Treesearch

Meiosis in an F1; hybrid. of Pinus nigra and P. densiflora, which was polymorphic for seven enzyme loci, was examined. To test recombination, lO8 seeds were analyzed by using starch qel electrophoresis of extracts from the haploid tissue of female gametophytes. Three loci segregated independently: acid phosphatase 1, qlutamic oxaloacetic transaminase 3, and qlucose-6-phosphate dehydroqenase 1/2. The four linked loci were alcohol debydroqenase 1, alcohol dehydroqenase 2, glucose-6-phosphate denydroqenase 2, and leucine aminopeptidase 2, arranqed in that order. The recombination percentages...

Tree diameter outside bark at an earlier period of growth can be estimated from the linear relationship of present inside bark and outside bark diameters at breast height. This note presents equations for estimating inside bark diameters, outside bark diameters, and past outside bark diameters for each of the mixed-conifer species in the central Sierra Nevada.

Given the polyploid chromosome constitution of Sequoia sempervirens, there was reason to question whether it would exhibit inbreeding depression. Preliminary results from studies of self and related outcross families are reported as a guide to the selection of trees for redwood seed orchards and breeding-orchards. The data indicate that, compared to outcrosses, selfing produced no additional cone abortion, no consistent effect on number of seeds per cone, and variable effects on germination. Consequently,there relative proportions of inbred and outcrossed offspring produced are normally...

During a 5-week study of the Nihoa Millerbird and Nihoa Finch, we censused birds using these techniques: two line transect methods, a variable-distance circular plot method, and spot-mapping of territories (millerbirds only). Densities derived from these methods varied greatly. Due to differences in behavior, it appeared that the two species reacted differently to the observer. Millerbirds appeared to be attracted to a moving observer, perhaps to forage on insects; finches appeared to be attracted to a stationary observer in order to feed on seabird eggs temporarily abandoned during the...

Age ratios and abundance of 61 migrant passerine species comprising more than 42,000 birds were analyzed in an attempt to determine patterns of migration. The data were collected at 10 stations from coastal Massachusetts to inland Pennsylvania. Age ratios are thought to be useful in determining routes of migration. The principal criteria for the edge of a species' route are suggested to be a higher proportion of young and a lower density of the species than in other areas. Almost all species in this area fell readily into 1 of 5 patterns that suggest 5 possible routes: (1) immediately...

Intensive variable distance circular-plot censuses and timed activity budget data were used to compare the effects of conspicuousness upon census results. In six of ten species no correlation was found, suggesting that all birds within the "Effective Detection Distance" (EDD) were seen. In four species there were significant correlations. Multiple regression analyses confirmed these results. Generally larger correlations were found with the number of birds per station than with density per ha; the latter is presumed to correct for changes in conspicuousness, possibly through changes in the...

Hundreds of papers, such as those presented in this volume, are produced annually by workers using various techniques. The purpose of this section is twofold: (1) to provide for readers unfamiliar with counting techniques a handy guide to the most common terms and methods used in the field; and (2) to attempt to set a consensus on the meanings of some terms that are too commonly used interchangeably in the literature. I have not attempted to set arbitrary standards here; rather, if two or more terms are commonly used to apply to the same method or unit, and if each is unambiguous, then I...

Counting birds has a long tradition. Since early in human history, man has noted and recorded the presence, absence, and abundance of birds. This long, and presumably honorable, pursuit that we all engage in, to a greater or lesser extent, is the common currency of many ornithological studies. These studies range from multiple regression analyses of habitat variables to life history studies.

Spatial data on wildland resource maps and aerial photographs can be analyzed by computer after digitizing. SCANIT is a computerized system for encoding such data in digital form. The system, consisting of a collection of computer programs and subroutines, provides a powerful and versatile tool for a variety of resource analyses. SCANIT also may be converted easily to another computer system. As a highly automated system, SCANIT requires a substantial investment in specialized instruments and assumes a central facility with a raster scanner and a minicomputer to serve many users. The...

This directory lists 120 documentation services concerned with forestry, forest products, or related fields in 28 countries. The entry for each service includes title of service, cost, publisher, subject coverage, formatting data, input sources, indexing and data-handling methods, and availability of special services other than the primary ones of indexing and abstracting.