288 
OTIS F. CURTIS 
have occurred between the other trees. Furthermore, the increases in 
carbohydrate content of the roots of ringed plants over that content found 
earher in the season, shown on June i6 for those ringed on February 9 and 
as shown on June 16 and August 4 for those ringed May 8, would be hard 
to explain except as resulting from individual variations or from the healing 
of the wounds. In the quince, an analysis on April 13 showed greater car- 
bohydrate content in the roots of the ringed tree than in those of the tree 
not ringed, but the stem of the ringed tree also showed a carbohydrate 
content greater than the stem of the check. Evidently the whole tree 
had a higher carbohydrate content. 
Hartig, Leclerc du Sablon, Butler (191 7), and others have shown that 
be''ore growth starts in the spring the roots may contain a higher percentage 
of carbohydrates than the stems, but the stems have more supporting tissue 
and the percentage composition may therefore mean nothing unless the 
total mass is known. The actual amount of carbohydrates in the roots 
may be less than that in the tops, even though the percentage composition 
is high. 
Data showing that the mass of carbohydrates stored in the roots is 
actually much less than that stored in the tops have been presented by 
Chandler (191 7) who has calculated, from percentage concentrations ob- 
tained by Butler, the relative amounts of food available in the roots and 
tops of an apple tree. His data are presented in table 2. 
Table 2. Approximate amounts of dry matter, starch, and saccharose at the time buds 
are swelling, in case of a seven-year-old Bismarck apple tree that has been growing in sod. 
Part of Tree 
Actual Dry Weights, 
Pounds 
Pounds of Starch 
Calculated 
Pounds of Sac- 
charose Calculated 
i-yr. twigs 
3-15 
0.98 
0.12 
Older branches 
21.00 
6.72 
0.17 
Trunk 
15-13 
5-14 
O.II 
Totals for parts above ground 
39.28 
12.84 
0.40 
14-15 
5.43 
0.28 
6.49 
2.37 
0.06 
Totals for roots 
20.64 
7.80 
0.34 
These figures are, of course, only suggestive, as the trees analyzed and 
the one weighed were grown under different conditions. But the error 
would tend to be in favor of large root storage, for the tree weighed had 
been grown in sod under conditions favorable to larger root growth. In 
this instance the roots weighed 52.5 percent as much as the tops. Pickering 
(191 7) gives data showing the relative weights of tops and roots of a number 
of trees varying from 10 to 20 years old. The average root weight of 461 
apple trees was 22.9 percent of the tops, that of 15 pears was 23.5 percent, 
that of 6 Damsons was 25.2 percent and that of 44 plums was 28.3 percent. 
