Treesearch

Minute-by-minute analysis of point counts of birds in mixed-conifer forests in the Sierra National Forest, central California, showed that cumulative counts of species and individuals increased in a curvilinear fashion but did not reach asymptotes after 10 minutes of counting. Comparison of the expected number of individuals counted per hour with various combinations of counting time and noncounting times (for record keeping and travel between counting stations) showed that 10-minute counts were most efficient in most cases. Counting longer than 10 minutes is not recommended, because of...

DEBRIS is a menu-driven, interactive computer program written in FORTRAN 77 for recording and plotting survey data and for computing hydraulic variables and depths of scour and fill. It was developed for use with the USDA Forest Service's Data General computer system, with the AOS/VS operation system. By using menus, the operator does not need to know any programming language. the five routines are: entering data, plotting scour and fill, hydraulic variables, and computing x-y coordinates.

Trials have been established in Hawaii to develop spacing guidelines for Eucalyptus saligna plantations. Substantial competition-related mortality occurred in densely planted plots of three spacing trials. Data on stand diameter and surviving number of trees on these plots were plotted in logarithmic form to estimate a "self-thinning" or maximum diameter-stand density line. An "operating" maximum line was defined-one representing 70 percent of the total number of trees that could reach any given mean diameter if the stand were allowed to reach the "self-thinning" level. This information...

Eight-year-old Scotch pine (Pinus sylvestris) were severely infected by dwarf mistletoe (Arceuthobium occidentale) when planted near infected Digger pine (P. sabiniana) in the foothills of the northern Sierra Nevada, in California. But 6-year-old knobcone x Monterey (P. attenuata x P. radiata) hybrid pines in the same plantation were unifected. To prevent infection, avoid planting Scotch pines near native California pines bearing dwarf mistletoe.

Little is known about Elytrodema disease (Elytroderma deformans [Weir] Darker) in seedlings or very young trees. Of 100, 2-0 Jeffrey pine (Pinus jeffreyi Grev. & Balf.) seedlings planted in the Taylor Creek area of South Lake Tahoe, about half survived from 1973 to 1987. During this period about two thirds of the surviving seedlings became infected with Elytrodema disease. Of the trees that died, only three were infected with the disease, and none was infected before 1981-82. Earliest infection of surviving seedlings was in 1976, with 1980-81 the only interval without infection. More than...

Eucalyptus saligna trees grown in short-rotation plantations on the island of Hawaii were measured, harvested, and weighed to provide data for developing regression equations using non-destructive stand measurements. Regression analysis of the data from 190 trees in the 2.0- to 3.5-year range and 96 trees in the 4- to 6-year range related stem-only and total above-ground biomass to diameter at breast height and total height. Equations developed for each age class are recommended over equations developed for the combined data base (286 trees). For younger stands (<4-years) recommended...

Rangewide samples from mature natural stands of Pinus brutia Ten. subsp. brutia, subsp. stankewiczii (Sukaczew) Nahal, subsp. pithyusa (Stevenson) Nahal, and subsp. eldarica (Medw.) Nahal from throughout the eastern Mediterranean display a continuum of allozyme variation for 30 loci. Ten geographic samples of subsp. brutia from Greek islands of the eastern Aegean Sea, and from Turkey, Cyprus, and Iraq have a mean expected heterozygosity of 0.12 (range from 0.10 to 0.14) and similar allelic variation suggesting that they share a common gene pool with minor geographic differentiation....

Interspecific crosses of Abies religiosa (HBK.) Schlecht. & Cham, (oyamel) with Abies concolor (Gord. & Glend.) Lindl. ex Hildebr. var. concolor (white fir) and Abies magnifica A. Murr. (California red fir) were undertaken to explore the relationships between these species. The cross with A. magnifica produced no germinable seed, but many sound seeds were produced from the cross with A. concolor. These were sown in the nursery in 1968 and outplanted in 1970. In 1983, morphological characteristics of seven putative hybrids were compared with those of the A. concolor seed parent, herbarium...

Ponderosa pine's (Pinus ponderosa Laws.) geographic range is centered in the montane western United States, where it is the most widely adapted and ubiquitous conifer. A western variety, P. ponderosa var. ponderosa, extends from the mountains of southern California, northward, on the western and eastern sides of the Sierra Nevada-Cascade crest to Canada. It comes into contact with an eastern variety, P. ponderosa var. scopulorum Engelm., near the Continental Divide in west-central Montana. The eastern variety extends southward throughout mountains, plains, and basins to scattered stands in...

At many universities nationwide, the new discipline of conservation biology has sparked broad interest. Recently developed courses, like the field of conservation biology itself, have successfully brought together biologists from many disciplines, not just in one classroom, but united by an urgent goal–nature conservation.