Browsing by Subject "Forest"
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Item Open Access Accessing the viability of HTR - Indonesia's community-based forest plantation program(2009-04-24T18:19:10Z) Schneck, JoshuaIn Indonesia, development of sustainable supplies of timber has failed to keep pace with industrial demand. After decades of overharvesting and clearing to bridge supply gaps, Indonesia’s forests and forest industries are in a crisis, with declining stocks of timber to support forest-dependent livelihoods and biodiversity, and large recurring emissions of atmospheric CO2 linked to deforestation. The Indonesian Government’s strategy of providing incentives to developers of large-scale industrial timber plantations has been of limited success, with only 30% of state targets reached after nearly twenty years of work. Difficulties can be traced to conflicts over land rights at the community level, and the limited financial viability of plantation investments in markets distorted by illegal and cheaply-priced wood supplies. In an effort to address these obstacles, the Indonesian Government introduced a new community-based plantation program in 2007, Hutan Tanaman Rakyat (HTR), which affords local communities rights and incentives for developing timber plantations on community lands. Country-wide targets for HTR are substantial, with 5.4 million hectares of plantations planned, however substantial challenges lie ahead in identifying suitable areas of land, creating effective institutional arrangements, and ensuring economic viability. Here, we examine the financial viability of developing pulpwood plantations under HTR at 22 proposed sites in West Kalimantan, and consider challenges to implementing HTR on the ground by surveying a local plantation company operating under a partnership model similar to the kind proposed for HTR. Investments in all 22 sites yield negative net present values, indicating HTR is not profitable under current market conditions. Results suggest HTR may be best facilitated by accompanying macroeconomic and forest-sector policies which reduce market distortions, improve market transparency and liquidity, and raise domestic log prices.Item Open Access Carbon for Conservation(2018-04-27) DeLyser, Kendall; Petro, Alison; Rudee, Alexander; Wang, ZiyueThe Nature Conservancy’s North Carolina chapter (TNC NC) is exploring opportunities to secure additional financing for their conservation work through the sale of carbon offset credits in regulatory or voluntary markets. This project assesses the prospects for TNC NC to develop carbon offset projects on forest lands and pocosin peatlands in North Carolina for that purpose, including risks associated with project development. We developed a site prioritization model to identify a subset of parcels meeting TNC NC’s criteria for establishing a carbon offset project, which we then evaluated for carbon sequestration potential and projected financial performance. Our analysis showed that conservation-oriented management activities may in some cases preclude a viable offset project on the site by decreasing carbon stocks or increasing leakage of timber harvests. However, opportunities do exist to align and carbon sequestration and conservation goals where the property requires little active management or has low baseline rates of carbon sequestration. Based on our analysis, we present recommendations on project types and locations within the state that may be attractive to TNC NC for a carbon offset project.Item Open Access Cashing in on Carbon--Land and Offset Project Valuation: Incorporating Climate Legislation and Environmental Incentives in Property and Project Appraisal(2010-04-30T18:29:50Z) Davis, Nicholas J.The CBO, EIA, and EPA predict carbon offset prices will rise to $15-30/ton CO2e in the next decade (ACESA). The creation of carbon offsets markets provides landholders with an alternative means of income generation on suitable tracts. Relevant businesses might recognize what carbon and offset prices mean for their companies, but little information exists for prospective suppliers of offsets like land owners, farmers, land trusts, etc. This project presents a customizable tool based on assumptions including but not limited to offset price forecasts, expected sequestration rates, and tax data (State, Federal). Users can tailor inputs like acreage availability, forest type, and start-up costs to yield rough estimates of project and property value based on planting-for-carbon initiatives. This paper demonstrates sample outputs produced by the model, conducts sensitivity analyses to evaluate project variability, and runs financial forecasts using Oracle’s Crystal Ball to predict outcome probabilities. It is important to note that at the current stage, this tool predicts carbon sequestration and financial outcomes for tree planting projects, not existing forest tracts.Item Open Access Duke Forest Carbon(2011-12-09) Downing, Eric; Fulton, Erin; Strauss, JoshuaDuke University is dedicated to achieving climate neutrality by 2024. With over 7000 acres of sustainably managed forest land, the Duke Forest has great potential for generating “in house” carbon offsets to help reach this goal. In this project we