This project evaluated the effectiveness of Maryland’s Best Management Practices for forest harvest operations through water quality monitoring on two forested watersheds. A paired watershed approach was selected as the study design. This approach requires two watersheds - control and treatment - and two periods of study - calibration and treatment (USEPA 1993). At the end of the calibration period, the data collected are used to establish a relationship between the treatment and control watersheds through regression analysis. At the end of the treatment period, a similar equation is developed, and the regression lines are then compared and tested for differences in overall significance, slope and intercept. The treatment watershed underwent a controlled level of timber harvesting with strict adherence to BMPs, while the control watershed remained unharvested. Water quality monitoring occurred on both watersheds before, during and after harvest activities. Suspended sediment concentrations and stream temperature were monitored to evaluate the effectiveness of BMPs in protecting physical water quality, and benthic macroinvertebrate communities were monitored to evaluate possible effects on living resources.
Three hypotheses were tested:
(1) There are no significant differences in stream suspended sediment concentrations/loads before and after logging using Best Management Practices;
(2) There are no significant differences in the average daily temperature or daily minimum/maximum temperatures of the stream before and after logging using Best Management Practices;
(3) There are no significant differences in the benthic macroinvertebrate populations of the stream before and after logging using Best Management Practices.
The Study Area.
Two small watersheds located on Sugarloaf Mountain (elev. 1282 ft.) in southeast Frederick County, Maryland were selected as the study site (Map1). Although it is located within the Piedmont physiographic province, Sugarloaf Mountain is a monadnock or isolated mountain, with characteristics more closely resembling the Blue Ridge province (Catoctin & Frederick SCDs 1985). The watersheds are on the property of Stronghold, Inc., a private non-profit foundation that owns most of Sugarloaf Mountain, which is within sight of Washington D.C. on a clear day. The land was once owned by iron companies who repeatedly harvested the timber for charcoal production. It was mostly acquired in the first half of this century by Gordon Strong, who dedicated it for use as an outdoor recreation and education area open to the public. Both watersheds are 100% forested and dominated by mixed Appalachian hardwoods, primarily red, white, scarlet, black and chestnut oaks, yellow-poplar, red maple and hickory.
The control watershed, which drains into Bear Branch, is 280 acres, oriented NE-SW, with elevations ranging from 520-1120 ft. and slopes ranging from 0-70%. Bear Branch is a second order stream (Strahler’s method) which has had no major harvest activity for about 75 years. It is considered to be a general use waterway (Class I), however, this upper portion of Bear Branch has the biological characteristics of Natural Trout Waters (Class III) based on Maryland’s Water Quality Standards (COMAR 10.50.01). The treatment watershed, which drains into Furnace Branch, is 330 acres, oriented N-S, with elevations ranging from 480-1282 ft. and slopes ranging from 0-70%. Furnace Branch is a second order stream (Strahler’s method), and is considered to be Natural Trout Waters (Class III). Some harvesting occurred on the Furnace Branch watershed in 1991-1992, as part of an existing Forest Stewardship Plan which includes a “Forestry Demonstration Area”. The soils in both watersheds are primarily of the Edgemont-DeKalb series (stony or steep, shallow soils of the mountain and elevated inter-mountain areas) and are made up of Edgemont gravelly loam, DeKalb very stony loam and Edgemont very stony loam. Nearly half of each site contains rough, stony land. The soils fall within the Capability class of IIe-10 through VIIs-2. Most of the soils are well drained to excessively drained, though poorly drained hydric soils are found near the lower reaches of both streams. The soils are all very strongly acid to extremely acid. The watersheds are similar in cover type and previous land use history.Table 1. Soil Types in the Treatment (Furnace Branch) and Control (Bear Branch) Watershed.
