A silvicultural experiment to mitigate pest damage

An optimal impact design experiment was established in 1997 to investigate silvicultural alternatives for reducing vulnerability of white spruce (Pice a glauca (Moench) Voss) stands to spruce budworm (Choristoneura fumiferana (Clem.)) damage. Ecosystem and insect population responses are being assess ed in stands, thinned using a cut-to-length harvest system that removed 25% or 50% of standing volume in three patterns: uniform sheltenwood cuts, sta ndard strip cuts, and strips with "feathered" edges. Clear-cuts and untreat ed checks support comparisons among the undisturbed state, conventional pra ctice, and thinning regimes. Subplots in the uniform shelterwood cuts and u ntreated checks were fertilized with 200 kg N/ha in early spring of 1998. T he experimental approach permits strong inferences to be made about treatme nt effects but requires several years to obtain the final results from the research program.