SHADE TREES. 



211 



the so-called winterkilling of conifers and rhododendrons in the spring 

 are in reality sun scorch. 



The rock maple is most commonly affected by sun scorch, although 

 other trees suffer to a certain extent. There is seldom a season that this 

 species does not sun scorch, and during the summer of 1913, 30 per cent. 

 of the trees in some localities were sun scorched so badly that the foliage 

 presented a decided reddish brown appearance. 



FIG. 84. Elm tree showing staghead from defective root system. 

 Note dead, stubby branches at the top. 



A> already stated, strong winds are one of the prime causes of sun 

 scorch. A few years ago in May there was a wind from the northwest 

 which blew at the rate of 71 miles per hour, and as a result many thou- 

 sands of rock maples sun scorched throughout the State. Burning in all 

 cases was confined to the northwest side of the tree. The particular winds 

 which cause sun scorch may easily be ascertained, for that part of the 

 tree exposed to the prevailing winds is always the one affected. 



Some trees are subject to sun scorch each year. Light, porous soils 

 having little water-retaining capacity are responsible for a great deal of 



