INJURIES TO TREES. 115 



poison should be used. It should be placed under the mulch 

 in tin cans laid on their sides so they may be readily found in 

 spring and will not be liable to poison the birds. When seed- 

 lings are thrown out of the ground by frost they should be 

 pushed back and have the earth pressed against them as soon 

 as the ground is thawed in the spring. 



Lats Spring Frosts are common in the low lands of this 

 section. They injure the trees by killing the new spring 

 growth after it has started several inches. A large number of 

 trees are seriously injured in this way and are classed as 

 frost tender trees, and those that are not liable to this injury are 

 termed frost hardy trees. Among conifers the spruces and bal- 

 sams are much injured by late spring frosts while our pines and 

 the Tamarack. Red Cedar and Arborvitae are seldom if ever in- 

 jured in this way. Deciduous trees recover from such injuries 

 more quickly than evergreens. Among the deciduous trees 

 most liable to injury from this cause are the Ash, Mulberry, 

 Oak. Maple, Basswood, Black Walnut, Butternut and Box 

 Elder, though they do not all suffer in the same degree. 

 Among those that are not sensitive to late frosts are the Elm, 

 Willow, Poplar. Birch, Hackberry, Wild Black Cherry and 

 Mountain Ash. 



Sleet Storms occasionally do much damage by breaking the 

 limbs. Little can be done to relieve the trees but preventive 

 measures may be taken. If no large crotches are allowed to 

 form in trees and growth kept as near as possible to one 

 central shaft, or the longer branches shortened so as they will 

 not exert too great a leverage, the losses may be reduced to a 

 minimum. Trees having brittle wood or weak crotches as the 

 Soft Maple are much more liable to this injury than those 

 with tough wood as the willows, oaks and elms and need 

 more pruning on this account. Evergreens are likely to be 

 broken by heavy snows that freeze on the leaves. This may be 

 prevented on lawn and shade trees by shaking the snow off 

 from them before it freezes. 



Frost Cracks are a rather infrequent injury caused by the 

 cracking of trees from center to outside due to uneven con- 

 traction in very cold weather, it is generally accompanied by 

 a loud report. Such cracks are often eight or ten feet long 



