Figure Captions

Figure 1. Site map. Location of sites sampled for fire history, aspen age structure and mixed-
conifer age structure.

Figure 2. Elevation vs. MFI with standard error bars. Triangles represent average MFI and elevation for each site pair. Italics represent sites in the lower slope topographic position. (See Table 1 for site names.)

Figure 3. A simple model to illustrate the "widespread-fire" threshold size. Sites are assumed to be the center point of a square-shaped, homogeneous (same fire history throughout) area. The average approximate distance between adjacent sites in Mormon Canyon is 500m. Therefore each site represents an area of 500x500m, or 25ha. Results suggest that when fire attains a size such that two sites record the event, there is a higher probability of the fire spreading throughout the canyon. A fire that ignites within one site area will, by definition, spread throughout it, growing to a size of 25ha. If the fire burns into the adjacent site area, it will again, by definition, spread throughout. Therefore, this fire, to be recorded in two sites, needs only to exceed a size of 25ha. This model is unrealistic on many counts, for example, fire history sites are not linearly arranged and topographic features that affect fire behavior are not incorporated; nevertheless, it provides a basis for conceptualizing fire size.

Figure 4. Fire History Chart of the elevation gradient sites. Horizontal lines represent the composite record for each site. Dashed portions show the period prior to first scar recorded at the site; solid lines delineate the fire-recording period. Only MCS recorded one fire prior to 1600, in 1471. Vertical bars represent fire years. The unshaded area is the Period of Analysis (PA) for single site (top portion) and multi-site fires (bottom portion) (see Methods for determination of Period of Analysis).

Figure 3. Fire History Chart of mixed-conifer sites. Horizontal lines represent the composite record for each site. Dashed portions show the period prior to first scar recorded at the site; solid lines delineate the fire-recording period. The unshaded area is the Period of Analysis (PA) for single site (top portion) and multi-site fires (bottom portion) (see Methods for determination of Period of Analysis).

Figure 4. Estimated pith dates for aspen stands. A. CPA; B. CPB; C. CPC; D. BSA; E. ASA; F. WCU; G. FPL1; H. FLP2; I. FLP3.

Figure 5. Stand structure data for LBS. A. Estimated pith date v Linear Position on the transect; B. Age distribution by canopy class; C. Species composition by canopy class; D. Species composition for dead trees.

Figure 6. Stand structure data for UBS.

Figure 7. Stand structure data for LCR.

Figure 8. Stand structure data for MCR.

Figure 9. Stand structure data for UCR.

Figure 10. Stand structure data for MOS.

Figure 11. A comparison of Engelmann spruce (circles) and Douglas-fir (triangles) seedling height in the Chiricahuas to seedling height in the White Mountains of eastern Arizona. Solid horizontal line is average height growth for a 6-7 year period. Dotted lines represent 1 standard deviation for Engelmann spruce seedlings; dashed horizontal lines represent 1 standard deviation for Douglas-fir seedlings. Vertical lines represent fire years. A. MOS; B. LCR; C. MCR; D. UCR; E. LBS; F. UBS.

Figure 11. SEA result of fire-climate analysis. A. Fire data from elevation transect; B. Fire data from mixed-conifer forest.

Figure 12. Erosion in upper Ward Canyon resulting from the Rattlesnake fire.