Silvicultural Prescriptions Research Articles

Felling and Skidding Costs Associated with Thinning a Commercial Appalachian Hardwood Stand in Northern West Virginia

Abstract Detailed cost information on thinning operations is needed to develop economic guidelines for managing immature central Appalachian hardwood stands. Three thinning treatments were applied in a 50-yr-old mixed-oak, cove hardwood stand in northern West Virginia. A commercial logging contractor using chain saws and a rubber-tired skidder conducted the logging operations. Time-study data were used to compute production rates for felling marked trees and skidding tree-length logs to roadside landings for each thinning treatment. Production rates ranged from 2.7 to 3.0 cunits/hr depending on the residual stocking treatment. The cost of merchantable material at roadside ranged from $10.79 to $11.99 per cunit. Regression equations for predicting felling and skidding times were developed for each treatment. Data from these equations can be used in estimating production rates and costs for similar thinning operations. A nomogram is provided for estimating felling and skidding costs for a 60% residual stocking treatment, the current recommended silvicultural prescription for stands similar to the study area. North. J. Appl. For. 3:159-163, Dec. 1986.

Significant Factors Affecting Performance of a Urus Cable Yarder

ABSTRACT THE Urus Cable yarder, rigged as a multispan skyline system, yarded tree length hardwood logs uphill 430 ft at a cost of $72 per thousand board ft. The silvicultural prescription was a diameter limit, partial cut which removed 5,770 board ft per acre. Regression analysis yielded the following equation for cycle time: cycle time, min = 2.95 + 0.0045 (slope yarding distance in ft) + 0.0204 (lateral yarding distance in feet); R^ = 0.46, SE = 1.93 min

Influence of Habitat on Silvicultural Prescriptions in New England

Abstract Silvicultural prescriptions in New England can be improved if land is classified by habitats within areas of a given rock type and climate. Habitat definition primarily in terms of glacial soil material provides insight into successional trends, species productivity, and managerial problems. On the basis of these factors, species and silvicultural treatments can be chosen logically for stands on granitic drift in the White Mountains of New Hampshire.

Smallwood Harvesting Using a Trailer Alp Cable Yarding System

ABSTRACT THE Igland-Jones Trailer Alp is a yarder for small-wood cable yarding systems previously tested in Nor-way, British Columbia, and western Oregon. Production as affected by silvicultural prescription, rigging tech-niques, yarding direction and distance, timber stand, and crew efficiency is compared for five trial conditions from previous studies. Maximum production was 14.0 mVyarding hour, achieved while yarding short distances in a western Oregon clearcut using no intermediate sup-ports. When intermediate supports were required, the double-tree system used in Oregon dramatically reduced the time required to set up and tear down a cableway compared to road changing time in Norway and interior British Columbia. The double-tree intermediate support system has advantages over the single-span system when yarding uphill over convex terrain.

Habitat Management for Hole-Nesting Birds in Forests of Western Larch and Douglas-fir

Abstract During a 3-year study in western larch (Larix occidentalis)-Douglas-fir (Pseudotsuga menziesii) forests of northwestern Montana, 273 active nest trees of 20 hole-nesting bird species were located. Stands with major components of old-growth western lurch, ponderosa pine (Pinus ponderosa), or black cottonwood (Populus trichocarpa) supported the highest density and diversity of hole-nesters. On commercial forests, managers should maintain units of old growth and prepare silvicultural prescriptions that will provide continuing replacement in the future.

Zwanzig Jahre Vorrats- und Zuwachskontrolle im Stadtwald Traunstein

The Traunstein municipal forest has been managed by the author for over 20 years and totals 581 ha of which 502 are productive. The forest lies in the Upper-Bavarian foothills of the Alps (annual precipitation 1600 mm, mean annual temperature 7.5°C). Major working plan revisions were carried out in 1949, 1959 and 1969. I. Annual cuts in cubic metres over bark were in 1948 8 cbm/ha, 1959 9 cbm/ha and 1969 10.5 cbm/ha. The species composition comprised 75% Norway spruce, 12% silver fir and 13% broadleaved species (mainly beech). The composition differed in the 71–120 years stands with 67% spruce, 25% fir and 8% broadleaves. Timber extracted, in the period 1949–1969 amounted to 87 000 cbm of which 44 500 cbm resulted from tending operations and 42 500 cbm from regeneration cuts. Management has produced a favourable economic profit of 180 DM/ha/annum. II. Standing volume was obtained for 201,3 ha from a complete diameter assessment and a local volume tariff. This gave 102 000 cbm in 1949, and 129 000 cbm in 1969. The estimated growing stock in young stands was 33 000 cbm in 1949 and 67 000 cbm in 1969. The average standing volume for the whole productive area was, therefore, 287 cbm/ha in 1949 and 389 cbm/ha in 1969, with a mean annual increment for the period 1949–1969 of 13,8 cbm/ha. III. The allowable cut was cross-checked in 1969 by 4 different estimations:—standing volume and a utilisation factor of 2.7% gave a volume of 10.8 cbm/ha; the reduced increment method gave 11 cbm/ha; silvicultural prescriptions produced 10.5 cbm/ha; and the age class method gave 10.5 cbm/ha. The recommended annual cut was thus fixed at 10.5 cbm/ha. Finally, a running control of standing volume is being prepared for 125 ha.