40 Forest Club Annual 



leaflets affected. The injury occurred at the tips and extended 

 half way toward the base. The leaflets were shed from the 

 petiole rather than falling with it. 



Golden Willow, (Sali.v lit^Uina L.) had nearly all its leaves 

 from one half to three-fourths frosted. The injury extended 

 diagonally across the leaf. The injury on the leaves of Salix 

 Babylonica dolasaca extended from the apex down the sides 

 and went nearly to the midrib. Salix vitcllina Linn., was simi- 

 larly affected and also showed that the north side of the trees 

 suffered most. 



Bass wood, (Tilia americana Linn.) had the leaves affected 

 on the sides as. well as the tips. The north side of the tree was 

 invariably more seriously affected than the south side. In a 

 row extending north and south on an exposed site, one tree had 

 50 per cent of the leaves affected while the other five were not 

 injured. 



Oaks in woodlot formation showed only the slightest injury. 

 Pin Oak, (Quercus palustris Muench.) in the open, had fully 

 one half of its leaves touched. Chestnut, Tulip Poplar, Red 

 Oak, and Mountain Ash were not affected. 



It was very noticeable that Green Ash and Box Elder 

 were more seriously injured on low ground than on high ground. 

 Other species might have shown the same effect had they been 

 found on both sites. The base of the crown was the zone in 

 which most species were injured but Cottonwood and Poplar 

 seemed to be exceptions and this may be due to the earlier leaf- 

 ing out in the top of the crown. Many trees in rows running 

 from north to south, showed the north half of each crown equally 

 injured. The effect o f such a frost on forest tree growth seems 

 to be a stimulation of dormant and adventitious buds. This 

 year's growth ring will probably be narrower in the trees that 

 suffered an almost complete defoliation. 