Soil Name Symbol % Slope Class Native pH Furnace Branch (Acres) Bear Branch (Acres) DeKalb VS Loam Dbc 0-35 % VIIs - 2 4 - 5 20 32 Edgemont-Chandler-Channery Loam EcB2 0-20 % IIe - 10 4 - 5 55 5 Edgemont VS Loam EdE 20-60 % VIs - 2 4 - 5 109 106 Rough Stony Land Re 20-70 % VIIs - 2 4 - 5.5 135 136 Wehadkee Silt Loam WcA 0-3 % VIw - 1 5.1 - 6.0 11 Chewacla Silt Loam CMA 0-3 % Vw - 1 4.5 - 5.5 1
A Forest Stewardship Plan prepared in 1991 for Stronghold, Inc. by the Maryland DNR - Forest Service included recommendations for a silvicultural demonstration area that would show landowners what various types of regeneration harvests look like over a period of years. Also included in the plan were recommendations for other stands in need of commercial thinning or selective harvesting consistent with the objectives for the property. This study presented an ideal opportunity to implement the Forest Stewardship Plan and to utilize the Plan to provide the specific silvicultural prescriptions for the treatment watershed. Seven separate harvest areas were marked and measured for sale, partly by MD DNR - Forest Service personnel, and partly by a private consulting forester contracted for by Stronghold, Inc.
One 48 acre sale in the northern portion of the treatment watershed consisted of a 5 acre clearcut, an 8 acre seed tree cut, a 5 acre shelterwood cut, a 5 acre group selection cut, a 5 acre single tree selection cut, and a 20 acre timber stand improvement thinning (Map 2). Of the 20 acres of the timber stand improvement cut, approximately 5 acres were outside the boundary of the treatment watershed, but the access system (and associated potential disturbance) for the sale was almost entirely within the treatment watershed. The second sale was 25 acres of selection harvest in the southern portion of the treatment watershed, on both sides of Furnace Branch, just above the monitoring station. Each of the two sale areas was purchased and logged by a different company.
The harvesting was done by relatively small 2-3 man logging crews, using chain saws to fell the trees and rubber-tired cable skidders to drag them to the landing. The logs were then loaded with knuckle-boom loaders onto trucks, with both tractor-trailer and straight trucks being used. This is typical of the equipment used for logging in central and western Maryland. On the northern sale, some pulpwood was removed along with the sawlogs, while on the southern sale, only sawlogs were removed. An estimated total of 233,000 board feet of sawlogs and 315 cords of pulpwood were harvested on the total 73 acres harvested, with an average of 3200 board feet and 4.3 cords per acre.
Following construction and improvement of the access system according to BMPs as described below, the timber in the northern sale was harvested in January - March of 1997. At this time conditions were very wet from previous rains and freeze and thaw conditions, and stability of the truck roads was a problem in some areas. When this part of the sale was completed, required areas were stabilized in April, 1997. The southern portion was harvested September - October, 1997, under generally dry and stable conditions. Stabilization, including removal of the temporary timber bridge, followed in October, 1997.
Best Management Practices
A major objective of this project was to install a suite of Best Management Practices on harvest sites in the treatment watershed. This was in order to evaluate their overall effectiveness in preventing sediment pollution and protecting living resources, and to visually and photographically document the success or failure of individual practices. Additionally, this area was to serve as an educational tool, illustrating the proper use and installation of forestry BMPs for loggers, landowners, etc. BMP planning and layout began as soon as the harvest areas were identified, and plans continued to be revised throughout the project. Some existing roads and trails were used, though most of these were improved to meet BMPs or practical needs of the operation, i.e, width, drainage, etc. Some of these were in less than ideal locations, but relocation would have created greater disturbance and expense. BMPs were applied only where and when required by regulation. A deliberate effort was made to strictly adhere to the minimum requirements, not to do the “best possible job.”
BMP installation began on September 27, 1996 with construction or improvement of major haul roads, landings, skid trail sections which required cut and fill construction, and stream crossings. This date marked the end of the calibration period of the study and the beginning of the treatment period. A wide range of BMPs were installed (see list below), including a 20 foot long portable timber bridge, a 21 inch diameter stream-crossing culvert, streamside forest buffer (streamside management zone), drainage out-sloping, broad based dips, rolling dips, grade breaks and water bars, and the use of geotextile and stone for haul road stabilization (Table 1). The logging contractors also complied with the BMPs by following marked skid trails (with some unplanned changes) and performing post-harvest stabilization of roads, landings and skid trails where required. On slopes over 10% roads, main skid trails, and landings were seeded, limed, fertilized, and mulched. The stabilization was completed sale on October 31, 1997.
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This study was funded through a Clean Water Act Section 319(h) Grant from the U.S. Environmental Protection Agency
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