610 likes | 741 Views
Myths & Facts… Forests, Carbon, and Global Warming Doug Heiken. O r e g o n W i l d (formerly Oregon Natural Resources Council) Mission : To aggressively protect and restore Oregon’s wildlands, wildlife, and water as an enduring legacy.
E N D
Myths & Facts… Forests, Carbon, and Global Warming Doug Heiken
O r e g o n W i l d(formerly Oregon Natural Resources Council) Mission: To aggressively protect and restore Oregon’s wildlands, wildlife, and water as an enduring legacy. Goal: To permanently protect roadless areas and old-growth forest ecosystems. Climate change threatens forests. Conserving forests will store carbon and help mitigate a threat to earth’s climate and to the forests themselves.
Facing Reality … • Nearly everything we do must change. • All net carbon emissions are adverse. None can be considered insignificant. • All ecosystems are important. Forests just happen to store a lot of carbon. • Forest conservation is part of the solution to a very large problem.
We can’t save the forests and continue to drive our SUVs. Ingerson, Ann L. 2007. U.S. Forest Carbon and Climate Change. Washington, D.C.: The Wilderness Society.
Understanding forest carbon flows • Forests absorb, store, and emit carbon. Forest management affects all three. • Relevant carbon pools include not just trees, but the atmosphere, dead wood, other vegetation, roots, litter, soil. • To debunk myths, find the grain of truth, “follow the carbon” and consider the longevity of carbon in each pool.
OVERVIEW • Young Forest Myth • Wood Products Myth • Harvest Myth • Fire Myth • Tropical Forest Myth • Albedo Myth • “Doomsday” Myth • Substitution Myth • Methane Myth • “No Surprises” Myth • SOLUTIONS
YOUNG FOREST MYTH: • Fast-growing young forests absorb more carbon and are better for the climate than slow-growing old forests. • Reality: • Most old forests are still growing and absorbing carbon. • Old forests store far more carbon than young forests. • Mature forests cannot be converted into young forests without losing most of the carbon to the atmosphere.
EXPERTS AGREE • “In contrast to the sink management proposed in the Kyoto protocol, which favors young forest stands, we argue that preservation of natural old-growth forests may have a larger effect on the carbon cycle than promotion of regrowth. ... [I]ncreasing life-span of the stand, proportionally more carbon can be transferred into a permanent pool of soil carbon ... [R]eplacing unmanaged old-growth forest by young Kyoto stands ... will lead to massive carbon losses to the atmosphere mainly by replacing a large pool with a minute pool of regrowth and by reducing the flux into a permanent pool of soil organic matter.” • Ernst-Detlef Schulze, Christian Wirth, Martin Heimann. CLIMATE CHANGE: Managing Forests After Kyoto. Science 22 September 2000: Vol. 289. no. 5487, pp. 2058 - 2059.
Photosynthesis stopped here … Where did the carbon go?
WOOD PRODUCTS MYTH: It’s better to store carbon in wood products, rather than in forests. Example: "Carbon stays trapped in the wood, locked in the lumber …." Reality: Carbon is stored more securely in long-lived forests than in short-lived wood products.
Where did the carbon go? The timber industry transfers most of the carbon in the forest to the atmosphere as logging slash, mill waste, and processing emissions. Ingerson, Ann L. 2007. U.S. Forest Carbon and Climate Change. Washington, D.C.: The Wilderness Society.
HARVEST MYTH: Timber harvest “absorbs” carbon. Source: California Forest Products Commission. Modern Forestry & Climate Change.
Actually, logging emits carbon. Just follow the arrows from harvest back to the atmosphere. Ingerson, Ann L. 2007. U.S. Forest Carbon and Climate Change. Washington, D.C.: The Wilderness Society.
Carbon is more secure in live trees than dead trees. Logging kills trees, stops photosynthesis, starves the soil foodweb.
Carbon is safer when protected by tree bark … rather than paint. Living trees have an arsenal of defenses that help keep carbon safe from decay, insects, and fire.
Carbon is safer in big pieces of wood, rather than small. Logging fragments large wood and increases surface area exposed to bacterial decomposition.
