Live-trapping and radio-tracking were used to monitor the movements of brush-tailed possums in and around an erosion-control planting of poplars. Possums' use of the planted area was monitored by traffic counters and by marking (with Rhodamine B dye) possums which climbed the poplars. The extent of browse damage to the poplars was also recorded. Over a period of 20 months, 358 individuals were trapped, marked, and released, and 50 were fitted with radio transmitter collars. The study area was mapped into nine 100-m-wide annular zones radiating out from the focus, Zone 0, which contained the poplars. Seventy percent of possums assigned to Zone 1 were caught in Zone 0, but only 24%, 5%, and 0% assigned to Zones 2, 3, and 4–8 respectively were caught in Zone 0. Trapping and radio-tracking revealed no increase in the use of the planted area during the spring flush although the poplars were being damaged. Traces of Rhodamine B dye on the possums showed that 87% of animals caught in Zone 0 had visited the poplars, but only 45%, 10%, and 0% of possums caught in Zones 1, 2, and 3–8 respectively. Possums in this area were sedentary and damage to the poplars during spring was attributed to local animals only. Protection of the poplars by fitting expandable plastic sleeves was found to be more cost-effective than aerial poisoning of the surrounding possum population.