100 General Care of Trees 
system is killed by winter cold has been discussed on page 
6, where injuries by frost are described. 
Pruning for Form. The removal of dead and broken 
branches and the smoothing and proper dressing of badly 
made wounds is, of course, the first concern of the pruner. 
The removal of green branches has usually for its object 
the regulation of the form, in order to favor invigoration, 
or new formation in other parts. 
Every branch or twig cut produces 
a change in the development of other 
branches or twigs, because these now 
enjoy different light, food, and water- 
supply. The skilful pruner keeps in 
mind, therefore, what new develop- 
ment will be induced by cutting 
away branches, and cuts accordingly, 
either to strengthen a weaker mem- 
re ber by removal of a stronger, or to 
Fic, 31. — “Lightning” help a stronger one by subduing 
double edged pruning superfluous feeders, favoring either 
aa the leaders by the removal of side 
branches, or inducing the spread and compacting of the 
crown by heading back the leaders. And, in pruning for 
form, he keeps in mind that the heading in of young shoots 
tends to develop dormant buds; that the tendency of most 
species is to develop the uppermost buds rather than those 
at the base of the shoot; that heavy pruning at the top 
tends to invigorate and produce better development of the 
lower portions, and vice versa. ) 
Of superfluous parts to be removed are the water-sprouts 
or suckers, for, as their very name indicates, they are rob- 
bing other branches of food materials. Water-sprouts are 
branchlets, arising from adventitious buds out of regular 
