Animal damage to coniferous plantation in Oregon and Washington. Part I. A survey, 1963-1975

Abstract

Mammal and bird damage recorded on Douglas-fir and ponderosa pine plots-randomly established in Oregon and Washington during 1963-64, then observed for 5 to 10 years-was evaluated for impact on survival and growth. In all, 194 plots were installed, and 10 of the 110 seedlings on each plot were caged to protect them from animals. All trees were examined after planting and after bud burst each year for 5 years. A selected sample of 45 Douglas-fir plots was observed another 5 years for long-term patterns and effects of severe plantation damage. Survival and growth were compared for caged and uncaged trees. The agents, kind, amount, and distribution of animal damage were evaluated by state, by subregion, and by relation to site features. Results indicate that stand damage in plantations exposed to heavy animal use, especially during seedling establishment, warrants expenditure for protective measures.