The guild composition of a hill dipterocarp forest was examined using growth traits of 1566 trees comprising 422 species through field observation at a 6-ha plot for 6 years in Sumatra. Three parameters, intrinsic growth rate, attainable maximum stem diameter, and stem hardness, were used for guild determination. The intrinsic growth rate showed a significant correlation with stem hardness, which suggested a trade-off between volume growth and architectural strength under the restraint of photosynthetic products. Four major guilds were determined, characterized as Soft wood-Small size-Fast growth, Soft-Big-Fast, Hard-Big-Slow, and Hard-Small-Slow traits. Ecological niches of these guilds were related to the large variance of resources in time and space of a tropical rain forest. A secondary forest part in the 6-ha plot retained high species diversity, but species composition was largely different from that of the mature stand. Human activities biased guild composition to reinforce the Soft-Small-Fast guild, with a reduction in the Hard-Big-Slow guild that included many marketable timber trees. Logging impacts on dipterocarp and fagaceous trees were assessed with reference to their spatial distribution and attributes of guilds.