Assisted natural regeneration (ANR) (also termed managed regrowth) is the human protection and preservation of natural tree seedlings in forested areas. Seedlings are, in particular, protected from undergrowth and extremely flammable plants such as Imperata grass. Though there is no formal definition or methodology, the overall goal of ANR is to create and improve forest productivity. It typically involves the reduction or removal of barriers to natural regeneration such as soil degradation, competition with weeds, grasses or other vegetation, and protection against disturbances, which can all interfere with growth. [1] In addition to protection efforts, new trees are planted when needed or wanted (enrichment planting). With ANR, forests grow faster than they would naturally, resulting in a significant contribution to carbon sequestration efforts. It also serves as a cheaper alternative to reforestation due to decreased nursery needs.
The most effective way to implement ANR is very site-specific, and many nations provide guidebooks on how to select and maintain an ANR project. [2] [3]
ANR is a common practice in many Asian countries. This method of protection has been used on Imperata grasslands in the Philippines for over three decades, as well as in China for more than five decades. [4]
According to the Food and Agriculture Organization of the United Nations (FAO), China has since 1999 funded extensive ANR in an effort to prevent soil corrosion in particular. [5] Also the FAO reports that ANR is a common practice in Thailand.
ANR is gaining popularity as global climate change becomes a growing concern.
ANR has typically been used most often in tropical forests, however, it is now being used to help restore forested areas across all ecosystem types. [6]
A wide variety of conditions are required to optimally implement ANR and ensure successful regeneration. One involves a sufficient density of naturally regenerated seedlings, though the specific density required is dependent on specific factors, such as, distribution, species composition, growth rates, soil fertility, etc. A density range of 200 to 800 seedlings per hectare has been suggested to ensure optimal regeneration. [7] The availability of seed sources from nearby remnant forests is necessary to serve as seed inputs for colonization of vegetation. The control or removal of all disturbances (such as, grazing, fires, and logging) is also crucial. [7]
The practice of ANR has a wide range of benefits. ANR focuses on reducing ecological barriers in order to accelerate natural regeneration and growth, rather than the planting of seedlings. [7] This allows for a low-cost method that removes the expenses associated with site preparation and planting/raising seedlings themselves, which can be appealing in large-scale restoration projects. Another benefit involves job opportunities. ANR requires high maintenance and can be labor-intensive, and involve methods of weeding, grass pressing, establishing and maintaining firebreaks, etc. This can ultimately help to create jobs and improve livelihoods in local and/or impoverished communities. [7] However, if the forestation is not a positive change, for example, if the land is needed for food, the people of the community will be unlikely to get involved and produce successful ANR.[ citation needed ]
Carbon sequestration, biodiversity enrichment and recovery are just a few environmental benefits ANR provides, which can help improve ecosystems and mitigate climate change. ANR focuses on native species and natural succession of existing vegetation, which ensures that plant communities and inhabiting wildlife are maintained and are not disturbed. [6]
A carbon sink is a natural or artificial carbon sequestration process that "removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere". These sinks form an important part of the natural carbon cycle. An overarching term is carbon pool, which is all the places where carbon on Earth can be, i.e. the atmosphere, oceans, soil, florae, fossil fuel reservoirs and so forth. A carbon sink is a type of carbon pool that has the capability to take up more carbon from the atmosphere than it releases.
A forest is an ecosystem characterized by a dense community of 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 United Nations' Food and Agriculture Organization (FAO) 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 use." Using this definition, Global Forest Resources Assessment 2020 found that forests covered 4.06 billion hectares, or approximately 31 percent of the world's land area in 2020.
Reforestation is the practice of restoring previously existing forests and woodlands that have been destroyed or damaged. The prior forest destruction might have happened through deforestation, clearcutting or wildfires. Three important purposes of reforestation programs are for harvesting of wood, for climate change mitigation, and for ecosystem and habitat restoration purposes. One method of reforestation is to establish tree plantations, also called plantation forests. They cover about 131 million ha worldwide, which is 3% of the global forest area and 45% of the total area of planted forests.
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on Earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area.
Tree planting is the process of transplanting tree seedlings, generally for forestry, land reclamation, or landscaping purposes. It differs from the transplantation of larger trees in arboriculture and from the lower-cost but slower and less reliable distribution of tree seeds. Trees contribute to their environment over long periods of time by improving air quality, climate amelioration, conserving water, preserving soil, and supporting wildlife. During the process of photosynthesis, trees take in carbon dioxide and produce oxygen.
Silviculture is the practice of controlling the growth, composition/structure, as well as quality of forests to meet values and needs, specifically timber production.
Agroforestry is a land use management system that integrates trees with crops or pasture. It combines agricultural and forestry technologies. As a polyculture system, an agroforestry system can produce timber and wood products, fruits, nuts, other edible plant products, edible mushrooms, medicinal plants, ornamental plants, animals and animal products, and other products from both domesticated and wild species.
