WESTERN YELLOW PINE IN OREGON. 15 
As is the case with other pines, freshly cut logs and lumber are apt 
to "blue" if not kept under water or dried soon after cutting; and the 
blue stain decidedly lessens their commercial value. The stain is 
caused by Ceratostomella pilifera 1 and other fungi. 
THE ELEMENTS. 
Yellow pine grows in a climate in which it is especially exposed 
to high winds, drought, severe winters, frost heaving, and lightning. 
The fact that it is able to survive as well as it does while other 
species can not is an indication that ijb is fairly immune to damage 
by these agencies. 
It is, comparatively speaking, a windfirm species, and normally is 
able to stand without the protection of surrounding trees. Some- 
times in the virgin forest a good many windfalls are found, but these 
are the result of an exceptionally high wind at a time when the trees 
were least able to withstand it, either because they were snow-laden 
or because the ground was wet. A recent storm in the Blue Mountains, 
such as is experienced in this region every year or two, blew down in 
a certain locality one tree to each 5 acres. The tornado of 1894 
mowed down all the timber in its path for a mile or more, the yellow 
pines succumbing to its force as well as all other trees. Where a part 
of the stand has been removed by cuttings, the trees which are left 
are more liable to windthrow than they were in the virgin forest. 
On one tract of 1,624 acres in Grant County, 1,600 trees over 12 
inches in diameter were thrown in the first two years after a partial 
cutting. 2 This is undoubtedly an exceptional instance, for similar 
areas of equal exposure have at the same time suffered merely a nomi- 
nal amount of windthrow. In heavy winds no class of tree in partially 
cut-over areas seems to be entirely immune to windthrow, though 
the risk increases with the height of the tree and the density of its 
crown. Where the trees are in groups, the wind damage is consider- 
ably greater than where the reserved trees are evenly distributed. 
The effect of the winds is particularly severe in a solid body of uncut 
timber along the lee edge of a cut-over area. 
Drought, of course, is a factor which limits the local distribution 
of this tree, for the yellow-pine forests in Oregon all abut on territory 
which is too dry for their growth. Drought seems to affect the 
reproduction chiefly, by preventing it from gaining a foothold on dry 
soils. After the sapling stage is passed, it is rarely killed by drought, 
though of course excessive drying of the soil affects the growth of the 
tree unfavorably. 
1 "The 'Bluing' and 'Red Rot' of Western Yellow Pine," by Herman von Schrenk, Bull. 36, Bureau 
of Plant Industry, U. S. Dept. of Agriculture. 
2 Manuscript report, "Windfall Damage on Cut-over Areas," by R. E. Smith, forest examiner, and 
R. H. Weitknecht, assistant forest ranger. 
