Treesearch

An outbreak of the balsam woolly aphid (Chermes piceae Ratz.) is damaging and killing Pacific silver fir, subalpine fir, and grand fir extensively in western Washington and Oregon. It is most serious in southern Washington where an outbreak on Pacific silver fir was discovered in 1954. Since effective methods for controlling this insect under forest conditions have not yet been developed, all that can now be done to minimize its destruction is to salvage the dead and dying trees. Because of rapid deterioration of dead timber, early detection of infestation is essential to enable logging of...

Many thousands of acres of young Douglas-fir stands in western Washington are ready for commercial thinning. This is true even after liberal allowance is made for premerchantable and under stocked stands, unfavorable topography, and lack of markets. However, with but few exceptions, regular systematic thinning is not being practiced even in favorably located, operable stands.

In 1956, a summary of references on Pacific Northwest forest soils research was developed to begin a systematic annual recording of regionally published material in this comparatively new field. This summary included references for all years through 1955.

In 1947, an outbreak of silver fir beetles, Pseudohylesinus grandis Sw. and P. granulatus (Lec.), was discovered in northwestern Washington. The epidemic flourished for the next six years, killing some 525 million board-feet of Pacific silver fir, Abies amabilis (Dougl.) Forbes. Prior to 1947, the silver fir beetles were considered to be of little economic importance because they had been observed to attack only slash, windthrows, and suppressed or otherwise weakened trees. While the recent destructive outbreak was in progress, it was reasoned that some factor or factors might have...

The Hemlock Experimental Forest near Grays Harbor in western Washington was established in 1949 in cooperation with the St. Regis Paper Company. A major effort in this cooperative research program is a study of commercial thinning in a stand of nearly pure, well stocked, even-aged western hemlock that originated in 1903, after logging.

A survey of ponderosa pine needle blight during 1955 and 1956, principally in eastern Oregon (where the disease is much more abundant than in Washington), provided information on extent of damage and on association of infection with certain environmental factors. Observations were largely confined to localities where the disease was known to be more than ordinarily common, and further bias was caused by restriction of the survey to the immediate vicinity of roads. Results, however, were in fairly close agreement with estimates by local foresters and with information from other sources, and...

Estimation of basal area by prisms offers intriguing possibilities for reducing time and effort in making stand inventories. Increased inventory efficiency is a particular need in stands that are relatively low in value due to small stems, predominance of low value species or heavy defect. In the Pacific Northwest, lodgepole pine characteristically forms dense low-volume stands with many small stems. Accordingly, during the course of a 1956 survey of lodgepole pine stands in the Blue Mountains of northeast Oregon, data were collected to compare prism estimation of basal area with a...

Considerable study has been made of the effects of logging and slash burning on chemical and physical properties of forest soils. However, little is known of the effect of such operations on microbiological properties.

Cleft grafting ponderosa pine proved best of five methods of vegetative propagation tested for field use in the dry hot climate of eastern Oregon. Ponderosa pine has been successfully grafted under many conditions elsewhere, but first trials in this area during 1955 were a failure. This study was made in 1956 at the U.S. Forest Service nursery at Bend, Oreg., to find a field method suitable for propagation of plus-tree stock.

Well-stocked patches of vigorous advance reproduction are found in many deteriorating old-growth stands in southwestern Oregon. If carefully released from the over story, this reproduction can shorten the rotation length of the next crop by many years. Often sugar pine is the fastest-growing component of the reproduction, but it is frequently infected with blister rust. Should a sanitation pruning be made to save these trees within areas being managed for sugar pine? A 1952 survey on the South Umpqua Experimental Forest in 1952 indicated that the number of sugar pine crop trees could...