Skid Trails Research Articles

Effect of Skid Trail Compaction on a Volcanic Soil in Central Oregon

AbstractA skid trail in the Ochoco National Forest, Oregon, was examined to assess the degree of compaction that had occurred as a result of traffic during log harvesting. The soil, classified as a Lithic Cryorthent is a sandy loam derived from rhyolitic and tuffaceous colluvium. Measurements of bulk density and shear strength were made at five positions across the trail and two locations in undisturbed soil. Cores were taken to measure bulk density, moisture content, and moisture retention. Compaction resulted in increases in bulk density of up to 25%, in shear vane strength up to 157%, and in cone index up to 220% along with a decrease in pore space > 10 µm of 69%. Bulk density, vane shear, and penetrometer measurements were found to be highly correlated.

Soil Compaction from Harvesting and Site Preparation in the Upper Gulf Coastal Plain

AbstractThe impact of intensive forest management practices on the physical properties of a Typic Paleudult was examined to a depth of 0.3 m by collecting 7.6‐cm core samples before harvest, after harvest, and after site preparation. Whole‐tree harvesting of a 22‐yr‐old loblolly pine (Pinus taeda L.) plantation caused significant changes in bulk density to a depth of 0.23 m outside of skid trails, and 0.30 m in primary skid trails. Subsequent chop/burn and shear/windrow site preparation treatments had little added impact on bulk density. Post site preparation differences in aeration porosity and saturated hydraulic conductivity among treatments were nonsignificant.

Effects of Tractor Logging on Soils and Vegetation in Eastern Oregon

AbstractSoil characteristics were investigated on a mixed conifer forest stand in Oregon's Blue Mountains. The most recent logging had occurred on the site 6 yr previously; 1 yr after harvest, slash was machine‐piled and burned. Five classes of ground disturbance including a control were identified, based on degree of soil and ground cover disruption. Bulk density of the disturbed classes was not significantly different from control areas. Infiltration and saturated hydraulic conductivity rates on both disturbed and control areas were high relative to projected storm intensities. Soil organic matter content in the upper 3 cm of disturbed areas was markedly below that of control areas. Understory vegetation production on seeded skid trails was 66% above that of control areas; however, below ground biomass of control areas, vegetated with native rhizomatous species, was three times that of skid trails.

Soil Bulk Density Recovery on Compacted Skid Trails in Central Idaho

AbstractIn west‐central Idaho, the bulk densities of soil in major skid trails were compared with those of adjacent undisturbed soil in order to determine rates of recovery. Five study sites on each of two soils, one formed from granitic material (mixed, frigid, Typic Xeropsamments) and the other from volcanic material (fine‐loamy, mixed Dystric Cryochrepts), provided two chronosequences (five 5‐yr periods) of time since logging. Bulk density was measured at 5.1‐, 15.2‐, and 30.5‐cm depths. The percent increase in bulk density of soil on a skid trail over that on an adjacent undisturbed area was greater in the volcanic than the granitic soil, but recovery rates (slope of the regression line) for the two soils were not significantly different. Linear regression models showed a significant (p < 0.05) recovery trend for all depths except the 15.2‐cm depth on the volcanic site. Except for the surface 5.1 cm of the granitic soil, none of the bulk densities in skid trails had returned to the undisturbed values in the 23 yr since logging.

Protecting Water Quality in the Midwest: Impact on Timber Harvesting Costs

Abstract Costs were evaluated for six forest practices designed to prevent degradation of water quality from 18 timber harvesting operations in the Midwest. Net revenue reductions ranged from 1.2% for redesigning landing and skid trail locations to 26.4% for meeting buffer strip requirements. Nine operations were profitable with application of all six practices. Limited production function information hinders such analyses. North J. Appl. For. 2:57-61, June 1985.

Towards sustained timber production from tropical rain forests in Suriname.

A summary account of the complementary Celos Harvesting System and Celos Silvicultural System developed by the Agricultural University of Wageningen and the Anton de Kom University of Suriname in a joint project over the last 20 yr. The harvesting system comprises: prior mapping of the trees to be selectively felled and opening up of skid trails; directional felling; winch extraction; and registration of log flow from stump to destination. This system has reduced skidding costs by 10-20% and skidding damage by 50% compared with existing unplanned operations. The silvicultural system comprises 3 treatments: refining 1-2 yr after selective logging, by climber cutting and poison-girdling of non-commercial trees (preferably

Impact of Intensive Forest Management Practices on the Bulk Density of Lower Coastal Plain and Piedmont Soils

Abstract Trafficking during harvesting significantly increased soil bulk density to depths of 3 to 6 inches in areas outside of primary skid trails and 9 to 12 inches in primary skid trails. On the Coastal Plain site, bedding was effective in offsetting soil compaction in areas outside of primary skid trails, forming a new soil surface, 7 to 8 inches in height, over the surface trafficked during harvest. Bedding may not be so effective in the skid trails, because the original soil surface under the bed was so compacted that root growth may be inhibited. On the Piedmont site, disking was effective in restoring bulk density to preharvest levels in the upper 3 to 5 inches of soil, but soil compaction in the upper 3 to 9 inches of drum-chopped areas may result in reduced root growth, because of mechanical impedance.

