HEARTVVOOD OF CRVTOMKRIA JAPONICA 



861 



heartwood had not y^t begun to develop, most of the wounded trees 

 had false heartwood of a brown color. This shows that the wounds, 

 being the indirect cause of the formation of the heartwood and its 

 darkening, instigate the transformation of the sapwood into the heart- 

 v/ood and induce at the same time the discoloration of the wood. The 

 results may be summarized as follows : 



Tabi^ 7. 



These figures evidently favor the above view. But such wounds as 

 are not externally visible are not usually found. So we examined 

 carefully five individuals of "black tree" which were suggested by 

 experts in the district of Yoshino to be entirely devoid of wounds. 

 Efifective wounds were found however in the interior of the stump of 

 each of these trees. Furthermore, we made a cut with a hatchet, one 

 and a half feet above the ground and extending into the heartwood, 

 on one side of the trunk of 18-year-old "red tree" on the grounds of 

 the Forest Experiment Station, and cut down the same tree after three 

 months. In a longitudinal section of the trunk through the cut, the 

 partial unilateral darkening of the heartwood, extending one foot 

 upwards and three inches downwards from the cut on the correspond- 

 ing side, was observed on the day after its felling and sawing. Among 

 three 50-year-old trees of "Sugi" growing closely together, only one 

 showed an extreme darkening after its felling and sawing into boards 

 and it possessed a big wound in the stump. 



But as is shown in Table 7, not a few "red trees" were wounded 

 as much as "black trees," while many of them, owing to the fact that 

 the phenomenon had only just begun, or was only of local occurrence 

 or weak in intensity, were practically classified in this district as 

 "red tree." The unilateral darkening was often found in the same 

 investigation. 



