Treesearch

As a first step in acquiring genetic information about oak species indigenous to California's hardwood rangelands we drew on experience from both forest regeneration and species conservation and applied biochemical techniques for rapidly assaying patterns of genetic variation. In a study sponsored by the California Integrated Hardwood Range Management Program we sampled 860 trees from 29 populations of three species of oaks spanning their distribution in California. Using leaf tissue collected from each tree we performed starch gel electrophoresis to assay allozymic variation within and...

A conceptual model of hardwood rangelands as multi-output resource system is developed and used to achieve a synthesis of Integrated Hardwood Range Management Program (IHRMP) research. The model requires the definition of state variables which characterize the system at any time, processes that move the system to different states, outputs (at the site and the landscape level) which are produced by processes as the system changes state and values which are derived from outputs or directly from the system's state. Processes can be further categorized as intensive (i.e. involving function...

A number of educational projects which focus on youth awareness and involvement with California oaks have been developed during the last five years. Primarily used in urban areas where oak populations have declined, many of these programs promote seedling propagation, tree planting and help to develop student understanding of environmental issues involving oaks while also promoting acquisition of stewardship values. A review and discussion of programs which feature oak awareness and participatory opportunities are provided. These programs could serve as models for groups involving youth in...

A long-term thinning study was established in ten stands of coast live oak (Quercus agrifolia Née) in the Central Coast of California. Information about diameter, basal area, and volume growth and yield has been obtained from unthinned control plots and from plots thinned to 50 and 100 square feet of basal area per acre measured in 1984 and 1989. Both basal area and total volume growth percentages were significantly greater in the thinned plots compared to the control plots. A preliminary economic analysis indicates the potential for modest returns on a thinning operation similar to this...

Over 2,000 acorns of Quercus agrifolia (coast live oak) and over 500 acorns of Q. engelmannii (Engelmann oak) were collected in the Jim Knight pasture area of the Santa Rosa Plateau. These were used to test for temperature and moisture conditions on germination of viable acorns in the laboratory under controlled environmental conditions. At 24°C Q. engelmannii had almost 90 percent germination after 6 days, while Q. agrifolia had about 20 percent (96 percent after 20 days). At 14°C completeness and speed of germination of Q. engelmannii was reduced to about 80 percent after 36 days, while...

We set up experiments at four locations in northern California to demonstrate minimum input techniques for restocking valley oak, Quercus lobata. Overall emergence of acorns planted in 1989 ranged from 47 to 61 percent. Use of supplemental irrigation had a significant positive effect on seedling growth at two of three sites. Mulch, of organic materials or polypropylene landscape fabric, significantly increased growth at all four locations. Seedlings enclosed in individual wire cages were effectively protected from browsing by deer or cattle.

During 1989 in east-central San Luis Obispo County, California, we studied the relationship of valley oak (Quercus lobata) and blue oak (Q. douglasii) acorn planting depth and number of acorns per planting site to acorn depredation, seedling emergence, survival, and height. Acorns were planted at three depths (1.3, 5.1, and 10.2 cm) at each of 960 planting sites with one or three acorns per site. Animal depredation of acorns was significantly (P < 0.05) greater for valley oak and seedling emergence and survival were significantly higher for blue oak. depredation of valley oak acorns...

Canopy effects and annual vegetation have been shown to strongly influence oak seedling survival. From the many elements composing canopy, shade was selected for experimental manipulation. A split-plot, multifactorial experiment was designed to test whether blue oak (Quercus douglasii) and coast live oak (Q. agrifolia) could establish seedlings in annual grasslands outside of canopy influence, and if there were differences in the responses of the two species to shade and sun treatments. All herbivory was excluded from three plots. All plots were constructed outside of direct canopy...

As part of an ongoing study of oak ecology in Sonoma County, California, we have begun to evaluate various environmental factors relative to oak seedling establishment at Annadel State Park. These factors, identified at three spatial scales (macro, meso and microscales), were correlated with the presence of oak seedlings in two contrasting northern oak woodland understory types - annual and perennial grass. No significant statistical correlations were found, but this is probably due to the small sample size. Preliminary analysis suggests that positive correlations will be found between...

We measured acorn production of five species of oaks (genus Quercus) over a ten year period (1980-1989) at Hastings Reservation in Monterey County, California. Crop production was highly variable and generally asynchronous between species. Variance in crop size decreased directly with increasing species diversity across sub-areas within the study site. Sources of variance in mean annual crop size include annual and interspecific differences and extrinsic factors correlated with different sub-areas of the study site. However, the majority of variance remains unexplained after controlling...