2 BULLETIN G58, U. S. DEPARTMENT OF AGRICULTURE. 



OBJECT OF FOREST DISEASE SURVEYS. 



Timber surveys have as their prime object the gathering of such 

 data upon proposed sales areas as will be of use in the appraisal and 

 administration of the sales, and it is this survey which makes the 

 sale possible. The collection of valuable data on the board-feet con- 



Fig. 1. — Pathological map of sections 22, 23, 24, 25, 26, and 27, T. 2 N., R. 15 W., 

 the Big Hole area, based upon the map of the timber survey of that area in 

 the Deerlodge National Forest, Mont., showing timbered areas infected with disease. 

 The rot percentages are indicated for heart-rot (Tramctes pini (Brot.) Fr.) and 

 butt-rot (Polyporus schweinitzii Fr.) only. Crosshatching indicates infection areas. 

 Other symbols on the map are part of the Forest Service map legend, such as Spr. 

 200, which indicates Engelmann spruce, 200-year age class ; L. P. 60, 0.7 equals 

 lodgepole pine 60-year age class, density 0.7 ; Gr. equals grassland ; Br. equals brush. 

 A, Pine rust (Cronartium coleosporioides (D. and II.) Arthur), gall and blister 

 forms, on lodgepole pine (Pinus contorta) ; B, smelter-smoke injury, principally of 

 alpine fir (Abies lasiocarpa) and Douglas fir- (Pseudotsuga taxifolia) ; C, honeycomb 

 rot (Trametes pvni (Brot.) Fr.), principally on Engelmann spruce (Picea engcl- 

 manni) ; D, porcupine injury — peeling of bark and girdling of lodgepole pine ; 

 E, cubical butt-rot (Polyporus schweinitzii Fr.) on lodgepole pine and white-bark 

 pine (Pinus albicaulis) ; F, mistletoe (Razoumofskya americana (Nutt.) Kuntze) 

 on lodgepole pine. 



tents of the stand, cull percentages, forest types, age classes, topog- 

 raphy, and logging factors is followed by an accurate map portray- 

 ing the topography, types, density, age classes, and timber estimates. 

 A careful stumpage appraisal of the area based upon these available 

 data and upon the various economic and topographic factors forms 

 the final step before contracts are let. 



