Field performance of silver-birch planting-stock grown at different spacing and in containers of different volume

Silver birch seedlings were grown in two types of trays differing in cell volume. For each kind of tray, three different spacings were achieved by growing seedlings in all, half or one quarter of the cells. The planting-stock so produced was out-planted at two forest sites and growth followed for five years. Container size had a large effect on seedling morphology and on field performance. Density also had a large effect on seedling morphology, but little influence on performance. The tightest relationship of field performance was to the mean dry weight of the stems of the planting stock (R-2 = 0.94). Mean height and 'sturdiness' index, defined as diameter divided by height, were not correlated with performance. Of the non-destructive measurements, mean root-collar diameter was the most closely correlated with performance.