Treesearch

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.

Crossing relationships were studies within and among the variable populations of Pinus muricata to test hypotheses about crossing barriers among certain populations. Crossability was assessed at the level of viable seed production following planned crosses. Populations north of Sea Ranch, Sonoma Co., California, crossed freely with parapatric but genetically distinct populations in central Sonoma Co., although some reduction in seed-set occurred in the F2 and backcrosses to F1. The distinctness of these adjacent poulations is most likely not maintained by post-pollination crossing barriers....

Allozyme differentiation at 32 loci was studied in the three Californian species of Pinus subsect. Oocarpae: P. attenuata, P. muricata, and P. radiata, and in a small sample of a Latin American species of the subsection, P. oocarpa. The Californian species were previously known to comprise highly differentiated, disjunct populations, but with uncertain phylogenetic relationships among several populations and species. All populations had clear affinities for single species. The controversial Channel Islands (Santa Cruz Island) population of P. muricata and the Mexican Island (Guadalupe and...

The lack of quality in symposia proceedings has recently been criticized by Bart and Anderson (1981). Their criticisms elicited 2 defenses of publishing symposia proceedings (Ca- pen 1982, Finch et al. 1982). These authors offered excellent suggestions for improving the quality of published proceedings: review papers before acceptance; use outside reviewers; request revisions; reject low quality papers; establish a strong organizing committee; and recognize proceedings as citable works. In this paper we build on these suggestions and offer additional guidelines for improving the quality of...

Comparisons between abnormal and normal sprout clumps of tanoak (Lithocarpus densiflorus [Hook. & Am.] Rehd.) in northern California indicated that sprouts in abnormal clumps had about five times the number of sprouts per dump, were three times as wide, and only one-fifth as tall. Stunted and chlorotic sprouts were examined for virus and disease organisms that might be used for biological control of this often weedy species. No pathogens or viruses that could account for the abnormal development were found in field or laboratory. but tests were not exhaustive. Decline could be from...

Regression equations to predict total and stem-only above-ground dry biomass for six species (Acacia melanoxylon, Albizio falcataria, Eucalyptus globulus, E. grandis, E. robusta, and E. urophylla) were developed by felling and measuring 2- to 6-year-old plantation trees on the island of Hawaii. Logarithmic transformations of the equations using diameter and height are recommended for estimating Albizia falcataria and E. grandis biomass, whereas logarithmic equations using diameter only are recommended for the other four species that have fewer sample trees collected from a single location.