This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Some Methodological Approaches to Estimate and Monitor Carbon Mitigation in the Forestry Sector1 Ben H.J. de Jong2 Abstract-Forestry and agroforestry are promlsmg land-use alternatives for reducing the increasing levels of global atmospheric carbon. To understand the role of forestry and agroforestry systems in the carbon cycle it is necessary to quantify both the net annual carbon fluxes and the total carbon content of the systems. The effect of a forestry project has to be compared with a "business as usual" baseline. There exist various methodological approaches to estimate the impact on carbon fluxes of forestry and agroforestry. Known problems of baseline assumptions, carbon flux reporting, and monitoring and verification are exemplified with field collected data and recent experiences of the Scolel Te Pilot Project for Community Forestry and Carbon Sequestration in Chiapas, Mexico (Scolel Te 1998). The "Greenhouse Gas Bubble (GGB)" concept as an alternative instrument for carbon offset trading and reporting is discussed. The third Conference of the Parties to the United Nations Framework Convention on Climate Change (UN-FCCC), held in December 1997 in Kyoto, Japan describe two marketbased mechanisms that will allow countries to trade in greenhouse gas emission (GHG) reductions: 1. Between two Annex 1 countries (countries with binding emission limits), known as Joint Implementation (JI), and 2. Between an Annex 1 country and a non-Annex 1 country (countries with no binq.ing emission limits, mainly developing countries), known as Clean Development Mechanism (CDM). The existence of carbon offsets in low-cost countries and demand in obligated high-cost countries may create a market for the buying and selling of GHG offsets. Under a possible future carbon offset trading program, countries would be most likely to pay for such reductions in another country where the cost for reducing emissions is lower. Al though forestry measures are not yet specifical:~l incl uded within the current articles relating to the CDM , it seems likely that provisions for forestry will be included at some stage, given the significance of developing country forests Ipaper presented at the North American Science Symposium: Toward a Unified Framework for Inventorying and Monitoring Forest Ecosystem Resources, Guadalajara, Mexico, November 1-6,1998. 2 Ben H.J. de Jong is Research Scientist at El Colegio de la Frontera Sur (ECOSUR), located in San Cristobal de las Casas; 29290 Chiapas, Mexico. e-mail:bjong@sclc.ecosur.mx 3 There is some debate on the interpretation of the Kyoto protocol relating to forestry. One particular discussion is whether forests are specifically excluded from the CDM. 130 within the global carbon cycle. Several studies have indicated that the global potential for enhancing carbon (C) storage by forestry and agroforestry may be as much as 60-90 x 109 tons of C (tC, Dixon et al. 1991; Winjum et al. 1992; Dixon et al. 1993; Trexler and Haugen 1994; Brown et al. 1995). Forestry and land-use mitigation measures can serve other environmental, economic, and social interest simultaneously, and may offer some of the most costeffective ways to climate change mitigation. GHG offset projects in the land use and forestry sector can particularly be attractive if they can be tied to local social and economic goals (Trexler 1993). In Mexico, the forestry sector is a key element in any national greenhouse emissions mitigation plan. Currently, land use /land cover (LUILC) change is the second source of C emissions to the atmosphere, accounting for an estimated 35% of total emissions. However, the forestry sector has the potential to convert Mexico from a net carbon source to a carbon sink, if proper actions are taken (Masera et al. 1997). Using forests as a means of mitigating climate change could be achieved both by conserving existing stocks of C in forests that are currently threatened, and by creating new stocks in growing trees. In forestry, as with other types of activities, the net effect of a project is the difference between the project scenario and a baseline, reference, or "business-as-usual" case (Fig. 1). Calculating emission reductions associated with a project scenario present certain difficulties in land use because carbon fluxes from vegetation and soil are complex, bidirectional and continuous. A number of methodological and policy questions need to be addressed before forestry carbon offset trading can provide reliable, verifiable emission reductions (Tipper & De Jong 1998). This paper discusses some of the methodological approaches related to the quantification of carbon sequestration in forestry projects: • Establishment of baseline assumptions • Accounting procedures to quantify the effect of forestry projects on carbon budgets • Monitoring and verification of project performance The following sections illustrate the effect of the different approaches applied to address these problems. Where necessary, particular reference is made to the Scolel Te Pilot Project for Community Forestry and Carbon Sequestration in Chiapas, Mexico (Scolel Te 1998) and the results of an assessment ofthe cost of a large-scale forestry program for CO 2 sequestration (Tipper et al. 1998). The "Greenhouse Gas Bubble (GGB)" concept as an alternative instrument for carbon offset trading and reporting in the forestry sector is discussed. USDA Forest Service Proceedings RMRS-P-12. 