quantified the carbon represented in Duke’s forest holdings and analyzed the potential for generating emissions-reducing offsets based on Climate Action Reserve (CAR) and American Carbon Registry (ACR) protocols. Throughout the process we focused on three varieties of forest offsets: Avoided Conversion, Improved Forest Management, and Afforestation/Reforestation, comparing the relative advantages and disadvantages of each under CAR and ACR carbon accounting systems. After completing these carbon calculations we conducted a financial analysis of our results in order to make recommendations to the Duke Carbon Offsets Initiative concerning how they might apply these forest offsets toward the university’s carbon neutrality goal. Ultimately we concluded that the Duke Forest has the potential to produce significant amounts of high quality carbon offsets at a cost considerably below that of purchasing them on the voluntary market. The generation of Improved Forest Management offsets under CAR protocols proved particularly compatible with current Duke Forest management practices, yielding substantial carbon and financial benefits with minimal project development investment. Based on the results of our carbon and financial models we determined that the Duke Forest could generate 358,109 offset credits over the next 50 years, saving the university over $1.5 million.Item Open Access Ecosystem Response to a Changing Climate: Vulnerability, Impacts and Monitoring(2017) Seyednasrollah, BijanRising temperatures with increased drought pose three challenges for management of future biodiversity. First, are the species expected to be vulnerable concentrated in specific regions and habitats? Second, are the impacts of drought and warming varying across regions? Third, could recent advances in remote sensing techniques help us in monitoring the impacts in real-time? This dissertation is an effort to address the above questions in the three chapters.
First, I used foliar chemistry as a proxy for drought vulnerability. I used soil and moisture gradients to quantify habitat variation that could be critical for alleviating drought. I used a large dataset of forest plots covering the eastern united states to understand how community weighted mean foliar nitrogen and phosphorus vary across climate and soil gradients. I exploited trends in these variables between species, traits, and habitats to evaluate sensitivity. Critical to our approach is the capacity to jointly model trait responses. Our data showed that nutrient demanding species strongly respond to environmental gradients. I identified a wide range of sites across low to high latitudes threatened by drought. The sensitivity of species to high temperatures is largely explained by soil variations. Drought vulnerability of nutrient and moisture demanding species could be amplified depending on local soil and moisture gradients. Although local soil moisture may dampen drought-induced stress for species with large leaves and high water use, nutrient demanding species remain vulnerable in wet regions during droughts. Phosphorus demanding species adapted to dry sites are drought resilient compared to communities in wet sites. This research is consistent with the studies that supports declining nutrient demanding species with increasing temperature and decreasing moisture. I also detected strong soil effects on shaping community weighted traits across a large geographical and environmental range. Our data showed that soil effects on controlling foliar traits strongly vary across different climates. The findings are critical for conservations and maintaining the biodiversity.
Next, I used space-borne remotely sensed vegetation indices to monitor the process of leaf development across climate gradients and ecoregions in the southeastern United States. A hierarchical state-space Bayesian model was developed to quantify how air temperature, drought severity, and canopy thermal stress contribute to changes in leaf opening from mountainous to coastal regions. I synthesized daily field climate data with daily remotely sensed vegetation indices and canopy surface temperature during spring green-up season. The study was focused on observation of leaf phenology at 59 sites in the southeast United States between 2001 to 2012. Our results suggest strong interaction effects between ecosystem properties and climate variables across ecoregions. The findings showed that despite the much faster spring green-up in the mountains, coastal forests express a larger sensitivity to inter-annual anomaly in temperature than mountain sites. In spite of the decreasing trend in sensitivity to warming with temperature in all regions, there is an ecosystem interaction: Deciduous-dominated forests are less sensitive to warming than are those with few deciduous trees, possibly due to the presence of developed leaves in evergreen species throughout the season. The findings revealed mountainous forests are more susceptible to intensifying drought and moisture deficit, while coastal areas are relatively resilient. I found that increasing canopy thermal stress, defined as canopy-air temperature difference, slows the leaf-development following a dry year, accelerates it after a wet year.
