Long Range Plan For The Klamath River Basin ... - KrisWeb

1960, selective cutting was the general practice in California when tractors and trucksbegan to be used. Starting in about 1960, clearcutting of the entire stand, using highleadand tractor yarding, became the predominant method in the redwoods but was alsoapplied elsewhere (ESA 1980). It had become more attractive to private landowners forprimarily economic reasons (Arvola 1976).The type of silvicultural system used today depends on the forest characteristicsand landowner, as well as the economic forces. For private lands harvested in 1985,35% of the proposed harvested acres in the Northern District (includes most of Siskiyouand Trinity Counties) were using even-aged systems (primarily seedtree andshelterwood) while 90% of the acres in the Coastal District (includes Del Norte andHumboldt Counties) were applying even-aged systems. The differences in use of thesilvicultural systems are attributed to the relative success rate and cost-effectiveness ofregeneration of the different species (e.g., redwood vs. Douglas fir vs. ponderosa pine)and the site quality. On the national forests, clearcutting became a larger share of theacres harvested, accounting for 46% of the total in 1986 in comparison to 28% in 1977(CDFFP 1988).Causes of Timber Harvesting ImpactsAlthough "any harvesting system will have some negative habitat impacts," theextent to which each type of harvest affects the stream habitat depends considerably onthe choice of equipment, geographical layout of the harvest unit, and the mode ofoperation. These methods include tractor, highlead cable systems, skyline systems, andhelicopters. (Hartsough 1989)Roads associated with timber harvesting account for a sizeable portion of theerosion from logged areas (Weaver et al. 1987). Poor road design, location,construction, and maintenance can cause erosion of all types: mass soil movement(slide, slump, debris flow, earth flow), surface (sheet and rill), gullies, and streambank(Brown 1988). Harvesting has expanded from established roads into more difficultterrain, and therefore into areas of greater environmental risk.One local study evaluated 237 miles of roads on 30,300 acres of commercialtimberland in the Six Rivers National Forest (McCashion and Rice 1983). Total erosionaveraged about 4.5 cubic yards per acre, while average erosion on the road rights-ofwaywas 47 cubic yards per acre, or 17 times the average erosion in the timber harvestareas. Overall, the road network contributed 40% (on less than 1% of the disturbedacres) and the logged area 60% of the total erosion, percentages which are similar tostudies in Oregon. While roads recover more slowly than harvest sites, the harvest siteswill be disturbed each time they are entered for additional cutting, the researchers noted,and will therefore add an increased proportion of erosion in subsequent years.In a study of timber harvesting on private lands in interior northern California, soilloss measurements averaged about 80 tons/acre/year and sediment reaching thestream averaged 50 tons/acre/year, "mostly from roads" (USFS 1983). Mass wasting