Research activities at UNB s Nexfor/Bowater Forest Watershed Research Centre

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1 Research activities at UNB s Nexfor/Bowater Forest Watershed Research Centre Research at the Nexfor/Bowater Forest Watershed Research Centre of the University of New Brunswick (see text box) is to enable forest managers to make a difference on the ground through the development of best management practices for forest operations. The particular research objectives of this Centre focus on: (i) how to effectively monitor and simulate biophysical conditions and impacts of forest operations on forest soils, water quality, and forest productivity in any forest terrain, and to do this costeffectively at any location; (ii) how to extend research results from a few experimental watershed trials across the landscape, by way of generic models that are easily initialized for other watersheds based on readily accessed watershed attributes such as size, orientation, change in elevation, geological substrate, forest cover type, extent of forest cover, etc.; (iii) how to develop, from these watershed attributes, detailed biophysical surface maps that are useful for planning and conducting best forest management practices. To date, the Centre has developed means: (i) to inexpensively monitor water-table reactions in terms of height and temperature to wholebasin harvest treatments, (ii) to profile forest streams along their length in relation to upland drainage channels that join the streams from its sides; (iii) to digitally map and visualize all essential surface features of each watershed based on existing information about these watersheds, such as aerial photographs, satellite images, digital terrain map, and likely flow patterns (flow accumulations) from uplands into streams and lakes below; (iv) to simulate year-round soil moisture and temperature conditions, with daily resolution (or finer), including the modelling of soil infiltration, percolation, basin discharge, water table height, snowpack depth, snowmelt, extent of soil moisture deficits, soil temperatures at any depth, and depth of frost penetration into soil. To test and apply much of this, the Centre has embarked on an extensive 10-year forest watershed experiment, where small upland catchments have been subjected to forest harvesting. The treatments involved: (i) (ii) (iii) stem-only harvesting in each of two basins; whole-tree harvesting in yet another basin, with the spreading of slash from that operation onto one of the two basins with stem-only harvesting, thereby doubling the slash load within that basin; maintaining one basin as an un-harvested control. The rationale behind these treatments is to determine effect of coarse-woody debris loading on overall basin behavior: it is suspected that increased coarse woody debris levels may assist in the sustainability of forest production, but may also lead to enhanced nutrient losses to the stream water by way of soil leaching. These experimental trials were further enriched by conducting the same treatments in basins covered entirely with tolerant hardwoods or softwoods (Figure 1 and 2). The particular area of the hardwood treatments is underlain by coarse-textured shales with low to moderate carbonate content. The substrate below the softwoods contains loamy textured till overlying light-coloured volcanic extrusions. Soil permeability underneath the hardwoods was found to be fairly high, but quite variable from high to impervious across the softwood basins. It all of this, it was important to know how many nutrients are 1

2 lost from each basin on account of harvesting and nutrient leaching through the soil, and whether these losses would be sustainable in the long-run, by way of atmospheric deposition and soil weathering. Water quality in the wells, ponds and streams of the treatment areas was monitored weekly in summer, and monthly in winter since The basins were harvested in late summer/fall of Early indications show significant pre- and post-harvest nitrate losses from the hardwood basins, and significant calcium carbonate losses from the softwood area. Forest productivity from the upland ridge to the stream channel was fairly similar for the hardwood basins, but varied considerably from poor on the ridges to high in the downslope areas of the softwood basins. Moisture content within the harvested wood of the trees varied with species, but was similar regardless of position within each basin, and across basins. Harvested trees were sorted and weighed by species. These weights were used to ascertain tree nutrient contents and related harvest exports. Forest harvest operations left much mineral soil exposed on the hardwood basins, but water infiltration rates into soils and soil substrates at this location remained high, even during wet weather. In contrast, road conditions became muddy on the softwood basins. Within the first post-harvest summer, however, the surface conditions of the softwood basins returned to well-drained, and remained so even during the resumption of wet weather in the Fall. Monitoring and further research activities, including modelling, will continue at the field locations into the foreseeable future. New plans include determining the effectiveness of variable buffer zone on protecting soils and streams from sediment movement. Data gathered regarding soil temperatures, water table height and temperature, stream temperature and water quality will be analyzed in terms of the upland weather conditions within the basins, year-round, pre- and post-harvest. Forest operations are influenced by this research in terms of learning how to: (i) Direct and time forest operations such that there will be little likelihood of damage to soils, roads, streams, or equipment; this directing and timing will be based on mapping soil trafficability day-by-day, year-round. Soil trafficability mapping, in turn, depends on daily weather, and knowledge of soil substrate distributions across the managed area. (ii) Examine alternatives for forest access roads, to minimize crossing of mapped and un-mapped stream channels while limiting road slope and curvatures. (iii) Locate and protect small unique areas, such as vernal pools and other wetlands that do not appear as such on the conventional forest management maps that are currently in use. (iv) Assist forest operations planners in cut-block design, a. to avoid soil and stream-channel stabilization, b. to protect adjacent stands against wind throw, and c. to prevent harvesting machine from crossing ephemeral flow channels. 2

