Beaver control and reforestation of drained beaver impoundments

In November, 1984, the Hobart Ames Foundation in cooperation with the University of Tennessee Agricultural Experiment Station began a beaver (Castor canadensis) control project on approximately 4000 acres of the North Fork Wolf River bottom in west Tennessee. Resident populations (169 beaver) were removed from the study area from 1 November 1984, to 31 May 1985. From June, 1985, through September, 1988, 162 immigrants were removed. Immigration October through May averaged 46.4 beaver. From June through September average immigration dropped significantly to 5.5. More immigrating males (86) were identified than females (55). More than 89% of all immigrants were in the 3-4 year age class or younger. In the spring of 1986 two drained beaver impoundments were planted with 1-0 bare-root stock of green ash (Fraxinus pennsylvanica Marsh.), sycamore (Platanus occidentalis L.), baldcypress (Taxodium distichum L., Rich.) and containerized seedlings of swamp white oak (Quercus michauxii Nutt.) and willow oak (Quercus phellos L.). A grass herbicide was sprayed over 1/2 of each plot in May and July of the. first growing season. At the end of the first growing season herbaceous competition on untreated subplots averaged 8185 kg dry weight per ha of which 53.8% was primarily swamp cut grass (Leersia oryzoides). On treated plots herbaceous competition averaged 6823 kg dry weight per ha with 15.2% grass species. First year survival of green ash, sycamore, baldcypress and swamp white oak was significantly greater in herbicide treatments (92% versus 85%). Herbicide treatments had no effect on third year heights or survival. Third year mean height for cypress (15 dm) was significantly less than green ash (25 dm) while sycamore was significantly taller than both (32 dm). Willow oak and swamp white oak failed due to poor quality seedlings. Results suggest that well stocked stands of desirable species can be established on drained beaver impoundments; however beaver control likely will be required to prevent recolonization.