POPULATION AND REGENERATION DYNAMICS OF Scaphium macropodum (Miq.) Beumée ex K.Heyne IN EVERGREEN BROADLEAVED FORESTS, VIETNAM

Scaphium macropodum is a multipurpose tree species, native to the Southeast Asia. Its fruits are used for tonic and medicinal beverages, while light timber is used for furniture making. Due to overharvesting for fruits by cutting trees, the population and density have dramatically declined in nature. Therefore, understanding population and regeneration dynamics is important for sustainable management of S. macropodum. The investigation was conducted in poor, medium, and rich evergreen broadleaved forests in central Vietnam. The trees (diameter at breast height/DBH ≥ 5 cm), saplings (DBH < 5 cm and height > 2 m), and seedlings (height ≤ 2 m) were surveyed in seven representative plots of 1,000 m2 each (30.0 m × 33.3 m). The results indicated that 45 S. macropodum trees/ha were found in the rich forest, reducing to 23 trees in the medium forest and 20 trees in the poor forest. Meanwhile, 800 saplings/ha were found in the poor forest, reducing to 200 saplings in the rich forest, and 120 saplings in the medium forest. A similar pattern was found in seedlings. The regression between total stand crown area and total density of S. macropodum was found (R2 = 0.37), indicating higher canopy cover leading to a lower density of S. macropodum. It is concluded that to enhance the growths of seedlings and saplings of S. macropodum for fruit production, reducing the crown cover of natural forests is necessary. It, then, improves sunlight reaching to seedlings and saplings, and reduces competition between S. macropodum and other vegetation.