63 
The prize tree, a Hammond Japanese-American hybrid of 1931, 
is now 7 feet high, at the end of its third year. The growth rate 
has obviously decreased from those of the previous two years. 
It was also cut back a little in the spring, on account of possible 
winter injury to the tips of the branches. We have now three 
Smith hybrids (3 yrs. old) which are over 5 feet in height. Here 
again we have an illustration of what is meant by ‘‘hybrid vigor.”’ 
Winter Injury.—The effect of the extreme cold of the winter of 
1933-34 on the various species and hybrids of chestnut was most 
interesting. The mercury fell as low as 24° below zero, the 
neighbors reported. In the two plantations, one in fine garden 
soil lower down the mountain and the other in poorer soil farther 
up, the differences in the extent of the damage were very marked. 
The upper plantation fared much the worse, some of the Folk 
(pure) Japanese being badly killed, even to the ground. One 
especially, which had grown to a height of 8 feet, was killed to the 
ground. ere also, many of the Europeans from Paris, Geneva, 
and Berlin (one year old), as well as the “Italian” seedlings set 
out in the spring of 1932, were killed to the ground, and some 
were killed outright. The European seedlings in the nursery at 
the Brooklyn Botanic Garden were also badly injured. Many 
of the Europeans, however, sprouted up from the base this year. 
The following is a general summary of the character and amount 
of winter injury in the different types. 
1. Castanea dentata, American chestnut; not injured in the 
slightest degree. 
2. C. crenata, Japanese chestnut; usually killed back along the 
tips of the branches and in some cases badly killed back to the 
main trunk. Ina few cases five year old trees were killed to the 
ground. Also, the buds were injured, as shown by peculiar one- 
sided, cup-shaped, deformed leaf development from these buds 
later in the year. Sometimes the wood was blackened, as seen by 
cutting through the twig. 
3. C. sativa, European or “Spanish”’ chestnut; badly affected: 
some killed to the ground, some entirely dead. 
4. C. mollissima, Chinese chestnut; came through the winter 
entirely uninjured. 
C. Henryi was badly winter killed. 
6. C. Seguinit was also winter killed (as usual.) 
MY 
— 
‘1 
