The Role of Isolated Trees in Facilitating Tree Seedling Recruitment at a Degraded Sub‐Tropical Rainforest Site

Successional development at abandoned farmlands in southern Queensland, formerly occupied by sub‐tropical rain forest is centred around scattered, isolated trees. Soil seed banks contain few woody plants and most tree species appear to be recruited from seed dispersed into the site by birds or bats. Scattered, low‐growing trees <3 m in height act as the initial focus for the activities of seed‐dispersing birds, but this process is accelerated by the development of taller trees> 6 m in height that act as bird perches. The identity of these trees and whether or not they offer a fruit reward appears to matter less than their structure and suitability as a bird perch. The process of seedling recruitment may be accelerated when two or more trees form a cluster. The proportion of seedlings that survive and grow beyond 150 cm in height appears to be very small. Most of those that do can be classed as secondary rather than primary forest species, even though many primary forest species initially colonize the site. These observations were used to develop guidelines to accelerate the recovery of rainforest at degraded sites. The guidelines promote the early establishment of species that are usually poorly dispersed (e.g., large‐fruited species), planted in scattered clumps. The guidelines should be suitable for situations where relatively large areas are in need of rehabilitation.