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Smog injury, root diseases and bark beetle damage in ponderosa pine

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Authors

R. W. Stark, University of California
F. W. Cobb, University of California

Publication Information

California Agriculture 23(9):13-15.

Published September 01, 1969

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Abstract

Photochemical oxidants (smog) are causing serious injury to ponderosa pine in the San Bernardino Mountains of southern California. Apparently, smog injury also renders the trees more susceptible to attack by two species of destructive forest insects, the western pine beetle, Dendroctonus brevicomis, and the mountain pine beetle, D. ponderosae. Recent studies have shown that photochemical oxidant injury to ponderosa pine results in reduced oleoresin yield, rate of flow and exudation pressure, sapwood and phloem moisture content and phloem thickness, all of which are believed important in the defense of the tree against bark beetles. Smog injury also affects growth rate and probably wood quality. Soluble sugars and reserve polysaccharides were reduced in diseased trees. Current studies indicate that similar injuries to ponderosa pine, with resulting increase in bark beetle attack, occur as a result of infection by root disease fungi, notably Fomes annosus and Verticicladiella wagenerii.

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Smog injury, root diseases and bark beetle damage in ponderosa pine

R. W. Stark, F. W. Cobb
Webmaster Email: wsuckow@ucanr.edu

Smog injury, root diseases and bark beetle damage in ponderosa pine

Share using any of the popular social networks Share by sending an email Print article
Share using any of the popular social networks Share by sending an email Print article

Authors

R. W. Stark, University of California
F. W. Cobb, University of California

Publication Information

California Agriculture 23(9):13-15.

Published September 01, 1969

PDF  |  Citation  |  Permissions

Author Affiliations show

Abstract

Photochemical oxidants (smog) are causing serious injury to ponderosa pine in the San Bernardino Mountains of southern California. Apparently, smog injury also renders the trees more susceptible to attack by two species of destructive forest insects, the western pine beetle, Dendroctonus brevicomis, and the mountain pine beetle, D. ponderosae. Recent studies have shown that photochemical oxidant injury to ponderosa pine results in reduced oleoresin yield, rate of flow and exudation pressure, sapwood and phloem moisture content and phloem thickness, all of which are believed important in the defense of the tree against bark beetles. Smog injury also affects growth rate and probably wood quality. Soluble sugars and reserve polysaccharides were reduced in diseased trees. Current studies indicate that similar injuries to ponderosa pine, with resulting increase in bark beetle attack, occur as a result of infection by root disease fungi, notably Fomes annosus and Verticicladiella wagenerii.

Full text

Full text is available in PDF.

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