DISTRIBUTION AND SILVICULTURAL CHARACTERISTICS OF Magnolia odora IN XUAN LIEN NATIONAL PARK, THANH HOA PROVINCE

Abstract

Magnolia odora (Chun) Figlar & Noot.) is a large-sized tree species that can reach 20 - 25 m in height. Its timber is of good quality, dark blackish in color, with straight grain and a fine, soft, and lightweight texture. The wood is relatively resistant to termite attack and shows little cracking upon drying; therefore, it is used in construction and household furniture production. The seeds contain fragrant essential oils and are traditionally used as a spice. This study provides scientific information on the distribution status and selected silvicultural characteristics of M. odora in Xuan Lien National Park, Thanh Hoa Province, Vietnam. The survey results showed that M. odora occurred at elevations ranging from 641 to 1,114 m a.s.l., predominantly in evergreen forests, where the species contributed to the emergent canopy layer. The density of the upper-canopy tree layer in forest stands containing M. odora ranged from 340 trees ha⁻¹ to 435 trees ha⁻¹. The mean diameter at breast height (D₁.₃) ranged from 20.3 to 25.9 cm, while the mean total tree height ranged from 17,8 to 19,5 m. The density of M. odora in the surveyed sampling plots ranged from 5 to 8 trees per plot, corresponding to 25 - 40 trees ha⁻¹, and the species occurred in three species-composition formulas of the upper-canopy layer. The density of natural regeneration in the forest stands ranged from 4,240 trees ha⁻¹ to 5,120 trees ha⁻¹. Overall, the quality of natural regeneration was relatively good, with the highest proportion of healthy regeneration recorded in sampling plot TH.01, at 81,3%. Crucially, no naturally regenerated M. odora seedlings or saplings were recorded within any of the surveyed plots, highlighting a severe regeneration bottleneck and urgent requirement for targeted conservation interventions.