MODELING AND MAPPING NUTRIENT SUPPLY DEMAND SENSITIVITIES TO FOREST BIOMASS HARVESTING, IN NEW BRUNSWICK

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1 MODELING AND MAPPING NUTRIENT SUPPLY DEMAND SENSITIVITIES TO FOREST BIOMASS HARVESTING, IN NEW BRUNSWICK Paul A. Arp, Jae Ogilvie, Mark Castonguay Faculty of Forestry and Environmental Management University of New Brunswick, Fredericton, New Brunswick, Canada Ian Demerchant, Canadian Forest Service, Fredericton, New Brunswick, Canada Shawn Morehouse, Departmental on Natural Resource, Timber Management Branch, Fredericton, New Brunswick, Canada Abstract. The recent rise in price for procuring oil and gas destined to heat homes, institutions and industries is making the search for alternative heat sources attractive again. An obvious choice is the gathering of post-harvest biomass residues in the form of low-quality wood, branches and twigs or slash. The gathering of these residues, however, may not be sustainable depending on each site-specific nutrient supply-demand balance. Hence, ways and means need to be found to determine what level of residue extraction is ecologically feasible without tempering with post-harvest growth potentials. This determination is important at two levels: to advise the forest industry and the public as to what harvest methods may be suitable for post-harvest biomass extraction; to estimate amount of harvestable biomass fraction for each given site, based on best available information of the nutrient demand supply situation on that site. This report deals with a brief outline regarding the methodology and modeling framework used for making this determination, and presents the results for the Province of New Brunswick by way of a series on maps, depicting: which of 4 nutrient elements (N, Ca, Mg, K) is likely to become growth-limiting depending on harvest method ( no harvesting stem-only harvesting, whole tree harvesting with and without foliage) what would be the likely nutrient supply-demand deficit for each of the elements, in tones per hectare per year the extent that these deficits would be compounded due to local rates of atmospheric acid as well as N, Ca, Mg, and K deposition. The resulting maps are based on an eco-unit basis, amounting to about 40,000 map units for the province, and are intended for illustrating the methodology used to derive the local and harvestsensitive nutrient supply-demand situation, in principle. This report needs to be followed up by research done in the context of the actual forest inventory, with an explicit evaluation for each forest stand, in reference to: its dominant tree species, expected biomass growth rate, and local conditions regarding atmospheric deposition, climate, soil substrate type, and drainage. Introduction. Energy from forest, generated by Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 1

2 way of forest biomass harvesting, is once again valued as readily marketable commodity, to assists home owners, institutions and industry in curtailing the otherwise rising costs of procuring oil and gas for heating (IEA Bioenergy, 2002). Within the forest industry, forest biomass has already been used for some time to lower the heating and operations costs of woodprocessing facilities such as saw, pulp and paper mills, through the use of hog fuels, and hog-fuel burners. The depressed market for pulp wood, and recent rise of the Canadian dollar relative to the US dollar, however, has added further incentives to value forest biomass as an alternative and readily marketed energy source beyond the immediate forestry sector. Several guidelines, however, must be put in place to ensure that forest biomass harvesting is done responsibly and sustainably, depending on local site and forest conditions. Such guidelines need to address an appropriate partitioning of harvested trees into what is a high immediate $-value product (i.e., raw material for manufacturing forest products), a low immediate $-value product (i.e., forest biomass), represented by post-harvest slash and other harvest residues that, nevertheless, translate into major cost savings when used as an alternative heating fuel a no immediate $-value product (un-used residues, left on site) but that translates into major cost savings when interpreted in terms of maintaining or enhancing local nutrient supplies for sustained or enhanced forest productivity, and maintaining required habitat component in the form of coarse woody debris for proper forest ecosystem functioning. With this new demand to extract post-harvest biomass residues from forests, and with the advance of new GIS-based technologies (Aronoff 1991), including region-wide mapping of nutrient supplies and demands of growing forests (Arp et al. 2001, Ouimet et al. 2006), it is opportune to develop an approach by which forest policy makers, managers and planners can include the concept of nutrient supply and demand in the context of sustainable forest management. In principle, nutrient supply and demand considerations are already at the core of sustainable crop management systems. Until recently, however, these considerations have been marginal because of comparatively long crop rotations, and fairly limited nutrient extraction by focusing on conventional stem-only harvesting practices in general. With increased timber productivity expectations, as in carefully planned forest plantations with multiple biomass extraction interventions from early stand-thinning to the final extraction of top-value logs, or with industrial expectations regarding the doubling of provincial wood supplies through increased stand tending and silviculture, sustainability of forest-related nutrient supplies and demands needs to be reassessed. The objective of this report is to outline procedures followed to estimate site-specific nutrient supplies and demands, for the Province of New Brunswick. to determine which of these elements: N, Ca, Mg, K likely become growth limiting under specific harvest practices (stem-only, whole-tree with and without foliage, and no harvesting) to determine additional nutrient losses that may occur on top of potential harvest deficits due to atmospheric acid deposition. In this, nutrient demand refers to the amount of nutrients removed from a site on account of forest harvesting, while nutrient supply refers to estimating the rates of primary nutrient supplies, Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 2

