Henky AM) Fi,ooD — The Douglas Firs. 83 



The tree is healthy enough, but is of no commercial value for planting, as its 

 lack of vigour and slow growth render it useless for the production of timber. 

 It has been recommended for shelter at high altitudes, as it bears exposure 

 well, but in our climate Sitka Spruce will prove much superior for this purpose. 

 The Colorado Douglas Fir was largely planted in mixture with European 

 Spruce and Scots Pine about forty years ago on good forest soil at Durris, 

 Kincardineshire, but proved unsuccessful as a timber tree. Growing more 

 slowly than either companion species, it was nearly all suppressed before its 

 thirtieth year. 



At Buckhold, Berkshire, it is less vigorous than Scots Pine on clay soil 

 overlying chalk at a considerable depth, and is regarded as a failure. Trees 

 planted twenty-four years average 30 feet in height and 20 inches in girth. 

 Oregon Douglas Firs alongside them, only nineteen years planted, have 

 attained an average of 46 feet in height and 29 inches in girth. 



The Colorado species makes very feeble growth on poor sand, as at 

 Westwick in Xorfolk, where a group of trees planted in 1902 were only 

 5 feet high in 191S. Close beside them, Oregon Douglas Fir, of the same 

 age, was 35 feet high. 



'The comparative rate of growth is also well seen ou good deep sandy soil 

 at Highfield, East Liss, Hants, where Mr. J. S. Gamble, F.E.S., has made 

 plantations of both species. In 1902, two acres were planted here with 

 Douglas Fir and European Spruce, alternately and four feet apart. Over 

 two-thirds of the area the Oregon species was used, and over the remainder 

 the Colorado species. In 1919 the Oregon Douglas Firs, which had com- 

 pletely killed the Spruce, were fine trees, about 40 feet in height, and 6 to 30 

 inches in girth. The Colorado Douglas Firs, which will be suppressed in a 

 short time by the Spruce, are now only 20 to 25 feet in height, and 3 to 15 

 inches in girth. 



The difference in growth of the two species in England is perhaps best 

 illustrated by the contiguous plots in Bagley "Wood, near Oxford, where the soil 

 consists of sand and stones, with a moderate admixture of loam. These plots, 

 each ^ acre in area and treated alike, were planted in the spring of 1907 

 with four- year-old trees, spaced at 4 feet apart. Early in 1919, twelve years 

 from the time of planting, measurements were made by Sir W. Schlich,* as 

 follows : — 



Oregon Douglas Fir — 2lo2 trees per acre, averaging 32 feet high and 3'4 

 inches in diameter ; basal area, 140 square feet per acre ; volume of timber, 

 1176 cubic feet per acre. 



Colorado Douglas Fir — 2466 trees per acre, averaging 16 feet high and 



' Quarterly Journal of Foreati ij, xiii, 266 (1919). 



K.I. A. PltOC, VOL. XXXV, SECT. B. [M] 



