1 'Watershed Management Technology Research and Development Center, Surakarta Development of meranti (S. leprosu!a) plantation forest is limited by e.g., seed/ seedling ~upply and seedling growth environment. Natural Dipterocarpaceae forest has irregular fruiting season. Not every year we can harvest a lot of its seeds, but there is an unpredictable time when the natural Dipterocarpaceae forest can be so productive, known as mass flowering. Most of seedlings supplied from seeds still face with some problems, such as short period of seed viability and short period of seed storage capability. To solve this problem, vegetative cutting is one of the alternatives to be developed currently. Growth of Dipterocarpaceae's, meranti seedling is influenced by several factors, mainly light intensity which can pass through all the way into forest floor. Light intensity factor is strongly correlated with the relative capability of genetic gain and plant physiologies for the growth in specific environment, and the capability to avoid low light intensity in general (Baker et al., 1987 in Daniel et al., 1987). Meranti is included in the plant group of Gap I. INTR ODUCTIO N Keywords: Shorea leprosuia, Acacia tllangit1111 stand, light intensity, height growth Development of meranti (S. leprosula) plantation forest is limited/ constrained by many factors, e.g. seed supply and seedling growth environment. The research deals with the observation of the current condition on A. tllangi111v stand and did not employ any treatments. Meranti seedling was obtained from vegetative cutting (Komatsu-Forda), at one year (old) post planted meranti under A. ma11gi11111 stands and spacing of 4 x 2 m, approximately two hectares of permanent sample plot (PSP) were made. In each hectare of young meranti plants with spacing 10 x 3 m (330 seedling/ha), 9 (nine) observation plots with size 10 x 10 m (6 seedlings/plot) were prepared, and placed in the middle of PSP. Totally, there were 108 seedlings available for the measurement of particular parameter, i.e. light intensity, height growth, and survival rate. Light intensity was measured by going around of 10 x 10 m plot. Result of measurement in each observation plot (10 x 10 m size) rescaled that light intensity ranged about 6,55 - 35,2% or being equal with 4908 - 26568 flux hour. Meanwhile, the best height growth response and survival rate were at 10 % light intensity or over. ABSTRACT Hern Dwi Riyanto 1 GROWTH RESPONSE OF ONE YEAR OLD POST PLANTED Shorea leprosula SEEDLIN G TO VARIOUS LIGHT, UNDER 19 YEARS OLD Acacia mangium STAND