3 generated through atmospheric deposition, and soil weathering (Moayeri 2001, Figure 1). A balance is achieved when demand = supply in the context of a complete forest rotation; i.e., all the nutrients exported through harvesting need to be replenished until the next scheduled harvesting event. Atmospheric input for wet and dry deposition: H +, NH 4+, NO 3-, SO 2-4, Ca 2+, Mg 2+, K +, Na +, Cl - Exports: Forest Harvesting / Fires Litter fall (S, N, Ca, Mg, K) Uptake (NH 4+, NO 3-, Ca 2+, Mg 2+, K + ) Base cation depletion increases with increasing Soil weathering atmospheric acid (S + N) deposition (Ca, Mg, K, P) & acid buffering Soil leaching: SO 2-4, NO 3-, Ca 2+, Mg 2+, K +, Al 3+, Na +, Cl - Figure 1. Overview of processes affecting primary nutrient supplies and demands in the context of fortest biomass harvesting. Background. Work on the above objectives is facilitated by preceding research that has already dealt with assessing impacts of atmospheric acid deposition on forest biomass and forest health in Europe (Grennfelt and Thörnelöf 1992, Posch et al. 1995, 1997, 1999, Werner and Spranger 1996), and North America (Ecological Stratification Working Group 1995, Environment Canada 1997, Forest Mapping Work Group 1999). Several national and international initiatives were undertaken to establish baseline data. Most notable among these is the Integrated Forest Study dealing with select sites mostly in the USA (Johnson & Lindberg 1992). In Canada, the federal government and several provincial governments launched a number of research and monitoring initiatives that were all coordinated by the Federal-Provincial Research and Monitoring Coordinating Committee (RMCC 1990; Acid Rain Working Group 2000). As a result, it is now possible to evaluate the extent and trends associated with H, S, N, Ca, Mg, K deposition across North America, albeit at varying level of intensity Ro and Vet (2002). In eastern Canada, atmospheric deposition of H, S, N, Ca, Mg, K includes, inter alia, rain, snow, fog, and dry deposition (dust, and absorption of air-borne molecular species, such as Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 3

