Present theories of tropical rain forest regeneration dynamics suggest that different tree species specialize on the microclimates of different sizes of canopy gap. A detailed analysis of the microclimates of closed forest and 10 canopy gaps of different sizes was carried out in lowland dipterocarp rain forest, Sabah, Malaysian Borneo. It reveals that gaps exhibit considerable spatial and temporal variation in microclimate. As a consequence the relationship between microclimate and gap sizes is not simple. Gaps of the same size do not necessarily have the same microclimate and may favour the growth of different seedling species. Chance location and timing of gap creation play an important role in regeneration dynamics.
