Thuya only attained about 110 by 7 feet, and had been overtopped by the larch, which ran from 140 to 150 feet high, and 7 to 14 in girth. The trees were extremely dense upon the ground, standing often only 12 feet apart, and averaging 200 to the acre. The ground was covered with seedlings of Thuya, 3 to 6 feet high, and more than thirty years old. The Thuya trees were being felled for telegraph and telephone poles, but never had clean stems, being covered with dead branches to 6 to 20 feet above the ground, and with living branches above this, and when of a large size were always decayed at the heart. The larch, as usual, was quite sound.
A wood near Whitefish, on flat land in a moderately rainy district at 3000 feet altitude, was composed of about nine-tenths larch and one-tenth Douglas fir, Pinus ponderosa, and Engelmann’s spruce. The larch were 160 feet high by 6 to 9 feet in girth, overtopping the other trees, and with clean stems up to 80 or go feet. A stump, 40 inches in diameter, showed 585 annual rings, the sapwood with forty-two rings being only an inch in thickness, and the bark two inches.
The largest tree which I saw was growing on a high bank beside the Stillwater Creek, some miles west of Whitefish. It measured 19 feet 4 inches in girth at 5 feet from the ground, but the top was blown off. Near it were many large trees, 12 feet to 15 feet in girth, but the tallest was only 151 feet in height.
With regard to the height attained by the western larch, Sargent in his Report on the Forest Trees of North America, 216 (1884), states that it ranges from 100 to 150 feet, but in the Silva he gives the maximum height as 250 feet. I could find no confirmation of the latter figure either at the Arnold Arboretum or Washington, and I am of opinion that 180 feet is rarely if ever exceeded. The tallest tree recorded by any accurate observer is, I believe, the one cut down by Ayres' in the Whitefish Valley at 3500 feet altitude, which measured 181 feet high, with a diameter of 3 feet on the stump, and scaled 3500 feet board measure. He mentions’ also another tree growing on the middle fork of the Flathead river, which was 180 feet high by 4 feet in diameter.
J.B. Leiberg states in his account of the Priest River Forest Reserve that the larch in the sub-alpine zone, above 4800 feet elevation, averaged 60 to 100 feet in height, 1 to 2 feet in diameter, and eighty to a hundred years old; while in the white pine zone, from 2400 to 4800 feet, the trees were 150 to 200 feet in height, 2 to 4 feet in diameter, and 175 to 420 years old. Here the heights are evidently estimates, and cannot be relied on implicitly.
The western larch is rarely seen as pure forest, and then only as the result of forest fires. Mr. Langille in his account of the Cascade Forest Reserve, p. 36, says that the larch "has done more than any other species to restock the immense burns that have occurred on a part of the reserve. This is largely due to the fact that the thick bark of this tree resists fire better than any other species, and more trees are left to cast their seed on the clean loose soil and ashes immediately after a fire. The seeds are small and light, and are carried to remote places by the wind and covered deeply by the fall rains. In the spring a dense mass of seedlings covers the
1 U.S. Geol, Survey, Flathead Forest Reserve, 256, 314 (1900).