4 NOx, SOx, HCl). Additional monitoring networks were established in Canada to detect early warning signs of forest damage due to acid rain and other factors by way of permanent sampling plots. The largest of these networks, the Acid Rain National Early Warning System network (ARNEWS), was started by the Canadian Forest Service in 1984 (D Eon et al. 1994, Moayeri 2001). Other monitoring efforts included (Acid Rain Working Group 2000): the joint U.S./Canada National American Maple Project (NAMP), to document changes in the condition of sugar maples in eastern Canada, and the northeastern United States and the Ecological Monitoring and Assessment Network (EMAN), which is a national network of about 80 long-term, multidisciplinary research and monitoring sites to monitor and study ecosystem responses to environmental stressors. In 1998, the New England Governors and Eastern Canadian Premiers Conference addressed regional forest health impacts of atmospheric deposition by formulating an Acid Rain Action Plan (Forest Mapping Work Group 1999). This Action Plan identified the mapping of forest sensitivity to acid deposition as one of its priorities, and the purpose is to develop regional maps to enhance regional policy dialogue on further emission reductions (Ouimet et al. 2006). The emphasis of this paper is placed on, and is restricted to, providing an outline of a modeling and mapping protocol designed to determine site-specific primary nutrient demand and supply rates as pertinent to forest biomass harvesting, and as affected by atmospheric deposition, by soil weathering, and harvest method, with harvest method ranging from no harvesting to whole-tree harvesting, with and without foliage. All of this done to prepare such calculations to become part of sustainable timber supply projections (Nielsen et al. 2006). Approach. Determining primary ecosystem-level nutrient supplies (nutrient inputs through atmospheric deposition, soil weathering, and upslope seepage) and demands (exports, and other outputs including soil de-nitrification and base cation leaching losses) is the focus of the analysis, as opposed to dealing with matters of secondary nutrient cycling (Arp and Marsh 1996, Bhatti et al. 1998, Hall et al. 1998, Oja et al 1998, Arp et al. 2001, Moayeri et al. 2001). Longterm averages of mean annual biomass extraction, or expected mean annual increments (MAI), drives the nutrient demand calculations, which includes tracking of biomass type(foliage, branches, bark, stem wood), because nutrient concentrations within these components differ, by species (Moayeri 2001). The scale of resolution of the nutrient-demand supply situation is intended to match the scale of currently affordable terrain analysis, specifically for determining nutrient demands and supplies for up- and down-slope positions and wet areas (Meng et al. 2006). The general operability and validity of these calculations is evaluated in the context of producing sustainable nutrient demand-supply information for harvesting particular stands, and for producing provincial nutrient-supply-demand policy guidelines. The harvesting methods considered refer to: No harvesting Stem-only harvesting (wood + bark) Whole-tree harvesting (green): wood + bark + branches + twigs + foliage Whole-tree harvesting (brown): wood + bark + branches + twigs Formally, nutrient exports can be calculated as follows: Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 4

5 Total nutrient export due to harvesting = wood biomass x nutrient concentration in wood + bark biomass x nutrient concentration in bark + bark branch and twig biomass x nutrient concentration in branch and twig biomass + foliage biomass x nutrient concentration in foliage Biomass fractions of wood, bark, branches and twigs and foliage within a tree are estimated by way of a look-up table (Table 1), by dominant tree species, as generated earlier by Moayeri (2001) from ARNEWS plots. The entries in this table are then used to partition the biomass into the 4 biomass fractions: wood, bark, branches (and twigs), and foliage. This table also informs about the density of wood, used to convert estimated tree merchantable tree volumes into tree biomass, as follows: Harvestable forest biomass (tonnes / ha) = merchantable tree volume (m3/ha) x wood density. The nutrient supply demand balance and related deficits are calculated as follows: Nutrient Demand (tons of nutrient / hectare year) = MAI (tons / ha year) x Nutrient Concentration (tons of nutrient / tons of biomass) Primary Nutrient Supply (tons of nutrient / ha year) = atm. Deposition + Soil weathering Nutrient Deficit (tons of nutrient / ha year) = Nutrient supply - Nutrient Demand The following is assumed in the modeling protocol (for convenience, as a first approximation): Nutrient content / above-ground tree biomass (kg of nutrients per ha of standing biomass) = nutrient uptake / biomass increment, i.e., kg of nutrients taken up each year and allocated to new biomass increment. It is further assumed that the annual nutrient allocation to foliage, bark, wood, branches remains the same each year. The calculations then proceed with the look-up of already estimated mean annual biomass increments (as they would be used as input in the usual timber supply calculations, the associate biomass fractions (wood, foliage, branch, bark), wood density, and nutrient content, by species type and stand type. In addition to nutrient losses incurred at harvesting time, there is the ongoing process of soil leaching, which, when there is an exceedance of atmospheric acid deposition, leads to gradual base cation depletion, i.e., the loss of exchangeable bases from the rooting zone (bases = Ca, Mg, K), over time (Arp et al. 2001, Ouimet et al. 2001), as shown in Figure 2. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 5

