Rapid response of large, drought-stressed beech trees to irrigation

Large, declining Fagus sylvatica growing on heavy clay soils in the highlands near Zurich, Switzerland, were amply irrigated in late summer. Trees with deep, narrow, dense crowns, growing in more open places and adapted over a long period to high irradiance remained healthy during drought. Prolonged, periodic water shortage reduced the amount of foliage up to 90% but during drought stimulated the growth of fine roots in the surface and upper soil layers. -from Authors