Finally, I demonstrate how space-borne canopy “thermal stress”, i.e. surface-air temperature difference, could be used as a surrogate for drought-induced stress to estimate forest transpiration. Using physics-based relationships that accommodates uncertainties, I showed how changes in canopy water flux may be reflected in surface energy balance and in remotely-sensed thermal stress. Validating with field measurements of canopy transpiration in the southeastern US, I quantified sensitivity of transpiration to thermal stress in a range of atmospheric and climate conditions. I found that a 1 mm change in daily transpiration may cause 3 to 4 °C of thermal stress, depending on site conditions. The cooling effect is large when solar radiation is high or wind speed is low. The effect has the highest control on water-use during warm and dry seasons, when monitoring drought is essential. I applied our model to available satellite and metrological data to detect patterns of drought. Using only air and surface temperatures, I predicted anomaly in water-use across the contiguous United States over the past 15 years, and then compared with anomaly in soil water content and conventional drought indices. Our simple model showed a reliable accuracy in compare to the state-of-the-art general circulation models. The technique can be used in varying time-scales to monitor surface water-use and drought in large scales.
Item Open Access Gabon’s Overlooked Carbon: A tropical forest study of coarse woody debris(2013-04-26) Carlson, BenLarge dead trees and other large forest detritus (collectively known as coarse woody debris, or CWD) play an important role in the global carbon cycle. In tropical systems, CWD stocks (necromass) have been found to constitute 5% to 33% of total biomass. Despite harboring the second largest rain forest on earth, in Central Africa there have been virtually no studies of coarse woody debris. In this study 15 plots were established in 5 forest zones in Gabon, Africa to measure CWD stocks and potential environmental and land-use determinants of CWD. Necromass of CWD was found to be positively correlated with precipitation and was higher in logged forests than in primary forests. Extrapolated to the entire country, Gabon is estimated to contain carbon CWD content of between 0.34 Pg C to 0.72 Pg C (14 Mg C ha-1 to 30.1 Mg C ha-1). The results of this study will help improve tropical forest carbon flux estimates.Item Open Access Health Forests: Scaling Up Urban Forests as a Health Response(2022-04-21) Toker, RachelIn the eastern United States, urban lifestyles, conditions, and constraints are causing a rise in chronic diseases like heart disease, stroke, and diabetes, which cost trillions of dollars annually to treat. Given the importance of forests for ecological restoration, this study explores whether regenerating native forest patches that incorporate health treatments (or “Health Forests”) in at-risk urban neighborhoods -- as a unified place-based response -- can treat these diseases more cost-effectively while accessing healthcare funding sources to improve environmental outcomes. The study suggests that Health Forests, distributed at large enough scale, could improve health outcomes and restore regional ecosystems at substantial cost savings. Nature experiences lower blood sugar, blood pressure, and cortisol levels, and they improve concentration, immune function, and heart rate variability; however, focused medical research showing treatment efficacy is still needed to enable corporate healthcare payers to justify funding this effort. This study finds that, if creating and operating Health Forests causes even a 20% net reduction of annual covered medical expenditures due to chronic diseases, corporate healthcare payers could reap substantial financial benefits from doing so.Item Open Access Management Prioritization in a Public-Facing Urban Wetland(2023-04-28) Carvalho, Juliana; Chase, BenjaminThe Museum of Life and Science is a nature center and science museum located in Durham, North Carolina, working to understand and improve the health of an urban wetland ecosystem located on their campus. The majority of the natural land cover within the wetland’s watershed is forested and managed by the Museum, so a forest inventory and management analysis was conducted to understand potential impacts on the wetland. Interviews and a literature review produced alternatives for community-based environmental management in urban ecosystems that formed a basis for a multi-criteria decision analysis framework. This paper provides a decision-making methodology for the Museum of Life and Science to assess potential environmental management decisions and recommendations through a forestry lens to improve watershed health while meeting their mission.Item Open Access Measurement and Modeling of Radiation and Water Fluxes in Plantation Forests(2009) Kim, Hyun-SeokAn increasing number of experimental studies attempt to maximize biomass production of trees in plantations by removing nutrient and water limitations. The results from these studies begin to inform operational managers. We investigated a Populus trichocarpa Torr. x P. deltoides Bartr. & Marsh plantation with a combined irrigation and nutrient supply