Aspen forests in the Great Lakes States support much of the regional timber industry. Management-induced soil compaction is a concern because it affects forest health and productivity and soil erosion. Soil compaction increases bulk density and soil strength and can also decrease air and water movement into and through the soil profile. Currently, most inventories, and specifically the Forest Inventory and Analysis program, use qualitative estimates of soil compaction. This study compared qualitative estimates with quantitative measurements on aspen clearcuts in five national forests in the Great Lakes States. Research sites were stratified into classes of high and low potential for soil compaction on the basis of soil texture. Qualitative visual assessments of compaction were made according to Forest Inventory and Analysis (FIA) phase 3 protocols and compared with physical measurements of bulk density, soil compression strength, and saturated hydraulic conductivity. No differences in compaction between high- and low-risk soils were detected using visual assessments, but quantitative measurements in high-risk, fine-textured soils indicated greater compaction than low-risk, coarse-textured soils. These results illustrate shortcomings in qualitative estimates of compaction made according to FIA phase 3 field protocols. Inexpensive quantitative measurements, such as those taken with a pocket penetrometer, may be sufficient to quantify compaction levels within the plots.
Maintenance of existing rights-of-way often involve dealing with exposed pipelines near stream crossings. Streams often shift over time. This adjustment can lead to erosion of the streambed and streambanks, exposing pipelines or other infrastructure to threats such as hydraulic pressure, buoyancy, debris collisions, or pipe vibration and fatigue. Under these conditions, managers can be faced with relocating the pipe, performing localized streambank stabilization, or employing stream restoration techniques to provide long-term protection.
When localized stabilization is the preferred approach, selection of techniques is often determined by what will protect the pipeline without consideration of the stream context surrounding it. However, due to site conditions, manager preferences, and regulatory considerations, techniques from the disciplines of stream restoration and habitat enhancement can provide cost-effective alternatives to traditional hard-armoring by concrete or stone depending on the site context. Using past experience and a series of decision analysis tools, it was determined that geomorphic context should be factored as a foremost consideration when evaluating the most stable and cost effective approach to correcting exposed pipelines. One of the most critical factors in assessing the feasibility of stabilization options is the height and orientation of exposed pipes relative to the stream’s bankfull elevation.
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