Selecting seed trees for a forest restoration program: a case study using Spondias axillaris Roxb. (Anacardiaceae)

Spondias axillaris Roxb. (Anacardiaceae) (synonym: Choerospondias axillaris (Roxb.) Burtt and Hill) is an exceptionally effective framework tree species for restoring seasonal tropical forest ecosystems to degraded sites throughout south and southeast Asia. Criteria were developed to select superior parent seed trees, based on nursery performance and field establishment. Seed progenies were collected from 41 S. axillaris parent trees, growing in Doi Suthep-Pui National Park in northern Thailand. Seedlings that survived in the nursery were more likely to have originated from small pyrenes, which germinated rapidly. Seedlings that survived in the field, over the first growing season, tended to be larger at time of planting than those that died. Four standards for selection of superior seed trees were recognised: (i) 70%, or higher, seedling survival in the field, (ii) a sapling height of 100 cm or taller after the first growing season in the field, (iii) 40% or greater germination in the nursery and (iv) 70% or higher seedling survival in the nursery. Twelve of the 41 seed trees met these standards and qualified as superior seed trees for forest restoration.