36 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



become necessary. Another advantage gained in pure planta- 

 tions is, that the danger of loss or deflection of the leading 

 shoot by winds, frequently noticeable in mixed plantations on 

 exposed sites, is nowhere apparent when dealing with the tree 

 planted and cultivated on common-sense principles. 



It would be matter for surprise, indeed, were any result other 

 than that of disappointment to follow the directions frequently 

 laid down for the planting of the Douglas fir in a mixture of 

 other trees; but should a mixed plantation for any reason be 

 decided upon, and the Douglas fir still be regarded as the 

 permanent crop, a distance of more than 6 feet apart should 

 not be contemplated, and the interspaces should be filled up to 

 3 feet over all with Norway spruce, which seems about the only 

 tree suitable for the purpose. 



In that case, 12 10 Douglas firs would be required per acre as 

 standard trees, and with the matrix composed of 3630 Norway 

 spruce, the cost of planting, where the plants had been purchased 

 of a size sufficiently large to enable them to be put directly out 

 to the forest, would be considerably lessened. 



As no area of pure Douglas fir in this country has yet 

 reached maturity, statements purporting to show the volume 

 and value of pure crops must be regarded as somewhat hypo- 

 thetical. There can be no doubt, however, that yield tables 

 dealing with the ordinary coniferous forest trees help us but 

 little in arriving at a true estimate of its productive capacity. 

 As a result of measurements taken in various parts of the 

 estate, and under varying conditions, I found that the increase 

 over spruce in cubical contents was never less than 50 per cent, 

 frequently 75 per cent., and in some cases as high as 120 per 

 cent. — the higher percentage showing at the higher altitudes. 

 As regards Scots pine, the increase was more pronounced, 

 varying from 150 per cent, to 200 per cent. Those figures 

 represent the mean of a number of measurements taken in each 

 plantation, and the trees selected were as nearly as possible an 

 average of their kinds. 



The Douglas fir plantation at Taymount is perhaps the oldest 

 pure wood of the species in this country, and it has at different 

 periods been dealt with by forestry experts. In 1888, the 

 plantation then being only 28 years of age, Dr Schlich esti- 

 mated the volume at 2956 cubic feet per acre, quarter-girth 

 measurement. In the winter of 1899 and spring of 1900 



