WARMING TEMPERATURES MAY FREEZE NORTH AMERICAN TIMBER INDUSTRY
COLUMBUS - Global warming trends may seriously harm North America's stronghold on the timber production industry, a recent study suggests.
But rising temperatures could mean an economic boom for the timber industry in regions with subtropical climates, such as South America, Africa and Asia-Pacific.
Global warming may cause forest growth patterns to slowly change, said Brent Sohngen, a study co-author and an associate professor of agricultural, environmental and development economics at Ohio State University.
This shift in timber production could have serious ramifications for growers in temperate regions, such as North America, the former Soviet Union, China, Australia, New Zealand and parts of Europe, areas that currently supply 77 percent of the world's industrial timber.
But at the same time, growers in the subtropics will be able to expand their plantations of fast-growing trees to gain a larger share of the world timber market.
"Timber growth rates in the tropics can double those in cooler, temperate climates," Sohngen said. "These plantations can raise the same amount of fast-growing softwood species in 10 to 30 years that their temperate counterparts can in 50 to 100 years."
His study predicts that the area occupied by timber plantations in the tropics will increase an average of 675,000 acres per year for the next 50 to 100 years - an annual increase roughly the size of Rhode Island. These new plantations will typically be built on farmland that is no longer used for conventional crops.
But productive temperate regions won't stop producing trees. Rather, a rise in temperature will cause their forests to undergo a shift in species. Temperate forests in Canada and the northern United States and Europe typically produce hardwoods such as cherry, oak and maple. But warming temperatures will allow softwood species, primarily southern pine, to slowly migrate north and eventually take over the hardwood forests.
The research appears in a recent issue of the Journal of Agricultural and Resource Economics. Sohngen conducted the study with Robert Mendelsohn of the Yale School of Forestry and Environmental Studies and with Roger Sedjo of Resources for the Future, an environmental and natural resources think tank in Washington, D.C.
The scientists used climate, ecology and economic models to predict changes in global timber growth patterns during the next 60 to 100 years. The climate models predict a 1.8 to 6 degree (1 to 3.4 C) change in global temperatures in the next 50 years.
"The ecological models predict northward shifts of mainly southern pine, but over very long time periods," Sohngen said. "The economic models suggest that humans speed up that transition, which could alleviate some of the negative market impacts caused by species loss in the north.
"We looked only at the effects of climate change on timber markets," he said. "It's likely that ecosystems will be largely affected, and not necessarily for the better. The supply of timber in the United States probably won't be affected, although timber markets in the north would suffer economically."
And as temperate regions adjust to climate change, the subtropics will have a prime opportunity to corner the timber market, Sohngen said.
If the researchers' predictions hold true, northern timber-growing regions may suffer an economic setback.
"As southern-growing species migrate northward, some species indigenous to the north will die," Sohngen said. "Markets will try to keep up by salvaging as many economically viable hardwood stocks as possible, but this could lead to a glut of timber in the global market.
"In theory, trees that die back as a result of climate change would flood the market, ultimately driving prices down," he said. "Not only will northern growers face dying trees and increased competition from subtropical plantations, but prices are likely to be lower, thus reducing profits."
But the demand for hardwood isn't likely to subside, in spite of the availability of inexpensive softwoods. Slow-growing hardwoods will slowly migrate north, eventually covering far northern and hard-to-access areas, such as boreal forests.
"We assume demand for hardwood timber continues to rise over time, and consumers are likely to benefit from lower prices," Sohngen said. "Early financial losses in northern regions are eventually offset by the maturation of softwood forests, but not enough to make up for the interim loss."
In the long run - after 100 years or so - an increase in timber production in northern and southern regions will likely increase the annual growth of marketable timber by raising global net production.
Still, most of the growth in harvestable timber will occur in non-indigenous plantations in the tropics, Sohngen said.
"The tropics can react more quickly to climate change than temperate zones can," he said. "Also, it costs relatively little to convert poor agricultural land - which is more common in the tropics - into a successful timber plantation. Trends are headed toward places that can establish fast-growing timber plantations -- places like Brazil, Argentina and South Africa."
Funds from the U.S. Department of Energy and Resources for the Future supported this research.