Growth assessment of some understorey planting models for native species in Soc Son district, Ha Noi

Abstract

Planting models of 4 native tree species, including Cinnamomum parthenoxylon, Erythrophleum fordii, Hopea odorata, Terminalia nigrovenulosa, under the canopy of pine, acacia and acacia-pine mixed plantations in Soc Son - Hanoi have a low to moderate survival rate, from 60.0% to 87.1%. For Cinnamomum parthenoxylon, at the age of 3 - 4, the average growth rate D 00 = 0.17 - 1.34 cm/year, Hvn = 0.83 m/year, Dt = 0.22 - 0.55 m/year; at the age of 8, D1.3 = 0.80 cm/year, Hvn = 0.83 m/year and Dt = 0.41 m/year. The average growth rate of 3 - 4 years Erythrophleum fordii is D00 = 0.22 - 1.23 cm/year, Hvn = 0.33 - 0.63 m/year and Dt = 0.22 - 0.54 m/year; up to age 8, D1.3 = 1.79 cm/year, Hvn = 1.00 m/year and Dt = 0.54 m/year. The figures for Hopea odorata at the same age range of 3 - 4 years are: D00 = 0.53 - 1.66 cm/year, Hvn = 0.82 - 0.85 m/yearand Dt = 0.32 -0.42 m/year. Terminalia nigrovenulosa at age 1 initially had good growth D00 = 1.08 - 1.18 cm and Hvn = 0.96 - 1.06 m. The species of Cinnamomum parthenoxylon, Erythrophleum fordii, Hopea odorata at the age of 3 and 4 have more light requirement. At low coverage levels, these species grows better than at higher levels in the same types of main plantations. On the model of re-establishing tropical forests, a total of 83 species of woody-species and shrubs were initially planted, but now there are only 10 - 17 species have a good growth and development, with an anual stand average growth rate of D1.3 = 0.39 - 2.69 cm, Hvn from 0.26 - 1.36 m, and Dt from 0.15 to 0.54 m.