6 Table 1. Look-up table for wood density, and fraction and elemental concentrations, by biomass fraction: wood, bark, branches & foliage FOREST TYPE TISSUE CODES Density Moayeri 2002 TYPE Balsam fir BF Intol. hardwoods IH,TA 0.47 Jack pine JP 0.33 Spruces BS,RS,XS, US 0.51 Tol. hardwoods TH,YB, RM,SM 0.62 White birch WB 0.61 Pines WP,RP,LP 0.33 White spruce WS 0.47 Biomass Elemental concentrations (mg. / kg ) partition N K Ca Mg P Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Wood Bark Branches Foliage Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 6

7 Soil exchangeable bases Deficit / rotation = 0 Deficit / rotation > 0 Sustainable Nonsustainable depletion Figure 2. Overview presenting the general relationship between harvest-induced nutrient deficits, and base cation depletion in forest soils The province-wide species type distribution, as used in the model, is depicted Figure 3. Figure 3. Cover-type assignments, by eco-site, across New Brunswick. Mean annual volumes (MAI) values by eco-site mapping unit are shown in Figure 4. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 7

8 Figure 4. Mean annual increments (MAI values) regarding merchantable timber volume, as obtained from the NB forest inventory. The calculations that deal with the supply of Ca, Mg and K nutrients through soil weathering are based on several soil properties: rooting depth, soil coarse fragment content, soil bulk density, soil organic matter content, and mineralogy of the soil parent material, as accessed through interpretation of the NB geological bedrock map, and by way of the forest inventory information as well. There are 5 substrate types: forested peatlands (0), slow chemical and physical weathering substrate (mostly granites and felsites, and metamorphosed equivalents, 1), medium weathering substrate (mostly sediments and granodiorites, and metamorphosed equivalents, 2), well weathering substrates (mafic substrates, 3), and calcareous substrates (4). Base cation depletion would be least on calcareous soil substrates, and highest on soils that are slow to weather. Province-wide substrate assignments are shown in Figure 5. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 8

9 Substrate type Forested peatland Mostly granite, felsite Mostly sedimentary, granodiorite Mostly mafic Mostly calcareous Figure 5. Assigning soil weathering classes, based on bedrock geology, across New Brunswick. In terms of quantifying net nutrient uptake, one needs to consider whether the forest is subject to disturbances other than harvesting or not. In principle, old growth forests are assumed to have a zero net uptake values, and hence zero values for MAI (i.e., the forest does not grow: there is no net biomass accumulation over time, because the system maintains a steady-state balance between all ecosystem-level inputs and outputs). In all of this, it is assumed that atmospheric deposition and soil weathering are the only processes to regenerate on-site primary nutrient supplies. This is generally the situation of welldrained upland soils. In areas receiving seepage water from upland locations, and areas where the water-table reaches into the rooting space, or rises above this, nutrients are added through seepage, either in the form of dissolved nutrients, or sediments. These areas, if well-drained, are expected to be free of nutrient deficits based on current or doubled harvest expectations. These areas are not mapped in this report, but they can be delineated, approximately, by way of the flow-channel, wet-area and depth-to-water modeling and mapping techniques described by Meng et al. (2006) and Murphy et al. (2006). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 9