system designed to optimize biomass production. Sap flux density was measured continuously over four of the six growing season months, supplemented with periodic measurements of leaf gas exchange and water potential. Measurements of tree diameter and height were used to estimate leaf area and biomass production using allometric relations. Sap flux was converted to canopy conductance, and analyzed based on an empirical model to isolate the effects of water limitation. Actual and soil water-unlimited potential CO2 uptakes were estimated using a Canopy Conductance Constrained Carbon Assimilation (4C-A) scheme, which couples actual or potential canopy conductance with vertical gradients of light distribution, leaf-level conductance, maximum Rubisco capacity (Vcmax) and maximum electron transport (Jmax). Net primary production (NPP) was ~0.43 of gross primary production (GPP); when estimated for individual trees, this ratio was independent of tree size. Based on the same ratio, we found that current irrigation reduced growth by ~18 % compare to growth with no water limitation. To achieve this maximum growth, however, would require 70% more water for transpiration, and would reduce water use efficiency by 27 %, from 1.57 to 1.15 g stem wood C kg-1 water. Given the economic and social values of water, plantation managers appear to have optimized water use.
Item Open Access North American tree migration paced by fecundity and recruitment through contrasting mechanisms east and west(2020-04-24) Sharma, ShubhiGlobal forest diebacks are the beginnings of change that will be controlled by tree migration, which combines two uncertain processes, tree fecundity and recruitment. Knowledge of how, and where, tree migration can proceed is critical for adaptive management of forest resources and conservation efforts. The initial stage of seed production is erratic and poorly observed, with most studies limited to few trees, few species and few sites. At the next stage, tree recruitment is typically too sporadic to characterize at landscape scales. Neither seed production nor seedling recruitment have been quantified or linked to climate and habitat variables at scales needed to evaluate the changes happening now or to anticipate the diversity and structure of 21st century forests. As part of the masting inference and forecasting (MASTIF) project, we synthesized continental-scale data for tree fecundity gathered over the last half century and combined it with forest inventories to connect adult trees (basal area) to i) fecundity (seeds per basal area) and ii) recruitment (recruits per seed). A dynamic model fitted to >107 tree years of fecundity data provided estimates tree-by-year fecundity. A predictive distribution for the continent combines the fitted mode with 105 trees from Forest Inventory Analysis (FIA), Canadian National Forest Inventory(CNFI) and the National Ecological Observatory Network (NEON). Results show continent-wide migration as a balance between regional shifts in fecundity that can diverge from conditions that favour establishment, with clear differences in eastern and western North America. In moist eastern states, the geographic centers for fecundity are most commonly displaced south of tree basal area for the same species. This relationship would be expected if optimal conditions for seed production lie to the south of optimal conditions for growth and survival, despite potential benefits of warming poleward. In the dry west and north-central, fecundity is for some species displaced northwest of tree basal area, as would be expected if the high-rainfall north-west is predisposed to lead migration as the continent warms. The east-west contrast diminishes at the transition from fecundity to recruits per seed, which tends to be shifted north in both regions. The net continent-wide migration by contrasting east-west controls highlight interactions, with fecundity primed to lead tree migration in the west, and fecundity slowing progress in the east. The possibility of fecundity limitation offers one explanation for migration lag in species expected to track climate warming by expanding poleward.Item Open Access Predicting Forest Responses to Changing Environmental Conditions(2016) Berdanier, Aaron BairdForests change with changes in their environment based on the physiological responses of individual trees. These short-term reactions have cumulative impacts on long-term demographic performance. For a tree in a forest community, success depends on biomass growth to capture above- and belowground resources and reproductive output to establish future generations. Here we examine aspects of how forests respond to changes in moisture and light availability and how these responses are related to tree demography and physiology.
First we address the long-term pattern of tree decline before death and its connection with drought. Increasing drought stress and chronic morbidity could have pervasive impacts on forest composition in many regions. We use long-term, whole-stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre-drought growth rates died within 10 years. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought-induced morbidity varied among species and was correlated with species drought tolerance.
