Estimating volume gains in genetically improved stands at rotation age is challenging because first-generation progeny tests in Douglas-fir were typically established to measure the relative growth performance of individual trees from open-pollinated parent trees. The overall goal of this dissertation research was to improve growth simulation of genetically improved Douglas-fir...
To investigate the movement of elements (N, P, k, Ca, and Mg) from the tree crowns by natural litterfall and leave wash, plots were established on six 450 year-old growth stands at the H. J. Andrews Experimental Forest. The following are the results of the data analyses. Elemental concentrations contained...
The relation of bud and cambial activity to root initiation and
elongation in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)
stem cuttings was studied through two successive growth cycles.
Stem cuttings of current season's growth were taken periodically
from field-grown Douglas-fir trees to determine: (1) origin and
development of root initials; and...
Experiments were conducted to determine if the plagiotropic
growth habit of rooted cuttings of Douglas-fir might result from a
system favoring the accumulation of indoleacetic acid in the adaxial
side of the shoot in response to vertical placement.
Actively growing excised branch terminals were subjected to
gravitational disorientation to determine...
Budburst, the initiation of annual growth in plants, is sensitive to climate variation and is therefore used to monitor physiological responses to climate change. Budburst timing can vary between regions of an individual tree, but this phenomenon it is unaccounted for in current monitoring efforts and may contribute to the...
An understanding of the dynamics of individual tree and stand
growth, development, and structural patterns during the immature
formative years of a commercial species is essential to determine
correct thinning practices necessary to attain desired objectives.
This study compared a natural, medium-site Douglas-fir stand
and an adjacent similar stand released...
Field and greenhouse bioassays were used to compare the mycorrhizal associations of Douglas-fir seedlings from undisturbed forests, and nonburned and burned portions of clearcuts on three Sites in the west-central Cascades of Oregon. Field soil transfers and greenhouse soil pasteurization and reinoculation were used to investigate soil biology and inoculum...
Pollen contamination was investigated in one block (block 4) of a 10-block Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard complex in western Oregon. Blocks (25 clones each) represent different breeding zones; thus, contaminant pollen sources not only included the adjacent natural stand of Douglas-fir, but also other blocks within the...