FROST PROTECTION IN LEMON ORCHARDS. 
17 
the freeze. In some of the nonheated plats, very few merchantable 
fruits were taken from the trees during the same period. On the 
other hand, in the heated plats the greater proportion of the fruit, 
even during the period immediately following the freeze, was mer- 
chantable, with a relatively small number of frozen lemons. 
In order to illustrate these comparisons graphically, 
some diagrams are presented. Figure 6 gives the pro- 
portion of frozen and merchantable fruits produced on 
plat 1, an acre of nonheated Lisbon lemon trees, and 
plat 4, an acre of heated Lisbon lemon trees, for each 
picking during the calendar year 1913. This diagram 
is based upon the data presented for these plats in 
Tables V and VIII. 
As pointed out in a previous discussion of the data 
presented in this bulletin, the only accurate way to 
compare the behavior of the fruits in the heated and 
nonheated plats is in terms of numbers of fruits rather 
than weights. The frozen lemons dried out so rapidly 
that no safe comparison could be made by using the 
number of pounds or even the number of boxes of fruits 
produced on an acre. For this reason, in this and all 
succeeding diagrams, the differences are shown graphi- 
cally in numbers of fruits. 
In the February picking in nonheated plat 1, the 
estimated number of frozen fruits taken from the trees 
was 183,410, as compared with 28,960 frozen fruits in 
heated plat 4. No merchantable fruits were taken from 
the nonheated or- 
chard at that pick- 
ing, 
—/^^A*OV,^VYrit^^L^ X^PtX/.^ 
II l«nll ■-nil 
i 
JL 
/2fS' ,':^fi>/^ /vAy' ^o'^^r Ac/S' ss^r oc/" iOrc 
Fig. 6.— Diagram showing the number of frozen and merchantable fruits 
produced on plat 1, a nonheated acre of Lisbon lemon trees, and plat 
4, an acre of heated Lisbon lemon trees. The figures here shown are 
taken from Tables V and VIII, respectively, which give the esti- 
mated production by grades for each month's picking for these 
plats during the calendar year 1913. 
while 92,460 
merchantable lem- 
ons were picked in 
the heated orchard 
during the same pe- 
riod. While many 
of the frozen fruits 
which were taken 
from the trees at that time normally would not have been picked until 
much later in the season, in order to obtain any records of these fruits 
it was necessary to pick all which showed signs of having been frozen. 
All fruits about which there was any question were left until later 
pickings. This condition applied to all the plats. 
In the April picking the estimated number of frozen lemons removed 
from the nonheated plat was 83,360, as compared with 1,980 from 
