UPWARD TRANSPORT OF ORGANIC MATTER 17 



bohydrates by the new leaves will be less and the depletion 

 of the stored supply will be more rapid and more complete. 

 The spring of 1919, in which most of these experiments 

 were completed, was especially favorable for the depletion 

 of stored foods. When the season is dryer and there is 

 more sunshine, growth is checked and the stored foods are 

 less rapidly drawn upon and the new leaves may even begin 

 depositing new stores in the young twigs. In such seasons, 

 therefore, the starch may never completely disappear 

 above the rings. These findings as well as those reported 

 in Sees. 4 and 7 rather clearly indicate that the widespread 

 idea is wrong that much of the carbohydrate stored in the 

 trunk and roots of woody plants is transported to the tops 

 in early spring and there used in shoot growth. (See also 

 Curtis, 19206.) 



6. The Disappearance of Starch as a Criterion of Car- 

 bohydrate Transport. — Since starch disappearance is not 

 always correlated with the removal of sugar, a few experi- 

 ments were completed in which sugar analyses also were 

 used. Such analyses were obtained with both Acer 

 saccharum and Fagus grandifolia. Several stems of Acer 

 saccharum were double-ringed on Apr, 6 and 7, 1919. 

 A number of them were cut between May 6 and 19. In all 

 cases starch was very abundant between the rings, entirely 

 absent or present only in traces above the upper ring, and 

 almost absent or fairly abundant below the lower ring. 

 The amount present below the lower ring and above the 

 upper ring depended on the time of cutting, the size of the 

 stem, and the position on the tree. Analyses were made of 

 one of the larger stems of the series. This stem showed 

 15 annual rings at the lower ring where it was 24.5 mm. 

 in diameter. The lower ring was 16 cm. from the main 

 trunk and the second ring was 107 cm. above the first where 

 the stem was 20.2 mm. in diameter. Starch tests and sugar 

 analyses for this stem are presented in Table 2 together 

 with similar tests for Fagus. 



A number of stems of Fagus grandifolia were double- 

 ringed on Apr. 7, 1919, and results very similar to those for 



