Effects of clearing belt, planting density and fertilizer on growth of Terminalia myriocarpa species in the North-Western region

Abstract

Study on using precious and indigenous tree species for enrichment of poor and degraded natural forest and for intensive forest plantation to supply sawlogs is one of important trends in Vietnam forestry development strategy 2006-2020. Currently, the number of indigenous tree species for forest plantation in Vietnam and in the North-western region is still very limitted. In North-western region, only two species of Cunninghamia lanceolata and Schima wallichii were recognized as main indegenous tree species for production forest, and only 10 indegenous tree species of total 23 species were identified for forest plantation. Therefore, study on using indegenous tree species for forest plantation in Northwestern region is a very important task that helps to improve the quality of
forest plantations and the biodiversify. Terminalia myriocarpa is a big precious indigenous tree species in Northwestern region, but to date there is no study on
techniques to plant this species in the region. This study was conducted to do research on effects of clearing belt, planting density and fertilizer on growth of Terminalia myriocarpa species. After 4.5 years planted for enriching degraded forest, the results revealed that the clearing belt of 4.5 m (equilevent 1/2 of total height of forest) is the best with the survival rate reached 86%, ground diamenter 3.86 cm, total height 3.56 m and diameter canopy 1.87 m. For planting density, the desity of 1.111 trees/per ha (3 m × 3 m) is most suitable for intensive forest plantation with the survival rate reached 75%, ground diamenter 3.86 cm, total
height 3.55 m and diameter canopy 1.89 m. After 3.5 years planted, the results showed that fertilizing with 300 g of NPK (5:10:3) is the best for forest plantation with the survival rate reached 81.66%, ground diamenter 2.42 cm, total height 2.49 m and diameter canopy 1.53 m.