10 MAPPING METHODS. The mapping and modeling of nutrient supplies, demands and deficits was done with the existing protocol and GIS database for calculating critical soil acidification loads for all of Eastern Canada, and Atlantic Canada in particular (Ouimet et al. 2006). To place this work into the actual forest policy, management and operations contexts for New Brunswick, we: (1) refined the scale of the calculations to the eco-site level, amounting to about 43,000 ecounits across the province; (2) developed an algorithm to use DNR-assessed MAI values for dominant species within the site-specific nutrient-demand(export)-supply context, as needed for evaluating site-specific levels of forest harvesting, and to evaluate the sustainability of different forest harvesting types. The following geospatial databases were consulted and used: Acid Deposition coverage from National Atmospheric Chemistry Database and Analysis System (NATChem), Meteorological Service of Canada; Ro and Vet 2002) Climate data coverage (from Canadian Forest Service) Actual Evapotranspiration (AET) - (calculated) National Forest Inventory - 1:20,000,000 (from Canadian Forest Service) Provincial Forest Inventories 1 km grid based on 1:12,500 (from Newfoundland Department of Forest Resources and Agrifoods) Soil Landscape of Canada - Canadian Soils Information System (CANSIS), Agriculture and Agri-Foods Canada Geological Map of Canada - 1:5,000,000 (from Natural Resources Canada) National Topographic Database 1:250,000 (from Natural Resources Canada) Digital Elevation Model - 1 km grid (from Natural Resources Canada) Ecodistricts 1:2,000,000 (from Agriculture and Agri-Foods Canada) The NB New Brunswick Ecological Land Classification database served to map the base polygons at the eco-site level. All attributes (soils, atmospheric deposition, bedrock, forest cover type, MAI, etc) were assigned to these polygons. The NB relevant atmospheric deposition data was available on a province-wide grid basis, 1 point every 50 km. This grid was transformed into a raster were through geospatial interpolation (kriging). The raster datasets was used to determine average atmospheric deposition per eco-site. Individual soil map sheets were captured from the CANSIS website at scales ranging from 1:10,000 and 1:250,000. Individual county (or regional) surveys were appended one to another to form a complete provincial (spatial) inventory. Soil horizon specific variables were calculated for forest floor and mineral soil depth (to C horizon), ph, organic carbon (% and total), clay (% and total), base saturation, total cation exchange sites (CES), % coarse fragments, and bulk density. Soil type values for the aforementioned variables were then generated by a soil depth based weighted averaging approach. CANSIS polygons are aggregations of several soil components (a single polygon contains between 1 and 3 soil types) and are assigned a map-unit value. The map-unit table identified the soil types that make up each map-unit, along with their relative proportion. Map-unit specific variables were then calculated by weighted averaging of soil type values. A spatial weighted averaging technique was then applied to assign each eco-site base mapping unit a set of soil parameters. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 10

11 The NB New Brunswick Forest Inventory Database (2003) was used to determine the dominant forest species for each eco-site base mapping unit, by calculating the relative proportion (area) each stand contributes and then determining the area of each species based the stand species percentages. The average age of the dominant species was also calculated by an area based weighted average. The ages were sometimes reported as a development stage, in which case an average age for that species in that development stage was used. Results and Discussion. The composite maps in Figures 5 to 10 show, by provincial Crownland management area, which upland areas in New Brunswick are likely sensitive to overharvesting, i.e., where the combination of atmospheric nutrient deposition and soil weathering is unlikely to keep up with intensified forest harvesting pressures, as these methods move from stem-only harvesting (SO-1x) to whole-tree harvesting, with (BWB-1x) and without foliage (WT-1x) removed, and as these methods may be further intensified though double harvest expectations (SO-2x, BWB-2x, WT-2x). The maps are organized to show the expected outcomes with stem-only harvesting (left), followed by whole-tree harvesting without (middle) and with foliage (right) removed. These maps appear in the following order: 1. a map depicting likely growth limiting element among Ca, K, Mg, P, and N (Figure 6) 2. maps showing expected Ca, K, Mg, and N deficiencies, in tons / ha / year, based on a 100 year frame (Figures 7 to 10) 3. a map showing extent of base cation depletion, over the course of 100 years, for each particular eco-site (Figure 11). In general, these maps indicate that the upland regions of New Brunswick are calculated to overharvesting. Stem-only harvesting based on current MAI expectations is seen to generate no particular nutrient deficits across the province. This situation changes as harvest expectations increase with whole tree-harvesting without and with foliage as part of the harvested biomass. Doubling the current MAI harvest expectations would strongly intensify the occurrence and size of the calculated nutrient deficits, as shown. Numerically, the deficits are calculated to be quite small on an annual basis, e.g., 10 kg of N for the worst-case scenario (double MAI expectation, with foliage remaining attached to the harvested biomass). These numbers, however, need to be interpreted in the context of the rotation length. For a rotation length of 50 years, the combined N loss would then amount to 500 kg / ha. Harvesting at that rate would then require an equivalent amount of N replenishment. Failure to do so would potentially reduce the overall availability of N on that site for the next forest rotation. A reduction in N availability should then necessitate a drop in forest productivity and forest health. Combining all the calculated nutrient losses, and transforming these losses into estimates regarding nutrient replenishment costs suggests that the overall provincial effort to maintain soil fertility under intensified forest biomass scenarios could be substantial, by changing from about $900,000 to $10,000,000 per year if whole-tree harvest expectations were to be doubled, province-wide (details not shown here). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 11

