| Abstract: | Summary Specimens of Pinus halepensis, from the forest of Patemisco Gallio (Taranto) which were tapped, have been studied. The following conclusions have been reached The control specimens formed a double ring from May to October. The specimens which were chipped with the scraper (herring-bone method) show a strong acceleration of the wood ring formation. From May to October three rings are formed, each with its own resin ducts, but these channels are atypic, different from those of the ase tapping. The accelerating stimulus caused by the scraper is transmitted at lower levels, as the wounding proceedes from the upper region downwards. Considering that the successive wounds reache, by and by, regions of the stem aready accelerated in cambium activity, the summing up of the successive stimuli causes a sort of exhaustion of the cambium, so that the last rings are rather narrow with irregular and poor resin ducts. The specimens chipped with the axe (french method) formed a double wood ring like the control ones, showing only a slyght acceleration in comparison with the control specimens. This fastening of the wood ring formation does not transmit neither upwards nor tangentially. The resin ducts in the wounded wood are formed in their normal anatomical region, they are more numerous and bigger than those of the control. Conclusively: in the axe system the resin ducts are hudge and numerous and the rhytm of the cambial activity is the same as in the control specimens. In the scraper system an acceleration of the cambium activity occurs, with the formation of several wood rings during one tapping season, but the resin ducts are poor and irregular. |
