Treesearch

The past five years have seen a very rapid expansion in the use of tractors for logging in the pine region of California. In 1923, when a previous bulletin of this series was published, steam donkey yarding, with which that study treated, was the prevailing method of yarding. During the season of 1928 probably not less than 60 percent of the timber output of this region was yarded with tractors of the track-laying type. This remarkable increase in the use of tractors has come about largely for two reasons: First, the power employed is split up into several units with the attendant possibili...

A large number of foresters, forest entomologists and others are now making use of the increment borer to investigate the effects of cutting, fire damage and other factors on tree growth, or the relation between tree vigor and insect attacks, besides many other factors. The measurement of increment cores economically with consistent accuracy is usually the most difficult part of such work. A brief description of a simple instrument that has proved helpful in District 5 of the Forest Service may be found interesting

Individuality in man is accepted without question. In domestic animals, also, good and bad individuals are generally recognized. Even in some cultivated plants —orange trees and rubber trees— the poor producers are searched out and eliminated. Indeed, individual variability is a normal condition in all groups of organisms. Yet forest trees are rarely thought of in terms of the individual. Forest products are seldom of sufficient value to justify tending the individual tree. But there is no more reason why two western yellow pine trees should grow with equal rapidity or bear equal amounts...

With a view to securing reliable data on the effects of cutting on growth and reproduction as a basis for revision of marking rules, the Forest Service about 10 years ago initiated a study of cut-over areas in the national forests of California. Some results of the study are presented to show what has actually been accomplished as a basis for sound future development in methods of cutting.

Sugar pine (Pinus lambertiana Dougl.) was first recognized by David Douglas, of the London Horticultural Society, on the headwaters of the Umpqua River in Oregon, October 26, 1826. The tree was given the specific name lambertiana in honor of Douglas's friend Aylmer Bourke Lambert, a founder and vice president of the Linnean Society of London and the author of a prominent work on pines. Sugar pine is the most valuable commercial timber tree on the Pacific coast, and its relative value among all the conifers of the world is very high. This is attributable partly to the characteristic...

Over five billion birds move each year across the Americas, flying great distances over almost every location and habitat on the continents (Weidensaul 1999). Over 350 of the over 800 bird species in the United States migrate each year to Latin America and the Caribbean (Degraaf and Rappole 1995). Some fly each way over 4000 miles, chasing the seasons across oceans and continents (Weidensaul 1999). In addition, migratory birds are very important to Americans. Over 75 million Americans participate in bird watching, photography, hunting, nature study, and feeding. These Americans support...

Highways cause significant impacts to birds in four ways: direct mortality, indirect mortality, habitat fragmentation, and disturbance. In this paper I discuss highway-related impacts, and suggest solutions from a highway management perspective. Non-flying birds (either behaviorally or structurally) such as gallinaceous birds and ducklings; waterbirds such as terns; owls; ground-nesters; scavengers; Neotropical overwater migrants; frugivorous birds; and birds attracted to salt are often killed from highway-related causes. Suggested solutions include highway crossing structures, diversion...