Double-stocking for overcoming damage to conifer seedlings by pocket gophers

A 5-yr study was conducted on national forests in Idaho and Oregon to evalu ate how doubling the seedling stocking rate of lodgepole pine (Pinus contor ta) would relate to 5-year survival and the uniformity of distribution of s eedlings in the presence of northern pocket gopher (Thomomys talpoides) dam age. Either 4 or 8 seedlings were planted in 40-m(2) subplots (1000 or 2000 seedlings/ha) and monitored for gopher damage. We found that the number of seedlings attacked by gophers, and consequently, the number of seedlings s urviving for 5 years, were directly proportional to the stocking rate, but the consistency of seedling distribution within each site las measured by t he proportion of 40-m(2) subplots with greater than or equal to 2 surviving seedlings) did not double with stocking rate. In some situations, increasi ng the stocking rate should be considered as a method for overcoming pocket gopher damage. (C) 1998 Elsevier Science Ltd. All rights reserved.