1999 Expected accumulation of carbon through Average accumulation project through project Net average project effect Average Baseline ~ Figure 1.-Hypothetical effect of a C mitigation project, compared to a "business-as-usual" baseline. Baseline Assumptions The definition of a suitable baseline or reference case involves the elaboration of a hypothetical or counterfactual scenario. Differences in the order of a single percentage point in the assumed rate ofloss of current carbon storage in the baseline assumption can halve or double the perceived net effect of a given intervention over the course of a 60 year . time frame. As such, the interests at stake are considerable. Since both the buyer and the seller of a carbon offset have interest in a high net effect of a project, they may exaggerate the baseline assumption, unless some form of regulatory mechanism is used to counterbalance these interests. The main problem to establish a baseline within the LUI LC sector relates to the prediction offuture changes. This is particularly difficult, because the proximal causes and driving forces behind land-use decisions are diverse, interrelated, and often discontinuous. At regional levels, factors such as demographic changes and government policies often have significant effects. At specific locations, uncertainties about land ownership, social conflicts, the impact of development projects, crop failure and fires can cause unpredictable changes in land-use decisions among farmers (De J ong et al. 1998). Methods used are either extrapolations of past rates of change of carbon stocks into the future (trend-based models), or process-based models that attempt to simulate the demographic and economic processes driving land-use change (Brown et al. 1989; Faeth et al. 1994; Fearnside and Malheiros-Guimaraes 1996; De Jong et al. 1998). One problem with trend-based predictions is the influence of the geographic domain used in the assessment-if the domain is restricted to areas where deforestation has been rapid in the past, then the baseline loss of carbon will appear high. Where records show considerable variations in the rate of LUILC change over time and/or space, it is not obvious which scenario will be most likely in the future (Box 1). Another approach is to apply process-based models. Although these models may be capable of assessing the USDA Forest Service Proceedings RMRS-P-12. 1999 relative vulnerability of different categories of vegetation, they generally require large investments in data collection to make credible representations of land-use change processes. In densely populated areas where various factors influence local and regional land-use decisions, if will be difficult to define which factor is the main driving force behind the L UILC change dynamics. Rudel and Roper (1997) tested various factors that are thought to contribute to deforestation in the tropics for 68 tropical countries. The factors they tested are, among others, population pressure, economic growth, and national land-use policies. Based on their results, they distinguish two types of deforestation processes: 1. a frontier model, characterized by the opening up of new areas, and 2. animmiserization model, characterized by a continuous fragmentation and deforestation in densely populated areas, dominated by resource-poor farmers. Both processes occur simultaneously in Chiapas. In the densely populated Highlands ofChiapas, the immiserization process dominates, while the frontier model prevails in the nearby tropical lowland forests of the Selva Lacandona. Thus, land-use policies may have a positive effect in one region, but can create negative impacts in the other region. In fact, during the 70's the Mexican government promoted the frontier model in the Selva Lacandona region at least partly to reduce the immiserization process in densely populated areas. This makes the development of a general process-based land-use model complex and very sensitive to variations between regions. As such, it is most likely that reliable process-based models that explain land-use decision-making will first be developed on a regional scale. On a project scale, baseline assumptions can also cause major problems in relation to credibility and probability. For example, forests not facing any threat cannot claim C offset (Trexler 1993). However, if forests do present threats, how to guarantee that the exploitative action that threatens the forest is not simply displaced to another area? 131 100 % of 1996 C stock 80 15 9 Comllas i i 60 1984 1990 1996 J--1996 A 2016 2006 2026 B Figure A is based on the interpretation of satellite images of 1974, 1984, 1990 (MSS), and 1996 (TM) of an area of approximately 300,000 