This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Commercial Fuelwood Harvesting Affects on Small Mammal Habitats in Central Arizona William H. Kruse Abstract-In a central Arizona fuelwood harvest area, 75 percent by burning affects the newly formed slash habitat for small of the overstory was cut in a commercial harvest, resulting in large mammals and plants and also reorganizes the nutrient base quantities of residual logging debris that altered habitat for many stored in the slash (Harrington 1989, Covington and DeBano wildlife species. Small mammals have intricate roles in ecosystem 1988). Natural decomposition of residual slash provides a function, and current fuelwood management practices have para­ slower and more complete return of nutrients to the system, doxical affects on small mammal habitats. In a small mammal while providing the protective effects of slash. J uni per slash, study, no differences in total animals capt,ured were detected among unlike pine slash, decomposes at a slower rate. treatment plots. Immediately following overs tory reduction or re­ Small mammal populations are impacted by overstory moval in 1992 and 1993, differences among species ca ptures, s pecifi­ disturbances (Turkowski and Reynolds 1970) while on-the­ cally deer mouse, increased significantly. The increased capture ground slash causes an increase in abundance of some rate remained significant throughout the remainder of the study. rodent species regardless of overstory condition (Severson Pinyon mouse captures declined significantly immediately follow­ 1986). Kruse and others (1979) found that when the over­ ing treatments, but were not detectablydifferent from pretreatment story was removed or reduced, rodents that preferred the levels a year later. woodland condition were fewer in number than those on the treated areas. This small mammal research was part of an effort to study the effect of nutrient cycling, other wildlife, and wood prod­ Commercial fuelwood harvesting generates greater and uct management on soil, water, tree, and range resources in more concentrated slash and has more affect on microsite pinyon-juniper woodlands. This paper discusses the effects conditions than noncommercial fuelwood cutting. This has of commercial fuelwood harvesting in an old-growth or late prompted some central Arizona USDA Forest Service Ranger seral pinyon-juniper woodland on small mammal popula­ Districts to assess the effects of commercial fuelwood re­ tions in central Arizona. moval and slash disposal, particularly by burning. Specifi­ cally, removal of slash habitat through burning is a concern. Fortunately, commercial harvest permits, however, can pro­ Study Area _________ vide detailed slash management directions to meet specific management objectives. Burning is usually not performed The Heber Ranger District, Apache-Sitgreaves National by the fuelwood permit holder but instead is included in Forest in central Arizona was the study-site area. Average Forest Service management plans. tree basal area (diameter measured at root crown) was Fuelwood removal and slash management also affects 23.2 ± 5.4 m2/ha, which produced 35.3 ± 12.7 m3/ha of fuel­ microsite nutrient cycling, miderstory production (specifi­ wood (Kruse and Perry 1995). One-seed juniper (Juniperus cally protecting forages from large ungulate grazing), and monosperma) was the dominant species (54 percent). The regeneration of overstory species. Small mammal popula­ second most dominant tree (25 percent) was Colorado pin­ tions are also affected by removal of overstory, understory yon (Pinus edulis), followed by alligator j uni per (J. deppeana) composition and structure change, and slash accumulation (13 percent). Ponderosa pine (Pinus ponderosa) occasionally and subsequent manipulation. Basic ecological information occurred on moist sites (8 percent). Mean pretreatment is needed to support current harvesting plans (Gottfried canopy cover was approximately 40 percent, while the mean 1987). The least understood management option has been annual herbaceous and woody plant potential productivity slash disposition (Severson 1986, Baker and Frischknecht was approximately 562 kg/ha. 1973). The study area is relatively flat, dissected by several small Retention or removal of slash provides or eliminates ephemeral drainages. Elevations are between 2,000 and specific habitat characteristics for certain small mammals. 2,060 m. The primary soil subgroups, derived from lime­ In addition, retention or removal of slash affects the poten­ stone, are Lithic Ustochrepts, Udic Haplustalfs, and Typic tial protective cover for emerging new plants. Slash removal Eutroboralfs. The mean annual precipitation is between 34 and 46 cm. Methods In: Monsen, Stephen B.; Stevens, Richard, comps. 