  Ecological communities exhibit pervasive patterns and inter-relationships
between size, abundance, and the availability of resources. We use scaling
ideas to develop a unified, model-independent framework for understanding the
distribution of tree sizes, their energy use and spatial distribution in
tropical forests. We demonstrate that the scaling of the tree crown at the
individual level drives the forest structure when resources are fully used. Our
predictions match perfectly with the scaling behaviour of an exactly solvable
self-similar model of a forest and are in good accord with empirical data. The
range, over which pure power law behaviour is observed, depends on the
available amount of resources. The scaling framework can be used for assessing
the effects of natural and anthropogenic disturbances on ecosystem structure
and functionality.