Next, we investigate differences among tree species in reproductive output relative to biomass growth with changes in light availability. Previous studies reach conflicting conclusions about the constraints on reproductive allocation relative to growth and how they vary through time, across species, and between environments. We test the hypothesis that canopy exposure to light, a critical resource, limits reproductive allocation by comparing long-term relationships between reproduction and growth for trees from 21 species in forests throughout the southeastern U.S. We found that species had divergent responses to light availability, with shade-intolerant species experiencing an alleviation of trade-offs between growth and reproduction at high light. Shade-tolerant species showed no changes in reproductive output across light environments.
Given that the above patterns depend on the maintenance of transpiration, we next developed an approach for predicting whole-tree water use from sap flux observations. Accurately scaling these observations to tree- or stand-levels requires accounting for variation in sap flux between wood types and with depth into the tree. We compared different models with sap flux data to test the hypotheses that radial sap flux profiles differ by wood type and tree size. We show that radial variation in sap flux is dependent on wood type but independent of tree size for a range of temperate trees. The best-fitting model predicted out-of-sample sap flux observations and independent estimates of sapwood area with small errors, suggesting robustness in new settings. We outline a method for predicting whole-tree water use with this model and include computer code for simple implementation in other studies.
Finally, we estimated tree water balances during drought with a statistical time-series analysis. Moisture limitation in forest stands comes predominantly from water use by the trees themselves, a drought-stand feedback. We show that drought impacts on tree fitness and forest composition can be predicted by tracking the moisture reservoir available to each tree in a mass balance. We apply this model to multiple seasonal droughts in a temperate forest with measurements of tree water use to demonstrate how species and size differences modulate moisture availability across landscapes. As trees deplete their soil moisture reservoir during droughts, a transpiration deficit develops, leading to reduced biomass growth and reproductive output.
This dissertation draws connections between the physiological condition of individual trees and their behavior in crowded, diverse, and continually-changing forest stands. The analyses take advantage of growing data sets on both the physiology and demography of trees as well as novel statistical techniques that allow us to link these observations to realistic quantitative models. The results can be used to scale up tree measurements to entire stands and address questions about the future composition of forests and the land’s balance of water and carbon.
Item Open Access Spaces of Order: An African Poetics of Space(2016) Edoro, Ainehi“Spaces of Order” argues that the African novel should be studied as a revolutionary form characterized by aesthetic innovations that are not comprehensible in terms of the novel’s European archive of forms. It does this by mapping an African spatial order that undermines the spatial problematic at the formal and ideological core of the novel—the split between a private, subjective interior, and an abstract, impersonal outside. The project opens with an examination of spatial fragmentation as figured in the “endless forest” of Amos Tutuola’s The Palmwine Drinkard (1952). The second chapter studies Chinua Achebe’s Things Fall Apart (1958) as a fictional world built around a peculiar category of space, the “evil forest,” which constitutes an African principle of order and modality of power. Chapter three returns to Tutuola via Ben Okri’s The Famished Road (1991) and shows how the dispersal of fragmentary spaces of exclusion and terror within the colonial African city helps us conceive of political imaginaries outside the nation and other forms of liberal political communities. The fourth chapter shows Nnedi Okorafor—in her 2014 science-fiction novel Lagoon—rewriting Things Fall Apart as an alien-encounter narrative in which Africa is center-stage of a planetary, multi-species drama. Spaces of Order is a study of the African novel as a new logic of world making altogether.