1999. Proceedings: ecology and management of pinyon-juniper communities within the Interior West; 1997 September 15-18; Provo, UT. Proc. RMRS-P-9. Ogden, UT: U.S. Field Methods Department of Agriculture, Forest Service, Rocky Mountain Research Station. The study area consisted of 33 units, 4 ha in size. Three William H. Kruse is Range Scientist (retired) USDA Forest Service, Rocky Mountain Research Station. The Southwest Forest Sciences Complex, units were treated with silvicultural prescriptions. Thirty 2500 S. Pine Knoll Dr. Flagstaff, AZ 86001. 4 ha study units were grouped into five blocks representing USDA Forest Service Proceedings RMRS-P-9. 1999 215 Figure 1-Typical overstory, preharvest conditions of Figure 3-Type conversion. Slash accumulation but late seral old-growth pinyon- juniper woodland at Heber/ not burned following harvest of commercial fuelwood. Mud Tank small mammal study area. Noncommercial stems cut and also remain. six overstory/slash treatments. Sixteen of the 30 were ran­ included were the silvicultural treatments and the commer­ domly selected for the small mammal study. Four of the cial harvest where the noncommercial stems were left uncut 6 overstory/slash treatments were replicated in the 16 units as advanced regeneration. Small mammal trapping was (Kruse 1995). conducted during July and August from 1990 through Trapping occurred on 4 overstory treatments: (1) controls, 1996. Before harvest, downed woody fuel was estimated at where the units were untreated (fig. 1); (2) burned, to 3.15 mtJha (Kruse and Perry 1995). Post harvest slash simulate a forest fire (fig. 2); (3) type conversion, where accumulation was estimated at 55.71 mtlha (fig. 3). fuelwood was harvested, the non-commercial residual trees Treatments were assigned randomly and were not neces­ cut, but slash was not burned (fig. 3); (4) type conversion, sarily contiguous; roads or drainage channels could separate where fuelwood was harvested, residual trees cut, and slash units within a given block. Harvesting began during fall! burned (fig. 4). Type conversion is clearcutting to convert a winter of 1991 and continued for 24 months. Burning com­ woodland to grassland. The two overstory treatments not menced when the slash was at least 2 years old. Treatment schedules are in Kruse (1995). A 100 m 2 trapping grid was located in the center of each unit. 8 x 10 x 25 cm Sherman live trap was placed at each grid point, 10 m x 10 m apart. At alternate points, a 10 x 12 x 40 cm Sherman live trap was placed near the smaller one. The bait was a mixture of chicken scratch and rolled oats. Each unit was sampled yearly with 150 traps for 3 nights and 2 days. Physical measurements were taken and recorded for each animal, then they were toe clipped Figure 2-Burned standing green woodland to simulated wildfire for type conversion (clearcutting to Figure 4-Type conversion. All overstory harvested or convert a woodland to grassland). cut, and slash burned. 216 USDA Forest Service Proceedings RMRS-P-9. 1999 Table 1-Species captured and percent of composition. 20 Species Common name Composition 16 Percent Peromyscus truei pinyon mouse 42 Peromyscus maniculatus common deer mouse 37 12 Eutamias dorsalis cliff chipmunk 9 Neotoma albigula white-throated wood rat 7 8 Neotoma mexicana Mexican wood rat 2 Peromyscus boylei brush mouse 2 Sylvi/agus auduboni desert cottontail 4 Spermophilus variegatus rock squirrel <1 Neotoma stephensi Stephens wood rat <1 0 Dipodomys ordi Ord kangaroo rat <1 90 91 93 94 95 96 Microtus mexicanus Mexican vole <1 90 vs 91 P = 1.0 mean 90,91 vs.93 P = < 0.001 mean 90,91 vs.94 P = < 0.001 mean 90,91 vs.95 P < 0.001 and released. Recaptures were noted. Relative abundance = and species composition of small mammals live trapped and mean 90,91 vs.96 P = 0.004 released on the study area are in table 1. Figure 6-The deer mouse captures. Captures were significantly increased immediately following treatments Analysis Methods in 1992-93 (p < .001). and remained higher through the remainder of the study (p < .004) while the slash habitat Replicated study units among 4 blocks were selected was on the ground aging. Some of the units were burned randomly as the experimental design layout (Ludwig and before the 95 and 96 trapping periods but it is unclear Reynolds 1988). Blocks were based on similarity of pretreat­ whether the burning impacted the deer mouse captures. ment overs tory conditions and characteristics. The treat­ ment units included combinations of no burning or cutting, burning standing green, cutting and no cutting (fig. 1-4). among treatments were tested by analysis of variance with The small mammal study replicated these