12 Since N is the element that becomes growth limiting the most, these numbers could rise further as efforts are made to reduce general N emissions into the atmosphere, regional and globally. This would, in turn, mean a systematic reduction in local N deposition rates across the province, thereby increasing the potential for projected N deficits. We emphasize that these maps and associated numbers are generated from generalized information about soil substrate, forest cover type, and mean annual increments, by eco-site. For site-specific decision making, these calculations need to be refined further, to be applicable to the actual forest management decision-making context, one stand at a time. For that, the following is required: to model expected nutrient supply-demand as well as expected nutrient deficits and depletion rate, at high terrain resolution pertinent to discern stand-level differences to obtain local data for nutrient contents (N, Ca, Mg, K, P concentrations) in dominant tree species (foliage, branches, bark, stemwood), and to evaluate these across the terrain, by stand type to re-visit the MAI-volume to MAI-biomass conversion formulation; potential biomass to be harvested under the 1x and 2x scenarios is likely underestimated based on the simple approximation Harvestable forest biomass (tonnes / ha) = merchantable tree volume (m3/ha) x wood density. A revision of the formula would take the following form: Harvestable forest biomass (tonnes / ha) = merchantable tree volume (m3/ha) x (1/wood_biomass_fraction) x (wood_biomass_fraction x wood_density + bark_biomass_fraction x bark_density + branch_biomass_fraction x bark_density + foliage_biomass x foliage_density) Applying this formula would likely increase the results shown in Figures 6 to 10 by as much as 40%. However, the simple approximation may, at least in part, account for variations in wood density, which are often lower than solid wood samples due to partial stem rot, and there would be further inefficiencies in collecting biomass residues, in principle. to perform these calculations in the context of the recently established depth-to-water map, to allow for model refinements regarding up-slope versus down-slope and wetland delineations of the nutrient supply-demand situation. In this, forests on up-slope terrain would be marked as being mostly dependent on atmospheric water and nutrient deposition; in contrast, forest nutrient uptake is less limited by atmospheric inputs in down-slope positions and flat areas; on wet areas, growth is limited by other factors, namely high water table and poor soil drainage. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 12

