1963 Volume 45 Issue 12 Pages 397-403
The authors have reported in previous papers on damages incurred upon Cryptomeria timber by the Cerambycid beetle, Anaglyptus fasciatus that heavier damages were observed in forest stands of inferior types, but it has not been referred to the degree of damages in relation to the status of growth of trees. In this connection the authors carried out a series of investigations to clarify the relations between the damage caused by the beetle and characteristics of branches of stands in sites of different soil types. The results are summarized as follows:
(1) The damages of single tree can be divided into 2 types in view of its vertical occurence. The damages of one type spread predominantly among the trees of a good site, and is mostly concentrated in the vicinity of clear length height, and becoming much less in the lower part of trunks. The damages of another type, which is severer than the former one are found in the trees grown at poorer sites where the points of damages are distributed upward from the lower part of the trunks.
(2) Based on the measurement of branches attached below the branches of the largest spread, comparisons of branches of the trees in different soil types are shown Table 2, 3 and Fig. 2. Furthermore, the significance of differences of measurements with respect to different soil types has been tested as indicated below:
(a) Total number of branches BD>BB(w) Non-significant (at 5% level) BD>BB Significant (at 5% level)
(b) Total number of damaged branches BB(w)at 5% levelBD Significant (at 5% level) BB>BD Non-significant (at 5% level)
(c) Number of dead branches and remains of broken branches BD>BB(W) Non-significant (at 5% level) BD>BB Non-significant (at 5% level)
(d) Number of damaged branches amoung dead branches and remains of broken branches BB(W)>BD Significant (at 5% level) Ba>BD Significant (at 5% level)
This is closely related to the occurrence of the “scattered rot” of timber, and it is more numerous in the stands of poorer sites such as BB(w) and BB soil type.
(3) Total number of galleries of the present and preexistent larval feeding and also their number of occurrence per damaged branch are larger in the stands of BB(w) and BB soil type.
(4) The frequency distribution for the diameter of damaged branches is different in each stand and its maximum is observed in the branches of comparatively slender size in the case of BB soil type. As for the length of branches, damaged branches under 60cm in length (containing remains of broken branches) are more numerous in BB(w) and BB soil type than in BD type.
(5) In the stands of the soil types BB(w) and BB, the trees grown in more less favourable surrounding condition, had sparse crowns and a large number of remains of broken branches and exhibited a poor growth rate. Such status of trees have a close relation to the damage of the Cerambycid beetle.
