Date of Award:

5-1-1965

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Entomology

Committee Chair(s)

Donald W. Davis

Committee

Donald W. Davis

Committee

Orson S. Cannon

Committee

LeGrand C. Ellis

Abstract

Insects that destroy the seeds of forest trees have an important bearing on reforestation. If a high percentage of a seed crop is destroyed in any year, seed collecting may be unprofitable, and nursery establishment and planting will be greatly hampered. A loss of seed may seriously threaten the natural re-establishment of commercially valuable tree species particularly on turned or cutover lands, where timing of seeding may be highly critical (Keen, 1958). Douglas-fir is one of this country's most valuable timber trees. Presently in the western United States about 24 million acres of commercial forest land are classified as Douglas-fir type. In 1952, 11.9 billion board feet of Douglas fir were harvested in the United States. Much of this cutover land, as well as fire destroyed forest land, has failed to restock satisfactorily. In 1952 there were 2,929,000 acres of unstacked commercial forest land of the Douglas-fir type in California and the Pacific Northwest alone. This figure is slowly increasing.

Share

COinS