13 Acknowledgement. The authors gratefully acknowledge receipt of provincial databases (NB forest inventory, NB bedrock geology, NB forest classification system, c/o Vince Zelazny), as well as national databases, as listed above. We are especially grateful for the Canadian National Atmospheric Chemistry (NAtChem) Database and its data contributing agencies/organizations for the provision of the mean wet deposition grid data that was used to derive wet atmospheric deposition rates for H, S, N, Ca, Mg, and K. This work was supported through an NSERC grant to PAA, with further financial support realized by way of the Nexfor-Bowater Forest Watershed Research Centre at UNB. References. Acid Rain Working Group A Review of Acid Rain Science Programs in Canada. Prepared to meet the requirements of the Canada-Wide Acid Rain Strategy for Post Presented to Federal/Provincial/Territorial Ministers of Energy and Environment, April Aronoff, S. (1991) Geographic Information Systems: A Management Perspective. WDL Publication, Ottawa, Canada, ISBN Arp, P.A., Oja, T.,and Marsh, M Calculating critical S and N loads and current exceedances for upland forest in southern Ontario, Canada. Can. J. Forest Research, 26, Arp, P.A., W. Leger, M. Moayeri and J.E. Hurley, Methods for mapping forest sensitivity to acid deposition for northeastern North America. Ecosystem Health 7: Bhatti, J.S., Foster, N.W., Oja, T., Moayeri, M.H. and Arp, P.A. (1998) Modelling potential biomass productivity of jack pine forest stands. Can. J. Soil Sci., 78, D Eon, S.P., Magasi, L.P., Lachance, D., and Desrochers, P ARNEWS: Canada s national forest health monitoring plot network. Manual on plot establishment and monitoring (revised). Natural Resources Canada, Canadian Forest Service, Petawawa National Forestry Institute, Chalk River, Ontario. Information Report PI-X-117. Environment Canada Canadian Acid Rain Assessment, Volume One - Summary of Results. Published by authority of the Minister of the Environment, Ottawa. Cat. No. En56-123/1-1997E. ISBN Forest Mapping Work Group NEG/ECP Forest Mapping Project Proposal. Prepared for the New England Governors/Eastern Canadian Premiers Acid Rain Action Plan, unpublished. Grennfelt, P. and E. Thörnelöf Critical loads for nitrogen. Nord, 41, Hall, P. W. Bowers, Hirvonen, H, Hogan, G., Foster, N., Morrison, I., Percy, K., Cox, R., and Arp, P.A Effects of Acidic Deposition on Canada s Forests. Canadian Forest Service. Natural Resources Canada, Ottawa. Information Report ST-X-15. IEA Bioenergy Sustainable Production of Woody Biomass for Energy. ExCo 2002:03 SustainableProductionofWoodyBiomassforEnergy.pdf Johnson, D.W. and Lindberg, S.E Atmospheric deposition and forest nutrient cycling. Springer Verlag, New York. 707p. Meng, F.R., M. Castonguay, J. Ogilvie, P. Murphy, P.A. Arp Developing a GIS-based flowchannel and wet-areas mapping framework for precision forestry planning. International Precision Forestry Symposium March Symposium Programme - "Precision Forestry in plantations, semi-natural and natural forests". University South Africa, Stellenbosch, South Africa Moayeri, M., B. Simpson, F.-R. Meng, P.A. Arp, N. Foster Evaluating critical soil acidification loads and exceedances for a tolerant hardwood site at Turkey Lakes, Ontario. Ecosystem. 4: Moayeri, M.H Mass balance related sustainability of forest biomass production: conepts and applications. University of New Brunswick, PhD thesis. 291 Moayeri, M.H., Simpson, B., Meng, F.-R., Arp, P.A. and Foster, N. W Evaluating critical soil acidification loads and exceedances for a tolerant hardwood site at Turkey Lakes, Ontario.Ecosystem. 4: Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 13

