BRANCH-GROWTH OF DOUGLAS FIR. 145 



apart, are similarly situated except with regard to soil, aspect, 

 and degree of slope. Both woods appear in good health and 

 in every way normal. Wood A was planted in 1898 and 

 is now 23 years old. The planting distance was apparently 

 about 4h feet by 4J feet. 



Wood B was planted in 1903 and is now 18 years old. The 

 planting distance was intended to be 3^ feet by 3^ feet. For 

 comparative purposes, the planting distances were arrived at 

 by actual measurement. 



In each wood six trees were taken at random over a range 

 of girth at breast-height as follows : — 



Wood A — 12 14^ 16^ 19 2ii 26^ inches true girth. 

 Wood B— 12 i4h i6h 18 21I 25I „ 



The branches of two whorls, namely the one above and 

 the one below breast-height, were pruned off" close to the stem 

 from each tree. All these branches were measured, but only 

 the five largest in each whorl were considered. The following 

 particulars were noted : — 



(a) Total length of branch to the nearest half-inch. Douglas 

 fir is very suitable for this experiment as its branches are so 

 persistent that, in nearly every case, even the slender tips are 

 present. Only in Wood B was there any sign of decay in the 

 branch tips. 



(/>) Diameter of branch at base to the nearest yV^^ ^^ ^" inch. 

 In many cases the basal area was eliptical, but the smallest 

 diameter was always taken. 



(c) Number of years the branches remained alive. This was 

 readily ascertained, as the annual growth in each branch was 

 easily discernible. 



In addition to branch measurements, the annual height-growth 

 of the stems between the whorls pruned off was measured, 

 together with the growth of the previous year and of that 

 following — a total of three measurements. This gives a useful 

 indication of the relative growth of the tree while the branches 

 were functioning. 



Horizontal measurements were also taken from the base 

 of each tree dealt with to the several nearest neighbours, 

 so that the average planting distance for that tree could be 

 found. 



The following are the results secured, being the averages 



VOL. XXXV. PART IL K 



