Treesearch

In a 40-year-old western white pine plantation developed as a seed production area, heavy thinning and application of fertilizer in the fall significantly increased strobilus production the following spring. Applying fertilizer increased seed weight and cone length significantly, but thinning did not. Insects severely damaged the cone crop in the thinned stand. This study indicates that abundant seed crops, relatively free from insect damage, may be produced without expensive thinning and area preparation operations.

Tree losses resulting from infestation by the mountain pine beetle (Dendroctonus ponderosae Hopkins) were measured in two stands of lodgepole pine (Pinus contorta Dougl.) where the beetle population had previously been epidemic. Measurement data showed that larger diameter trees were infested and killed first. Tree losses ranged from 1 percent of trees 4 inches (d.b.h.) to 87 percent of those 16 inches and greater d.b.h. Numbers of adult beetle emergence holes averaged 1.3 per square foot of bark area in trees 7 inches d.b.h. and 62 in trees 28 inches and greater d.b.h. The observations...

In the central Rocky Mountains, some pattern of clearcutting has generally been the initial step in converting old-growth stands of Engelmann spruce (Picea engelmannii Parry) subalpine fir (Abies lasiocarpa (Hook.) Nutt.) into manageable stands of young growing stock. Low stumpage values coupled with the difficulty of establishing artificial regeneration have made restocking clearcut areas with natural regeneration a fundamental objective in spruce-fir management.

The forest vegetation of the northern Rocky Mountains is potentially a rather simple mosaic determined by macroclimate, microclimate, soil fertility and soil drainage. In actuality, however, the vegetation consists mainly of a wide variety of intergrading, disturbance-induced communities that are difficult to treat except as developmental series related to specific climaxes. These relatively stable units, the associations, are defined primarily on the basis of the relative reproductive success of trees, as this indicates which species will become self-perpetuating dominants of the overstory...

Nearly everywhere in eastern Washington and northern Idaho as one leaves the steppe at the foot of the mountains and enters the forest, the first coniferous tree encountered is Pinus ponderosa. The ability of this species to endure dry climates· well exceeds that of our next most drouth-tolerant conifer, Pseudotsuga menziesii. Therefore, typically a belt of climax pine forest separates steppe from Pseudotsuga forest. Pinus ponderosa does indeed extend farther up the moisture-temperature gradient than this marginal belt in which no other tree challenges its supremacy. But there it either...

Spring peak flows recorded over a 25-year period in Benton Creek, a small forested watershed in northern Idaho, were studied in their relation to meteorological events. More peak flows were generated by rain-on-snow than by clear-weather snowmelt; the two types of peaks differ in magnitude and in other characteristics. Two rather simple techniques were used to calculate the generative capacity of a rainfall-temperature event and the hypothetical outflow of water from a snowpack during rainy and rainfree periods. Similar data on spring peaks on two regional subbasins were considered also.

Fries (1821) established Tribe xxii, Pholiota of Agaricus, for many of the species here placed in the genus Pholiota. The history of the genus may be said to start from this publication since it is the official starting date for the nomenclature of agarics. Although the Greek word Pholiota means scale, some glabrous species such as Agaricus caperatus were admitted to the group. He included sixteen species, some of which (e.g., P. aurivella, P. adiposa, P. flammans, P. squarrosa and P. mutabilis) are still included.

This paper describes some xylem characteristics of the more important shrub species of the Northern Rockies and presents a key for identifying shrub-wood specimens by microscopic characters. The paper contains photomicrographs of 55 shrub woods.

In one test, 45 out of 318 (14 percent) needle fascicles from 2-year-old seedlings of Pinus monticola Dougl. were rooted. Eight of the needle fascicles produced shoot growth. In another test, 392 out of 742 (53 percent) needle fascicles were rooted, but none of these produced shoot growth.

The usefulness of stand density index (SDI) has been limited by lack of a way to partition its nonlinear expression into additive components to describe the relative stocking of a stand by species or quality classes. In this paper, a linear equation is derived to permit such a partition. A closely related expression for grand fir stocking is given that retains the merits of SDI, but is more nearly proportional to growth of individual trees within a stand. Hence, the partitioning of stocking into components will be more meaningful to the forest manager with this revised form.