Reproductive period of a sub-montaneous tropical forest: estimation of seed availability for forest restoration in mount Masigit-Kareumbi, Indonesia

Abstract

The ability of local tree species (LTS) to produce seeds is an intrinsic factor that contributes to the success of forest restoration efforts through a natural regeneration process. The aim of this study was to investigate the reproductive period of LTS in order to estimate seed sources availability for the forest restoration process in the sub-montaneous forests. Twenty permanent plots (20 × 20 m) were identified at Mt. Masigit-Kareumbi. Observations regarding flowering and fruiting were conducted on 399 individual LTS (78 species, 29 families) that had a diameter at breast height of more than 10 cm. This activity was done every month: period I was from July 2015 to June 2016, and period II was from July 2016 to June 2017. The results showed that the number of flowering–fruiting trees in period I was higher than it had been in period II. Peak flowering–fruiting occurred in period I (30.1% of the total individuals), and the lowest flowering–fruiting occurred in period II (10.5% of total individuals). 242 individual trees (60.7%) in total, comprising 57 species (73.1%), were flowered–fruited. Most LTS had short durations of reproductive phases. The shortest flowering duration was 0.1–0.8 months (61.7%), the shortest flowering–fruiting duration was 0.1–0.5 months (80.0%), and the shortest fruiting duration was 0.1–1.0 months (59.4%). Flowers and fruits or seeds were always available all year round. To support seed availability for forest restoration, the best time for fruit or seed collection is December to January.