ha in the highlands of Chiapas. For each major LU/LC class C-densities were measured in 39 field plots. To project possible C loss in the future, the C-density of the completely deforested LU/LC classes (agriculture, pasture and settlements) were assumed to have lost all the vulnerable C stock, thus their C density was set to O. From the C densities of all other classes the average C density of the completely deforested LU/LC classes was subtracted to estimate the C pools that were prone to be lost through LU/LC change (So called vulnerable C). The C density of each LU/LC class was incorporated in the LU/LC statistics to calculate the decrease in C stock during the periods 1974-1984,1984-1990,1990-1996, and 1974-1996. The highest, lowest and average decrease in C-stock, expressed in % per year was used to predict future trends in vulnerable carbon storage. Depending on the rate of C storage depletion, in 2050 the expected C stock fluctuates between.3 and 15 x 106 tC. Figure B is based on the comparison of LU/LC between an historical vegetation map (which was elaborated through interpretation of aerial photographs of the 1970s) and the interpretation of a 1996 TM satellite image. C densities of the major LU/LC classes were collected in 29 field plots. C densities and LU/LC statistics were then used to derive estimates of change in carbon stocks, as expressed in % per year, for the whole region and separately for the three SUb-regions, using natural or political boundaries as the separation criteria. The Northern region and Marques de Comillas present the highest depletion in carbon stock, whereas the carbon stock in the Lacandon Community remains almost unchanged. The first two regions are subject to government induced settlement programs, whereas the Lacandon Community, which contains the Montes Azules Biosphere Reserve, is subject to government conservation efforts. Total C stock in The Nothern Region and Marques de Comillas would decrease with about 35 % in the next 30 years, while the stock in the Lacandon Community would reduce with about 5 % in the same period. C stock for the whole region would decrease with about 20%. 132 USDA Forest Service Proceedings RMRS-P-12. 1999 Carbon Fluxes in Managed Systems _ _ _ _ _ _ _ _ __ Various carbon accounting procedures exist to explain the system C dynamics, relative to a baseline (Tipper and De Jong 1998). All accounting procedures are somehow based on flux models that try to estimate temporal changes in carbon pools and fluxes between pools (Box 2). The results of the flux estimation can be reported as: • Yearly fluxes between the vegetation and the atmosphere (expressed in tC/year) or the sum of the yearly fluxes at a given cut-off date (expressed in tC, Nabuurs and Mohren 1993, 1995; De Jong et al. 1995,1998). • Long-term average increase in the carbon stock of a managed stand relative to a hypothetical baseline (expressed in tC, N abuurs and Mohren 1995; De J ong et al. 1998). • Cumulative carbon storage (expressed in tC.years, Tipper and De Jong 1998). Yearly Fluxes This method is conceptually the simplest way to provide carbon offsets to reduce emissions. In this procedure changes in pools and fluxes between pools are calculated and presented on a yearly basis. One ofthe main shortcomings of this approach is related to the fact that carbon fluxes in The C flux models C02FIX, developed by Nabuurs and Mohren (1993) and GORCAM, developed by Schlamadinger and Marland (1996) derive carbon accumulation and storage by a tree plantation over the course of a number of rotations, based on an "expected growth" curve. Adjustments can be made for product lifetime. Soil C fluxes generally are simulated by a litter, humus and deadwood decomposition fraction and a litter humification factor. Tree mortality, leaf, branch and root turnover rates, and harvesting can change the living biomass, while decomposition, humification and burning are factors that can affect dead biomass and product pools. In GORCAM, part of the medium and long lived products can be assigned to energy, when a fuel substitution factor is used (Schlamadinger and Marland, 1996). USDA Forest Service Proceedings RMRS-P-12. 1999 133 forestry ecosystems are irregular and bi-directional. In the simplest case, a plantation system generally shows a slow uptake of carbon during the growing cycle and high emissions shortly after harvesting (Fig. 2). If the offset trading assign credits on the yearly flux basis, what to do with the negative flux (emission) after harvesting? An economic assessment of the effect of a forestry project based on yearly fluxes requires the summation of the flows over a specific period of time, to derive a total expressed in tC. In the case of conservation of forest reserves, this is rather straightforward, as this alternative prevents a oneoff release of carbon. However, when the management scheme includes periodic harvesting of (part of) the stand, the total C accumulated will depend largely on the relationship between rotation length and the time horizon set as the project limit. The buyer of the offset credits will prefer to set the time horizon just before harvesting, whereas the carbon offset will be at least partly lost when harvesting takes place. :r " '. Long-Term Average Increase Many projects in the pilot phase of the UN-FCCC program of Activities Implemented Jointly are assessed on the basis of the long-term average increase in the carbon stocks relative to the baseline, expressed in tC (Fig. 2, Tipper and De Jong 1998). This approach assumes a long-term maintenance of the alternative system, calculates the yearly fluxes related to C dynamics and estimates the average effect ofthe system on a long time horizon (typically 100-150 years). 