Beware the fad of hybrid poplar trees

In the 1958 World Series, Yankees catcher Yogi Berra advised Hank Aaron, the greatest hitter in the world (still), to turn his bat so he could read the label. Aaron responded that he was there “to hit, not to read." The reason was simple. When the label faced up where the batter could read it, the ball hit where the wood grain is tightest and, therefore, where the bat is strongest.

It is advice we should keep in mind when we hear about the latest fad in “green forestry.” Like the Pacific albus of Daniel Jack Chasan’s recent Crosscut article, for hybrid poplar or any other fast-growing tree, the faster the growth, the wider the rings and the less structural strength. That shortcoming is just one reason these types of trees, while useful in satisfying a market for furniture and pulp, are not the panacea that some claim. What’s more, they create as much environmental controversy as they solve. Maybe more.

People have been pointing to hybrid poplar as an environmental savior for years. A few years back, the high-tech magazine Business 2.0 even claimed fast-growing poplars would put an end to clear cuts forever. They printed a photo of a clear cut in Washington, claiming such scenes would soon be a thing of the past. So elementary was their knowledge of forestry, however, that the picture showed not a harvest, but the aging stumps at the bottom of Seattle’s reservoir, Keechelus Lake along I-90. Their understanding of the drawbacks of hybrid poplar was just as flawed.

First problem is the speed of growth, which makes trees like the Pacific albus attractive to some, because the forests re-grow quickly, but that is also the reason these trees are only suitable for pulp and in furniture. The trees are too weak for houses and other frame construction.

Second, they don’t replace Douglas fir or tropical hardwoods. Douglas fir, hemlock, and other softwoods are used primarily as structural timber. When I worked at at the Department of Natural Resources (DNR), we did a quick overview of timber harvests on state land and found that more than 90 percent were for structural timber. Wood waste from Douglas fir can be used for pulp, but this is one of the least valuable aspects. Chasan notes that “you don’t need big Douglas fir to get wood fiber.” True, but you do need it for structural timber than poplar can’t provide. Foresters aren’t harvesting Doug fir for toilet paper.

Tropical hardwoods are either used locally for firewood by the poor in equatorial countries or processed for tropical oils not present in poplar. Thus, poplar won't replace demand for tropical trees where rainforest deforestation is a concern.

A third drawback is that poplars like the Pacific albus create environmental problems of their own. They demand a tremendous amount of water and are picky about the type of land on which they are grown. DNR found that only about 2 percent of the land owned by the state would be suitable for the poplar. Many of the lands where they can grow are near dams where irrigation water is available. Given the battles over water and the presence of the dams, increasing the demand for water for poplars is a questionable environmental trade off. Who wants more water for trees and less for fish?

Lastly, hybrid poplars have come under fire (literally) for what some claim is genetic engineering. The firebombing of the UW’s Center for Urban Horticulture in 2001 was done in the name of stopping research on similar types of trees. The terrorist group, the Earth Liberation Front, has threatened to attack other locations where such research goes on, including a Forest Service center in Olympia. Some other environmentalists, obviously not resorting to arson to make their points, share some of these concerns.

If we truly care about “green forestry,” we should stop looking for a cure-all in the form of one fast-growing tree. Often the search is based neither on the reality of forestry in Washington nor science. Some people express concern that we are harvesting old-growth trees. (We aren’t.) Others raise alarms that there will be less forest and fewer trees in the future due to over harvesting. (Both the number of trees and total forest area are increasing in North America.) And there are many who argue that we need to stop harvesting to protect the spotted owl, only to find that a more aggressive animal, the barred owl, is moving into the habitat left in unharvested forests. That is not to say that harvesting helps the spotted owl, only that not harvesting doesn’t help it either.

Forestry science evolves and we learn more all the time, doing it better today than ever before. Harvests are designed to match the historic pattern of forest fire in Washington forests, creating a mosaic of habitat types that suit a diversity of creatures. Washington has perhaps the toughest rules in North America protecting forest streams and preventing erosion. And we need to remember that wood is the best material for construction, since it uses less energy than any alternative and trees remove carbon from the atmosphere.