National Geographic : 1898 Sep
BITTER ROOT FOREST RESERVE most precipitous ridges, especially on the southern slopes, are found straggling trees, but for the purpose of graphic illustra tion it has been represented as it has. Along the crest the growth is very sparse, but as the project ing spurs reach out to the westward and attain lower altitudes they are usually covered with a forest growth, except where their sides are too precipitous to admit of vegetation. There are on the western slopes of the Bitter Root mountains three primary forest zones, namely, the subalpine fir, the white pine, and the yellow pine. The subalpine-fir zone extends from the crest alti tudes to about 5,800 feet above sea-level and includes the white bark pine, the lodge-pole pine, the Engelmann spruce, the Lyall larch, and the subalpine fir. The white pine zone has an ap proximate range from an altitude of 5,800 feet to about 2,000 feet, and includes the white fir, the lodge-pole pine, the Engel mann spruce, the cedar, and the yew. The yellow-pine zone extends from elevations of 2,500 feet in the valleys to nearly 6,000 feet on the western and southern slopes, and to 4,500 on the northern and eastern slopes, and includes the yellow pine, the white fir, the hemlock spruce, the lodge-pole pine, the west ern birch, the paper birch, the balm of Gilead poplar, and the aspen, besides various willows and alders. The distribution of the growth in the subalpine zone is about the same as in the similar zone east of the crest. The trees constituting the white pine zone are divided approximately into three equal portions. the white fir forming one portion, the cedar the second, and the lodge-pole pine and Engelmann spruce the third. The species of trees occurring in the yellow-pine zone may be divided approx imately into two portions, the hemlock spruce constituting one and the yellow pine and white fir the other, the former, however, being about three times more abundant than the latter. From the foregoing it will be observed that at least 98 per cent of the trees in the Reserve are coniferous, the exceptions being a few cottonwoods, maples, and various bushes bearing berries. The most striking feature presented by this map is the large portion of it that has been burned over, nearly all of it having been visited at different times by fires and at least one-third of the standing timber having been destroyed. The map indicates clearly the burned zones, and an attempt has been made to show by the percentage figures the proportion of the timber that has been completely destroyed.