Treesearch

Although the principal hardwood species in the forest zone of the Sierra Nevada (California black oak, tanoak, Pacific madrone, and canyon live oak) are key components of many ecosystems, they have received comparatively little study. Currently they are underutilized and unmanaged. This paper brings together what is known on the silviculture-ecology of these species and weaves it into a framework that has value to the academician and the practitioner. With species amounts, utilization, adaptations, and ecology as background, seed production, regeneration, early seedling growth, root crown...

The effects of small openings in forest stands has interested silviculturists and ecologists for years. Interest generally has centered on the vegetation in the openings, not on that immediately outside of them. Quantitative information on the growth of trees adjacent to group-selection openings, although often mentioned in forestry textbooks as contributing to cost effectiveness, is scant. Five conifer and three hardwood species bordering 9-,18-, and 27-m diameter openings in the northern Sierra Nevada of California were examined for diameter growth 10 years before and 10 years after an...

Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is generally a much better predictor than water discharge. Although it is now possible to collect continuous turbidity data even at remote sites, sediment sampling and load estimation are still conventionally based on discharge. With frequent calibration the relation of turbidity to SSC could be used to estimate suspended loads more efficiently. In the proposed system a programmable data logger signals a pumping sampler to collect SSC specimens at specific turbidity thresholds. Sampling of dense field...

Abstract - Streamflow, suspended sediment, and bedload have been gauged continuously since 1962 in the 473-ha North Fork and the 424-ha South Fork of Caspar Creek on the Jackson Demonstration State Forest. From 1963 to 1967, both 90-year-old second-growth watersheds were measured in an ""untreated"" condition. In 1967, logging roads were built in the South Fork. From 1971 through 1973, about 65% of the stand volume was selectively cut from the South Fork watershed. Logging began in the North Fork in 1985 and ended in 1991. The timber volume removed from the North Fork watershed approximated...

Abstract - Large organic debris (LOD) was inventoried in two coastal streams to assess the impacts of forest harvesting on LOD recruitment in 90-year-old, second-growth redwood and fir stands on the Jackson Demonstration State Forest in northern California. One stream, North Fork of Caspar Creek, drained a 508-ha watershed that had been 60% clear-cut, with riparian buffer strips left, four years earlier. The second stream, South Fork of Caspar Creek, drains a 424-ha catchment that 60% of the timber volume had been selectively harvested and the stream cleared of LOD twenty-five years...

Sediment delivery was estimated for 13 tributary watersheds and the North Fork of Caspar Creek. The ratio of sediment to erosion averaged 16.4%, ranging from 1.0% to 89.7%. Because the data were so highly skewed their median is a better indicator of central tendency than their mean. The median delivery ratio was 6.3%

Factorial combinations of insect, nutrient, and weed control treatments were applied repetitively to eight Pinus ponderosaDougl. ex Laws. var. ponderosa(ponderosa pine) plantations across a broad span of site qualities in California. Findings from the first 6 years showed that plantation growth potential was several times greater than previously realised. On the average, tree volumes from combined treatments were 4 times greater than for untreated controls. Sites of poor quality were limited primarily by soil drought, and fertiliser offered no further advantage over weed control alone....

Street trees are an important component of the 'green infrastructure' in cities but damage caused by roots to sidewalks, kerbs and gutters and sewers is a multimillion dollar problem. To determine the magnitude of this problem, municipal foresters were surveyed in 15 cities. Total annual concrete and sewer repair costs attributed to tree damage averaged $4.28 per street tree and ranged from $0.18 to $13.65 per tree. On average, repair costs are equivalent to 25 per cent of annual tree maintenance expenditures; sidewalk repair costs are the single largest expense in all cities, averaging...

Electric utilities in California currently sponsor planting of approximately 75,000 yard trees annually as an energy conservation measure. In this study we evaluated the potential effects of tree shade on residential air conditioning and heating energy use for a range of tree orientations, building insulation levels and climate zones in California using computer simulation. Trees shading a home's west exposure produced the largest savings, both annual (kWh) and peak (kW), for all climate zones and insulation levels considered. Next largest savings were for southwest (annual and peak) and...