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Abstract
The Missouri Ozark Forest Ecosystem Project (MOFEP) is a long-term, multidisciplinary, landscape-based research program studying effects of even-aged (EAM), uneven-aged (UAM), and no-harvest (NHM) management on forest communities. The first MOFEP timber harvests occurred from May through November 1996. Harvest- related disturbance occurred on 69 of 180 permanent 0.2-ha study plots in which interactions between
Armillaria populations, forest structure, and forest management are being studied. On each of these 69 plots, we mapped and measured 1) all injured non-harvested trees !? 5.0 cm d.b.h. (diameter at breast height) and their injuries, 2) all stumps and girdled trees, and 3) all vehicle paths. Roots !? 1.0 cm diameter and their injuries were characterized in 0.2-m deep x 0.25-m?? excavations beneath skidder tracks that passed through the 69 study plots. Excavations exposed an average of 1.0 m of root, and multiple- and single-haul skid trails averaged 1.3 vs. 0.7 injuries per meter of discovered root, respectively. Skidder tracks disturbed an estimated 3 percent of the forest floor, resulting in > 900 root injuries per hectare harvested. Partial cutting occurred on 56 of our 69 disturbed plots (14 EAM and 42 UAM). In 22 partially cut plots (15 UAM and 7 EAM), all trees !? 5.0 cm d.b.h. (both injured and non-injured) were mapped and characterized. Approximately 11 percent of non-harvested saplings and 3 percent of larger stems were broken, shattered, uprooted, or pushed over; an additional 4 percent of saplings and 10 percent of larger stems incurred xylem-exposing injuries; and another approximately 3 percent of non-harvested trees incurred phloem wounds. Average wound size was smaller for saplings than for larger stems, but percentage stem circumference injured was similar (27 vs. 23 percent, respectively). Frequency of buttress root injury increased with tree d.b.h. An average 62 percent of all injured plot trees occurred !A 2.0 m from vehicle paths, whereas 54 percent of trees this close to vehicle activity were injured. For the 22 completely mapped plots, we used stepwise logistic regression to explore each tree's probability of injury based on tree characteristics, harvest-related factors, and site factors. Probability of stem injury was positively associated with north- to east-facing slopes, the length of truck haul road passing through the study plot, and the number of stumps !? 45 cm diameter created within the study plot. Probability of stem injury was negatively associated with stem quality, distance from vehicle paths, day of year harvested, two specific logging crews, and UAM.
Parent Publication
Citation
Bruhn, Johann N.; Wetteroff, James J.; Mihail, Jeanne D.; Jensen, Randy G.; Pickens, James B. 2002. Harvest-associated disturbance in upland Ozark forests of the Missouri Ozark Forest Ecosystem Project. In: Shifley, S. R.; Kabrick, J. M., eds. Proceedings of the Second Missouri Ozark Forest Ecosystem Project Symposium: Post-treatment Results of the Landscape Experiment. Gen. Tech. Rep. NC-227. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station. 130-146.
