82 TREE WOUNDS AND DISEASES 



the young leaves of several healthy elm and 

 other trees situated about half a mile from the 

 chimney of an electric producing plant were 

 completely blackened in one night by the 

 fumes being carried in that particular direction 

 by the wind. The foliage never recovered, but 

 crumpled up and fell off, though later in the 

 season it was replaced by a second crop of 

 leaves. This, if often repeated, is distinctly 

 injurious to the health of the trees, and points 

 to the fact that these should not be planted 

 within range of such fumes, and particularly 

 in the direction from which the prevailing 

 winds of the district may be expected to carry 

 the smoke. 



Lightning causes damage to trees, principally 

 isolated specimens, but, comparatively speak- 

 ing, the amount of injury done is trivial and 

 cannot be prevented. The oak, Lombardy 

 poplar, and elm suffer most, and particularly 

 when grown in the open park, by the field- 

 side, in the avenue or hedgerow. It is a 

 strange fact that trees in certain parts of a park 

 or grounds are frequently struck by lightning, 

 while others of a similar kind and size at no 



