782 



by overgrowth or, in some cases, by a new formation of bark (cf. Barking 

 of Fruit Trees). The bark may also be worn off by rubbing and blows, 

 but in this the half-loosened remnants remain on the edges of the uninjured 

 bark in the form of tatters, or small rapidly drying and, therefore, curling 

 strips. Usually the traces of hair on the bark remain. Since deer and 

 roebuck rub their horns up and down against the tree, to free them from 

 the velvet, these rubbing wounds are longer than the peeling wounds and 

 more frequently extend around the trunk. Now, the roebuck sheds its 

 velvet in February and March ; the deer about the first of May, and others 

 four weeks later. The wounds, due to the latter, therefore, fall in a time 

 when the tree has the greatest amount of plastic material at its disposal. 

 They will, therefore, heal much more quickly than wounds made in the 

 winter and spring. It thus happens that the wound does not once reach 

 the cambium, but only removes the outermost bark layers. If the inner 

 bark remains in place the annual ring develops almost normally beneath it 

 from the cambium, at least, so far as the arrangement of wood and vascular 

 elements is concerned. The wood cells, however, are usually thinner 

 walled, with broader lumina, the ducts much more numerous, the whole 

 annual ring broader. If the weather is wet, or the habitat of the trees 

 shady and damp, a callus tissue frequently develops on the outerside, from 

 the cells of the youngest bark which has been left in place. This callus 

 tissue leads to the formation of new bark ; in rarer cases, with luxuriantly 

 growing trees, to the formation of isolated wood bodies. 



Wounds from blows and splitting of the bark also arise at the time of 

 "rubbing" and in the period of "heat" in the late summer. A different 

 method of healing the wounds now often sets in, since a callus tissue is 

 formed from the youngest sapwood layers on the wood body, which has 

 been freed from the bark; it fills out the hole, as in budded trunks (cf. 

 Budding). 



We have still to consider gnawed wounds, as produced by mice and 

 rabbits, beavers and hares. The latter, with their teeth, cut young branches 

 or weak plants. Real gnawing, which is so disastrous for our fruit trees, is 

 found usually only after deep snows. The wounds extend to the older 

 wood on which may be recognized the tooth marks. If these reach around 

 the trunk in connected surfaces, the tree is lost. If, on the other hand, 

 isolated particles of bark are left in place, an overgrowth takes place from 

 these. 



According to v. Berg, it is advisable to fell Aspens and Sallows {Salix 

 caprca), which game peels, at once, in order to protect the other trees from 

 similar injury. Finally, the scattering of food, during the winter, might be 

 cited as the best means of protection. We insert this chapter on the injury 

 due to game only in its relation to the anatomical processes of healing 

 wounds. This subject is treated very thoroughly in a recent work by 

 Eckstein^. 



Eckstein, Die Technik des Forstschutzes ffegen Tiere. Berlin 1904, Paul Parey. 



