Forests play a key role in the global carbon cycle and climate change
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EmailForests are good carbon sinks as long as they’re managed and remain as forests. Management and forest products can significantly increase the amount of sequestered carbon and reduce additions from fossil fuels.
Carbon has become a growing issue with forests and forest management, usually spoken about in terms of carbon dioxide and climate effects.
There are conflicting schools of thoughts about the role of forest management and use of wood products. The research background is extensive and growing rapidly. The bulk of that research demonstrates that management and wood products are critical to reduce the effects of rising carbon dioxide levels in the atmosphere. Forests can also be managed to become more resilient in the face of potential climate change patterns.
Jim Bowyer and others summarize the carbon role of forests in four tenets:
- Keep forests as forests and manage appropriate forests for carbon.
- Recognize that substantial quantities of carbon are stored in wood products for long periods of time.
- The substitution effect is immediate, irreversible and cumulative.
- It is imperative in policy development that objective, science-based analyses are used, that holistic thinking that encompasses the full suite of options in forest management be employed, and that particularly close attention be paid to assumptions and models underlying analyses.
To better understand this somewhat counter-intuitive idea, envision various pools where carbon is stored. There are pools in forests, the oceans, the soil and the atmosphere. The carbon volumes vary from pool to pool. Carbon also cycles normally among the pools both naturally and through human activity.
The carbon balance in the forest pool varies with the age of the forest, the volume of timber and other forest factors. Moving carbon from the atmosphere into forests is called sequestration. However, forests will not sequester carbon forever. Older forests may actually become carbon emitters.
Management helps keep forests younger and more rapidly sequestering carbon. However, harvesting forests also releases carbon, at least temporarily. Some of that carbon goes into deep soils (long storage times) and some temporarily moves into the atmosphere, from whence it came. Within a few years, that atmospheric carbon is re-absorbed by forests or other normal pools. The overall balance is maintained, as long as forest acreage remains.
A large pool, sometimes referred to as a “sink,” outside the normal carbon cycle lies within wood products, especially lumber and landfills, about 28 to 29 million tons annually between 2005 and 2007 in the United States. That’s about 12-13 percent of what the U.S. forests sequester each year. Growing this pool has advantages.
Together, annual forest growth and wood products sequester between 12-19 percent of total annual fossil fuel emissions. This percentage could be larger.
Additionally, a “substitution effect” increases the value of management and wood products in reducing carbon dioxide effects. When wood is used in place of other raw materials, considerably less fossil fuel is consumed. Construction materials such as concrete, metals and plastics use many times more fossil fuel for extraction, processing and distribution.
Carbon from burning fossil fuels comes from sources outside the normal carbon cycle. Fossil fuel carbon has been stored for millions of years from when the earth was a different kind of place. Over the past 50-75 years, massive quantities of this ancient carbon have been released. Substituting wood products for other raw materials substantially reduces the inflation of the normal carbon cycle.
Most scientists agree that increasing atmospheric carbon (enlarging the normal carbon cycle) has begun to affect Earth’s climate. Reducing the use of fossil fuels is one counter-active measure. More managed forest and use of forest products is another.
Forest management already provides revenue streams, economic benefits, environmental services, healthy forests and expanded recreational opportunities. A tool for carbon management can be added to the list of benefits.
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