Fig. 1

Percentage of leaves remaining on the trees during leaf fall in autumn for the 0 N (open circles, solid line), limited (full squares, dashed line) and control trees (full triangles, long dashed line). Each symbol is the mean of six trees plotted with standard errors. The means were ranked (a, ab, b) from the lowest to the highest values. They are significantly different if coded with different letters. Statistical significance was inferred from randomisation tests based on the generation of 2500 random orders