Reduction of pocket gopher damage to conifer seedlings is important to successful reforestation in many regions of the Pacific
Northwest. The objective of this study was to determine the factors that influence the local distribution of the northern pocket gopher (Thomomys talpoides Richardson) in a forested region of south-central Oregon....
The capacity for root growth and concentration of indole-3-acetic acid and abscisic acid in the roots of western hemlock seedlings was investigated. The root regenerating capacity (RRC) was defined as the increase in root length, greater than 5 mm, following a 28-day test period. RRC measurements over a two-year period...
The objectives of this investigation were two-fold: (1) to examine possible seed and cone characteristics and their usefulness as seed maturity indices, and (2) to examine the effects of artificial ripening on seed maturation and germination. Cone fresh weight, cone length, cone specific gravity, cone color, seed fresh weight, seed...
Roots are considered to be the major production site of amino acids that appear in the xylem sap of conifers. The carbon skeleton of amino acids is derived from photosynthetically reduced carbon dioxide while the nitrogen is derived from the inorganic forms taken up by the roots. An experiment was...
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...
Snags, standing dead trees, are used by many species of wildlife. Despite the importance of snags their basic ecology remains unknown.
Some forest management practices eliminate snags from the forest with a concomitant effect upon snag-dependent wildlife. My objective was to describe the density, spatial distribution, and physical character of...
The vegetation following forest site preparation was examined in ten clearcut units located in the western Oregon Coast Range. The site preparation techniques used in these units included scarification, slash burning, and chemical spraying. The ages of the clearcut units studied varied from one to nine growing seasons for the...
From a preliminary 1969 foliar analysis, eight provenances were chosen from the sixteen included in a region-wide, reciprocal Doulgas-fir provenance study for further study of variation in foliar nutrition. In the fall of 1969 separate foliar samples were collected from ten
trees per provenance at each of ten plantations ranging...
This study was divided into two parts. Part I was a quantitative description of some aspects of plant-water relations in Douglas-fir seedlings, and part II was tests of several techniques of screening selected families of Douglas-fir seedlings for drought resistance. Part I. During 20 mild summer days in 1976 at...
Foliage of Douglas-fir seedlings [Pseudotsuga menziesii (Mirb.) Franco] from two contrasting environments was sampled during progressive stages of two consecutive cycles of induced drought for leaf resistance, plant water potential , and abscisic acid content (ABA). One group of seedlings was placed in a controlled environment room while another group...