The willow (Salix babylonica L) was used as the experimental tree, and sodium arsenite and sodium chloate were applied to a ring barked part.
After the trees withered, some blocks were cut away from them as testing wood. Our measurements of the force required for barking were done twice for a testing wood, immediately after cutting and after two months storage.
The measurement of the force required for bark ing was conducted as follows.
The testing block was kept to level and a little pan was attached at the end of the bark. The weight of the pan was gradually increased by adding the weights to the pan. When the barking was to begin, the weight of the pan was measured. The measured value correspond to the force required for barking.
It was found that the forces required for barking differ remarkably among each individual tree treated in the same way and even among each measured position in the same testing wood.
In the case of applying 17% sodium arsenite and 17% sodium chlorate, no remarkably decrease of the force required for barking was observed either after cutting or after storage.
In the case of applying 43% sodium chlorate, remarkable decrease of the force required for barking was observed only after storage, although no remarkable decrease of the force observed immediately after cutting.