Treesearch

An interdisciplinary approach to resistance breeding is discussed with emphasis placed on documenting genetic variation and developing an understanding of the causal mechanisms responsible for variation in host susceptibility. The specific features and effectiveness of phenotypic and genetic selection are contrasted and examples of documented genetic variation in susceptibility of trees to insects are provided.

Both gypsy morh host preferences and the foliage characteristics thaL have been implicated as factors in host selection were monitored from 1979 to 1982 in a Quercus-Acer-Ostrya forest near Montreal, Quebec. The preliminary analyses of these data suggest the hypothesis that gypsy moth larvae preferentially attack trees that have high sugar:tannin ratios in their young foliage.

This guide shows, in 110 photos, how discoloration and decay form in trees. An expanded concept of tree decay is given. After wounding, trees form boundaries to resist the spread of pathogens. The boundary-setting defense process is called compartmentalization, and model of the process is CODIT. The expanded concept and the model are used to reexamine many other tree problems. Defects are major causes of low quality in trees. Use of the information in the guide can help foresters and urban foresters to grow healthier, higher-quality trees.

Spruce budworm larvae grew faster than gypsy moth larvae both in a temporal and relative sense. The budworm larvae had a higher relative growth rate (RGR), biomass conversion efficiency (EGI), and nitrogen utilization efficiency (NOE) than the gypsy moth larvae. As both species matured, relative growth rates, rates of consumption, and conversion efficiencies declined. The differences between species and the decline in rates with maturation are, at least partially. allometric (related to body size). The relationship can be expressed by the equation y = aXb, where y is the rate of the...

Manufacturers of furniture and cabinets use more than 2 billion board feet of hardwood lumber annually. As demand intensifies, we will need to utilize more of the abundant lower grade hardwood resource to assure future supplies at reasonable prices. Conventional processing of standard-size hardwood blanks manufactured from log-run red oak lumber, a resource containing over 40-percent low-grade No. 2 Common lumber, has been shown to be technically and economically feasible. Internal rates of return from 26 to 40 percent are possible when blanks are produced for outside sales or to replace...

Manufacturers of furniture and cabinets normally use over 2 billion board feet of hardwood lumber or about one-third of all hardwood lumber demanded each year. Although the current market for hardwood lumber reflects the overall economic downturn, competition for limited better grade hardwood resources will intensify when the economy improves. So, we need to improve the utilization of the abundant lower grade hardwood resource to assure adequate supplies at reasonable prices. A breakthrough toward this end came when we found that nearly all of the thousands of individual dimension-part...

Information about the attitudes and objectives of the private forest-land owners is essential to understanding New York's forest resources. Ninety-four percent of New York's 15.4 million acres of commercial forest land is in 506,500 private ownerships. Eighty-nine percent of these ownerships are individual and joint ownerships. A majority, 66 percent of these owners, live within a mile of their nearest tract and 84 percent own only one tract. Benefits other than timber production are most important to New York's landowners, but 45 percent of the ownerships have harvested timber from their...