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As the Nature Conservancy reports, every year, millions of hectares of native forests are cleared for other land uses, including urban development, croplands, grazing lands and tree plantations. In the process, most of the organic carbon stored in the trees is lost to the atmosphere. Most deforestation is driven by commercial agriculture; there are lots of opportunities to improve production on existing agricultural lands, so that we can avoid unsustainable forest conversion. Forest protection is particularly important in the tropics, which have the highest rates of forest loss.
As the U.S. Forest Service describes land cover trends in the United States reflect a gradual decline, with a reduction from 46% cover in 1630 to 34% cover in 1997 – today’s forested land area equates to about 70% of area at the time of European settlement. Because much of this land was converted to agriculture, there are unique opportunities to restore converted forest land and their carbon sequestration benefits. Protection and restoration efforts can support carbon storage.
A 2007 Congressional Budget Office report notes that the United States accounts for roughly one-quarter of global CO2 emissions from fossil-fuel combustion, or about 6 billion metric tons per year. While its current land-use and forestry practices have the net effect of removing the equivalent of about 0.8 billion metric tons of CO2 from the atmosphere annually, studies estimate that biological sequestration has the technological potential to sequester about 40 billion to 60 billion metric tons of CO2 in the United States over the course of 50 years and another few tens of billions of tons over the following half-century, highlighting the vast potential for improved forest management to provide natural climate solutions. The Pacific Forest Trust emphasizes the opportunities for enhanced forest protection, management, and restoration in the United States. Actions in these three areas could permanently increase forest carbon stocks in the U.S. by millions of tons annually at a cost per ton equivalent to the lower end of the range of mitigation costs.
As TNC reports, avoiding forest conversion is a relatively low-cost pathway that’s ready to be put into practice immediately. In the past, critics have argued that it was premature to take action given the limitations of measuring and monitoring the world’s forests. As measurement and monitoring techniques have improved, this argument is no longer a significant barrier to action. Despite some political and economic hurdles, we have the tools we need to stop deforestation now. These include sensitive habitat mapping capabilities and ecosystem services valuation models such as InVEST that can help land managers identify costs and benefits of targeted protection efforts. In part in response to increasing understanding of carbon mitigation opportunities and data availability that enables quantification of forest protection benefits, groups such as the Pacific Forest Trust have been engaging in campaigns to “Retain, Sustain, and Gain” conservation areas and working forest lands to support carbon sequestration benefits.
Improving forest management practices allows natural forests to store more carbon while maintaining wood production for the long term. Logging should certainly be halted in some sensitive places, but the lost production can be made up by new wood production in reforested lands and plantations. Extending harvest cycles, for example, allows trees to grow more before they’re felled, increasing the average carbon stock across a working forest. Reduced-impact logging practices like cable winching can avoid damage to unharvested trees. And competing vegetation, such as vines, can be thinned to allow trees to grow faster and bigger. Implementing such techniques can allow working forests to sequester more carbon, and are often compatible with existing land trust management efforts.
In a 2015 research article from the U.S. Forest Service, all 50 state forestry agencies weighed in on family forest owner participation in carbon management and carbon markets in their respective state programs. The agencies identified that landowners with an existing forest management plan and previous forester interaction were more likely to be interested in carbon management and carbon markets.
Methods most likely to be employed by forest landowners for carbon sequestration were: thinning or other stand-release techniques, reforestation, tree stocking and adjusted rotations, activities which also yield benefits in terms of improve stand species diversity, old growth protection, improved wildlife habitat, tree stocks, and aesthetics. While research indicates that enhanced land management has numerous co-benefits that may be as much if not more of a driver than climate mitigation goals, as best practices emerge, additional economic and ecological synergies may be identified for carbon sequestration projects. You can learn more about land trusts engaging in management efforts to support carbon sequestration here.
A wide variety of opportunities for forest restoration exist around the world, ranging from natural regeneration, to enrichment planting, to high-yield timber plantations. As a 2009 Congressional Research Service paper reports, reforestation refers to planting trees or other activities to establish tree stands (such as assisting natural tree regeneration or preparing sites and sowing tree seeds) on areas recently cleared of forest through timber harvesting or natural disaster, while afforestation refers to planting trees on sites that have long been cleared of forests, such as crop, pasture, and brush lands.
In addition to other ecological benefits, these practices have significant carbon sequestration potential: reforestation is estimated at 1.1 to 7.7 metric tons of CO2 per acre per year while afforestation of crop or pasture land is estimated to have the potential to sequester between 2.2 and 9.5 metric tons of CO2 per acre per year. These estimates have a very wide range of possibilities because tree growth and forest soil carbon accumulation varies widely among species and locations. Although quantifying site-specific restoration benefits can be technically challenging, some land managers The Conservation Fund are already leveraging existing carbon funding mechanisms to support restoration projects in the United States. You can learn more about land trusts engaging in forest restoration efforts to support carbon sequestration here.
With an estimated 37% potential mitigation potential of "natural climate solutions" worldwide, forests can play a major role in supporting climate impact mitigation through implementation of natural climate solutions.
In addition to promoting conservation of highly productive forest systems, improving forest management practices allows natural forests to store more carbon while maintaining wood production and reducing ecological impacts for the long term. For example, extending harvest cycles allows trees to grow more before they’re felled, increasing the average carbon stock across a working forest. Reduced-impact logging practices like cable winching can avoid damage to unharvested trees. Implementing such techniques can allow working forests to sequester more carbon.
Source: American Forest Foundation
Natural climate solutions pathway differ considerably among countries and regions, however, numerous mitigation opportunities exist that may complement existing resource management efforts.
Forest pathways offer over two-thirds of cost-effective NCS mitigation needed to hold warming to below 2 °C and about half of low-cost mitigation opportunities. Moreover, reforestation is the largest natural with tremendous potential for low-cost mitigation opportunities. Read the full report here.