37 



DISEASES OF TREES. 



The relations of forest fires to insect mvages, insects to forest fires, 

 diseases of trees to insects, and insects to fungous diseases are not obvi- 

 ous at first sight, but Dr. A. D. Hopkins shows in a report on the insect 

 enemies of forests in the north-west, just issued by the U. S. Depart- 

 ment of Agriculture (Division of Entomology), that there is a close 

 connection, and, to a certain extent, inter-dependence,of all these factors 

 in the destruction of valuable forest products. Tr^es dying from injury 

 by fires, or weakened in vitality, offer favourable conditions for the mul- 

 tiplication of vast numbers of destructive insects. Moreover, trees 

 which have been killed by insects furnish, in their fallen branches, 

 standing and fallen partly decayed trunks, and dry bark, a most favour- 

 able condition for the starting, rapid spread, and perpetuation of forest 

 fires. It IS well known that forest trees weakened bv disease contribute 

 to the multiplication of their insect enemies; therefore the study of the 

 insects associated with unhealthly forest trees should lead to results v.f 

 economic importance. As an example of insects contributing to the 

 spread of fungous diseases, Dr. Hopkins reports that the heartwood of 

 the white fir throughout the region examined by him was commonly 

 rendered worthless by decay as the result of wounds in the living bark 

 made by Scolytus bark beetles. — (Nature.) 



JAPAN WAX AND VARNISH. 

 Japan Wax. 



This is afforded by several species of Rhus, the most important 

 being R. succedanea, which flourishes especially in the W. provinces of 

 Japan, as far as 35 ® N. lat. ; second in order is R. vernicifera which 

 extends to 38 ® . 



The cultivated wax-tree (R. succedanea) was originally imported 

 from Loo-Ohoo Islands, but growers now distinguish 7 different 

 varieties. The tree flourishes in great abundance on the mountainous 

 declivities of the island of Kiushiu, and in the provinces of Higo, 

 Hizen, Chikugo, and Chekuxen, but less plentifully in Satsuma. It is 

 planted along the road-ways, and around the edges of most cultivated 

 fields, except rice-land when two years old, at distances of about 3 ft. 

 between the stems; when set in squares,the interval is doubled. It is kept 

 low by topping, and pruned to a pyramidal shape; propagation appears to 

 be effected by shoots from the root. According to Simon, in the 5th 

 year after planting, each tree gives 4:1b. of berries, 61b. in the 8th, 181b. 

 in the.lOth, 401b. in the 12th, 601b. in the 15th, and declines after the 

 18th year ; 41b. of berries should yield lib. of wax. 



The tree puts forth new leaves in April, blossoms in June, and 

 ripens its berries in October to November. The berries are of the size 

 ot small peas, united in bunches ; the wax is contained between the 

 kernel and the other skin. The bunches are gathered, sun-dried for a 

 few days, and stored in straw ; when sufficiently mature, they are 



