152 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



Setting aside this rather uncertain question of parentage, we 

 may come to matters of perhaps greater interest to the forester, 

 namely, the rate of growth and Hability to become injured by 

 fungi, insects or frost. One of the oldest groups of " hybrid 

 larch " that I know is on the Murthly estates.^ The site selected 

 for this group was not by any means an ideal one for larch, 

 being rather low. In fact, the place is an ideal one for the 

 spread of disease. The soil is poor and gravelly, but on the 

 whole not unsuited to conifers. In the spring of 1908 about 

 three hundred 3-year old plants twice transplanted were planted in 

 this place at an average distance apart of about 4 feet. Growth 

 immediately after planting was only moderately fast, but it has 

 been making up every year since then. Unfortunately no 

 measurements were kept, so that now, in order to find out 

 something of the rate of growth, it has been necessary to have 

 recourse to the method of "stem analysis." The method of 

 making a stem analysis is quite simple and would provide much 

 matter of interest to the forester who can find time to make it. 

 A stem was selected for analysis, and in this case it was 

 considered that for all ordinary purposes measurement in 

 four-foot lengths would be sufficient. These four-foot lengths 

 were then marked on the stem as shown in Fig. i (by dotted 

 lines). 



*--i'--*>--2'--^.->'. 



Fig. I. 



Each of these divisions was again divided into two (marked in 

 the diagram by heavy line), and a section was taken at each of 

 these new divisions. These sections were taken to be the mean of 

 the four-foot divisions to which they referred. 



In order to check the results and also to give a rather more 

 representative diagram, sections were made at the four-foot 

 divisions also, but this is not usually necessary. 



The number of year-rings in each section was then counted, 

 and the diameters at the several ages measured. The measure- 



^ It is possible that plants about two years older exist on Dunkeld estate. 



