Period 7 in a line of trees

In a line of model trees the heights tend to vary with period 7 in many cases. This is the observable effect of an interesting structural reason: in the parameter space just beyond the border of the stability range of homogeneous heights stationary solutions with long spatial periods and irregularities can be observed before simpler short periodic solutions become stable. The model can be solved mainly analytically. The models ecological significance concerns the onset of patchiness in forest systems.