Growth of some native tree species in mixed plantation for timber in Cau Hai, Phu Tho province

Abstract

Mixed plantation experiments by native species for timber at the Forest
Science Centre for Central of North Vietnam in Cau Hai, Phu Tho province was established in 2001 on degraded forest land with different types of nurse trees such as Tephrosia candida and Acacia mangium. Measurement data in 2014 showed that, after 14 years of planting Cinnamomum obtusifolium and Lithocarpus fissus species in the experiments reached 86.5 to 87.8% survival rate, they have good growth and development. Some Lithocarpus fissus trees was able to supply timber (DBH over 30 cm), while the Canarium album and Endospermum chinensis species have a low survival rate (from 61.1 to 66.5%) and poor growth and development. At age of 14, the growth of Lithocarpus fissus species has D1.3 = 21cm, Hvn = 14.2m, Dt= 5.9m; Cinnamomum
obtusifolium species reached D1.3 = 13.3cm, Hvn = 11m, Dt= 3.7m;
Endospermum chinensis species has D1.3 = 8.6cm, Hvn = 8.8m, Dt= 2.7m
white Canarium album speices reached only D1.3 = 7cm only, Hvn = 7.5 cm
and Dt= 2.2m. The average yield of native species in the models ranged from 69.4 - 94.7 m3/ha (average is 86 m3/ha), the average increment from5.4 - 6.7 m3/ha/year (average is 6.1 m3/ha/year). Quality trees (including the small branches, stem straightness and development canopy) of Lithocarpus fissus and Cinnamomum obtusifolium species are good while Canarium album and Endospermum chinensis species are bad due to competed by other species in the experiments, especially in the experiment of nurse tree of Acacia mangium not been thinning at the age of 14 yet. Lithocarpus fissus and Cinnamomum obtusifolium species growth best in experiment of nurse tree is Acacia mangium.