PINE TREES OP ROCKY MOUNTAIN" REGION. 29 



form of this pine usually designated as Pinus ponderosa scopu- 

 lorum. 1 



The earliest published notice of western yellow pine is in the jour- 

 nal of the Lewis and Clark expedition, which records that in 1804 

 cones of a pine (now believed to be western yellow pine) were found 

 floating in the White River and doubtless came from a growth of 

 this species in northwestern Nebraska. To David Douglas, however, 

 belongs the credit of having first brought this tree to the notice of 

 dendrologists by his discovery of it in 1826 on the Spokane River, 

 Wash. The following year (1827) he sent seeds to the London Hor- 

 ticultural Society, from which a tree was raised in the Caledonian 

 Horticultural Society's garden. 2 The first technical description was 

 taken from this tree; and its present name, Pinus ponderosa, was 

 established for the first time by Lawson 3 in 1836, although David 

 Douglas had previously proposed this name (but without a definite 



1 A long field study of the Rocky Mountain form of the western yellow pine and of the 

 generally longer-leafed yellow pine of the Pacific region has convinced the writer that the 

 two are geographic forms only of one widely distributed species, which was technically 

 described first in 1836 as Pinus ponderosa. The Rocky Mountain yellow pine is, there- 

 fore, here united as a silvical form with the Pacific slope yellow pine, under the name 

 P. ponderosa. The writer can find no constant characteristics to separate satisfactorily 

 the Pacific slope tree from its so-called variety " Pinus ponderosa scopulorum " of the 

 central and southern Rocky Mountain region. The most distinctive types of "P. ponderosa 

 scopulorum " occur in the Dakotas, Nebraska, eastern Wyoming, adjacent sections of Colo- 

 rado and in Texas, where the leaves are shorter and the cones smaller than are generally 

 found on trees occurring west of these outlying sections. Short-leafed and small-coned 

 trees are, however, not infrequent in the central and southern Rockies, along with leaf and 

 cone forms that are clearly intermediate between the most eastern and the interior moun- 

 tain trees. Marked differences in the soil and climatic conditions under which the short- 

 leafed and the longer-leafed trees grow can easily account for the supposed specific and 

 varietal distinctions relied upon to separate the Rocky Mountain yellow pine from the 

 Pacific tree. It seems much wiser to consider the trees of these two regions silvical forms 

 of one variable species than to try longer to maintain them as distinct by characteristics 

 which are clearly only individual variations. Exactly parallel cases are the attempted 

 separations of the Rocky Mountain form of lodgepole pine from the Pacific coast form and 

 of the Rocky Mountain form of Douglas fir from the Pacific slope form, both of which 

 grow under totally different soil and climatic conditions. 



2 Elwes and Henry (The Trees of Great Britain and Ireland, V, 1074, 1910). 



3 Agric. Manual, 354, 1836. The Pacific slope form of Pinus ponderosa appears to be 

 well adapted to the climate of England, where, according to Elwes and Henry (opus cit., 

 1076), several trees raised from Douglas's seed, sent in 1827, and planted in 1829, were 

 living in 1909 and had attained heights of from 96 to 104 feet, with diameters of from about 

 26 to 35 inches. Many other trees planted since then are said to be in thriving condi- 

 tion. As might well be expected, it is successfully grown there only in well-drained soils. 

 The German Government in the early nineties imported considerable quantities of seed 

 of the Pacific slope form of this tree for experiments in forest planting. The stock 

 raised grew well for several years and then died from some unknown cause (Schwappach, 

 Anbau. Fremdl. Holzart., 57, 1901). Presumably, however, the Rocky Mountain form 

 would have proved to be adapted to German conditions. Trials of both the Pacific slope 

 and the Rocky Mountain form of Pinus ponderosa in the region of New England have 

 not been successful (fide, Sargent, Gard. and For., 470, 1897). It is too early yet to 

 predict the success of this tree set in forest experimental plantations in the Letchworth 

 Park Forest and Arboretum at Portage, Wyoming County, N. Y., where so far, how- 

 ever, 3 to 5 year old stock raised from Rocky Mountain seed is in thrifty condition and 

 promises to grow well. A single tree now standing in the grounds of the U. S. Depart- 

 ment of Agriculture, Washington, D. C, raised from seed collected in the Pacific slope 

 region, was planted here about 30 years ago by William Saunders. Its growth has, how- 

 ever, been exceedingly slow, the height being about 15 feet. 



