First year survival of Douglas-fir seedlings outplanted in areas
characterized by intense vegetative competition is heavily dependent
on available soil moisture. To test this hypothesis, five distinct
classes of Douglas-fir planting stock were planted on the south slope
of McCulloch Peak in McDonald Forest in February of 1975. The
stocking...
Fine roots are a dynamic component of Douglas-fir ecosystems. Changes in standing crops indicate that fine roots require a major portion of the stand's energy resources to fulfill their role in the
functioning of these systems. We observed standing crops of live and dead fine (< 1 mm diameter) and...
Cercocarpus ledifolius (curlleaf mountain- mahogany), a small, hardwood evergreen tree, was studied to provide information on germination and initial seedling growth characteristics, and the species' relationship to its environment.and associated vegetation. Exceptional germination for this species resulted from both a wet cold treatment at 4°C for 170 days (88 percent),...
An apparatus was designed to permit freezing tests of
needles and other tissue parts from coniferous trees under
controlled rates of temperature change with time. The design
is based on the principle of a balanced system of refrigeration
demand and heat input to achieve a steady temperature state.
The apparatus...
Root biomass studies were conducted in an old-growth stand of
conifers in the western Cascades of Oregon. The root systems of three
Douglas-firs (Pseudotsuga menziesii var. menziesii (Mirb. ) Franco)
with diameters at breast height of 94, 110, and 135 cm were excavated
and weighed to provide a basis for...
The relative freezing resistance of tissues in the stem, foliage and buds of terminal twigs from Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was investigated at about ten-day intervals from summer until the following spring. Tissues from growing twigs collected before development of dormancy had no freezing resistance and were killed immediately...
Western redcedar, western hemlock, and Douglas-fir seedlings were transplanted into pots in one of two soils representative of high and low levels of available NO3 (and total N). The soils were collected from sites at Cascade Head (Oregon Coast) and Wind River (Washington Cascades). Whole plant and component relative dry...
Oscilloscope display of modification of a square wave signal passed through stem tissue was evaluated as a means of detecting depth of dormancy and survival potential of coniferous seedlings. Trace form did not change during release from deep dormancy in Douglas fir. This release was judged by observing speed of...
The succession of plants over a period of 25 years was analyzed on clearcut areas in the western Cascades of Washington and Oregon. Thirty-three paired burned and unburned plots were reexamined in 1975. Data were combined with records from prior examinations by Morris (1970). Cover trends of six major brush...