SPRUCE, SCOTS PINE AND JAPANESE LARCH. 29 



5. Observations on the Annual Increment of Spruce, 

 Scots Pine and Japanese Larch. 



By J. H. Mii.xK Home. 



Some notes upon this subject were published in the 

 Transactions on three previous occasions (vol. xxiv. p. 52 ; vol. 

 xxvi. p. 160; and vol. xxvii. p. 34). The records for some of the 

 plantations have now been taken for five years, and others have 

 been added from time to time which also give interesting results. 



The means by which the observations have been taken, and 

 the nature of the soil and situation of the different areas, have 

 been referred to in the earlier articles and need not be again 

 detailed. 



The object of this article is to summarise the results so far 

 obtained, and to point out such conclusions as may be of value 

 in forestry statistics and calculations. 



The table on page 30 gives an abstract of the results for each 

 plantation separately. Five stems have been taken in each 

 group. 



The mean annual increment is calculated without any 

 allowance for intermediate returns from thinnings, regarding 

 which there are no records. The cubic measurements are 

 quarter-girth. 



The plantations not referred to in previous articles are B 

 (spruce), and D (Japanese larch). The former is on a soil which 

 was formerly hill pasture of moderate quality, with thin peat lying 

 on a somewhat retentive subsoil. The aspect is easterly. The 

 Japanese larch are growing on what is undoubtedly a favourable 

 soil, consisting of a good loam with a considerable deposit of 

 humus. The aspect is easterly with a good slope. 



The four spruce areas are typical of different soils and elevations 

 between 250 feet and 600 feet. Two are on fairly good soil, 

 and two on poor soil. They also present considerable variation 

 as regards density and number of stems per acre. In no instance 

 has the early management of these crops for, say, the first 15 or 

 20 years been ideal, and better results should certainly be got 

 from young woods recently established. In spite of such draw- 

 backs it appears that a mean annual increment of fully 70 cubic 

 feet per acre has been secured, with a current annual increment 