Item Open Access Tennessee Forest Carbon(2013-08-12) Alexander, Leslee T.In 2012, the California Air Resource Board initiated the first Cap-and-Trade (Cap) compliance market in the United States. It is a rigorous and iterative program that was launched under extreme scrutiny, with protocols that command high performance. So far, the Cap appears to be promoting new opportunities for greenhouse gas reductions and improving land conservation. Forest carbon is one of the four approved protocols under the Cap and projects can be developed throughout the United States. There is a projected shortfall in forest carbon offsets available to satisfy the growing demand. This could be a new incentive for land conservation throughout forested areas of the United States. The Southeastern United States contains a large amount of forested land in the hands of non-industrial private landowners, and appears to be a prime target for new forest carbon projects under the protocol. The region is also under immense development pressure, even though more agricultural land is turning back into forests than being developed. But ecosystem services are not well-understood throughout the United States, and resource conservation services in general are under-utilized in Tennessee. So the situation begged whether or not the forest carbon market could incentivize land conservation by non-industrial private landowners in Tennessee. A policy analysis was conducted to compare four alternatives that are in practice elsewhere in the United States with six separate criteria developed from the extensive research of existing literature. The Cap came out on top dues to its rigorous protocols, current success, and strict oversight. The compliance regime also assured a new level of assurance for the price of the carbon offsets. Project developers certainly have an opportunity in Tennessee, but the real challenge will be in identifying and developing relationships with willing landowners.Item Open Access The Effect of Warming on Phenology, Physiology, and Leaf Nitrogen in Six Deciduous Tree Species Over the Growing Season(2013) Stine, Anne WaltonThere is no consensus on climatic warming's effect on phenology, photosynthesis, and leaf nitrogen content in temperate deciduous tree species. A major question is whether or how these trees will utilize a longer growing season. Data on leaf photosynthetic rates, leaf nitrogen content, and leaf phenological status were collected weekly or biweekly in 2012 for Acer rubrum, Liquidambar styraciflua, Liriodendron tulipifera, Quercus alba, Quercus rubra, and Fraxinus americana at Duke Forest in Orange County, North Carolina. Seedlings were grown in open-topped chambers established in 2009 that were maintained at either ambient or 5 degrees Celsius above ambient temperatures. Half the chambers were shaded, half were under gap conditions.
Four of six species had advanced spring phenology with warming treatment, and four of six species delayed leaf senescence with warming treatment. Shade delayed spring phenology later more than earlier in the season, and gap conditions delayed fall phenology. Warming had an inconsistent effect on photosynthetic rate. Two species increased photosynthetic rate with chambered +5C conditions, another decreased photosynthetic rate in unchambered plots. Half of the species studied had no significant correlation between temperature and photosynthetic rate. The timing of photosynthetic decline was simultaneous within species across warming treatments, even in species which delayed visible senescence with warming.
There were major differences between years in terms of the effect of warming on nitrogen content and resorption. In 2011, percent leaf nitrogen was lower in warmed chambers, and nitrogen resorption efficiency was not correlated with warming treatment. In 2012, warmed chambers had higher nitrogen concentration and a wider range of nitrogen resorption values than ambient, and resorption efficiency was positively correlated with warming in 2012. It is possible that these differences between years are driven by differences in availability of soil moisture. 2011 was much drier during the senescent period than 2012. The direction and magnitude of warming on nitrogen was consistent within years, but varied by year.
Warming often causes visible change in the timing of phenology, but the timing of photosynthetic decline was unaffected and changes in nitrogen content and resorption were interannually variable. The benefits of delaying visible senescence are unclear. The effect of interactions between warming and soil moisture on leaf processes must be explored further. It is possible that the delay in visible phenology without a concurrent delay in leaf decline is due to a mismatch in environmental cues under a warmer climate. Because of the lack of obvious benefit to plant carbon uptake with warming, it is possible that there is no true extension of the growing season in fall.
Item Open Access Three Essays on Evaluating Forest Conservation Programs in Developing Countries(2021) He, WumengDeforestation and forest degradation in developing countries are leading causes of environmental problems such as soil erosion, biodiversity loss, and climate change. As a result, policies aimed at slowing down or reversing the trend of deforestation and forest degradation have attracted considerable attention. This dissertation consists of three essays on evaluating forest conservation programs in developing countries. Although the focus of each essay differs, they all use rigorous econometric methods to provide insights on impacts of historical forest conservation programs and assist stakeholders in modifying existing policies and making future ones more efficient and effective.
