WESTEEN 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 ^ 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 it is fairly immune to damage 

 by these agencies. 



It is, comparatively speakmg, a windfirm species, and normally is 

 able to stand without the protection of surrounding trees. Some- 

 times in the virgm 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 locahty 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 hable 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 hi 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. 



> "The 'Bluing' and 'Red Rot' of Western Yellow Pine," by Herman von Schrenk, Bull. 36, Bureau 

 of Plant Industry, U. 8. Dept. of Agriculture. 



2 Manu;-:cript report, "Windfall Damage on Cut^over Areas," by R. E. Smith, forest examiner, and 

 It. II. Weitknecht, assistant forest ranger. 



