subtree (18 inches to 4.5 feet), the nearest tall shrub (over 8 feet), and the nearest low shrub 

 (18 inches to 8 feet). Quadrants were oriented with the contour so that two of the distance 

 measurements in each set of four could be corrected for slope. Trees were categorized by 

 diameter class, and shrub size was estimated by measuring two diameters and the height of the 

 plant crown. 



To supplement these measurements, we have taken representative black and white and 

 color photographs each year, both within the study area and from a permanent photographic 

 point on the cross-canyon slope facing the burn. No individual shrubs were marked prior to 

 burning, but representative marked plants of each important shrub species have been measured 

 and photographed annually since the fire. 



Calculations .- -Techniques for converting quadrant -distance measurements to estimates 

 of plant density lack the mathematical proofs required for application to populations with 

 unknown distribution. Several formulas can be used. To provide an empirical test of method, 

 fieldwork in 1964 was expanded to include both the distance to the nearest shrub and a total 

 count of all shrubs within 50 feet of sampling points. Since plant densities in the circular plots 

 were similar to density estimates using the angle method, the angle-method formula 5 has been 

 used throughout the study. 



PREFIRE VEGETATION 



Before the Neal Canyon site was burned, vegetation consisted of 54 species, including six 

 types of trees and 12 kinds of shrubs 6 (listed in Appendix 1). A summary description of the 

 plant community, based on average numbers of plants and plant sizes per 1,000 square feet, is 

 presented in table 1. As a result of the two timber sales, the number of overstory trees is 

 lower than might have been recorded in an undisturbed forest community. However, there was 

 no evidence in the form of burned snags or charred material on the ground to suggest that the 

 stand had been recently disturbed other than by logging. A few large stumps show that trees up 

 to 36 inches in diameter were present at one time, and increment cores from four of the domi- 

 nant Douglas-firs revealed ages ranging from 28 to 170 years. A cross section from the 

 largest willow stem tested had 34 annual growth rings. Figure 2 is representative of the 

 prefire vegetation. 



THE FIRE 



Firing of the Neal Canyon site began just after 8:00 a.m. , August 1 , 1963, and was com- 

 pleted before 5:00 p.m. the same day. Moisture content of fuel-moisture sticks examined at 

 3:30 p.m. each day during the week preceding the fire had been a relatively constant 5 to 6 

 percent. During the firing period, air temperatures rose from the mid- 50 's to nearly 80° F. 

 and the relative humidity dropped from around 50 percent to 10 percent or less. 7 Surface winds 

 were mostly under 5 m.p.h. during the day, but fire -induced gusts to 30 m.p.h. were recorded 

 during the peak of burning and estimates of wind velocities within the fire were even higher. 



Mean area per plant = — — , where r is the distance to the nearest individual in a 



4N 



quadrant and N is the number of sampling points. 



6 Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J. W. Thompson. Vascular 

 plants of the Pacific Northwest. Univ. Wash. Press. 1955. 



7 Data from U.S. Weather Bureau mobile stations at Eagle Creek and on the hilltop above 

 the fire show generally warmer and drier conditions at the hilltop. These figures represent a 

 broad summary from both stations. 



3 