250 Stock 150 250 nnrmm6 1111111111111 m1TI' Baseline 100 200 . 150 100 Tei 50 ----------:-Acc ----- ------- ---- _. --- _. ----- --- -- ---------- ----- ----- -- --- -- ---------- -~A-v o ------ --~,.,.,.",...---- a 20 60 40 10 -20 The cumulative carbon storage approach is based on the expected lifetime of carbon emissions and radiative forcing of the CO 2 in the atmosphere (See Tipper and De Jong 1998 for the theoretical explanation of this approach). It assumes that most of the CO 2 emitted at the present will be absorbed within a time scale of about 100 years, and that the cumulative radiative forcing produced by the emission will be proportional to the area under the depletion curve, expressed in tC.years. Calculation of this area provides an estimate of the cumulative carbon storage that would be required to offset an emission of 1 tC at the present time (About 50 tC.years per tC emission). To apply the tC.years to tC conversion factor to forestry projects, a cut-off date needs to be defined that will limit the amount of credit that can be obtained from a given project activity. A cut-off date ~ ~lllIlllilill 200 -10 Cumulative Carbon Storage Plantation TC/ha 0 Some of the major shortcomings of this accounting system is that it is not compatible with national level emission reporting so that additional inventory work would be required to reconcile the reporting systems and that the performance ofthe system over such long time horizons will be difficult to estimate and that various insurance mechanisms have to be developed in case the system fails within the time horizon. This approach is attractive since up-front investment may be credited in expectation of future increases in terrestrial carbon stocks. In fact, this approach currently applies to the Scolel Te Pilot Project (Scolel Te 1998). 80 Yearly flux I r:=:==:: ~ v- ,.....-==-:: v Yr 50 a 100 ----- Figure 2.-Graphical representation of the various accounting procedures to explain the system C dynamics, relative to a baseline. Stock = accumulated carbon in the system; TC I = emission offset in tC, using the cumulative carbon storage approach; Av. Acc =long-term average accumulation increase of C in the system, relative to the baseline; Yearly flux =net yearly C flux of the system. 134 USDA Forest Service Proceedings RMRS-P-12. 1999 in the order of 100 years has already been applied to various projects assessed on the average stock increase approach and seems also rational for the cumulative carbon storage approach. Even if the system is broken off before the cut-off date, it still contributes to the overall radiative forcing reduction, and the amount oftC emission offset obtained up till then can be calculated with the following formula: tC emission offset in year i = Li (Cacc,i - Cbase) / Conversion Factor Where Cacc,i is the C accumulated in the alternative system and Cbase,i the C accumulated in the baseline, both in year i (Fig. 2). This approach is attractive as it resolves the accounting problems between emissions and uptake and there is no need to assume the conditions for indefinite sustainability of an equilibrium state of forest management (For a discussion on the advantages and disadvantages of this approach see Tipper and De J ong 1998). The a pproach is also in line with the global climate change concern: the greenhouse effect of certain gases in the atmosphere. This approach would require international agreement on the conversion factor. Once agreed upon, it needs to be reviewed periodically to take into account changes to the nature of the sinks due to climate change and land cover change, such as change in ecosystem productivity through climate change and CO 2 fertilization. Monitoring and Verification Notwithstanding the overwhelming literature available about potential biotic mitigation measures, there is still a large gap between accepting that C fluxes can in fact be modified to help mitigate climate change and accepting that this modification can take the form of individual projects that can be monitored and verified as part of a C emissions control system (Trexler 1993). By definition, monitoring activities of C mitigation projects typically measure all significant flows, whereas verification aims at evaluating the accuracy and reliability of the monitoring scheme. Monitoring programs are important for land-use projects to increase the reliability of data and to improve project performance. To ensure that