The Forest Health Driver
of Silvicultural Options: Forest
Disease
Gregory Filip, Forest
Science, Oregon State University, Corvallis, OR
There are numerous
interactions between silvicultural options and forest diseases in the Pacific
Northwest. Silvicultural options such as site preparation, regeneration method,
thinning, and harvesting can either create or remedy disease problems. For
instance, thinning creates stumps and tree wounds and can leave susceptible
tree species resulting in increased root disease, stem decays, Swiss needle
cast, or dwarf mistletoe. These problems, however, can be reduced or prevented
by planting or favoring resistant species, preventing tree wounds, or treating
infected stumps. As options vary among even-age management, uneven-age
management, retention-based systems, and reserves, so do the pest problems and
management opportunities.
Keywords: Diseases, site preparation, thinning,
even/uneven-age management.
Darrell Ross, Forest
Science, Oregon State University, Corvallis, OR
Forest insects and diseases
can cause disturbances that dramatically alter the structure, composition, and
ecological processes of forest ecosystems.
They also respond to other types of disturbances including silvicultural
treatments. The changes in forest
ecosystems caused by insects and diseases can negatively impact a variety of
resource values. Resource managers must
develop silvicutural systems that include consideration of major insects and
diseases to prevent undesirable tree mortality and growth losses. Application of the principles of integrated
pest management to the forest ecosystem will help to ensure healthy forest
landscapes. Whenever possible
silvicultural treatments that create unfavorable conditions for forest insects
and diseases should be implemented.
Examples of forest insect responses to silvicultural activities in the
major forest types of the Pacific Northwest will be discussed.
Keywords: disturbance, insects, disease, integrated
pest management.