2. Uncut. An adjacent uncut area was used as the 

 control. 



Residue reduction treatments on the clearcut included 

 the following: 



1. Broadcast burning resulted in a 20 percent duff re- 

 duction (Artley and others 1978). High water content in 

 the duff layer was responsible for not reaching prescrip- 

 tion levels of 50 percent mineral soil exposed. The surface 

 condition used for temperature measurement consisted of 

 blackened litter, ash, and small charcoal pieces. Areas with 

 large, partially burned residues were avoided. Burning was 

 done in early September 1975. 



2. To simulate close utilization, all residues down to 

 1 inch in diameter were removed. Except for skyline 

 corridors, the understory vegetation was essentially un- 

 disturbed. The surface was a mosaic of vegetation and 

 exposed litter surfaces. The surface condition used for 

 temperature measurement was a litter surface made up of 

 small twigs, leaf and needle litter, and duff. Little mineral 

 soil was exposed. The following tabulation shows the sur- 

 face conditions evaluated for each overstory and residue 

 reduction treatment: 



Overstory 

 treatments 

 evaluated 



1. Clearcut 



2. Uncut 



Residue reduction 

 treatments 



Broadcast burn, 

 close utilization 



Surface 

 conditions 

 evaluated 



Burned, 

 litter 



Litter 



Annually for 4 years following both treatments, 25 bare 

 root (2-0) seedlings of Douglas-fir and Engelmann spruce 

 were spring planted. Survival and grovirth measurements 

 were made periodically. 



Union Pass— This site is 40 miles southwest of Dubois, 

 WY, on the Bridger-Teton National Forest at an elevation 

 of 9,200 ft. Slope ranges from 5 to 20 percent on an east 

 aspect. Climatic data for this area are not available, and 

 the nearest stations are considerably lower in elevation. 

 Correcting for elevation and slope, annual precipitation is 

 estimated to be 35 to 40 inches. Mean July maximum air 

 temperature is about 70 °F, and mean July minimum air 

 temperatures are 35 to 40 °F. 



Tree cover prior to treatment was overmature lodgepole 

 pine (160 years old) with small amounts of Engelmann 

 spruce, subalpine fir, and limber pine (Pinus flexilis 

 James). Habitat type (Steele and others 1983) is Ahies 

 lasiocarpa/Vaccinium scoparium (ABLA/VASC). Under- 

 story vegetation was sparse. 



Overstory treatments on this study site were: 



1. Clearcut. Clearcutting was done in 1971 using a 

 feller buncher and ground skidding (Benson 1982). 



2. Uncut. An adjacent uncut area was used as the 

 control. 



Residue reduction treatments within the clearcut in- 

 cluded the following: 



1. Broadcast burning, done 2 years after logging (spring 

 1973), resulted in 30 percent mineral soil exposed and 

 reduction in litter depth from 1 inch to 0.71 inch (Benson 

 1982). The surface condition used for temperature mea- 

 surement consisted of blackened litter, ash, and small 



charcoal pieces. Areas with large, partially burned 

 residues were avoided. 



2. To simulate close utilization, all residues down to 



1 inch in diameter were removed. This treatment exposed 

 mineral soil on 42 percent of the surface and reduced the 

 understory vegetation cover considerably. After treatment, 

 19 tons per acre of woody material remained. The surface 

 condition used for temperature measurement was a litter 

 surface made up of small twigs, leaf and needle litter, and 

 •duff. 



3. On half of the close-utilization treatment area, an 

 amount of residue equivalent to that removed was chipped 

 and spread back on the site (fig. 2C). The average depth of 

 the chips was about 4 inches. No mineral soil or vegetation 

 was exposed. The surface of the chips was used as the sur- 

 face condition for temperature measurement. 



Surface conditions evaluated on each of the overstory 

 and residue reduction treatments are shown in the follow- 

 ing tabulation: 



Overstory Surface 

 treatments Residue reduction conditions 

 evaluated treatments evaluated 



1. Clearcut 



2. Uncut 



Broadcast burn, 

 close utilization, 

 chips spread 



Burned, 



litter, 



chips 



Litter 



Bare root (2-0) seedlings of lodgepole pine were planted 

 in the spring the first year after treatment on all treat- 

 ments. Spot seeding was also done. At the time of plant- 

 ing and seeding, 18-inch square areas were scarified 

 around each spot or seedling. 



Measurements 



Surface, air, and soil temperature were monitored for the 

 overstory treatment and surface conditions described for 

 each study area. Specific temperature measurements taken 

 for each study site and treatment combination are shown 

 in the tabulation for each study area and in table 1. The 

 time and duration of measurements by site are shown in 

 table 2. The term "surface" is used to indicate the surface 

 exposed to the atmosphere, whether the exposed material 

 is litter, ash (from burning), mineral soil, or chips. Mea- 

 sured surface temperatures are actually 0.04 to 0.08 inch 

 below the true surface. Temperature sensors were in- 

 stalled close to the surface by covering with one layer of 

 the surface material— for example, one leaf, one thickness 

 of needles, one layer of soil (enough to cover the metal), 

 or one layer of chips. It was necessary to frequently visit 

 the sensors and reset them if they were uncovered. Air 

 temperatui'e sensors at 4.5 ft above the surface at 

 Lubrecht and Coram were placed in standard Cotton 

 Region type shelters. 



At Union Pass, air temperatures were measured at 

 8 inches and 4.5 ft above the surface. Sensors were placed 

 in specially constructed shielded tubes. SoD temperatures 

 in the humus layer at 0.4 to 1.2 inches below the surface 

 were measured at Lubrecht and Coram. Temperatures in 

 mineral soil at 2, 8, and 15.7 inches deep were measured 

 at Union Pass. Sensors at Union Pass were pushed hori- 

 zontally into the undisturbed soil of the wall of a hole dug 

 to the proper depth, which was then backfilled. 



4 