forestry projects used for GHG mitigation are reliable and verifiable, guidelines are needed to provide structure and direction for project managers (Sathaye and Ravindranath 1997). These authors also point out that carbon pools in forest systems as well as forest products and energy should be evaluated for their significance (pool size) and vulnerability (rate and direction of change). Decisions about appropriate methodology and intensity depend on the relative importance of the individual pools (significance, speed and direction of change). Possible leakage issues must be addressed within a regional or national context (Leakage is the term used to describe the shifting of activities with GHG implications outside the boundaries of a project in space and/or time, Andrasko 1997). The Scolel Te project in Chiapas, Mexico gives an example of how monitoring and leakage can be addressed in a project in which many individual farmers participate (Andrasko 1997; De Jong et al. 1997). The project is designed to increase farmer income by implementing a set of alternative practices chosen by the farmers that also increase carbon stocks. Each farmer presents a "plan Vivo" current land-use plan of his land, which is a starting point to monitor possible land-use changes in USDA Forest Service Proceedings RMRS-P-12. 1999 the future. Furthermore, the project is designed to also reduce potential leakage off-site, especially to the Selva Lacandona rainforest (De Jong et al. 1995, 1997). Definition of the project boundary is important to facilitate decisions about questions such as if observed carbon fluxes relate to a certain project or not. The project boundary has to be set into a regional or national context to avoid what Andrasko (1997) calls ''Edge Effect", that is the set of policy and technical issues emerging at the boundaries of monitoring domains. To avoid leakage or double accounting of carbon offsets it is essential to establish a linkage between individual carbon sequestration projects and regional or national flux reporting. Selecting the monitoring domain boundaries between project and regional and national accounting involves decision-making about the accuracy desired at both levels and financial resources available. Assessment of offset reliability will ultimately require international agreements on a risk assessment methodology that can commonly be applied across projects and project types. Crucial to offset reliability is the timeline over which projects should be assessed and whether all projects should be subject to a common timeline analysis (Trexler 1993). Greenhouse Gas Bubble (GGB) __ Many scientists believe that the uncertainties in estimating the size of fluxes related to LUILC changes can be reduced to acceptable levels if that is the desire of the international community (Noble 1998). Monitoring programs can be designed to provide credibility to forestry carbon offset projects. The effectiveness, cost and reliability of methods vary by type of project, scale, and the fluxes being monitored (Sathaye and Ravindranath 1997). One solution to cope with the monitoring domain problem is the development of what Andrasko (1997) calls "nested" monitoring systems. While developing countries, including Mexico, are not obliged to accept national binding emission limits, they could establish voluntarily GGBs covering specific regions and/or sectors (Tipper and De Jong 1998). To establish a GGB, the government sets an emission ceiling over a specific region and/or sector, such as a major forest area. Once the limit of a GGB is established, any extra emission reduction could then be credited. Such a system would allow to set up a reporting scheme that is mutually compatible and information flows between the monitoring entities could improve the accuracy of both systems. For example, up till now an average carbon density for each land cover class is used as the basis to estimate fluxes by comparing land-cover statistics. Project-level monitoring schemes could develop carbon density equations wi thin each land cover class, based on satellite image interpretation. These equation can be adopted and incorporated in the periodic regional land cover change detection system, that has to be set up to comply with the GGB agreement. The U.S. Acid Rain Program uses the GGB concept to control S02 and NO x emissions (Solomon 1994). As with other management systems, the procedures of monitoring and verification of GGB and project performance should be constantly subject to improvement and refinement. The key to improvement is to reflect upon the main sources of error within the system. In the Scolel Te 135 Pilot Project, for example, the carbon densities and fluxes of the land management systems are currently based partly on direct biomass measurements, supplemented by the best available data in the literature. New data will be used to improve C-flux modelling, as these come available from project and GGB monitoring and verification. Figure 3 illustrates the potential information flows that can occur during the planning and implementation stages between