404 Forestry Quarterly. 



Such a method may also prove useful in case of litigation when 

 it is necessary to determine the exact time of a trespass cutting. 



Is there any way of determining with accuracy the time of cut- 

 ting? 



From what is known of the chemical changes which take place 

 in the tissues of trees at different seasons of the year, and from 

 the structural development of the annual ring, one naturally turns 

 to chemical and microscopical methods for finding characteristic 

 differences in the wood cut at different seasons of the year. 



Chemical Methods. 



During the vegetative period the tissues, especially the living, 

 active tissues, contain albuminous or proteinous substances which 

 enter into the composition of the living cells, but very little starch. 

 In the fall, just after the tree enters into its dormant stage, it con- 

 tains considerable reserve material in the form of sugar, dextrin, 

 and especially starch, deposited in the medullary rays and the 

 pith. One would expect, therefore, that a piece of wood cut in 

 winter when treated with an alcoholic or watery solution of iodine 

 would assume a yellow color, while the pith and the medullary 

 rays containing starch would assume a dark blue color. If the 

 piece were cut in summer all the tissues would become of a 

 uniform yellow color. This method, theoretically at least, should 

 enable us to determine broadly whether a given piece of wood 

 was cut in winter or summer. In practice, however, it gives 

 dubious results ; first, because the differences in the chemical 

 substances found in the wood of trees in summer and winter are 

 not so much qualitative as quantitative, and second, because 

 trees of the same species, like all living beings, are subject to 

 variations depending upon climatic and soil conditions. 



Another chemical method which suggests itself is the deter- 

 mination of the amount and the composition of the ash contents 

 of the wood cut in summer and winter. The amount of mineral 

 substances in the wood as represented by the ashes obtained after 

 burning the wood is supposed to vary with the season of the year. 

 At least this has been proven with certainty in regard to the 

 foliage. It is generally assumed that the wood in summer con- 

 tains a larger amount of mineral substances (and consequently 

 yields a larger amount of ashes), of which a larger per cent, is 

 insoluble in water, than is usually found in wood during winter. 



