318 Sltilc Iloiiiciillnral Socicly. 



it is not frozen, the cells separate, as llu' ])r(jti>])]asni in them dies and the 

 leaf dries rnit. The corky ]a_\er left protects the stem from injnry 1)\- dry- 

 ing out, or l)y the entrance of rain and sleet during the winter. In this 

 way the tree is covered naturally with a water-])r()()f, corky layer during 

 the dormant season, which allows hut little loss of water. 



Wounds which exj>ose large surfaces to the air at the time the tree 

 is dormant make severe drains upon the water content of the tree. It is 

 unable to make up the loss of water by new supplies from the rtxjts and 

 consequentl\ sulTers damage. 



The trees shown in figures 2 and 3 are in the worst possible shape 

 for enduring the winter. Not onl)- are the beauty and symmetry of the 

 tiees com])letely ruined, but the large exposed surfaces will allow serious 

 loss of water while the tree is in a condititm least able to withstand it. 

 In cases where it is necessary to make large cuts (which are rare) it 

 should be done in the spring, and then the wound should be painted 

 over. 



CAKE OF TKliliS. 



Assunn'ng that the tree has been properly planted, we may now con- 

 sider what shoidd be done from year to year to keep it in growing con- 

 dition. 



Protection Ai^^ain.st Injuries. — All trees, but es])ecially street sha<le 

 tixos, are exiiosed lo injuries of various kinds. Witli the development 

 of our cities and towns, the adverse conditions multiply from year to 

 year. 



Excavations for buildings, sewers, etc., destroy portions of the root 

 system, thereby cutting off the food supply. The street pavements and 

 sidewalks are well-nigh impervious to water and hence diminish the supply 

 of moisture in the soil on which they lie. 



Unless ])roper precautions are taken, street trees suffer badly from 

 having the bark gnawed of! by horses. As has been shown, this destroys 

 some of the most important tissues in the tree. The trees may be pro- 

 tected by a wrapping of burlap, tied on with tarred rope, l)ut a substantial 

 iron or wooden frame (Figs. 4 and 5) is better, because the burlap makes 

 a breeding place for injurious insects. 



The mulch should be removed from the base of the tree at the ai)- 

 proach of winter, because it is likely to become inhabitated by mice, which 

 girdle the trees when food is -scarce in winter. If other rodents become 

 troublesome, the bases of the trees should be enclosed with a guard of wire 

 screen eighteen inches high, or the trunks may be painted with a lime 

 wash made rather thick and containing one tablespoonful of Paris green 



