Io8 TRANSACTIONS OF ROVAL SCOTTISH ARBORICULTURAL SOCIETY. 



acre for agricultural purposes. In 1876 this area was partly 

 covered with the natural oak woodland of the locality, which 

 consisted of about 15 standards per acre with wide-spreading 

 crowns, the intervening gaps being occupied by small oak scrub. 

 The scrub was cut out, the remaining standards were left for 

 shelter, and were underplanted with a mixture of Douglas fir, 

 Thuja gigantea and a very few larch. The plants were notched 

 in about 4 feet apart ; the sizes of plants used were 2-year 

 seedlings and 2-year i-year transplants. The two species were 

 planted alternately, equal proportions of each being used, while 

 a few larch were planted along the exposed edges. On the 

 north-west side, where the soil was wet, surface drains were cut 

 at an average cost of 2s. 6d. per 100 yards. 



Treatment. — From the evidence of partly decayed stumps, it 

 would seem that a partial thinning had been made about twenty 

 years ago ; unfortunately, however, no actual records of the value 

 of this thinning are obtainable. The old crop of standard oaks 

 was sold by private bargain in the year 1905, when considerable 

 damage was done to the young crop by their fall and removal. 

 A number of the Douglas firs were injured and broken, and 

 large gaps were thus left in the young wood. In addition, 

 the removal of these old trees left the plantation exposed for the 

 wind to obtain an entrance. As a result of this a portion was 

 blown in the November gale of 191 1, while the remainder was 

 levelled by another gale in 1912. 



Normal condition. — Two years ago the plantation was fully 

 stocked, the trees standing from 4 to 9 feet apart. The average 

 height-growth of the Douglas fir was about 70 feet, while that 

 of the Thuja was about 60 feet. The stems of the Douglas 

 fir showed natural pruning up to two-thirds of their height 

 (see Plate VIII. fig. i), the average annual increment per stem 

 being -6 cubic feet, and that of the Thuja -3 cubic feet The 

 forest floor has a covering of 2 to 3 inches of humus. It is 

 evident that this cleaning effect has been largely due to the 

 occurrence of Thuja in single mixture with the Douglas. In the 

 year 191 1 there was a full seed year of both species. The trees 

 all show healthy development, there being no signs of insect 

 pests or fungus disease. 



The stems number on the average about 890 per acre, one- 

 half of that number being of pole size while the remainder are 

 of timber size and consist of equal numbers of Douglas fir and 



