration is appropriate wherever biodiversity recovery is one of the main goals of reforestation, such as for wildlife conservation, environmental protection, eco-tourism or to supply a wide variety of forest products to local communities. Forests can be restored in a wide range of circumstances, but degraded sites within protected areas are a high priority, especially where some climax forest remains as a seed source within the landscape. Even in protected areas, there are often large deforested sites: logged over areas or sites formerly cleared for agriculture. If protected areas are to act as Earth’s last wildlife refuges, restoration of such areas will be needed.[6][7]

Many restoration projects are now being implemented under the umbrella of “forest landscape restoration” (FLR),[8] defined as a “planned process to regain ecological integrity and enhance human well-being in deforested or degraded landscapes”. FLR recognizes that forest restoration has social and economic functions. It aims to achieve the best possible compromise between meeting both conservation goals and the needs of rural communities.[9] As human pressure on landscapes increases, forest restoration will most commonly be practiced within a mosaic of other forms of forest management, to meet the economic needs of local people.

Natural regeneration

Tree planting is not always essential to restore forest ecosystems. A lot can be achieved by studying how forests regenerate naturally, identifying the factors that limit regeneration and devising methods to overcome them. These can include weeding and adding fertilizer around natural tree seedlings, preventing fire, removing cattle and so on. This is "accelerated" or "assisted" natural regeneration.[10] It is simple and cost-effective, but it can only operate on trees that are already present, mostly light-loving pioneer species. Such tree species are not usually those that comprise climax forests, but they can foster recolonization of the site by shade-tolerant climax forest tree species, via natural seed dispersal from remnant forest. Because this is a slow process, biodiversity recovery can usually be accelerated by planting some climax forest tree species, especially large-seeded, poorly dispersed species. It is not feasible to plant all the tree species that may have formerly grown in the original primary forest and it is usually unnecessary to do so, if the framework species method[11][12] can be used.

See also

References

  1. ↑ Elliott, S., D. Blakesley and K. Hardwick, in press. Restoring Tropical Forests: a Practical Guide. Kew Publications, London
  2. ↑ Sgró, C.M., A. J. Lowe and A. A. Hoffmann, 2011. Building evolutionary resilience for conserving biodiversity under climate change. Evolutionary Applications 4 (2): 326-337
  3. ↑ Lamb, D., 2011.Regreening the Bare Hills. Springer 547pp.
  4. ↑ http://www.treesearch.fs.fed.us/pubs/22209
  5. ↑ "Assisted natural regeneration of forests".
  6. ↑ Lamb, D., 2011.Regreening the Bare Hills. Springer 547pp.
  7. ↑ http://www.treesearch.fs.fed.us/pubs/22209
  8. ↑ Mansourian, S., D. Vallauri, and N. Dudley (eds.) (in co-operation with WWF International), 2005. Forest Restoration in Landscapes: Beyond Planting Trees. Springer, New York
  9. ↑ Reitbergen-McCraken, J., S. Maginnis A. Sarre, 2007. The Forest Landscape Restoration Handbook. Earthscan, London, 175 pp.
  10. ↑ Shono, K., E. A. Cadaweng and P. B. Durst, 2007. Application of Assisted Natural Regeneration to Restore Degraded Tropical Forestlands. Restoration Ecology, 15(4): 620–626.
  11. ↑ Elliott S, Navakitbumrung P, Kuarak C, Zankum S, Anusarnsunthorn V, Blakesley D, 2003. Selecting framework tree species for restoring seasonally dry tropical forests in northern Thailand based on field performance. For Ecol Manage 184:177-191
  12. ↑ Goosem, S. and N. I. J. Tucker, 1995. Repairing the Rainforest. Wet Tropics Management Authority, Cairns, Australia. Pp 72. http://www.wettropics.gov.au/media/med_landholders.html

External links

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