The structuring of canopy arthropod communities was reviewed and investigated in relation to tree species diversity and its component factors, interspersion of different species and density of each tree species. Fifteen treatments of Douglas-fir (Pseudotsuga menziesii) and red alder (Alnus rubra) (various densities and proportions of each) were randomly assigned...
The biomass and the composition of 15 stands of red alder (Alnus rubra Bong.) on river bottom sites in western Oregon was measured during August and early September, 1969. These stands ranged in age from two to 64 years. Biomass was found to vary from 134 k/ha (kilograms per hectare)...
Dihydroquercetin [(2,3-trans)-3,3',4',5,7-pentahydroxyflavanonol]
was shown to be the precursor to the phenolic
stains that often develop in Douglas-fir [Pseudotsuga
menziesii (Mirb.) Franco] sapwood. Douglas-fir sapwood was
extracted with methanol and the methanol solubles were
fractionated by solvent partition, thin-layer chromatography,
silica-gel column chromatography, and Sephadex gelpermeation
chromatography. Tyrosinase, a commercially
available...
The authors varied the number of red alder retained with 300 Douglas-fir per acre on a high-quality site in coastal Oregon. Alder densities of 0, 20, 40, and 80 per acre were tested. The authors' fifth treatment eliminated nitrogen-fixing alder, but substantial nitrogen fertilizer. Treatment 6 had neither thinning nor...
Competitive interactions between Douglas-fir seedlings (Pseudotsuga menziesii), and seedlings of a nitrogen-fixing hardwood
associate, red alder (Alnus rubra), were investigated in an addition series experiment. The primary objective of the research was to identify and quantify key processes underlying intra- and interspecific competitive interactions of Douglas-fir and red alder seedlings....
When Douglas-fir and red alder grow in mixture, interactions between the two species can be competitive, facilitative, or a combination of both over time. A number of factors have recently led to increased interest in managing these two species together for commercial production, and ongoing investigations are yielding important information...
It doesn’t come easy! Does any of your woodland
property look like the alder stand at the left? If your goal
is to convert this kind of ground to a productive conifer
forest, you should know it can be a challenging task.
You’ll have to do something with all that...