332 TRANSACTIONS AND rROCEEDINGS OF [Sess. lvl 



on an early or late development of the leaf. Ceclrus 

 Beodara is one of the earliest among the Evergreens to put 

 out its young shoots in spring, but is the latest among my 

 measured Conifene to put on the mass of its girth-increase. 

 Indeed, I have shown in the paper already quoted that a 

 very considerable girth-increase takes place in some Pines 

 before the leaf-buds open. This increase may be accom- 

 plislied in them by aid of the old foliage ; but even in the 

 Deciduous group it is remarkable that girth-increase begins 

 in some species as soon as the leaf-buds swell, and before 

 tliey have opened, and that Acer Fscudo-platamis, one of the 

 first to appear in full foliage, is slow to start its girth-increase, 

 while it is the reverse with the much later Qucrcus. 



Monthly Hcmr/c of Girth- Increase in the Species. — As 

 a very general rule, the range of increase in each month, 

 year by year, is great both in trees individually and in 

 species, showing, it is to be presumed, a great susceptibility 

 to meteorological inlkiences ; nevertheless a remarkable 

 general agreement between members of the same species is 

 frequent, and proves obedience to law. Exceptions are, no 

 doubt, due to some .special cause affecting tlie health of 

 individual trees, which in some eases can be pointed out. 



Monthly Rate of Girth-hicrease. — Tiiis varies much 

 in the different species, particularly in the first and last 

 months, when some increase substantially enough, while 

 others do not increase at all. Generally speaking, the rate 

 of the Conifera' is greater than that of the Deciduous trees 

 in these months. Among the young trees 0"15 was the 

 highest rate attained by any specimen of the Deciduous 

 grou)) in a single A])ril, and 0'20 by one of the Conifera'. 

 Similarly for S(;])tember the figures were 0'25 and O'oO. In 

 May none of the Deciduous trees grew half an inch, but Ahieii 

 Loviona. attained it once. In .June, during the quinquennial 

 period, instanc(is of half an inch or upwaixls of girth-increase 

 occurred sixteen times in the Deciduous group, and oidy 

 once in the Conifene; in -Inly eleven times among the 

 former, and not at all among the latter ; in August six tinuis 

 in the Deciduous class and thrice in the Coniferte ; and in 

 September once in the Conifera; oidy. The .species which 

 showed this amount of vigour of growlii in a single month 

 were Acer TfieuOo-platamis^Vrunvs Padvs, Papulus fastigiata, 



