576 



raised cf)rk into many tatters. In drying, the xarious tatters curl backward 

 and thereby expose tlie bark parenchyma which has been C(jvered. It 

 should also be observed that such cork tatters are most trc'iucntly found 

 directly at the base of the young, still smooth barked trunks, while the 

 younger shoots seem outwardly unaffected and also sprout but, yet, after 



some time, the leaves turn yellow and wilt. 

 1"he life of the tree depends (ju the 

 extent and frequency of such holes in the 

 cork which are found repeatedly separated 

 from one another b\- healthy spots. The 

 tree usually dies since the cambium under 

 the Idackened parts of the bark is dead. 

 The region near the buds or near cut 

 branches seems especially dis})osed to such 

 injuries 1 rom frost. 



TiiK l*HF..\c)iMi;x.\ OF Discoloration' in 



Tr U N K S ;\ M ) B RAN CH ES. 



bruit growers in spring pruning usu- 

 all\' decide after a consideration of the cut 

 surface, whether a \ariely of fruit ha:- 

 pro\ed hardy ior a certain region, or has 

 been injured by the cold. The decision is 

 made according to whether the cut surface 

 is uniformly white or browned in places. 

 Tlie browning sometimes occurs in circular 

 zones, sometimes in flat surfaces. In the 

 first case (often on one side of the branch ) 

 the cam])ial region, or the periphery of the 

 pith disc, the so-called pilh crcnun where 

 the innermost ducts of the wood ring pene- 

 trate into the pith parenchyma, is the centre 

 of the discoloration. In the surface brown- 

 ing, a part of the wood surface together 

 with the pith body is usually attacked on 

 that side of the branch where the bud lies 

 which belongs to it. The discoloration is a 

 sign of the humification which sets in 

 gradually in the walls wlicn the cell con- 

 tents dry up. Not infreciuentiv phenomena of swelling are noticed in the 

 l)r()wn cell walls. 



If difl'erent parts of the trunk are frozen, brown stripes are found at 

 times extending downward to different depths in ihe wood body; in the 

 browned parts through its whole diameter. These stripes often have a 

 symmetrical arrangement so that a cross-section through the semi-healthy 



127. Raggedly 

 lac on branches 

 fi-ost. 



11 red 



