FIG. 3. Time course of depth growth of roots (bottom) and height increment of shoots (top) of 3-year-old Betula pendula (averaged data from twelve plants) during the first vegetation period in the Eberswalde root laboratory. Each dot represents a growing root tip. The solid line represents the mean depth increment of all growing roots; the dashed line shows the course of the maximal depth of root penetration (data from Hoffmann, 1966a).