thers, food reserves are transferred from shucks, hulls, or burs to
the nuts. Abscission layers are formed and shucks, hulls, or burs split
open on drying out, thus partially or wholly releasing the nuts. There
is a very direct relationship between the degree to which the nuts are
filled and their time of and normality of maturing; well filled nuts
mature early and normally, whereas poorly filled nuts mature late, if at
all, and shucks, hulls, or burs fail to open properly.

+Growth in Size+

The size of the nuts produced by a tree is determined by a number of
factors, one or all of which may operate during the course of the
season. These are: (1) Age of tree; (2) position of the nuts on the
tree; (3) fertility of the soil and moisture supply, or the nutritional
status of the tree; (4) size of the crop borne.

In general, old trees bear smaller nuts than do younger trees. Hence
size of nut for a particular variety is only relative. The first few
crops produced by a tree usually consist of nuts large in size for the
variety; and then, as the tree attains age, nuts become smaller in size.
Young trees make longer and thicker shoot growth than do older trees.
There is, then, under normal conditions, a direct relationship between
the growth made by a tree and the size that the nuts attain. The more
vigorous trees not only produce larger nuts than those produced by less
vigorous trees, but the hulls and shells of such nuts are thicker and
constitute a higher total percentage of the total weight of the fruit.

The position of the nuts on a tree has an important effect on the size
that they ultimately attain. In general, the nuts in the top are larger
than those nearer the ground; and those on the strongest and most
vigorous shoots of the top or lateral branches will attain a larger size
under normal conditions than those located on weaker and shorter shoots
or on the inside of the tree. Here again there is a direct relationship
between growth of the tree and growth in size of nuts. All normal trees
make longer and stronger shoot growth in the top than they do on the
terminals of lateral branches, and the shortest and weaker shoots as
well as the smallest nuts are generally on the lateral branches inside
of the tree top.

Fertility of soil and moisture supply determine in large measure both
the growth made by the tree and the size of nuts. The nuts borne on
trees growing on fertile soils adequately supplied with moisture