Impact of Harvesting and Site Preparation on Physical Properties of Piedmont Forest Soils

AbstractThe impact of intensive forest management practices on soil bulk density, aeration porosity, and saturated hydraulic conductivity was examined to a depth of 0.3 m before harvest, after harvest, and after site preparation. Harvesting caused significant changes in soil physical properties to an average depth of 0.17 m in whole tree harvest plots and 0.22 m in skid trail plots. Disking was effective in restoring soil physical properties to preharvest levels in the upper 0.07 to 0.12 m of soil. Soil compaction in chop/burn plots may result in reduced root growth because of mechanical impedance, reduced aeration, or both.

The Impact of Harvesting and Site Preparation on the Physical Properties of Lower Coastal Plain Forest Soils

AbstractThe impact of intensive forest management practices on soil physical properties was examined by collecting intact, 7.6‐cm diameter soil core samples to a depth of 30 cm before harvest, after harvest, and after site preparation in plots established in primary skid trails and areas receiving whole‐tree and conventional tree‐length harvesting treatments. Site preparation for all plots was shear, burn, chop, and bed. Harvesting increased bulk density and decreased aeration porosity in all sampled areas. Significant changes in these properties were detected to the 30‐cm depth in the skid trail plots. However, significant changes in the whole‐tree and tree‐length plots were limited to the upper 15 cm of soil. Harvesting also significantly decreased saturated hydraulic conductivity to a depth of 8 cm in the skid trail plots and 15 cm in the tree‐length plots but had no significant effect in the whole‐tree plots. Bedding proved to be effective in offsetting soil compaction in the whole‐tree and tree‐length plots by forming a new soil surface, 19 cm in height, over the surface which was trafficked during harvest. Bedding may not be as effective in the skid trail plots because the soil found at the original surface under the bed was compacted to the extent that root growth may be inhibited.

Whole-Tree Utilization System for Thinning Young Douglas-Fir

Abstract The Washington State Department of Natural Resources is commercially thinning naturally established 40-year-old Douglas-fir (Pseudotsuga menziesii) stands which were once considered too small to be merchantable. Efficient, cost-effective thinning is accomplished by whole-tree chipping in the woods. The logging system includes a portable chipper, a chain-flail delimber, two rubber-tired grapple skidders, and three rubber-tired or tracked tree-to-tree feller-bunchers with accumulators. This system provides total utilization of the harvested material. An average of 100 to 125 green tons of pulp chips with less than 7-percent bark can be produced in an eight-hour shift. Approximately 1,000 stems per acre, averaging 4 inches in diameter at breast height, are removed to leave 200 of the best trees. This stocking gives adequate growing space and provides operational maneuverability. The feller-buncher operators are trained to select trees by following rules that describe leave trees. Stand damage can be kept within acceptable limits, preferably under 5 percent of the leave trees, by requiring prelocated skid trail systems and rub trees. Successful tree selection and avoidance of stand damage depend upon operator cooperation.

Tree Species Response to Clear-cutting a Southern Appalachian Watershed

A 16. 1-ha watershed was experimentally clear-cut in 1939 and again in 1962. All material over 1 cm in diam was cut and left in place, thereby minimizing soil disturbance. Density data collected on permanent quadrats before cutting, 13 years after the first cut and 15 years following the second cut, indicate vegetation response varies by species and physiographic position. There was also a difference in response between the two clear-cuts. There was little change in number of tree species found per unit area following the two clear-cuts. However, certain species such as Liriodendron tulipifera became much more abundant while others decreased in abundance especially on lower slope to cove and mid to upper N and E physiographic positions following the second cut. INTRODUCTION Disturbances, such as clear-cut harvesting, in the eastern deciduous forest ecosystem change the relative composition of tree species (Oliver, 1980). For example, Liriodendron tulipifera has been shown to increase in density relative to other species following clear-cutting throughout most of the eastern United States (Swank and Helvey, 1970; Kovner, 1957; Merz and Boyce, 1958; Potzger and Friesner, 1934). Seed source, vegetative and advanced reproduction, site characteristics and time of year are important factors determining compositional changes of forest stands following disturbance. Many tree species regenerate by stump or root sprouts or from seedlings already on the ground while others originate from stored seed pools (McGee and Hooper, 1970; Roach, 1962; Marks, 1974). Autumn and winter clear-cut harvesting has been shown to increase establishment of Liriodendron tulipifera seedlings (Trimble and Tryon, 1969). The degree of disturbance appears to be more important in influencing species change than either topography or aspect for much of the eastern United States (Merz and Boyce, 1958; Roach, 1962). Liriodendron tulipifera has been observed to spread across the moisture gradient from stream valleys to dry ridges in southern Indiana following clear-cut harvests on the Hoosier National Forest. This apparently is not true for central and northern hardwood forests of the Appalachian Mountains (Trimble and Hart, 1961). The length of time these composition changes remain for various positions along the moisture gradient has not been fully studied (Collins, 1962; Cristofolini and Cristofolini, 1967; Levering, 1968). One of the first experimental clear-cuts in the eastern deciduous forest occurred at Coweeta Hydrologic Laboratory in the southern Appalachians. A 16.1-ha watershed (WS13) was clear-cut in 1939 and again in 1962. These cuts are different from a commercial clear-cut because no material was removed from the site, thereby eliminating skid trails and logging roads. 1 Contribution from Purdue Univ. Agr. Expt. Sta. Paper No. 6851. Research supported in part by the Southeastern Forest Experiment Station, USDA and in part by National Science Foundation Grant No. DEB-8012093.