3 Fraser Papers Inc Small Watershed Treatment Area Stream Extra-slash Whole-tree Control Stem-only Pond Road Figure 1. Visualization of the hardwood treatment area of the Nexfor/Bowater Forest Watershed Research Centre in northwestern New Brunswick, on provincial Crown lands near Lake Gounamitz, west of Kedgwick. Shown is an aerial photograph taken during the winter after cutting, depicting the four treatment basins in a three-dimensional view. Also depicted are the watershed boundaries, the main flow accumulations towards the stream and pond below, and the location of the four monitoring wells (circles). These wells are used to monitor the ground water table and its temperature, year-round, by way of automatic recording. The stream, pond, and wells are visited regularly by Nexfor Fraser Papers Inc. staff, to retrieve water samples, and to determine nutrient concentrations in the water. 3

4 Stem-only Bowater Maritimes Inc. Small Watershed Treatment Area Control Stem-only Extra-slash Whole-tree Road Streams Figure 2. Visualization of the softwood treatment area of the Nexfor/Bowater Forest Watershed Research Centre in northcentral New Brunswick, on provincial Crown lands near Island Lake, south of Dalhousie. The watershed monitoring setup is similar to the one described for Figure 1. Streams, ponds, and wells (locations circled) are also visited here to retrieve water samples by staff from Bowater Maritimes Inc. Figures 1 and 2 were constructed by generating a three-dimensional view of the treatment area (ArcView 3.1), based on digital elevation modelling. The aerial photograph was then attached to correspond to the exact coordinates of the existing road and stream network. 4

Nexfor/Bowater Forest Watershed Research Centre The Nexfor/Bowater Forest Watershed Research Center was established at the University of New Brunswick in 1996 as part of a 10-year research and

5 Nexfor/Bowater Forest Watershed Research Centre The Nexfor/Bowater Forest Watershed Research Center was established at the University of New Brunswick in 1996 as part of a 10-year research and development agreement. This Centre has a Steering Committeee, co-chaired by Don Tardie, Vice President of Woodlands and Procurement for Nexfor Fraser Papers Inc., and Brian Mooney, Director, Environment for Bowater Canadian Forest Products Inc. The Centre is a partnership of industry, university and government, dedicated to the development, application, and communication of watershed research. Research relates to water, nutrients, air, energy, and soil productivity and the development of sustainable forest management policies and practices. To learn more about the Nexfor/Bowater Forest Watershed Research Center, visit our web site at: Authors Paul Arp, Professor, Forest Soils, Centre Coordinator, UNB, arp2@unb.ca Fan-Rui Meng, Associate Professor, Forest Watershed Management, Centre Research Director, UNB Matthew Steeves, Graduate Student, Forest Watershed Management, UNB Acknowledgements This research is in part supported by the sponsors of the Centre, and by NSERC: operating grant to PAA, NSERC-CFS-Industry Partnership Program, and several NSERC scholarships for summer students, and graduate students. 5

Modelling Dissolved Organic Carbon and Nitrogen in Streams and Rivers Across Atlantic Canada

Modelling Dissolved Organic Carbon and Nitrogen in Streams and Rivers Across Atlantic Canada Marie France Jutras, Mina Nasr, Thomas Clair, Paul Arp Presented by: Marie France Jutras Introduction OBJECTIVES: