Abstract: The natural forest in Tabalong District has been degraded, proved by the fact that Ulin trees (Eusideroxylon zwageri T. & B.) are rarely to be found. Ulin is in the status of endangered species, thus it must be protected and under the development efforts. Therefore, it needs information of the optimum growing requirements. The aim of this research is to analyze the relationship between land characteristics with the presence of Ulin. The data required are primary data collected by sampling method and secondary data by indirectly through institutions. Sampling was done by line observations followed the mapping unit representation which consists of land system majority, elevation, and slopes. Transects made the cut contour, thus the line observation represent the condition of ecological site from the lower land to the upper land. Data collection include data spatial of Ulin, relief, climate and soil sample. Land system and relief spatially analyzed using geographic information systems, while the land characteristics analyzed in the laboratory. The results of this study are optimum growing requirements on the attributes Ulin temperatures ranging from 25-32 oC, the availability of water (w): the number of dry months <3 month per year, rainfall >2000 mm per year, rooting medium (r): soil permeability is medium class, soil texture is sandy clay, soil effective depth >50 cm, soil porosity 55-65 percent, field capacity water >45 percent, nutrient available (n): does not require sufficient nutrient supply with low-grade organic C and relief (s) of slope <25 percent.