In addition to this amount, an immense quantity of wood is used each year for fuel, posts and other domestic purposes, and the total annual consumption is not less than 20 billion cub. ft.

The years 1890 to 1906 were marked by rapid changes in the rank of the important timber trees with reference to the amount of timber cut, and a shifting of the important centres of production. Among coniferous trees, white pine has yielded successively to yellow pine and Douglas fir, while the scene of greatest activity has shifted from the Northern forest to the Southern, and from there is rapidly shifting to the Pacific Coast. The total cut of coniferous lumber has increased steadily, but that of the hardwoods is falling off, and in 1906 it was 15% less than in 1899, while inferior hardwoods are gradually assuming more and more importance, and the scene of greatest activity has passed from the middle west to the south and the Appalachian region.

Conifers.—The coniferous supply of the country is derived from four forest regions: (1) The Northern forest; (2) the Southern forest; (3) the Pacific Coast forest; and (4) the Rocky Mountain forest.

1. The Northern forest was long the chief source of the coniferous lumber production in the United States. The principal timber tree of this region is the white pine, usually known in Europe as the Weymouth pine. It has an average height when mature of 110 ft., with a diameter a little less than 3 ft., but the virgin timber is approaching exhaustion. White pine was one of the first trees to be cut extensively in the United States, and Maine, the pine tree state, was at first the centre of production. In 1851 the cut of white pine on the Penobscot river was 144 million ft., that of spruce 14 million and of hemlock 11 million. Thirty years later the pine cut had sunk to 23 million, spruce had risen to 118 million, and hemlock had passed pine by a million feet. Meanwhile, the centre of production had passed from the north woods to the Lake States, and for many years this region was the scene of the most vigorous lumbering activity in the world. The following figures show the cut for the Lake States from 1873 to 1906. It is certain that the remarkable decline in the cut of white pine which these figures show will continue still farther.

18733,993,780,00018908,597,659,352
18743,751,306,00018917,879,948,349
18753,968,553,00018928,594,222,802
18763,879,046,00018937,326,263,782
18773,595,333,49618946,821,516,412
18783,629,472,75918957,050,669,235
18794,806,943,00018965,725,763,035
18805,651,295,00018976,233,454,000
18816,768,856,74918986,155,300,000
18827,552,150,74418996,056,508,000
18837,624,789,78619005,485,261,000
18847,935,033,05419015,336,000,000
18857,053,094,55519025,294,000,000
18867,425,368,44319034,792,000,000
18877,757,916,78419044,220,000,000
18888,388,716,46019053,777,000,000
18898,183,050,75519063,032,000,000

Second to the white pine among the coniferous lumber trees of the Northern forest is the hemlock (Tsuga canadensis). It is used chiefly for construction purposes and furnishes a comparatively low grade of lumber.

The spruce (Picea rubens) is used chiefly for lumber, but it is in large and increasing demand in the manufacture of paper pulp. For the latter purpose hemlock, poplar (Populus tremuloides and P. grandidentata) and several other woods are also employed, but on a smaller scale. The total consumption of wood for paper in the United States for 1906 was 3,660,000 cords, of which 2,500,000 was spruce. Of this, however, 720,000 cords were imported from Canada.

2. The chief product of the Southern forest is the yellow pine. This is the collective term for the longleaf, shortleaf, loblolly and Cuban pines. Of these the longleaf pine (Pinus palustris Mill.), called pitch-pine in Europe, is the most important. Its timber is probably superior in strength and durability to that of any other member of the genus Pinus, and in addition to its value as a timber tree it is the source of naval stores in the United States. The average size of the mature longleaf pine is 90 ft. in height and 20 in. in diameter. Shortleaf (Pinus echinata) and loblolly (P. taeda) are other important members of this group. Their wood very closely resembles that of the longleaf pine and is often difficult to distinguish from it. The trees are also of about the same size and height. Loblolly is, however, of more rapid growth. The total cut of yellow pine in 1906 was 11,661,000,000 board ft.; it has perhaps not yet reached its maximum, but is certainly near it.

Another important coniferous tree of the Southern forest is the bald cypress (Taxodium distichum), which grows in the swamps. The cut in 1906 was 839,000,000 board ft., a gain of 69% over 1899.

3. But the great supply of coniferous timber is now on the Pacific Coast. The Douglas fir (Pseudotsuga taxifolia), also known as Douglas spruce, red fir and Oregon pine, is the foremost tree in Oregon and Washington, and the redwood in California. When mature the Douglas fir averages 200 ft. in height and 4 ft. in diameter, and the redwood 225 ft. in height and 8 ft. in diameter. Other important trees of the Pacific Coast are sugar pine (Pinus lambertiana), western red cedar (Thuja plicata), western larch (Larix occidentalis), Sitka spruce (Picea sitchensis), western hemlock (Tsuga heterophylla) and western yellow pine (Pinus ponderosa). These trees will all be of increasing importance.