A secondary forest is a forest or woodland area which has regenerated through largely natural processes after human-caused disturbances, such as timber harvest or agriculture clearing, or equivalently disruptive natural phenomena. It is distinguished from an old-growth forest, which has not recently undergone such disruption, and complex early seral forest, as well as third-growth forests that result from harvest in second growth forests. Secondary forest regrowing after timber harvest differs from forest regrowing after natural disturbances such as fire, insect infestation, or windthrow because the dead trees remain to provide nutrients, structure, and water retention after natural disturbances. Secondary forests are notably different from primary forests in their composition and biodiversity; however, they may still be helpful in providing habitat for native species, preserving watersheds, and restoring connectivity between ecosystems.
Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from conservation in that it attempts to retroactively repair already damaged ecosystems rather than take preventative measures. Ecological restoration can reverse biodiversity loss, combat climate change, support the provision of ecosystem services and support local economies. The United Nations has named 2021-2030 the Decade on Ecosystem Restoration.
Afforestation is the establishment of a forest or stand of trees in an area where there was no recent tree cover. There are three types of afforestation: natural regeneration, agroforestry and tree plantations. Afforestation has many benefits. In the context of climate change, afforestation can be helpful for climate change mitigation through the route of carbon sequestration. Afforestation can also improve the local climate through increased rainfall and by being a barrier against high winds. The additional trees can also prevent or reduce topsoil erosion, floods and landslides. Finally, additional trees can be a habitat for wildlife, and provide employment and wood products.
Forest ecology is the scientific study of the interrelated patterns, processes, flora, fauna, funga, and ecosystems in forests. The management of forests is known as forestry, silviculture, and forest management. A forest ecosystem is a natural woodland unit consisting of all plants, animals, and micro-organisms in that area functioning together with all of the non-living physical (abiotic) factors of the environment.
Secondary succession is the secondary ecological succession of a plant's life. As opposed to the first, primary succession, secondary succession is a process started by an event that reduces an already established ecosystem to a smaller population of species, and as such secondary succession occurs on preexisting soil whereas primary succession usually occurs in a place lacking soil. Many factors can affect secondary succession, such as trophic interaction, initial composition, and competition-colonization trade-offs. The factors that control the increase in abundance of a species during succession may be determined mainly by seed production and dispersal, micro climate; landscape structure ; bulk density, pH, and soil texture.
Forest management is a branch of forestry concerned with overall administrative, legal, economic, and social aspects, as well as scientific and technical aspects, such as silviculture, forest protection, and forest regulation. This includes management for timber, aesthetics, recreation, urban values, water, wildlife, inland and nearshore fisheries, wood products, plant genetic resources, and other forest resource values. Management objectives can be for conservation, utilisation, or a mixture of the two. Techniques include timber extraction, planting and replanting of different species, building and maintenance of roads and pathways through forests, and preventing fire.
Conservation grazing or targeted grazing is the use of semi-feral or domesticated grazing livestock to maintain and increase the biodiversity of natural or semi-natural grasslands, heathlands, wood pasture, wetlands and many other habitats. Conservation grazing is generally less intensive than practices such as prescribed burning, but still needs to be managed to ensure that overgrazing does not occur. The practice has proven to be beneficial in moderation in restoring and maintaining grassland and heathland ecosystems. Conservation or monitored grazing has been implemented into regenerative agriculture programs to restore soil and overall ecosystem health of current working landscapes. The optimal level of grazing and grazing animal will depend on the goal of conservation. Different levels of grazing, alongside other conservation practices, can be used to induce desired results.
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", 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. 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. Additionally, the potential impacts of climate change on restoration goals must be taken into account, as changes in temperature and precipitation patterns may alter the composition and distribution of climax forests.
Gap dynamics refers to the pattern of plant growth that occurs following the creation of a forest gap, a local area of natural disturbance that results in an opening in the canopy of a forest. Gap dynamics are a typical characteristic of both temperate and tropical forests and have a wide variety of causes and effects on forest life.
The Buffelsdraai Community Reforestation Project was initiated in 2008 to alleviate climate change impacts associated with hosting elements of the 2010 FIFA World Cup in Durban. The proposed carbon offset was to be achieved through the planting of more than 500 000 indigenous trees within the buffer zone of the Buffelsdraai Landfill Site. Restoring the forest ecosystem was identified as a way of "absorbing event-related greenhouse gas emissions while enhancing the capacity of people and biodiversity to adapt to the inevitable effects of climate change".
Carbon farming is a set of agricultural methods that aim to store carbon in the soil, crop roots, wood and leaves. The technical term for this is carbon sequestration. The overall goal of carbon farming is to create a net loss of carbon from the atmosphere. This is done by increasing the rate at which carbon is sequestered into soil and plant material. One option is to increase the soil's organic matter content. This can also aid plant growth, improve soil water retention capacity and reduce fertilizer use. Sustainable forest management is another tool that is used in carbon farming. Carbon farming is one component of climate-smart agriculture. It is also one way to remove carbon dioxide from the atmosphere.
May Be’ati is an exclosure located in the Dogu'a Tembien woreda of the Tigray Region in Ethiopia. The area has been protected since 1968 by the local community.
Khunale is an exclosure located in the Dogu'a Tembien woreda of the Tigray Region in Ethiopia. The area has been protected since 1990 by the local community.
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