This soil moisture study was initiated in 1960 to investigate the effects of patch clearcut logging and slash burning (1962-63) in an old-growth Douglas-fir forest in the Oregon Cascade Range. Since soil moisture and vegetation sampling continued regularly until 1980, this is a unique data set that represents nearly two decades of post-treatment information.
Plant cover exerts a profound influence on soil moisture levels through its effects on interception, infiltration, evaporation, and transpiration. In the Douglas-fir forests of the Pacific Northwest, clearcut logging and slash burning are common practices that can dramatically alter plant cover and soil moisture. Logging can increase soil moisture by temporarily reducing cover and associated water use, and burning may further augment soil moisture levels by suppressing the survival and regrowth of vegetation. Indeed, part of the rationale for slash burning in the region is to control shrubs and other vegetation that would otherwise compete with conifer seedlings for available moisture, light, and nutrients. Within a few years after burning, however, invading vegetation may deplete soil moisture to levels comparable to forested areas. Such observations point to the value of long-term information to better understand dynamic soil moisture and plant cover responses to forest practices.
Alan L. Flint, Alfred B. Levno, Donald L. Henshaw, Jack S. Rothacher, Paul W. Adams, Richard L. Fredriksen
To study the relationship between vegetation cover and soil moisture during the re-establishment of vegetation after logging and burning of a Douglas-fir forest; to study the relationship between vegetation cover and soil water deficit and use, the change in soil moisture storage by depth over time, and the precipitation interception changes over various successional changes during re-establishment; also, to examine soil temperature by depth over time.