A new technique for studying plant interactions.
A new technique is described which can be used to separate the effects of root and shoot interactions between spp. or populations. The technique allows the following attributes to be varied independently: the size of the stand; the overall density; the relative density of component spp.; the relative density of spp. in soil space and in aerial space separately. Since the effects of the relative density of spp. can be investigated separately, above ground and below ground, it is possible to unify the complementary techniques of Donald and de Wit in the analysis of plant interactions. Other, more complex, comparisons are suggested which involve different effective densities above ground and below ground.