Soil Compaction from Logging with a Low‐Ground Pressure Skidder in the Oregon Coast Ranges

AbstractIncreased bulk density of a clay loam soil on logging skid trails in the Oregon Coast Ranges was most highly correlated with the logarithm of the number of turns with a low‐ground pressure (FMC) skidder. The surface 15 cm of soil was impacted more by uphill than by downhill yarding. Downhill skid trails with three or fewer turns had small increases in bulk density, usually < 10%. The regression relationship (r2 = 0.411; Sy·x = 23.16) developed for the 7.5‐cm depth indicated that nine turns with an FMC skidder would increase soil bulk density approximately 25 and 45% for downhill and uphill yarding, respectively. After approximately 18 turns with an FMC skidder, the predicted bulk density increase at the 22.5‐cm soil depth was 25% (±5% at α = 0.1). Modified 10‐blow Proctor tests slightly overestimated increases of soil bulk density on high‐use downhill skid trails. The 15‐ and 10‐blow Proctor tests very closely estimated these density increases for the 7.5‐ and 15‐cm depths, respectively, for uphill skidding.

Change of the forest vegetation and growth of Picea glehnii MAST. on the skid trails

Change of the forest vegetation and growth of <i>Picea glehnii</i> MAST. on the skid trails

Soil Disturbance Associated with Timber Harvesting in Southwestern British Columbia

Soil disturbance associated with timber harvesting was evaluated in five localities in southwestern British Columbia, along transects located away from main haul roads and associated sidecast soil material. Small skid trails and associated sidecast material were included in the evaluation. Of the several disturbance indices evaluated, the percentage of area occupied by exposed mineral soil (EMS) appears to be most useful. For 13 high-lead logged sites, EMS averaged 29% and ranged from 5 to 56%. Low EMS (9%) was associated with a high-lead site logged over snow. High EMS was associated with steep slopes (greater than 70%) and shale-rich soils. Less disturbance occurred on soils derived from granitic parent materials. On two tractor-logged sites with 25 to 60% slopes, EMS was 71 and 68%, respectively. On a helicopter-logged site, EMS was only 5%. These data are compared to estimates of soil disturbance caused by logging in other regions of western North America.

SOME OBSERVATIONS ON THINNING FORESTS IN THE COASTAL REGION OF BRITISH COLUMBIA

Thinning is a potential forest practice awaiting economic evidence of its merit. In the south coast zone of British Columbia, nearly 2 million acres of immature Douglas fir and western hemlock forests offer the possibility of making thinnings to maximize the productive capacity of sustained yield units. The commercial feasibility of any one thinning should not overrule the silvicultural attributes of repeated thinnings to mould the stands in a forest to a desired structure. There is no economic or biological necessity to clearcut immature stands on short rotations rather than adopt thinning regimes within a rotation twice as long. Careful attention to location of skid trails, landings and roads should precede the marking job. If thinnings become widely applied, the need for mechanization of yarding processes to cope with difficulties of terrain may probably give rise to thinning schemes which alternate thinned patches with clearcut patches. Management, engineering and silvicultural aspects are very much in need of integrated research on a scale large enough to entertain sustained yield objectives and realistic costs. The application of crown thinnings meets economic and biological requirements. Experience rather than science must still underlie marking techniques until facts are available concerning the growth performance and intrinsic wood qualities of particular phenotypes in relation to tree-spacing. As a result of tending plantations since they were 13 years old, the gross and merchantable volumes per acre at 21 years of age are lower in a plot having 400 free-growing stems than in a plot with 1,200 competitors, but different stand development is expected in the next decade as the degree of competition becomes a more important influence. There is evidence that a thinning which yields #3 logs to an 8″ top and/or poles and piling will return a small profit, terrain and transportation permitting, and that when a thinning yields only pulpwood or the larger percentage of the total thinning yield is pulpwood, that it will not usually meet the costs of the operation.