154 TRANSACTIONS OF ROVAL SCOTTISH ARBORICULTURAL SOCIETY. 



obtainable, these investigations only refer to increment in 

 wood. 



To facilitate comparisons the following results have been 

 tabulated : — 



Height-Increment. 



The mean annual height-increment for the ten years' period 

 has been 2 ft. 3 ins. 



No explanation can be offered for the very erratic growth 

 between the third and fifth years. It may have been due to 

 atmospheric or soil factors, but leaving this out of account it 

 is seen that the annual height-increment has been exceptionally 

 good. 



Although it is rather unfair to compare these. figures with 

 those for true Larix leptolepis grown in another part of the 

 country, still something may be gained by doing so. Probably 

 the figures so obtained will be more valuable if it is stated that 

 Japanese larch on Murthly estates does not compare favourably 

 as regards measurements with those that are given. From 

 Mr Leven's report in vol. xxviii., part 2, it is seen that at seven 

 years from planting the highest tree recorded is 15 feet, or exactly 

 7 ft. 6 ins. smaller than that of this average "hybrid" tree. 



The increase in diameter can also be traced out, and it is given 

 on the following page. 



Here again some irregularity is to be noted in the increment. 

 This is not uncommon near the base of young stems, however. 

 The drop last year is probably due to increased density of 

 canopy. The girth may be compared with that of the Japanese 

 larch quoted above. It is then found that there is a difference 



