ture, December 1903, and of which an abstract appeared in Transactions of Royal Scottish Arboricultural Society, xvii. 269. This was based on measurements made in June 1903, by the late Mr. Pitcaithley, forester to the late Earl of Mansfield, who selected two typical areas of 1⁄10 acre each, on which he counted and measured the trees, of which he found eighteen on one and twenty-five on the other area, and accurately measured the cubic contents of two trees, one of which contained 46.76 cubic feet and the other 39.49 cubic feet measured down to 3 inches diameter. Dr. Somerville, assuming Mr. Pitcaithley’s measured trees to be average ones, brings out the total cubic contents per acre by quarter-girth measure as 7977 cubic feet, and comparing this with Dr. Schlich’s estimate of 2934 cubic feet made fifteen years previously, comes to the conclusion that the average increase per acre in that period was no less than 336 cubic feet per annum.
This in my opinion is a mistaken calculation, and if compared with the annual increment of 150 feet per acre per annum in Lord Ducie’s plantation and the results of the measurement of Gunoak wood, both on better land than that at Taymount, we must hesitate to accept it as even approximately correct.’
The important point to consider is how long these trees will continue to main- tain their rapidity of growth, and what will be the value of the timber? My own belief is that they fall off in their rate of increase; that the larger ones will continue to suppress and starve out the weaker ones, as they have already done to a great extent; and that the timber of Douglas fir grown in the country will never compare in quality or value with the imported timber, which, it must always be remembered, is from 200 to 300 years old, and selected both in the forest and the mill from a very much larger quantity.
Dr. Schlich writes me as follows:—"As to the quality of the Douglas fir timber, I merely quoted what the late Mr. M‘Corquodale told me. Since then I have paid some attention to the subject and noticed that in timber from young Douglas firs there is a considerable difference between spring wood and summer wood; hence I am sure, and in this I agree with you, that only trees of considerable age will yield timber equal in quality to that of larch, if at all.”
There are other causes, which tend to make the production of clean, straight timber difficult, in many situations and on many soils in this country, and which should be considered by all who contemplate planting this species largely for profit.
The first is its tendency to form large and spreading branches, which it shows in a very marked degree. In order to prevent this, the trees must be crowded to an extent which is only possible with success on soils of unusual depth, or on slopes composed of rock which is sufficiently disintegrated to allow the roots to penetrate deeply ; in which case they may clean themselves when they attain a height of 60 to 80 feet ; though | have never seen any in England which have naturally cleaned
1 After this was in print I sent it to the Earl of Mansfield for his opinion, and am informed that in 1908 a careful
measurement was made by his forester, Mr. A.T. Kinnear, of the whole of Taymount plantation, which now contains 1536
Douglas firs on the whole area = 192 trees to the acre. These contain 51,456 cubic feet (under bark) or 6432 cubic feet per
acre, being an increase of 3498 cubic feet per acre since it was measured by Dr. Schlich in 1888, equal to about 134 feet per acre per annum since it was planted, the rate of increase from 1888 to 1908 being about 175 feet. The largest tree is 93 feet
high, and contains 118 cubic feet.
