8o5 



produce accessory organs in the form of adventitious buds and roots. In 

 fruit culture, the girdhng process is used only as the most extreme means 

 of obtaining the setting of fruit in trees exhausted by a too vigorous forma-' 

 tion of wood. 



Personal Observations. 



To test the processes described 

 by earlier observers, the bark was 

 peeled from a considerable number of 

 strong, about 5 year old, sweet cherry 

 tree trunks in July. The upper and 

 lower parts of the barked places were 

 scraped for a length of 2 to 4cm. with 

 a knife to destroy the sap wood ; the 

 remaining part of the exposed surface 

 was left untouched (see Fig. 187). 

 Some of the experimental saplings 

 grown on open ground were bent from 

 their natural, vertical position to one 

 inclined toward the ground. 



The formation of new bark did 

 not take place in all specimens, but in 

 a few it occurred to a considerable 

 extent. Among the latter were found 

 some small specimens which had 

 formed new bark on all sides with 

 the exception of the perfectly dry, 

 scraped places near the upper and 

 lower edges of the cut. The new bark, 

 therefore, had no connection whatever 

 with the old bark. The initial stages 

 had appeared simultaneously on all 

 sides. The thickness of the new bark, 

 however, was more than twice as 

 great on the lower part of the exposed 

 surface as on the upper part ; in fact, 

 at the lower edge, it had spread in 

 short bands with wartlike thickenings 

 in places on the scattered scraped 

 areas. In an inclined trunk the con- 

 tinuation of the bark had turned away from the scraped place and started to 

 grow down toward the ground, as Fig. 187 e' shows. 



In Fig. 187, u is the lower and u the upper overgrowth edge of the 

 peeled surface. This overgrowth edge, which in structure resembles the 

 callus of the grapevine, has not been developed all around the trunk, since 





Pig. liiT. A ijuiked trunk of a sweet 



cherry. All young- tissue has been 



removed from the upper and lower 



edges of the place barked. 



