Treesearch

When overmature conifers die and deteriorate gradually while standing, a mound of decayed wood builds up about the base of the stem. When such trees fall to the ground, similar material is laid down along the path where the tree fell. Further deterioration results in low mounds or ridges of decayed wood in a state of semi-incorporation with the soil. Depending on the state of decomposition, structure of this organic material may vary from cubical, crumbly yet identifiable wood remains to red-brown masses of finely divided material (fig. 1A).

Records from a mature Douglas-fir stand on the Mount Hood National Forest in northwestern Oregon indicate that very high rates of gross growth are maintained up to ages as high as 250 years. Where such stands are held in reserve for future clear cutting, forest managers have an opportunity to recapture a large share of this gross production by salvaging mortality at frequent intervals.

Land managers often express a need for more complete information about the vegetative cover that develops on cutover areas between harvest of old-growth Douglas-fir (Pseudotsuga menziesii) and establishment of a young-growth forest. The composition and density of this cover frequently determines the management techniques that must be used to establish the new stand and provide for watershed and wildlife resources. This paper presents data on the frequency of occurrence of shrub and herbaceous species during the first 6 years after logging and slash burning. The study was made on 14...

Germinative capacity of loblolly, shortleaf, and Virginia pine may be seriously reduced if the seed is repellent-coated and then stratified when fresh. In contrast, cold storage for a few months may largely forestall damage from later repellent treatment and stratification.

An adaptation in the use of Lemmon's spherical densiometer, has been developed to measure low overstory crown foliage as intercept above a line transect. This adaptation provides added information for the evaluation of ecological relationships within and among plant communities where some species are too low for overstory density estimates and too high for direct intercept measurements, e.g., mountain mahogany (Cercocarpus ledifolius) and western juniper (Juniperus occidentalis).

Many range technicians, agronomists, foresters, biologists, and botanists of various educational institutions and government agencies in the Northwest have been using a four-letter symbol list or code compiled 12 years ago from records of plants collected by the U.S. Forest Service in Oregon and Washington, This code has served well as a means of entering plant names on crowded field sheets without requiring a lot of memorization, In this respect it has proved superior to the old three-letter symbol list. Yet, about 400 changes in nomenclature have occurred since 1948 among the plants...

Increasing interest in the management of red alder (Alnus rubra) has created a need for reliable yield information. Existing yield tables for red alder have been very useful as interim sources of information, but they are generally inadequate for current and prospective management needs. The advisory committee for the Station's Olympia Research Center, at the suggestion of several members, sponsored a subcommittee to promote the construction of new tables suitable for regionwide application. Through cooperative efforts of both public and private forestry organizations, the project was...

A number of investigations have shown that treatment with gibberellic acid can replace the cold period required to break dormancy in certain seeds. In several instances, acid treatment has also caused significant increases in the root and top growth of seedlings. This combination of abilities suggests that the use of gibberellic acid in reseeding bitterbrush merits serious consideration.

Photo-mensuration techniques are often used in obtaining elevation differences in areas where topographic maps are unavailable. These differences can be obtained with simple instruments such as the parallax wedge or the parallax bar. Although the accuracy of measurements with this equipment is not as high as that obtained with the complicated plotting instruments used in topographic mapping, past experience has shown that elevation differences can be measured within k10 percent two out of three times.

A large proportion of present-day timber cruising is done by measuring or estimating three tree dimensions: diameter at breast height, form class, and merchantable height. Tree volumes are then determined from tables which equate volume to the varying combinations of height, d.b.h., and form class. Assumptions concerning merchantable height were made in constructing the volume tables, and although these assumptions were probably correct at the time the tables were developed, they may now be in error. Standards of utilization change, and the merchantable height of the past may not be the...