Resumen de Studies on seed biology and growth performance of dipterocarps in Chittagong University campus
The study was conducted to assess the seed morphology, germination behavior and growth performance of major dipterocarps (Dipterocarpus turbinatus, D. costatus, D. alatus, Anisopterascaphula, Shorea robusta and Hopea odorata) at Chittagong University campus. The fruit size, wing length and breadth, nut length and breadth and weight differ from each other. Seedorientation and sowing position significantly affect the germination and initial seedling growth attributes among the species. D. turbinatus revealed highest germination percentage (91.7%), germination speed (2.56), germination energy (42.31%), germination value (55.05) and seedling vigor index (5967.83) in vertical half-buried position but mean germination time (14.27) and plant percent (85%) was highest in horizontal full-buried position. Height and collar diameter of the seedlings was not significant among the treatments. D. costatus showed highest germination percentage (48.33%), germination speed (0.89), germination value (13.74) and plant percent (38.33%) in vertical half-buried position but germination energy (17.50%) and seedling vigor index (1949.50) was highest in vertical half-buried with wings position. A. scaphula revealed maximum germination percentage (81.7%), germination speed (1.50), germination value (30.46) and seedling vigor index (2198.89) in horizontal half-buried position but mean germination time (11.38) and germination energy (30.69%) was highest in vertical full-buried and vertical halfburied with wings position respectively. H. odorata revealed highest germination (93.3%), germination value (83.33) and plant percent (83.3%) in horizontal full-buried position but germination speed (1.81), germination energy (36.9%) and seedling vigor index (5683.4) was highest in vertical half-buried position with wings. Maximum height (66.86 cm) and collar diameter (9.8 mm) was found in vertical half buried and vertical half-buried with wings position respectively. The status of dipterocarp plantations in Chittagong University campus was also assessed. D. turbinatus plantations volume/ha was highest (1040.5 m3) in 25 years plantation. In 14 years mixed plantations, D. turbinatus show better growth than H. odorata, while 9 years old H. odorata revealed better growth than D. turbinatus. 20 years old plantations attained highest dbh (18.97 cm) for H. odorata, followed by S. robusta (16.81 cm) and lowest dbh (15.49 cm) in D. turbinatus, while maximum height was found in D. turbinatus (11.78 m) followed by H. odorata (11.74 m) and minimum height in S. robusta (9.98 m). It is prevailed that in 3 years old plantation growth performance of D. alatus was better than the Dipterocarpus turbinatus, D. costatus, Anisoptera scaphula, Shorea robusta and Hopea odorata. Again in 3 month old plantation growth of D. turbinatus was better than D. costatus, D. alatus, Anisoptera scaphula, Shorea robusta and Hopea odorata. Therefore considering the early growth, timber value, available seeds sources and all other aspects D. turbinatus and Hopea odorata may be recommended for large scale plantation programs in the hilly areas of Chittagong University campus.
