DOUGLAS FIR ON THE DURRIS ESTATE. 187 



might average 6 inches in diameter at breast height, a useful 

 size, which could be readily marketed. All thinnings must be 

 executed with caution if the ultimate aim is to produce the best 

 quality of timber. 



An even-aged mixture of Douglas fir with light-demanders 

 would not, I think, lead to very successful results, as most 

 light-demanders grown in this country are of a slower rate of 

 growth; hence, they would soon become dominated. To obtain 

 the best results in such a mixture, the light-demanding species 

 must be given a start, Douglas fir being introduced at a later 

 period. Here we have an excellent example of this, the Douglas 

 fir having been introduced as an under-crop to larch twenty-five 

 years ago. The management then was not, however, what would 

 be commended now. There had been no careful selection of the 

 larch stems left on the ground, and the Douglas fir was intro- 

 duced at a too late period. The example is, however, instructive. 

 From the excellent leaf-canopy of the Douglas fir humus is 

 accumulated, which maintains ample moisture to permit the full 

 development of the larch. From this we may infer that it is 

 good forestry, in localities where broad-leaved species cannot be 

 profitably grown, to plant larch where the soil and climate are 

 suitable, and adopting the advice given by an expert, to thin out 

 strongly between the twentieth and thirtieth year, in order to 

 introduce Douglas fir as an under-crop. 



This tree seems to enjoy a happy immunity from disease, as no 

 trace of such is to be found on the Durris estate. But then there 

 is no larch cancer here. To injury by weevils it is somewhat liable, 

 especially when planted after a crop of Scots pine which had 

 been felled the previous season. The damage by game is nothing 

 serious. It has been often observed that Douglas fir will not grow 

 to a useful height, as a timber tree, in exposed situations. When 

 grown as a standard, it does not present the erect outline of Abies 

 nobilis; but grown as a pure plantation, or as an under-wood to 

 a light-demanding crop, it will be difficult to find a divided stem. 

 Here may be seen many excellent arboricultural specimens, grown 

 in favoured localities. I will give the dimensions of one in 

 particular, which is 100 feet high, having a diameter at breast 

 height of 3 feet 8 inches, with the crown extending almost to 

 the ground. This tree is nearly sixty years of age. Others 

 there are of forty years' growth, with a height of 75 feet, and a 

 diameter of 2 feet at breast height. These contain on an average 



