Weather and Tree Growth Associated with White Fir Mortality Caused by Fir Engraver and Roundheaded Fir Borer

Weather and Tree Growth Associated with White Fir Mortality Caused by Fir Engraver and Roundheaded Fir Borer

Author: Craig D. Whitesell

Publisher:

Published: 1974

Total Pages: 182

ISBN-13:

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Ohia forest decline-its severity and rate of spread-was studied by aerial photographic techniques on a 197,000-acre (80,000-ha) portion of the island of Hawaii. In 1954, only 300 acres (121 ha) showed signs of severe decline; by 1972, the acreage of severely affected forest had increased to 85,200 acres (34,480 ha). Rate of decline and current severity were related to mean annual precipitation and to elevation. The epidemic is continuing. Some forests on other Hawaiian islands also display decline symptoms.


Forest Insects

Forest Insects

Author: Alan A. Berryman

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 284

ISBN-13: 1468450808

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This book is intended as a general text for undergraduates studying the manage ment of forest insect pests. It is divided into four parts: insects, ecology, manage ment, and practice. Part I, Insects, contains two chapters. The first is intended to provide an overview of the general attributes of insects. Recognizing that it is impossible to adequately treat such a diverse and complex group of organisms in such a short space, I have attempted to highlight those insectan characteristics that make them difficult animals to combat. I have also tried to expose the insects' weak points, those attributes that make them vulnerable to manipulation by human actions. Even so, this first chapter will seem inadequate and sketchy to many of my colleagues. Ideally, this book should be used in conjunction with a laboratory manual covering insect anatomy, physiology, biology, behavior, and classifica tion in much greater depth-in fact, this is how I organize my forest entomology course. It is hoped that this first chapter will provide nonentomologists with a general feel for the insects and with a broad understanding of their strengths and weaknesses, while Chapter 2 will provide a brief overview of the diverse insect fauna that attacks the various parts of forest trees and their products.


Using Indicator Plants to Assess Susceptibility of California Red Fir and White Fir to the Fir Engraver Beetle

Using Indicator Plants to Assess Susceptibility of California Red Fir and White Fir to the Fir Engraver Beetle

Author: George T. Ferrell

Publisher:

Published: 1986

Total Pages: 6

ISBN-13:

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Using a Vegetation Drought Index (VDI) for estimating the susceptibility of California red and white firs to the fir engraver beetle (Scolytus ventralis) was evaluated in northern California forests where these true firs (Abies species) occur in mixed conifer and true fir stands. Midway through the summer drought, true fir moisture stress-a known predisposing factor-was highest on sites with highest VDI values (most xeric). In mixed conifer stands, the susceptibility of white firs-as indicated by the mean percentage of their basal area killed annually-was highest on sites with highest VDI values. But in true fir stands, the susceptibility of mixed red and white firs was highest on sites with the lowest VDI values. Regression models with VDI, stand basal area, and percentage of true fir as regressors lacked the required predictive range and precision, suggesting that VDI will likely have to be used in combination with predictors other than, or in addition to, those analyzed.