DURING the past 30 years more than 2.14 million ha of plantation was established in Vietnam. However, survival rate was very low, with less than 50% of plantations developing to commercially valuable forest. As a result, productivity of plantations is low in comparison with other countries. It was estimated that the mean annual increment (MAl) of plantations in Vietnam is only about IOm3/halyr (Forest Science and Technology Department 1994). Site and species (provenance) matching and the application of intensive cultivation techniques are important silvicultural practices to increase the productivity of plantations. The aim is to achieve an MAl of up to 15-20m3/halyr in large-scale planting.Determination of climatic requirements by Dr Trevor Booth's method (VIET climatic mapping program) is a valuable method suggesting where suitable climatic conditions exist for a given species (see other paper by Nghia in these proceedings). It was found in Vietnam that species such as eucalypts and acacias can be planted widely over the whole country, however, they generally grow better in the southern part adapting to southern climates and soil conditions more readily than in the northern provinces (Nghia and Kha 1993; Nghia et al. 1993). For example, Acacia mangium Willd. planted in northern Vietnam can return a mean increment of 2 m/yr for height and 2.5 cm/yr for diameter, however, in southern provinces, they can achieve more than 2.5 m/yr for height and more than 3.0 cm/yr for diameter. Acacia auriculiformis A. Cunn. ex Benth. and Eucalyptus camaldulensis Dehnh. have also shown similar figures.Providing approximate predictions of how well a species may grow on a particular site is important work in Vietnam. Beside climatic requirements, soil conditions are decisive factors for growth of trees. These conditions include soil fertility, soil depth, soil texture, physical and chemical properties, water drainage and depth of the water table.Planting the right species or provenance on a suitable site requires many years of evaluation. At present, prediction of growth for certain species and provenances is generally done through evaluation of species/provenance trials, evaluation of pilot plantations, comparison of site conditions with the provenance's origin, and experience gained from planting tree species within and outside their natural distribution. Using species provenance trials and pilot plantations, it takes 3-4 years to give preliminary predictions for fast-growing species (eucalyptus and acacia) and 10-15 years for pines and other broadleaved species.
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- Climatic Requirements of Some Main Plantation Tree Species in Vietnam
- Role of exudation of organic acids and phosphate in aluminum tolerance of four tropical woody species
- Distribution of Accumulated Aluminum and Changes in Cell Wall Polysaccharides in Eucalyptus camaldulensis and Melaleuca cajuputi under Aluminum Stress
- STRUCTURAL AND DYNAMIC PROPERTIES OF THE DRY DIPTEROCARP FOREST IN CENTRAL HIGHLAND OF VIETNAM
- Natural forest restoration at Tan Lap, Dong Xoai,in the province of Binh Phuoc
