Root strength changes after logging in southeast Alaska /

Abstract

The shear strength was measured of western hemlock (Tsuga heterophylla) Sitka spruce (Picea sitchensis) and huckleberry (Vaccinium parvifolium) root segments in different diam. classes from sites in the area of Stanley Creek that had been logged in 1966, 1970, 1972 and 1974. For small diam., the strength of live roots was greatest for hemlock and least for huckleberry; differences decreased with increasing diam. The loss of strength of smaller roots of all species was rapid in the first 2 yr after logging. The av. residual strength increased due to an increased proportion of resinous roots in those surviving after about 4 yr for spruce and 6 yr for hemlock. After 10 yr even the largest roots had lost a considerable proportion of their strength.