1886-87.] Monthly Increase in Girth of Trees. 55 



selected as the most remarkable for activity in April, two 

 showed no movement whatever in February and March, and 

 in none of the others did the apparent movement, one way 

 or other, much exceed the twentieth of an inch. Similar 

 results were obtained at Craigiehall from three evergreen 

 trees, which, however, were not measured so early in spring 

 as the trees in the Botanic Garden. 



III. The End of the Growing Season in Deciduous and 

 Evergreen Trees. 



The limit of the growing season was more evident in 

 autumn than in spring. Deciduous trees grew but little after 

 August, although their increase in girth during that month 

 was very substantial. The aggregate increase of twenty-eight 

 trees in September 1884, 1885, and 1887, the only years 

 tested, was seven-tenths of an inch, one inch, and four-tenths 

 of an inch respectively. In 1884 eighteen, in 1885 fourteen, 

 and in 1887 twenty-two of the twenty-eight trees did not in- 

 crease in September at all. With evergreens it appears to 

 be much the same. The September growth of twenty ever- 

 green trees amounted in 1884 to half an inch, in 1885 to one 

 inch, and in 1887 to sixty-five hundredths of an inch. At first 

 sight it seems as if this result was somewhat in favour of the 

 evergreens, because their aggregate increase in September 

 equals that of the deciduous group, while the number of them 

 measured was smaller. But it must be remembered that the 

 proportional annual growth of the evergreens was consider- 

 ably gi'eater than that of the deciduous trees. In 1884 

 thirteen, in 1885 ten, and in 1887 thirteen of the twenty 

 trees did not increase at all. 



On the whole the following conclusions may be come to 

 on this branch of the subject: — 



1. There may have been a slight fluctuation in the girth 

 of some trees, particularly of the deciduous class, but there 

 was no progressive increase in February or March. 



2. Progressive increase began in some trees in April, but 

 the amount, except in rare instances, was trifling. 



3. Substantial growth ceased by the end of August, but a 

 certain number, both of deciduous and evergreen trees, con- 

 tinued to grow a little in September. 



