New York Agricultural Experiment Station. 257 



and some where there was apparently only a separation somewhere 

 in the inner phloem with a subsequent dying of the loosened bark. 



The most conspicuously affected trees seemed to vary in age from 

 9 to 15 years, and range from 11 to 18 cm. in diameter. In a small 

 park near the Experiment Station were 12 Acer platanoides and 2 

 A. saccharinwn trees injured to such an extent as to cause their 

 removal in the fall of 1910. 



In these particular cases the injury had occurred during the winter 

 of 1909-10, as evidenced by the fact, shown in cross-sections, that 

 the separation took place after the close of the growing season of 1909 

 and before growth was resumed in 1910. The portion of the tree 

 trunk from 6 to 20 cm. above the ground nearly up to or even includ- 

 ing the lower branches, was usually involved. In some instances the 

 clefts in the bark were also accompanied by clefts in the wood, as 

 shown in section in Plate XX. Such clefts in the wood sometimes 

 even extended entirely through the cyhnder though in most instances 

 they only went to the center or pith. All of the cases of bark loosen- 

 ing in and around Geneva dating back to the winter of 1909-10 were 

 most severe on, and sometimes entirely confined to, the west or south- 

 west sides. Usually there was sufficient injury in the imier bark of 

 the entire circumference of the affected portion to show as a discolored 

 circle in cross-section. On sawing short cross-sections from severely 

 affected portions of a trunk the past season's growth of wood some- 

 times fell away from the central part of the section, along the dis- 

 colored line. tJsually both surfaces were of a dark brown color, but 

 they were always more or less thickly covered by scattered pin-head- 

 like, white specks. The raised white specks of one surface were 

 found to coincide with those on the other when the pieces were placed 

 together again. Apparently these irregularly scattered white specks 

 were column-like living l^ridges connecting the wood of 1909 and 

 1910 through the thin, discolored or dead tissues between the two 

 years' growths. The line of separation was chiefly somewhere in the 

 phloem or the inner bark; but there was evidently much variation in 

 the location of the place of separation, as judged by the differences 

 in the growth and regeneration taking place in 1910. 



Some of these matters will become clearer by a study of a cross- 

 section of one of the tree trunks. Plate XX is a section of Acer 

 'platanoides, taken about 25 cm. above the ground; its shortest diam- 

 eter is 12 cm. In this case the wood cylinder was cleft into two nearly 

 equal parts near the base, but about a meter higher up the cleft 

 extended only to the pith; and towards the upper limits of the exter- 

 nally visible injury the wood was not cleft at all, although the place 

 of inj ury is marked by a discolored circle nearly around the whole 

 circumference. Plate XXII, figure A, shows a large piece of the same 

 trunk. On the unpeeled part the bark, although having an unbroken 

 outer surface, is undulating or wavy owing to differences in the rate 



