Greenwire: A warmer climate and planting on previously logged pieces of land could be causing more Douglas fir trees in Oregon and Washington to fall victim to a fungal disease, according to a new study by Oregon State University researchers.
The disease, Swiss needle cast, which originated in Europe and has spread throughout the Pacific Northwest since 1996, typically stunts the trees’ growth, causing them to become discolored and lose their needles. Now affecting more than 300,000 acres in the region, Swiss needle cast could eventually become prevalent in up to 2 million acres of forests along the Oregon coast, researchers said, costing the timber industry tens of millions of dollars per year.
The study, published in Forest Ecology and Management, suggests commercial forestry practices may be contributing to the spread of the disease. While coastal forests historically included trees of various ages and species, Douglas fir forests are often planted simultaneously, allowing buildup of the fungus among similarly aged groups of trees, researchers say.
Fungicides have been impractical because of cost and environmental concerns. A better solution, researchers say, would be to plant fewer Douglas firs, instead mixing in trees such as the western hemlock and red alder (Scott Learn, Portland Oregonian, April 5). – GN