186 



THE GYPSY MOTH. 



diate attention. It is necessary to cut away the stump 

 which is left and to remove as much of the wood as will be 

 required to make an even surface ; also to cut away all the 

 bark which has been loosened below the wound. Otherwise 

 such a wound will in time present an appearance similar 

 to that shown in Fig. 22, and the injury may continue to 

 extend. If such wounds are not immediately treated and 

 covered with coal tar, their inner surface often 

 becomes decayed, threatening the life of the 

 tree. If the decayed wood is carefully cut 

 away and the exposed surface thoroughly 

 covered with coal tar, the tree will remain 

 healthy. Though the new wood and bark 

 may never entirely cover the wound, there 

 will be no further decay. 

 FIG. 22. A cavity A cavity treated in the manner above de- 



caused by the tearing . . 



away of a large limb, scribed is shown in tig. 23. Decay has been 

 stopped, and the new bark and wood have entirely covered 

 the edges of the wound, leaving the tree in a healthy condi- 

 tion. The directions given by Des Cars 

 for the use of coal tar on trees are so ad- 

 mirably stated that we give an extract 

 from them : 



Coal tar has remarkable preservative prop- 

 erties, and may be used with equal advantage 

 on living and dead wood. A single application 

 PIG. 23* A cavity properly without penetrating deeper than ordinary paint 

 treated; decay arrested forms an impervious coating to the wood cells, 



and healing begun. . . .. . , . . 



which would without such covering, under ex- 

 ternal influences, soon become channels of decay. This simple 

 application, then, produces a sort of instantaneous cauterization, 

 and preserves from decay wounds caused either in pruning or by 

 accident. The odor of coal tar drives away insects, or prevents 

 them, by complete adherence to the wood, from injuring it. After 

 long and expensive experiments the director of the parks of the 

 city of Paris finally, in 1863, adopted coal tar in preference to 

 other preparations used for covering tree wounds, as may be seen 

 in all the principal streets of the capital. . . . 



One coat of coal tar is sufficient for wounds of ordinary size ; 

 but when they are exceptionally large, a second coat may after 

 a few years be well applied. In warm countries, like the south 