14 Murphy, P., M. Castonguay, J. Ogilvie, T. Connors, P. A. Arp Forest operations planning based on high resolution wet areas mapping: verifications. International Precision Forestry Symposium March Symposium Programme - "Precision Forestry in plantations, semi-natural and natural forests". University South Africa, Stellenbosch, South Africa. Nielson, E. T., MacLean, D. A., Arp, P. A., Meng, F-R., Bourque, C. P-A. and Bhatti, J. S Modeling carbon sequestration with CO2Fix and a timber supply model for use in forest management planning. Can. J. Soil Sci. 86: Oja, T. and Arp, P.A Critical Loads of S and N. In: Maynard, D. (ed.) Sulfur in the Environment, p Marcel Dekker, Inc. New York. Ouimet, R. L. Duchesne, D. Houle, and P. A. Arp Critical loads and exceedances of acid deposition and associated forest growth in the northern hardwood and boreal coniferous forests in Québec, Canada. Water, Air and Soil Pollution. Water, Air and Soil Pollution. Focus: Ouimet, R., P. A. Arp, S. A. Watmough, J. Aherne, and I. DeMerchant Determination and mapping of critical loads of acidity and exceedances for upland forest soils in Eastern Canada. Water, Air, Soil Pollution. (2006) 172: Posch, M, de Smet, P.A.M., Hettelingh, J.-P., and Downing, R.J. (eds.) Calculation and Mapping of Critical Thresholds in Europe: Status Report Coordination Center for Effects. National Institute of Public Health and the Environment, Bilthoven, Netherlands. RIVM Report No , ISBN No Posch, M, Hettelingh, J.-P., de Smet, P.A.M. and Downing, R.J. (eds.) Calculation and Mapping of Critical Thresholds in Europe: Status Report Coordination Center for Effects. National Institute of Public Health and the Environment, Bilthoven, Netherlands. RIVM Report No , ISBN No Posch, M., de Smet, P.A.M., Hettelingh, J.-P., and Downing, R.J. (eds.) Calculation and Mapping of Critical Thresholds in Europe: Status Report Coordination Center for Effects. National Institute of Public Health and the Environment, Bilthoven, Netherlands. RIVM Report No , ISBN No Ro, C.U. and Vet, R..J Analyzed data fields from the National Atmospheric Chemistry Database (NAtChem) and Analysis Facility. Air Quality Research Branch, Meteorological Service of Canada, Environment Canada, 4905 Dufferin St., Toronto, Ontario, Canada M3H 5T4 Werner, B. and Spranger, T. (eds.) Manual on methodologies and criteria for mapping critical levels/loads and geographical areas where they are exceeded. Prepared by the UN ECE CLRTAP Task Force on Mapping and the Coordination Center for Effects (CCE), Umweltbundesamt, Berlin, Germany. ISSN X Zelazny, V DNR s ecological site classification initiative (Our Landscape Heritage: The story ofecological land classification in New Brunswick. Unpublished manuscript. Abbreviations ARNEWS Acid Rain National Early Warning System; CANSIS Canadian Soils Information System EMAN - Ecological Monitoring and Assessment Network EMEP - European Monitoring and Evaluation Programme GIS Geographic Information System; MAI Mean annual increment NAMP - North American Maple Project; NAtChem National Atmospheric Chemistry Database and Analysis System NEG/ECP - New England Governors/Eastern Canadian Premiers Conference RMCC - Federal/Provincial Research and Monitoring Coordinating Committee Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 14

15 Figure 6. Identifying areas New Brunswick with potential nutrient-induced growth limitations, by forest harvesting type: SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). This is done for current (1x) and doubled (2x) biomass supply expectations. Borders and numbers in the map refer to the 10 Crownland Forest Management areas. Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 15

16 1X 2X SO BWB WT Calcium Deficit 100 year period Figure 7. Determining locations with likely Ca nutrient deficits across New Brunswick, by forest harvesting type: SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 16

17 1X 2X SO BWB WT Potassium Deficit 100 year period Figure 8. Determining locations with likely K nutrient deficits across New Brunswick, by forest harvesting type: SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 17

18 1X 2X SO BWB WT Magnesium Deficit, 100 year period Figure 9. Determining locations with likely Mg nutrient deficits across New Brunswick, by forest harvesting type: SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 18

19 1X 2X SO BWB WT Nitrogen Deficit, 100 year period Figure 10. Determining locations with likely N nutrient deficits across New Brunswick, by forest harvesting type: SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 19

20 1X 2X NO SO BWB WT Base Cation Depletion Equivalents, per ha per year Figure 11. Determining locations with likely acid-rain + harvest induced base cation depletion across New Brunswick, by forest harvesting type: NO no harvesting; SO stem-only; BWB whole-tree without foliage (brown biomass); WT whole-tree with foliage (green biomass). Modeling and mapping nutrient supply demand sensitivities to forest biomass harvesting 20