Treesearch

Ninety-year-old stands of the Pacific ponderosa pine and Pacific ponderosa pine-Douglas-fir types yielded 53 to 110 tons of slash to the acre after logging on the Challenge Experimental Forest, Yuba County, Calif. Fine slash (under 4 inches d.i.b.) contributed 61 to 64 percent of this weight.

In clearcutting 90-year-old stands at the Challenge Experimental Forest, all merchantable trees greater than 12 inches d.b.h. were removed. Felling costs averaged $3.86 and required 0.55 man-hours per M bd. ft. in cut volumes averaging 19,700 bd. ft. per acre. Yarding, at a rate of 0.54 hours per M bd. ft., cost $4.42.

Dwarfmistletoe on red fir in California can be aged rapidly and reliably by counting the number of annual rings showing swelling and then adding 1 year for the lag period between infection and swelling. Infections were correctly aged in 70 percent of the cases observed, and were aged to within 1 year in the other 30 percent.

Preliminary curves for estimating crown and tree weight are given for madrone, black oak, and tanoak. These curves complement previously published slash weight tables for westside Sierra Nevada mixed conifers. Tanoak crowns in trees 12 to 20 inches d.b.h. were two to three times heavier than black oak and madrone crowns.

A preliminary progress report of the research on the stream ecology of Caspar Creek by Humboldt State College was submitted by Dr. John DeWitt in December,1965, (DeWitt 1965). Further analyses of data collected during the summer of 1965 allows a more complete report to be made at this time. Although the contract was for the period July 1, 1965 to June 30, 1966, field work was started in June, 1965, and this work is included in this report. The 1965-1966 study program was designed to identify and to obtain preliminary measures of the more important variables which should be monitored in...

Foresters sometimes must estimate the timber volume that recently existed on cutover forest land. This may be necessary, for example, if a stand killed by fire was salvage logged before an inventory of killed timber could be made; or in cases where the timber was cut and removed by a trespasser. Usual procedure in these situations is to cruise the tract, taking diameter inside-bark (d.i.b.) measurements on stumps. Then tree diameter breast high (d.b.h.) is estimated using the rule-of-thumb that "d.b.h. equals stump d.i.b." Finally, given an estimate of d.b.h., tree volume is obtained from...

At the Challenge Experimental Forest, 29 acres of slash were broadcast burned on five small clearcut plots (2 to 10 acres) at a cost of $57.00 per acre. Fuel-weight measurements showed reductions of 68 to 84 percent after the burn. Modifications to plot size, shape, and orientation could reduce this cost.

To approximate a group selection cut at the Challenge Experimental Forest, 48 small openings of three sizes—30, 60, and 90 feet in diameter—were logged in 1963. One aim was to create conditions of light and soil moisture that would favor establishment and growth of Douglas-fir, sugar pine, and white fir over ponderosa pine. Seed fall and first-year regeneration were comparable within the three openings for the three species.

In 1961, the cooperative watershed management research program in the Lower Conifer Zone of California was started. Research in the Lower Conifer Zone was designed to obtain information and develop principles to give greater insight into the effect of land management in the Zone upon water quality, floods and sedimentation, water timing, and water yield. The research was conducted by the Pacific Southwest Forest and Range Experiment Station of the U. S. Forest Service with the cooperation of the State of California, Department of Water Resources, and the Division of Forestry. In 1964, the...