GGB and project assessments. Project monitoring, as handled by the Scolel Te Pilot Project is also set up to improve farmers' compliance with monitoring schedules. This will be subject to gradual improvement through modification of the Plan Vivo methodology, training of farmers, and linkage of incen tive payments to fulfillment of reporting requirements. GGBs could be established in regions where: • Already exist interest in carbon sequestration • Poverty alleviation is critical and al tern a tive options are lacking (e.g. immizeration areas) • Biodiversity conservation is of national and/or international importance • Data on LUILC changes and related carbon fluxes are available • Inward and outward fluxes or leakage are limited and measurable Mexico, as a non-Annex 1 country, is very keen to explore the CDM potential, especially of the forestry sector. The Level government is currently setting up a Mexican Office for Greenhouse Gas Mitigation (MGGM). The National Institute of Ecology (INE), which is in charge of the Global Climate Convention, has already initiated studies that are required under the commitments of the Kyoto protocol and was the first country in Latin America to provide initial communication under the protocol. To comply with the increasing requirements of the UNFCCC and subsequent protocols, INE is currently improving its capacity to: • Identify, adapt, and implement methodologies for GHG emissions assessment of the various sectors • Calculate emission baselines to assess GHG mitigation initiatives • identify promising forestry mitigation options, presenting their main technical and economic features Table 1 presents a summary of activities and their requirements, necessary to set up and manage GHG offset programs. Some of these activities are already in progress, whereas others fit well within a GGB framework, such as nested GHG accounting frameworks, policy instruments to standardize accounting and presentation procedures, and data integration procedures. Data collected within a GGB framework can be used to improve the accuracy of national GHG emission reporting, and GGB can eventually be the starting point to establish future binding national emission limits. Monitoring Verification National reporting PLANNING Region Baseline Assessment Baseline studies of C-flux estimation of LU/LC change dynamics I Project Results: Refining Baseline assumptions • Refining C-sequestration models of new systems Estimation of C-sequestration potential of project, based on regional baseline and ~----------, accepted sequestration models IMPLEMENTATION Region Periodic LU/LC Change detection Results: Baseline reports to comply with voluntary limits of emissions Project Monitoring of project performance -oE<~--- Results: GHG-flux reporting System performance reporting Refining system revision criteria Evaluation of C accumulation in new systems and control plots Results: Refining C-sequestration models • Guidelines for system establishment and maintenance • Providing new data for project performance reporting Figure 3.-lnformation flows between the reporting entities, within a Greenhouse Gas Bubble (GGB) framework. 136 USDA Forest Service Proceedings RMRS-P-12. 1999 Table 1.-Activities and their requirements, necessary to set up and implement a Greenhouse Gas Bubble. bold: activities and requirements in process; normal: proposed activities and instrument development; italic: aditional activities and requirements that have to be developed. Level Activities Requirements Planning stage Greenhouse Gas Bubble (GGB) • Identification of critical areas (INE 1998) • Identification of project opportunities (INE 1998) • LUILC change modelling with associated GHG flows (Tipper et a11998) • Identification of government policies and short and medium term development programs • Identification and quantification of sources of leakage Policy instruments to define baseline determination Agreement on default values of major parameters Guidelines on format data reporting LUILC change detection protocols Leakage tracking procedures Quantification procedures to measure GHG impact of policies • Identification and acceptance of a minimum set of credible, well designed, verifiable forest mitigation activities (De Jong et al 1997) • Data on carbon densities and variation in LUILC classes (De Jong et al 1999) Project • Elaboration of proposals of farmer and community management plans • Ex ante estimation of GHG fluxes in management systems • Identification of possible project level sources of leakage • Policy instruments to standardize accounting, modelling and data presentation procedures Interactions between levels • Exchange of information to improve accuracy of data at both levels (De Jong et a11997, Figure 3) • Standardization of data presentation • Data Integration procedures • • • • • • Implementation stage GGB • Periodic LU/LC change assessments Project • Plot and system wise monitoring and verification of GHG fluxes in managed and control plots References ____________________ Andrasko, K 1997. 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