Douglas-fir is the most commercially important timber species in the US Pacific Northwest due to its ecological prevalence and its superior wood attributes, especially strength and stiffness properties that make it highly prized for structural applications. Its economic significance has led to extensive establishment and management of plantations over the...
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...
In coastal forests of the Pacific Northwest, young coniferous plantations typically contain a mixture of planted and natural Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla). Swiss needle cast (SNC) disease inhibits the growth of Douglas-fir to varying degrees in these stands, depending on SNC severity. In addition to the...
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...
We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI)...
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...
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...
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...