138 
MISCELLANEOUS. 
[Part II. 
The growth in 
girthing de¬ 
scending from 
the head or any 
particular 
branch is gene¬ 
ral round the 
stem, though 
it is greater on 
the side proper 
to the branch; 
and the growth 
may be me¬ 
chanically 
and continually 
turned from 
the notches nearest the head are the first to 
heal, and those nearest the root the last to heal. 
The new growth on the notches will be free 
in proportion as they are in the line with large 
branches above them : and I imagine that, though 
the returning sap from branches deposits round 
the whole stem, it deposits most freely on the 
proper side of the branches; and the larger 
annual deposit found on the outsides of the out¬ 
side trees of plantations, which has been attri¬ 
buted by Duhamel and Buffon to their having 
their largest roots on that side, is, I have no 
doubt, the result of their having their largest 
branches on that side. An exposed tree stand¬ 
ing singly will throw out its roots equally all 
round it ; but the new layers of wood round the 
stem will be much the largest on the leeward 
side, because the largest branches are on the 
leeward side; yet, if the upper part of one half 
of the side of a stem is dead, the opposite living 
side will deposit round the whole living part 
below. And I imagine that it is thus that the 
windward roots of an exposed tree are nourished 
by the descending sap from its leeward branches. 
Indeed, the downward stream of the growth 
in girthing may at will be mechanically stopped 
on one side of the stem, and projected to the 
