Deer use of managed forest openings in northern lower Michigan.

Abstract

Deer use, spring and fall forage production and utilization, and management costs were compared for several methods of forest opening enhancement. Deer use was monitored using track counts from fall 1976 through spring 1978 on rye plantings, fertilized openings, burned openings, untreated (control) openings, and recent aspen cuttings. Seasonal pellet counts were also made to evaluate deer use, but the results were inconsistent. Deer use of openings varied seasonally. Rye openings received significantly higher deer use than all the other opening types during early spring and fall, and also during early winter the second year when acorns were not available. Deer use in the fertilized and burned openings was greater than in untreated openings from late spring through early fall. Burned openings also received higher use than untreated openings during early spring. Aspen cuttings received higher deer use than permanent openings during winter. From spring through early fall use of aspen cuttings was lower than in the burned and fertilized opening, but similar to use in the untreated openings. Spring and fall rye production ranged from 55 to 170 g/m$\\sp2$, with percent utilization ranging from 25 to 56%. Compared to the untreated openings, forb production was significantly lower on the fertilized openings, and grass production was significantly lower on the burned openings. Comparisons of production by herbaceous forage types on paired exclosure and exposed plots showed a statistically significant utilization of forbs on all permanent opening types. Initial treatment costs for the rye, burned, and fertilized openings were $222, \\$80, and $42 per acre (0.4 ha), respectively. Cost effectiveness was determined by calculating the difference in deer use between the untreated openings and each of the managed opening types, and adjusting the results by the management costs. On an annual basis, cost effectiveness was highest for fertilized openings followed by burned openings. Cost effectiveness was highest for the rye openings only during the spring and fall periods. Although rye openings are the most expensive of the management alternatives considered, they appear to be the most cost effective when deer forage is most critical, immediately before and after snow cover.