Branch development of eight-year-old Mytilaria laosensis plantations in response to planting density.

Branch development is related to the formation of wood knots and affects timber quality and future market value of plantations and native forests alike. This study provides a theoretical basis and reference for knot-free timber production in a Mytilaria laosensis plantation. The branch diameter, length, angle, status (alive or dead), azimuth, and branch height under 12 m were measured for 60 dominant or co-dominant trees in response to five planting density treatments (625, 833, 1111, 1667, and 2500 stems ha-1). With increasing planting density from 625 to 2500 stems ha-1, the mean branch diameter and branch length decreased by 7.09% and 8.70% respectively. Dead and live branch angle decreased by 10.54% and 9.66% respectively, while number of living branches increased by 31.67% from 625 to 2500 stems ha-1. Analyzing the spatial distribution using branch azimuth, we discovered that branches pointing north were more abundant and had larger diameter, larger branch length, and higher branch angle than branches pointing south. Branch diameter, length, and number were positively related to the relative branch height. Our results underline that increasing the planting density from 625 to 2500 stems ha-1 considerably affect branch growth. Thus, optimizing planting density when establishing Mytilaria laosensis plantations according to the forest management targets and future pruning can improve the timber quality and future value. [ABSTRACT FROM AUTHOR]