Carbon is more secure in a cool forest than a warm forest. Reducing canopy cover warms the soil surface and increases the rate of decomposition.
Long-lived forests are better than… short-lived wood products.
FIRE MYTH: Forests are not good places to store carbon because forest fires release stored carbon through combustion. Example: “When a tree burns it releases all the carbon it previously stored."
Some trees die … … so that others may live long and grow large. Fire is an essential ecological process that helps forests stay healthy.
Fires occur in limited areas for a limited duration, while photosynthesis dominates everywhere else. BIG PICTURE: The places that don’t burn absorb more carbon than is emitted by the places that do burn.
Most forest fires emit far less carbon than logging. Wayburn, Laurie A., et al. 2000. Forest Carbon in the United States: Opportunities & Options for Private Lands. San Francisco: Pacific Forest Trust.
Most carbon remains on site after forest fires.Large dead trees can last for many decades.
TROPICAL FOREST MYTH: Forests outside the tropics are unimportant because they do not contribute significantly to global carbon storage. Reality: Pacific NW temperate rainforests can attain the greatest biomass per acre of any ecosystem on earth. Temperate and boreal forests are very extensive and currently serve as net carbon sinks.
http://www.fao.org/forestry/static/data/fra2005/maps/2.2.jpg
Global Ecosystem Carbon Density. Olson, J.S, J.A. Watts, and L.J. Allsion. 1985. Major World Ecosystem Complexes Ranked by Carbon in Live Vegetation: A Database. ORNL/CDIAC-134, NDP-017. Carbon Dioxide Information Analysis Center, U.S. Department of Energy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. (Revised 2001) http://cdiac.ornl.gov/epubs/ndp/ndp017/ndp017.html
http://www.fao.org/forestry/static/data/fra2005/maps/2.7.jpg
ALBEDO MYTH: Forests are dark green, so they exacerbate global warming by absorbing rather than reflecting the sun's energy.
Actually, albedo only trumps forest carbon storage when forests are replaced by snow for long periods. This might happen in boreal areas with long, cold winters, but not in temperate forests of the Pacific Northwest.
Forests can also have a cooling effect by increasing albedo. Forests transpire a lot of water and emit “cloud condensation nuclei” which help create reflective clouds.
THE “DOOMSDAY” MYTH: Protecting forests won’t help because climate change will be extreme, causing forests to release large amounts of carbon due to stress and disturbance. http://www.x-cd.com/mcss04/S01a.pdf
Actually, many forests may thrive before they decline. Forests will first … “Green Up” Then … “Brown Down” Longer growing seasons Drought tolerance CO2 fertilization Fire Insects Drought
Increased CO2 makes trees more drought tolerant. With more CO2 in the air, plants quickly get their fill of carbon, then actively close their stomata to reduce water loss.
Even under extreme climate scenarios, forest conservation still makes sense. • Keeping more carbon in the forest instead of the atmosphere will help prevent a bad situation from getting worse. • Even if forests switch from being carbon sinks to carbon sources, we could make the source worse through mismanagement of forests. • If the effects of economic exploitation of forests are added to anticipated climate stresses, carbon emissions will increase.
Don’t forget all the other reasons to protect forests. Managing forests for carbon storage is complementary with other important ecosystem services that flow from forests. Clean water Fish & wildlife habitat Soil conservation Quality of life Economic diversification Capture, storage & release of water, nutrients & sediment.
Water Wildlife
METHANEMYTH: Allowing wood to rot in the forest releases methane (CH4) which is 23 times worse than CO2. Reality: A small fraction of burning and rotting wood may be converted to methane instead of CO2.Allowing wood to rot in the forest is no worse than wood that rots in our cities and landfills.
SUBSTITUTION MYTH: Using wood products from short-rotation clearcutting reduces carbon emissions by substituting for more carbon intensive products like steel and cement. Reality: Using wood does not guarantee that fossil fuels will stay in the ground, and extending harvest rotations is still best for the climate.
The alleged value of wood product substitution. Ingerson, Ann L. 2007. U.S. Forest Carbon and Climate Change. Washington, D.C.: The Wilderness Society.