474 



This "sabre" or curved growth is explained by the annual bending by 

 the wind when the shoots are forming in the spring and summer. The tip of 

 the trunk, continuing its growth at this time, tends always to maintain the 

 perpendicular position and bends only as the tree is quickly blown toward 

 the horizontal. All that has been said here, in reference to the main axis, 

 refers also to all branches which, in windy positions, actually produce a 

 one-sided, flag-like top. 



The flag-like character results from branches bending away from the 

 wnid (with us toward the east) and from the scanty branching, with a 

 considerably longer main shoot, while the branches growing against the 

 wmd remain shorter and at times die back. 



Ludwig Klein^ gives very instructive examples in two spruces from 

 the pastures above the road Haldenwirthshaus-Wiedenereck. The trees on 

 the windy side had lost their branches almost entirely, as if one-half of the 

 top had been cut off with scissors (the pninivKj action of the wind). This 

 is ascribed by Klein to the drying action of the wind. To the eft'ect of the 

 wind is added an api)reciably greater warmth and consequently increased 

 transpiration. 



In fruit trees, the flag-like tops often bear fruit only on their outer 

 edges, since the interior growth is too dense. When the trunk has been con- 

 siderably bent from the perpendicular, a great difference in nutrition shows 

 itself between the upper and under side of the branch in the production of 

 a more luxuriant foliage on the upper half. The attraction of the luxuriant 

 wood shoots for the raw food substances from the soil, brought from the 

 roots, increases in proportion to their (le\elopment. The more they utilize 

 this solution, the more is lost for the horizontal part of the tree top, and 

 consequently some branches are pressed downward and begin to die, while 

 the new leaf axes shoot upward in the perpendicular and form water sprouts. 

 Thus is caused a sterility of many years duration. In various forest planta- 

 tions near the coast, this one-sided development of the crown is also notice- 

 able. The drying of the branches at any rate may be traced partially to the 

 constant rubbing due to the wind. The difficulty of reforestration of coast 

 stretches should not be explained by the salt content of the sea winds, as is 

 often done-, but simply by their mechanical action. 



The stunted forms of trees on coasts and upper limits of the tree line 

 is, in most cases, due to the wind. The tips are partly dried and broken off 

 by the wind. The weight of snow on the branches may have the same 

 result. In the next period of growth the tree attempts to develop a new top 

 shoot from one of its lateral eyes, which succeeds in conifers only when 

 there is local protection, and only rarely in stormy regions. As a result of 

 the broken top, the lateral branches grow with increased rapidity and often, 



1 Klein, Tj., Die botanischen Naturdenkmiiler des Gro.ssherzog-tums Baden usw. 

 Karlsruhe 1904, Fig. 26. 



- Anderlind, Leo, Bericht liber die Wirkung des Salzgehaltes der Luft auf die 

 Seestrandskiefer (Pinus Pinaster). Forstl.-naturwiss.. Zeitsch. 1897, Part 6. 



