Hung Pham Quoc

PhD project

Successional Response to the Light Regime in Evergreen Moist Forests of Vietnam

In Vietnam land use and forest cover has changed significantly during decades. For many reasons, the forested areas had reduced from 14.2 million ha (43%) in 1945 to 9.3 million ha (28%) in 1996. In reaction the Government of Vietnam, has launched various reforestation programmes, such as: PAM from 1976 to 2000, National Programme for Upland Development from 1993 to 1998, and recently the 5 Million Hectares Reforestation Programme (5MHRP) from 1998 to 2010. The goal of the 5MHRP is to establish the forest cover rate of the country by the year 2010 up to 43% (14 million ha). After years, hundreds of thousand hectares of Eucalyptus, Acacia, Pinus plantations (monoculture or polyculture) and naturally rehabilitated forests have been established. In some aspect, Vietnam has achieved its initial purpose of regreening the bare lands in mountainous areas with the forested area of 12.3 million ha in 2004. However, the management of those forests or plantations principally for wood production may cause nature bias because of insufficient knowledge of ecology of various tree species in the forests/plantations, especially their light requirement for growing. In moist evergreen forests light becomes a limiting factor and light intensity requirement of a tree for its growth depends on the characteristics of each species (light demanding, shade bearing or opportunist). The objectives of this study are to find out the relationship between forest structures, species components and the light regime under the canopy of each successional stage of forests, and the effects of those on the regeneration characteristics. Also in this study, carbon stable isotopes of some species are initially studied to identify whether there is any difference between shade tolerant and light demanding species in 13C values with the hope of using carbon stable isotopes as a useful tool to identify light requirement level of species.

Prof. Dr. R. Mitlöhner (Burckhardt-Institute, Dept. Tropical Silviculture and Forest Ecology, University of Göttingen)