ing Habit of Nut Trees+

Since the growth and fruiting habits of our different kinds of nut trees
are closely related, it is desirable to point out some of these
relationships. All of our different species of walnuts, the pecan and
all hickory nuts, as well as hazelnuts and filberts, are borne
terminally on shoots of the current season. In other words all walnut
species, pecan, and all hickory species bear the pistillate flowers that
develop into nuts at the terminal end of the shoots produced the same
year that the nuts mature. The staminate or pollen-producing flowers of
all these species arise from lateral buds on shoots that grew the
previous year. In the case of hazelnut and filbert the pistillate
flowers are borne in lateral buds on shoots of the previous season, as
are also the staminate flowers or catkins. In this case, however, the
pistillate flowers are formed and pollinated before the current year's
shoot growth is made. Almonds are borne laterally on shoots produced the
previous season. All chestnuts are borne laterally on shoots produced
the same season as the nuts.

The chestnut bears most of the staminate flowers separately in staminate
catkins whereas the pistillate flowers are in mixed catkins, but all are
formed laterally on shoots of the current season. The almond, which has
perfect flowers, produces these in lateral buds on shoots of the
previous year. Both the hazelnut and the almond flower before any
current-season growth is made, whereas all of the other kinds of nut
trees mentioned produce almost all normal shoot growth before flowering
occurs. These differences in growth, flowering, and fruiting habits
provide a basis for the explanation of why growth of almond trees, for
example, is harder to maintain than is that of walnut or pecan.
Flowering and early development of the fruit before shoot growth is made
tend to check such growth, so that flowering and fruiting trees will not
make as much new growth as they would have made had flowering and
fruiting been prevented.

In general, it can be stated that, in the case of bearing trees, the
longer the shoot growth and the greater its diameter in proportion to
length, the greater is the number of pistillate flowers that may be
formed at its terminal. Furthermore, the set of nuts and the size that
they attain are in proportion to the length and diameter of the shoots
bearing them. In other words, the number of flowers formed, the nuts
set, and the s