38 Forest Club Annual 



part curled up underneath the leaf rather than folding back 

 as it did on the poplars. Regeneration occured at the end 

 of the twig first and the new growth came largely from dormant 

 buds. Careful count was made of the leaves killed on a row 

 of one year old transplants. The injury varied from 50 per 

 cent on some trees to 98 per cent on others. Here, terminal 

 leaves were most seriously affected and new growth developed 

 from lateral buds. These trees were situated on high ground 

 in a very exposed position. Camperdown Elm (Ulmus scabra 

 pendula Loud.) had an average of thirty per cent of its leaves 

 injured. The bases of the injured leaves were persistent. 

 English Elm (Ulmus campestris Smith.) was very slightly af- 

 fected. Slippery Elm (Ulmus pubescens Walt.) was not at 

 all affected as the buds did not open until after the frost. 



Horse Chestnut, (Aesculus hippocastanum Linn.) had every 

 leaf affected. The apex and margins were badly injured, leav- 

 ing uninjured only a small area containing the midrib. Fully 

 80 per cent of the leaves were shed, the leaflets falling before 

 the petiole. New leaves were formed quickly from axillary 

 buds which normally would not have developed until the next 

 year. A large number of dormant buds and a few adventitious 

 shoots also developed. 



Cucumber Tree, (Magnolia acuminata Linn.) at the time 

 the frosts occured had a large number of leaves well developed. 

 The apex and the outer half of all leaves were killed back and 

 the dead part folded in a flap on either the under or the upper 

 surface of the leaf. The uninjured portion was characteristi- 

 cally diamond shaped. The tips of the fruit were just touched 

 by the frost. There was a slight stimulation of dormant buds. 

 Magnolia grandiflora Linn, had some of the leaves entirely killed. 

 All those which remained had their tips injured, but their mar- 

 gins were not affected. There was a strong stimulation of 

 dormant buds. 



Silver Maple, (Acer saccharinum Linn.) had 70 per cent 

 of its foliage injured. The lobe was the zone of most charac- 

 teristic injury but the tips and the margins up to the point where 

 serrations began, were badly affected. The margin at the ser- 

 ration was free from injury. Most of the injured leaves were 

 shed. 



Green Ash, (Fraxinus lanceolata Borkh.) is another species 

 which clearly showed more injury on the north side of the 

 crown than on the south side. The leaves were frosted at the 

 apex and along the margins. In two plantations at the Nebraska 

 Experiment Station which had the same exposure and were 

 planted on the same site, one was badly injured while the other 



