98 INTRODUCTION TO BOTANY 
92. Competition among buds and branches. Seen from a 
little distance the top of a tree usually appears like a some- 
what conical or hemispherical mass of leafy branches, but on 
looking along the trunk up into 
the tree top one sees that the 
interior of the crown is hollow, 
nearly destitute of leaves, and 
with few live twigs on the 
trunk (except near its upper 
end) and few on or near the 
bases of the branches. A very 
large proportion of all the 
much-shaded twigs that might 
be developed into branches 
during the growth of a tree 
are actually killed by light- 
starvation. They cannot do 
photosynthetic work and are 
therefore without food. 
Cutting off the top or the 
main branches of many kinds of 
trees ( pollarding) causes buds 
along the trunk and _ larger 
branches to develop into slen- 
der twigs, used for withes and 
for basket-making (fig. 82). 
93. Fruit spurs. A fruit spur 
is a short fruit-bearing twig 
Fic. 82. A pollarded willow send- 
ing out many slender twigs from ‘ 
buds which would not have grown borne on the side of a branch 
if the main branches had not been (figs. 83 and 84). Apple, pear, 
cut awa: 
- plum, and cherry trees afford 
capital examples of the production of fruit spurs. At the tip 
of the spur a flower bud (or a mixed bud) is borne, and this 
usually develops into a cluster of flowers, one or more of 
which, under favorable conditions for growth, may mature 
into fruit. In the apple and the pear (fig. 84), although the 
