Effects of Clearcut Logging on Wild Ungulates in the Central Albertan Foothills

Abstract

The effects on big game of clearcut logging a mature white spruce forest (Picea glauca) in strips 10-chains wide, with residual strips 5-chains wide to be logged 12 years later, were studied in a 6-square-mile area of the Rocky Mountain foothills near Hinton, Alberta. Use by deer, elk and moose decreased during the first 5 years following clearcut logging with the decrease most pronounced in scarified cut-overs. Five years after logging, browse production in the unscarified area exceeded the 529 lb./acre in the unlogged forest. In years 9 and 17 the logged unscarified area produced three and four times as much browse as the unlogged forest while production in the logged scarified area averaged 10% below the unscarified area. Changes in species composition and height affected both browse utilization and cover. These habitat changes were further evident in estimates of ungulate use. Observed numbers of big game 17 years after logging and scarification were much lower than expected from the forage carrying-capacity estimates. Forage carrying capacity potentials were one moose/7.7, one elk/3.6 and one deer/0.7 acres. However, in summer, observed populations were one moose/213.3, one elk/71.1 and one deer/40.0 acres respectively. Observed use of the area dropped drastically in winter, apparently due to the absence of adequate cover, to no moose or elk and only one deer/1280 acres.