96 QUINCE CULTURE. 
their places, in which case it is likely to be winter-killed. 
A mulch sufficient to protect the roots from freezing 
during the winter is a wise precaution, not only to pro- 
tect the newly-planted trees from intense cold, but will 
be a safeguard against winter-killing in those well estab- 
lished. It has been found highly beneficial to trees to 
have a mantle of snow cover the ground all winter, be- 
cause it protects the ground from sudden changes. A 
winter rain freezing on the limbs will do little harm, 
unless accompanied by winds, because there is no danger 
of drying out the sap. The cold may be severe enough 
to weaken the vitality of fruit-buds, and they may all 
drop off after they have blossomed. 
Trees are able to endure greater cold in a dry atmos- 
phere than in a moist one. In elevated situations, trees 
will endure a severer temperature than in valleys or low » 
down the hill-sides. 
It will operate favorably to so cultivate the trees as to 
secure an early growth and ripening of the wood, that it 
may be in thé best condition to endure the severity of 
winter frosts. When stimulated to grow very vigorously 
late in the season, the young wood is more likely to suffer 
than that produced earlier in the season. 
The thermometrical and hygrometrical conditions act 
together, and the hardiness of trees will be determined 
by the power of the tissues to withstand the pressure 
that will burst them if they contain too much sap, or to 
shrivel them by drying out their moisture, and so de- 
stroying their vitality. 
A wise precaution against winter-killing in sections 
where there is danger, is not to cultivate late in the . 
season. The culture that stimulates a late growth of 
soft wood that does not ripen before the severity of 
winter sets in is to be avoided. The immature wood is 
easily injured, the grain is ruptured by freezing and 
thawing, and the disorganized cells in spring are no 
