Douglas-fir trees from 39 open-pollinated families at four test locations were assessed to estimate heritability of modulus of elasticity (MOE) and basic density. After trees were felled, sound velocity was measured on 4-m logs with the Director HM200. Disks were taken to estimate dry and green wood density; dynamic MOE...
Stem sinuosity is a highly visible stem-form trait in the leaders of fast-growing Douglas-fir (Pseudotsuga menziesii var. (Mirb.) Franco) trees, yet its cause is unknown. We tested the hypotheses that sinuous stems have longer expanses of primary growth than nonsinuous stems (putting the leader at higher risk curvature, induction of...
The relative importance of density, acoustic velocity, and microfibril angle (MFA) for the prediction of the stiffness (MOE) and strength (MOR) has not been well established for Douglas-fir (Pseudotsuga menziesii). MOE and MOR of small clear specimens of mature wood were better predicted by density and velocity than by either...
Wood density, moisture content, tracheid width and cell wall size were examined in trees from plots that were sprayed for 5 years with chlorothalonil (Bravo®) fungicide to reduce the impact of Swiss needle cast (SNC) and from trees in adjacent unsprayed plots. The unsprayed (more heavily diseased) trees had significantly...
The land area required for a marker-aided selection (MAS) program to break-even (i.e., have equal costs and benefits) was estimated using computer simulation for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Pacific Northwestern United States. We compared the selection efficiency obtained when using an index that included the phenotype...
ASTM standard sizes for bending tests (either 50 × 50 mm or 25 × 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the...
Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity (MOE), modulus of rupture (MOR), microfibril angle...
It would be valuable economically to know what are the biological triggers for formation of mature wood (currently of high value) and (or) what maintains production of juvenile wood (currently of low value), to develop silvicultural regimes that control the relative production of the two types of wood. Foresters commonly...
I construct and examine the properties of Lie and Clifford algebras which are used to describe certain types of particles. These algebras are then related to the traditional theory of division algebras. Quaternions are applied to these algebras and their properties are exploited to model physical properties of particles. The...