METHOD OF PLANTING. 21 



soon dries and seems dead. The blisters from sun scald frequently extend 

 from near the ground to well within the crown of the tree, and in the 

 worst cases a scar is left covering the entire southern half of the stem, 

 there being no living wood within the scar (PI. II, B). Sometimes in 

 very small, rapidly growing trees these long scars, will heal over by 

 growth from the edges of the bark surrounding the wound. More fre- 

 quently they never heal, but sapwood decays on the scar and a hollow 

 forms in the trunk of the tree. 



The species most subject to sun scald are those with thin, smooth bark, 

 especially those which naturally grow in dense, shady woods, as maple, 

 beech, linden, tulip poplar, and some of the magnolias; while the oaks, 

 elms, and ashes are seldom affected. As trees, even of the tenderest 

 species, become older and the bark becomes rough, they lose their sensi- 

 tiveness and no longer sun scald. Small trees of tender species, unless 

 they have been hardened by being grown in open nursery rows, require 

 , a shade protection on the southern sides. When a guard of wooden slats 

 is used, that is sufficient. When no slat guard is used, a cheap triangular 

 shade guard can be made of one solid, vertical board, which is placed to 

 the south side of the tree. A few rows of horizontal slats form the two 

 other sides, being nailed where they meet to a vertical post (PI. IV, A). 

 This guard should be anchored securely by means of stakes driven deeply 

 in the ground, to which it is nailed. The tree, as has been explained, 

 should be fastened to it by leather or cloth bands across the top to pre- 

 vent rubbing. A guard of this kind is preferable to wrapping the stem 

 with straw or sacking. 



Wounds resulting from sun scald should be treated like other wounds. 

 The loose and diseased portions of bark, under which the inner bark has 

 darkened or discolored, should be cut away until healthy tissue is exposed 

 around the entire wound. The surface of the exposed wood and the edge 

 of the living bark should be well covered with a linseed oil paint and the 

 stem of the tree suitably shaded to prevent further extension of the 

 injury. In case further blistering takes place the dead bark should again 

 be cut away. Such a wound, though large, will, if carefully managed, 

 heal on a small tree. 



Suckers frequently appear from the base of trees which have been badly 

 sun blistered. They should be removed at once. Sometimes, following 

 very heavy pruning, which admits direct sun-light, sun scald takes place 

 on the upper part of the trunk which has been exposed. Such. wounds 

 should be cared for as suggested, and heavy crown pruning subsequently 

 avoided for such species. 



