Perennial woody plants have a complex annual cycle keyed to the environment. Temperate plants have an annual dormant period commonly broken by exposure to low temperatures, although daily photoperiods of 16 hours or longer may partially substitute for the chilling. Shoot growth in the spring is normally stimulated by rising...
"We describe a test procedure developed during growth room and field trials for which we processed hundreds of test lots of seedlings, mainly Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa), as well as lodgepole pine (Pinus contorta), Jeffrey pine (Pinus jeffreyi), and Sitka spruce (Picea sitchensis), noble fir (Abies...
Results reported here are from a large study designed to evaluate the effects of certain nursery procedures on subsequent survival of Douglas-fir seedlings. The effects of storage conditions and lifting dates were reported elsewhere (9). The determination of the optimum size of seedling for planting on different sites has been...
Reforestation sometimes is delayed by planting seedlings that do not have high potential for survival. Several factors influence survival. Unstored Douglas-fir lifted and planted in early fall generally are increasingly harmed by moisture stress the farther south in the Douglas-fir region they are. Such early-lifted seedlings are harmed even more...
Although the Douglas-fir region of the northwestern United States and British Columbia is frequently considered to have a common silviculture, obstacles to successful regeneration of the species range from competing vegetation and mammals on the mesic sites to extreme drought and heat on the xeric southerly exposures in northern California...
The effects of a range of thermoperiods and soil temperatures upon growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were studied. The seeds, of varieties glauca and menziesii, came from eight widely separated areas. Plants from both varieties made maximum growth with soil and air temperatures between 18 and 24...
The Dwight L. Phipps State Forest Nursery at Elkton annually supplies 22 million 2-0
Douglas-fir seedlings to Oregon land managers. Some managers report excellent success in
planting, but others report failures, particularly when planting late in the season. In some
instances poor survival seemed to be related to storage.
Physiological...
The effect of lifting Douglas-fir seedlings from the nursery bed
and replanting them, either immediately or after storage at 2 C for
periods up to six weeks, was investigated through a series of experiments
conducted in controlled-environment chambers and under field
conditions. Seedlings lifted prior to December, or after buds...
In recent years much of the logging in the Douglas fir region has been by the staggered setting system. Consequently, the effects of this system upon natural coniferous regeneration have become increasingly important. This study was designed to analyze the effects of setting size and environmental factors upon natural regeneration...
To determine if squirrels (Sciurus douglasii var.) cut cones before the seeds are ripe, a series of collection points was established in the Willamette Valley and the Cascade Mountains in the summer of 1954. The areas were inspected at intervals during August, September and October of 1954, and freshly cut...