»t>TAMCAL 



TORREYA 



Vol. 23 No. 6 



November-December, 1923 



RESISTANCE OF TREES TO ICE STORM IXJCRV 



Walter E. Rogers 



In a previous paper the writer* presented seme data on the 

 extent of accumtdation of ice on trees during the glaze storm of 

 1922 in the Great Lakes region. Seeleyf in Monthly Weather 

 Review gixes general estimates from various observers in 

 Michigan on the amount of damage to trees. The present paper 

 deals in a detailed way with the extent of injury to different 

 species. 



During the weeks following the storms examinations were 

 made of over two thousand trees, representing nearly forty 

 species. These grew within a ten mile radius of the northern 

 end of Lake Winnebago, Wisconsin, and included trees of a 

 variety of habitats such as city street, country roadside, river 

 bank, farm woodlot, and swamp. 



In the field the trees were listed in three divisions on the basis 

 of size, the mature trees being designated as "large," the saplings 

 as "small," and those of intermediate size as "medium." The 

 trees in each division were classified on the basis of damage 

 received, those having half or more of the crown broken being 

 designated as "heavily damaged;" those having lost less than 

 half the crown, but still badly injured, were indicated as having 

 received "medium damage," while trees with no injuries at all, 

 or with injuries no more severe than a broken branch or minor 

 limb were placed in the column with the "slightly injured." 

 Finally, trees which were permanently bent, but not broken, 

 were noted. The results of the study are embodied in the 

 table on the following page. 



In making out the ranking of the species in the order of their 

 resistance to storm injury, the figures of column 15 were added 

 CNi to those of column 14. This assumes that permanent bending 

 T- is equivalent to at least medium damage. 



^^ * Rogers, Walter E.: Ice Storms and Trees. Torreya, 22: 61-63. 



t Seeley, D. A.: The Great Glaze Storm of February 21-23, ir* jNIichigan. 

 ^ Monthly Weather Review, 50: 80-82. 



*!? 95 



