1888-89.] Annual Increase in Girth of Trees. 



393 



the averages. In addition to the results of these observa- 

 tions, the age of four measured yews being known to be eighty- 

 four in 1878, we arrive at their annual upward growth for 

 that period previous to our experiments. In the same way 

 the rate of an AMcs Douglasii for fifty-four years has been 

 ascertained. 



From this table I have excluded some trees which were 

 measured, but which proved very unhealthy. The very slow 

 upward rate of the largest yew is probably due to its great 

 tendency to spread outwards. Ahics Lotviana, Pinus excelsa, 

 and Finu^ Laricio can only be classed as fairly healthy but 

 not vio'orous trees. 



3. Annual Range of Girth- Increase in the Trees 

 individually. 



On taking a general view of the ten years' observations, 

 one of the most striking results is the great variation in the 

 annual increase of the vast majority of the trees, indicative, 

 it is to be presumed, mainly of a marked sensitiveness to 

 the varying meteorological conditions of the different seasons 

 through which they have j)assed. Not one of the measured 

 trees has escaped without suffering a marked depression in 

 its growth in one or more seasons, while in the majority of 

 instances the amount of this depression has been very large. 

 Thus in no less than eight out of thirty-four deciduous trees 

 available for this investigation, the maximum annual increase 

 was more than four times areater than the minimum annual 



