Effect of Planting Method and Density on Initial Growth of Carya tonkinensis – a Multipurpose Tree

Carya tonkinensis Lecomte is a multipurpose tree species, naturally distributing in India, China, and Vietnam. Extract from leaves of C. tonkinensis contains pinostrobin acting as anti-bacteria and anti-infection. It is used as traditional medicine. Seeds are edible and contain oil. In addition, seed cover can be used to produce activated charcoal. Therefore, growing C. tonkinensis may contribute to poverty reduction in mountainous areas. This study aims to analyze suitable planting method and density for growing C. tonkinensis in Son La province, Northwestern Vietnam. Three treatments in planting method were considered: mixed planting of C. tonkinensis and Chukrasia tabularis, pure planting and scattered planting. Four treatments in planting density were considered: 625 plants/ha, 830 plants/ha, 1,000 plants/ha and 1,100 plants/ha. Stem height and stump diameter (Do) were measured at one year after planting, and death trees were counted for survival rate. The results indicated that scattered planting is the most suitable for C. tonkinensis and pure planting could also be applied. Meanwhile, planting density of 625 plants/ha (spacing of 4 × 4 m) and 830 plants/ha (spacing of 3 × 4 m) achieved the best performance. In both planting densities, the survival rate of the plants achieved >90%, their growths were >80 cm in height and >0.8 cm in Do after planting one year. It is recommended that site preparation should be conducted by cutting bands of 2 m width and un-cutting bands of 2 m. In addition, seedlings of >1-year old, which are taller than 0.6 m, should be used to ensure higher survival and growths of plants.