Figure 1. (A) Subdivision of Larix decidua tree rings according to the time of formation: the first formed cell layer in which TRD formation usually occurs as the result of injury during the dormant season (d), early (ee), middle (me) and late (le) earlywood as well as early (el) and late (ll) latewood. (B) The relative tangential extent of traumatic resin ducts (TRDs) at the wound height takes account of the area available for resin duct formation and the absence of cambial activity in the injured segment. The portion of the ring with cambial activity thus represents 100% of the surface where TRDs can theoretically form.