Effects of Timber Harvesting and Related Management Practices on Water Quality in Forested Watersheds

Abstract

Undisturbed forested watersheds are generally recognized as a primary source of high‐quality water. The physical and chemical nature of these waters fluctuate constantly in response to natural stresses but are most influenced by man's activities. Three major forest land management activities—timber harvesting, fertilization, and herbiciding—which may have an adverse affect on water quality are reviewed. In general, research results indicate that nutrient losses, particularly nitrogen, following forest clearcutting are small to negligible. Similarly, forest fertilization studies indicate that nitrogen concentrations in streams are not drastically increased. Large areal applications of selected herbicides in the West have demonstrated that, if carefully applied, they can be used without impairment of water quality.

Effects of Clearcutting and Slash Burning on Streamwater Chemistry and Watershed Nutrient Budgets in Southwestern British Columbia

“…Initial increases in streamwater chemical concentrations following the treatments are probably due to alterations in forest nutrient cycling pathways [e.g., Fredriksen et al, 1975;Sopper, 1975;Vitousek, 1977;Stone et al, 1978]. Vitousek and Reiners [1975] proposed that nutrient loss from watersheds was controlled to a large extent by net biomass increment or net accumulation of nutrients in living and dead biomass.…”

Chemical characteristics of small streams near Haney in southwestern British Columbia

“…The watersheds lie in the dry subzone of the Coastal West-1970] may occur, while dissolved oxygen levels may decrease ern Hemlock biogeoclimatic zone of British Columbia [Kra- [Hall and Lantz, 1969]. These results have been reinforced by jina, 1969] and are covered mainly with Tsuga heterophylla more recent studies as summarized by Bell et al [1974] and (western hemlock), Thuja plicata (western red cedar), and Sopper [ 1975].…”

FIRST‐YEAR EFFECTS OF CLEARCUTTING AN OAK‐HICKORY WATERSHED ON WATER YIELD1

“…The unanimous conclusion of these studies is that forest cutting does not threaten water or site quality and that stream water nutrient concentrations are quickly reduced with revegetation of the site (Brown, et at!, 1973;Cole, et aL, 1973;DeByle and Packer, 1972;Fredriksen, et aL, 1975;Stark, 1979;Aubertin and Patric, 1974;Corbett, e t a l , 1978). Sopper (1975) reviewed research results on the effect of forestry practices on water quality and concluded that "results indicate that nutrient losses following forest clearcutting are small to negligible" and the "amounts of nutrients discharged following clearcutting are generally small in terms of the total nutrient capital and should not reduce site productivity.'' Patric (1978), in a summary of the effects of timber harvesting on soil and water in the eastern hardwood forest states, "There is overwhelming evidence that neither productivity of forest soil nor the quality of forest water are substantially lessened during or after responsibility managed harvests of wood products.…”