Effects of shade on growth and mortality of maple (Acer pseudoplatanus), ash (Fraxinus excelsior) and beech (Fagus sylvatica) saplings

We compared shade tolerance of maple, ash and beech in the saplingstage from two sites with rich soils differing in water supply,growing in dense thickets underneath a beech shelterwood ofvarying canopy densities. Shade tolerance was described by twocomponents: mortality in shade and height growth in high light.At low light, beech showed the least mortality, maple the highestand ash in between on both sites. The decline with increasinglight was steepest in beech and more gradual with ash and maple.At 15 per cent above canopy light, all three species approachedzero mortality. Beech as the most shade-tolerant species hadthe highest survival rate under low light and the least lengthgrowth rate under high light (>17 per cent). Ash had a lowersurvival rate at low light than beech and a highest growth rateat high light. Maple showed a bit weaker trade-off with thelowest survival rate but a growth rate inferior to ash. On thebetter water-supplied site, height growth was significantlysuperior in all three species only under high light. On thebasis of these results, silvicultural conclusions are drawnwith respect to appropriate light levels and cutting types.