nal is an article by
Meredith P. Reed read before the Western Association of Nurserymen at
their annual meeting in Kansas City, Mo., December 1915 entitled the
Pecan Areas of the United States, describing the limits between which
the pecan may be grown. In this paper the matter of the Pecan Belts of
the country are discussed and their extent determined pretty largely by
the length of the season (in average years), that is by the number of
days between the latest spring frosts and the earliest fall frosts. A
map was shown on which these areas were marked out, and it has been very
useful to the writer in answering inquiries from persons who want to
know if pecans can be grown in _a_ given section.

Mr. John Garretson, Aspers, Adams Co., Penn., has on his place bearing
Stuart and Schley pecans, two of the standard southern varieties. These
bear nuts of typical shape but which are only a fraction of the size
that these nuts would be if grown in southern Georgia. This clearly
shows that some of the standard southern pecans require something which
they do not get at Aspers to enable them to properly mature their nuts.
The trees stand the cold of winter but the fruit does not properly
mature. Mr. Jones has suggested that it is heat that is lacking and has
advanced the idea that even though the trees are hardy to winter cold
they have not sufficient summer heat at Aspers to enable them to mature
their crops. This has brought up the question as to whether there was
any method of measuring the summer heat available for causing pecan nuts
to grow and mature.

Observations on northern pecans (and some southern ones) on my place at
Baldwin caused me to note that no pecans started to vegetate at Baldwin
before May. May is the first spring month here when the pecan will
leave out. May is also the first spring month when the average monthly
temperature here will reach 50 deg.F. It occurred to me that if we note the
excess average monthly temperatures over 50 deg. and sum these items for a
season we would get what might be termed a figure for "pecan growing
heat units." This figure of 50 deg. is doubtless capable of some refinement.
There is no reason to suppose that further study may not show that it
should be somewhat more or less but it is the best we have so far and
seemingly it is proving useful.

If we calculate these figures for Evansville, Ind., for 1914, for
example, and show the method of doing it we will have