148 Trans. Acad. Set. of St. Louis. 



soft wood has little resisting power. The tops of these 

 trees were broken very badly, and such as were not broken 

 were bent so far from the vertical position that they did not 

 go back to the same. The soft maples (Acer dasycar- 

 pum) were most affected. Large and small limbs of this 

 useful shade tree were broken off, and there were few trees 

 which escaped entirely. The honey locust {Robinia pseud- 

 acacia) lost many branches, likewise the oaks, ash, peach and 

 apple trees. Some trees escaped entirely, notably the cypress 

 (Taxodium disticltum), which likewise successfully resisted 

 the tornado ; furthermore, thegingko ( Gingko biloba), whose 

 long, sweeping branches bent under the load, but did not 

 break. The pines suffered very severely. 



The ice remained on the shrubs and trees for several 

 days, and not until March 5th was it entirely gone. The 

 branches gradually resumed their original position, while the 

 trunks did so more slowly. The lower figures on PL X, XI, 

 are from photographs taken just one week after the storm, 

 March 6th. The camera was placed at the same points as it had 

 been in taking the photographs immediately after the storm. 

 The branches of the hornbeam returned to their former 

 position, with the exception of one branch which was broken 

 by the load. The maples on Flora avenue show some residual 

 effect. The ice remained on the trees for so long a period 

 that the wood on the convex side became stretched, and when 

 the top returned to the vertical position, the stretched side 

 remained somewhat convex. How long the bent position 

 will last, cannot be guessed at this time. These trees are 

 still bent at this writing (April 2d). The trees in the cen- 

 tral row are birches (at the left of the figure). They have 

 straightened completely. The arbor vitae and related conif- 

 erous trees show the residual effect of the ice more than the 

 trees of the hardwood type. 



The weight of ice which the trees were called upon to bear 

 was a very great one, greater than any that has been known 

 in this region for many years. The ice can hardly be con- 

 sidered an ecological factor in the life history of a tree in 

 this climate, for it is a factor which exerts an influence on 



