A branch mortality dating technique and whorl
sampling strategy were implemented to model five-year
crown recession from data collected on temporary
plots. Twenty-eight Douglas-fir from two levels-of-growing-
stock studies in Oregon and Washington were
first dissected to validate the proposed dating
technique and assess alternative sampling strategies.
Branch mortalities in...
Knowledge about the relationship between habitat structure and abundance of a target species
facilitates biodiversity conservation in managed forests. However, modeling the relationship
for infrequent small mammal species in silvicultural experiments introduces the challenge of
excessive zero counts and complex hierarchical sampling. A common solution has been to
ignore infrequent...
Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa pine (Pinus ponderosa
Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex. Loud.) stands in central Oregon. Basal area
growth was modeled as a function of other stand and tree variables to address three general objectives:...
Studies of nutrient limitation in Douglas-fir forests of the Pacific Northwest focus predominantly on nitrogen, yet many stands demonstrate negligible or even negative growth response to nitrogen fertilization. To understand what nutrients other than nitrogen may limit forest productivity in this region, we tested six fertilizer treatments for their ability...
Swiss needle cast (SNC) severity in Douglas-fir (Pseudotsuga menziesii) has been shown to vary spatially and temporally in response to climatic factors both within its native range and in regions where it has been planted as an exotic species. Survival models were developed for different Douglas-fir needle cohorts to enhance...
Swiss needle cast, a foliar disease caused by the Ascomycete Phaeocryptopus gaeumannii (T. Rohde) Petr., continues to afflict Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in north coastal Oregon. Permanent plots were installed in 1998 to assess growth impacts and monitor disease severity. Gross periodic annual increment was measured for three 2-year...
Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based...
The influence of fertilization on disease severity is unknown in most forest pathosystems. Fertilization treatments were randomly applied to 0.01 ha plots centered on individual dominant or co-dominant Douglas-fir trees in ten Douglas-fir stands from coastal Oregon to the foothills of the Oregon Cascade Range, USA. This region is affected...
The quality of lumber and veneer recovered from logs of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is directly influenced by the maximum limb size attained on the crop tree. Because limb sizes are influenced by standdensity regimes, a need has arisen for quantitative tools that link a wide array of silvicultural...
Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i) estimate the...