I begin by assessing the nutritional impact of payments for ecosystem services (PES) in the context of rural China (i.e., Chapter 2). PES is a special type of conditional cash transfer (CCT) in which the conditionality is explicitly attached with conservation practices. In this chapter I develop a stylized household-farm model to show that when households participate in a land-diversion PES program, they would settle for lower levels of food consumption if they lack market access. Exploiting panel data from the China Health and Nutrition Survey (CHNS), I use a triple difference (TD) model to examine the impact of China’s Sloping Land Conversion Program (SLCP), one of the largest PES programs in the world, on the nutrient intake of farming households. My findings suggest that the SLCP had a significant negative impact, though small, on calorie intake and this effect was likely driven by missing market in areas that implemented the SLCP. This essay demonstrates that land-diversion PES, which is a dual conservation and development tool, could affect food consumption and nutrition in ways very different from other conservation programs such as protected areas (PAs) as well as regular CCT programs that only aim for poverty reduction.
I then shift the focus from PES to PAs by implementing innovative evaluation methods to assess the effectiveness of mangrove protection in Southeast and South Asia (i.e., Chapter 3 and Chapter 4). Economists typically estimate the average treatment effect on the treated (ATT) when evaluating government programs. The welfare interpretation of the ATT can be ambiguous when program outcomes are measured in purely physical terms, as they often are in evaluations of environmental programs (e.g., avoided deforestation). In Chapter 3, my co-authors and I present an approach for inferring welfare impacts from physical outcomes when the ATT is estimated using propensity-score matching. We employ the discrete-choice Roy model of selection into treatment to show that the ex post net social value of a forest conservation program can be proxied as a weighted ATT, with the weights being utility measures derived from the propensity of being treated. We apply this new metric to mangrove forest conservation in Thailand during 1987–2000. Wefind that the Thai government’s conservation program protected approximately 30% of the social welfare that would have been lost if all the protected mangrove area had been deforested. This magnitude is very similar to the magnitude of a conventional ATT that measures avoided deforestation, but we show that the potential range of the welfare-based ATT extends from barely a quarter of the conventional physical measure to nearly twice as large as it.
While Chapter 3 adopts an indirect approach to infer the welfare impact of PAs, Chapter 4 exploits the same idea in a direct approach. In Chapter 4, my co-authors and I exploit rich data on carbon stock and land values in India toestimate and predict spatial heterogeneity in the benefit (i.e., carbon sequestration) and cost (i.e., forgone land value) of mangrove conservation. We combine this information with satellite-based data on India’s mangrove coverage in 1990– 2010 to construct a net land value, and then estimate the causal impact of PAs on the net land value. This new approach allows us to account for spatial heterogeneity in the net economic benefit of conservation. Our results show that incorporating the economics of conservation into evaluation could detect impact of PAs that would not be detected under the conventional approach that focuses only on avoided deforestation. Estimates from our heterogeneity treatment effect model suggest that the level and direction of PA’s impact is associated with the road proximity of mangrove sites and differs between the short run and the long run.
The three essays in my dissertation examine the heterogeneity in effects of forest conservation programs in one way or another. They highlight that the efficiency and effectiveness of conservation programs depend on local contexts. When designing and implementing future conservation programs, policymakers should assess local contexts and adjust program features accordingly.
Item Open Access Viability and improvement of constructive wildlife corridors in tropical forests, proposing a new method for evaluating corridors geospatially using MaxEnt(2022-12-14) Markus, CaitlinHabitat corridor ecology remains a new and developing field in wildlife and forest management. Little is known about how corridors statistically work or how they should be established and monitored. Stuart Pimm and his non-profit Saving Nature build constructive habitat corridors in tropical forests, and he now hopes that the data collected from these corridors can contribute to the growing knowledge in this field. In this study, I analyzed camera trap data from Saving Nature’s corridors in Colombia, Ecuador, and Brazil. Occupancy models were run to determine general corridor efficiency based on the species detected in the camera traps and species that were expected to appear based on environmental variables. I also attempted to propose maximum entropy models as an alternative way to achieve the same goal. Finally, least cost path corridor models were run to identify the areas animals are most likely to be found in, so that cameras can be repositioned to collect more data. Overall, all corridors were determined to be working adequately, but with room for improvement. MaxEntmodels show some potential as a method to evaluate corridor projects, but model refining and further research and development are required.