242 Forestry Quarterly. 



trees here reported. {Acer saccharuin was not examined for 

 fat.) That is to say, fat was at a minimum at the time of un- 

 folding of buds, increased slowly through the summer to attain a 

 maximum in late autumn or early winter, to decline again to the 

 minimum of spring. The trees showing considerable quantities 

 of fat were Popuhis deltoides, Juglans nigra, Tilia americana, and 

 Ulmus americana; while those showing but little fat were Salix 

 alba and Carya glabra. The fat was in largest amounts in the 

 phloem and rays of the twigs ; the roots of none of the trees 

 showed more than traces of fat in any of the tissues. 



SUMMARY. 



The work reported in the present paper, and that of the 

 European investigators, may be summarized in the following 

 statements : 



1. There is in the stems of all trees in temperate climates a re- 

 duction in November and December of the amount of starch 

 present in autumn, the reduction being so great in some trees as 

 to lead to the complete disappearance of the starch throughout the 

 stem, while in most trees the xylem retains more or less starch, 

 and in still others both xylem and phloem retain some starch 

 through the winter. 



2. A few trees have shown a considerable increase of fat in the 

 phloem and xylem in late autumn or early winter; but there is 

 insufficient evidence for the belief that starch is transformed 

 into fat. In most trees the increase of fat is not marked. 



3. The trees that contain considerable fat in winter are some of 

 them hard-woods and some of them soft-woods, as Populus del- 

 toides, Tilia americana, and Juglans nigra in the present paper, 

 the first two being soft-woods and the last a hard-wood. The 

 so ft- wooded Salix alba contains but little fat, but considerable 

 starch in its stem in winter. From these results and those of 

 European authors, it would hardly seem justified to name broad- 

 leaf hard-woods generally as starch trees, and the soft-woods 

 and gymnosperms generally at fat trees, as proposed by Fischer. 



4. As claimed by Sablon, so the work reported in this paper 

 seems to indicate no great increase in the content of sugar in 

 stems and roots, except in the spring as the buds unfold. 



5. In the root, the transformations do not keep pace with those 

 in the stem, and starch remains the year round, the greatest reduc- 



