Treesearch

The 10 experimental forests and ranges in California administered by the Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture, are described. The purposes of these facilities, and how to request their use for approved scientific study are given, and the natural resource base, data bases, studies, and general features of each are also described.

A primary goal for JDSF is to carry out research on the various aspects of forestry in the redwood region. One avenue to do this has been to encourage university forestry departments to do experimental projects here. Since 1980, funding for many researchers has been provided through CDF's Forest Resource Improvement Fund (FRIF). Each year, money is made available to various State Forests for Research projects which the Manager feel have the highest priorities. Graduate students have often been the actual principal field investigators and many theses have been produced.

Growth of ponderosa pine (Pinus ponderosa) was monitored for 24 years after planting at five different square spacings (6, 9. 12, 15, and 18 ft) in the presence or absence of competing brush on the westside Sierra Nevada. Spacing strongly influenced both mean dbh and basal area/ac. In plots maintained free of brush, diameters ranged from 5.1 in. at the 6-ft spacing to 11.4 in. at the 18-ft spacing after 24 years. Over all spacings, brush reduced mean dbh by 20% and basal area/ac by 37%. Projections of mean dbh suggest that yield losses resulting from brush competition depend on the...

Growth and stand development of ponderosa pine (Pinus ponderosa) were monitored for 20 years after planting at five different square spacings (6, 9, 12, 15, and 18 ft) in the presence or absence of competing shrubs on the westside Sierra Nevada. Mean tree size was positively correlated and stand values negatively correlated with spacing in the absence of competing shrubs. Trees growing with competing shrubs attained 76% of the diameter, 80% of the height, and 58% of the cubic volume of trees free of shrub competition when all spacings were combined. This study suggests that the major...

Soil ammonification, nitrification, and N mobility were studied for 1 yr in three Sierra Nevada (USA) mixed-conifer stands to examine the long-term influence of timber harvesting on soil N dynamics. Clearcutting had a persistent effect on soil N mineralization, detectable by in situ incubation but not by conventional low-tension lysimetry. Mineralization rates were greater in 5- and 17-yr-old regenerated clearcuts than in an adjacent 100-yr-old uncut forest. Annual rates of N mineralization averaged 12 kg ha−1 for the uncut forest, and 49 and 31 kg ha−1 for the 5- and 17-yr-old clearcuts,...

California black oak (Quercus kelloggii) exceeds all other California oaks in volume, distribution, and altitudinal range. Yet this deciduous hardwood has had little sustained commercial use and almost no management, even though its wood closely resembles that of its valuable, managed, and heavily used counterpart-northern red oak (Quercus rubra)-in the Eastern United States. First collected in 1846 near Sonoma, CA, the species was not named until 1857 when John Newberry called it kelloggii in honor of Albert Kellogg, a pioneer California botanist and physician. In later botanical works,...

Stream temperature measurements have been collected in the Caspar Creek drainage on Jackson Demonstration State Forest periodically over the past 25 years. Review of this data and other recently collected data from western Mendocino County illustrates much about the temperature regimes of small coastal drainages, and how they are impacted by timber harvesting. This article gives a synopsis of these studies and summarizes reasons for concern. Additionally, it presents a model currently in use by the U.S. Forest Service to predict changes in maximum summer temperatures resulting from canopy...

Streamflow data for a 21-year period were analyzed to determine the effects of selective tractor harvesting of second-growth Douglas fir and redwood forest on the volume, timing, and duration of low flows and annual water yield in northwestern California. The flow response to logging was highly variable. Some of this variability was correlated with antecedent precipitation conditions. Statistically significant increases in streamflow were detected for both the annual period and the low-flow season. Relative increases in water yield were greater for the summer low-flow period than for...

Abstract - The precision of timing devices in modern electronic data loggers makes it possible to study the routing of water through small drainage basins having rapid responses to hydrologic impulses. Storm hyetographs were measured using digital tipping bucket rain gauges and their routing was observed at headwater piezometers located mid-slope, above a swale, and near the swale. Downslope, flow was recorded from naturally occurring soil pipes draining the 0.8-ha swale. Progressing downstream from the swale, streamflow was measured at stations gauging nested basins of 16, 52, 156, 217,...

Using a previously treated basin as a control in subsequent paired watershed studies requires the control to be stable. Basin stability can be assessed in many ways, some of which are investigated for the South Fork of Caspar Creek in northern California. This basin is recovering from logging and road building in the early 1970s. Three storm-based discharge characteristics (peak discharge, quick flow, and total storm flow), daily flows, and concentration of suspended sediment were studied to see if the South Fork can be used as a control in a second experiment. Mean sediment concentration...