Pleasanton, CA, United States
Pleasanton, CA, United States

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Collins B.M.,U.S. Department of Agriculture | Kramer H.A.,U.S. Department of Agriculture | Kramer H.A.,University of California at Berkeley | Menning K.,University of California at Berkeley | And 5 more authors.
Forest Ecology and Management | Year: 2013

We built on previous work by performing a more in-depth examination of a completed landscape fuel treatment network. Our specific objectives were: (1) model hazardous fire potential with and without the treatment network, (2) project hazardous fire potential over several decades to assess fuel treatment network longevity, and (3) assess fuel treatment effectiveness and longevity over a range of two critical fire modeling inputs: surface fuel models and canopy base height. Modeling results demonstrate reductions in the hazardous fire potential across much of the treated landscape, relative to the untreated condition. These reductions persist throughout our modeling duration, 2010-2050. However, there was a strong effect of varying ingrowth levels, which were manipulated to generate different estimates of canopy base height over time, on hazardous fire potential over time. Under the low ingrowth level, which resulted in the highest predictions of canopy base height, hazardous fire potential steadily declined over time for the untreated landscape condition. The effect of varying fuel models in treated areas had much less impact on hazardous fire potential, indicating a robust treatment effect. Our results demonstrate a coordinated fuel treatment network that incorporates local knowledge of fire weather and likely fire behavior patterns can have a substantial impact on reducing hazardous fire potential. However, even with planned maintenance of the treatment network, hazard grows in untreated areas over time, resulting in an increase in overall fire hazard. This suggests additional treatments, including fire use, would be necessary to maintain low hazardous fire potential. © 2013.


Buchholz T.,University of Vermont | Buchholz T.,Spatial Informatics Group LLC | Da Silva I.,Strathmore University | Furtado J.,KTH Royal Institute of Technology
Proceedings of Institution of Civil Engineers: Energy | Year: 2012

Wood gasification systems have the potential to contribute to rural electrification in sub-Saharan Africa. This paper presents an operational and economic analysis of two wood-based gasification systems (250 kW and 10 kW) installed in Uganda in 2007. Both systems proved their potential to compete economically with diesel-generated electricity when operating close to the rated capacity. At an output of 150 kW running for approximately 12 h/day and 8 kW running for approximately 8 h/day, the systems produced electricity at USδ0.18 and 0.34/kWh, respectively. A stable electricity demand close to the rated capacity proved to be a challenge for both systems. Fuelwood costs accounted for approximately USδ0.03 kWh for both systems. Recovery of even a small fraction of the excess heat (22%) already resulted in substantial profitability gains for the 250 kW system. Results indicate that replicating successful wood gasification systems stipulates the integration of sustainable fuelwood supply and viable business models.


Saah D.,Spatial Informatics Group LLC | Patterson T.,Forest Service | Buchholz T.,Spatial Informatics Group LLC | Buchholz T.,University of Vermont | And 3 more authors.
Ecological Economics | Year: 2014

Integrated ecological and economic solutions are increasingly sought after by communities to provide basic energy needs such as home heating, transport, and electricity, while reducing drivers of and vulnerability to climate change. Small rural communities may require a coordinated approach to overcome the limitations of economies of scale. Low-carbon development strategies present potential for large payoffs at a household and community scale. Southeast Alaskan forests previously harvested for timber are currently re-growing and require thinning to maintain ecosystem service benefits such as wildlife habitat and hunting. Thinned material presents a potential biofuel source. However, without verification among decision alternatives, communities may not have the momentum, vision, or conviction to stimulate a shift to a new energy source. We present a network approach to evaluating multiple energy delivery pathways, and a calculation of carbon, energy, and dollar savings presented by each pathway. We quantify chain of production impacts; from the point of energy extraction and transport (upstream), through consumption and emission accounting (downstream). Our findings suggest substantial greenhouse gas emission savings of over 70% as well as heating cost savings for all bioenergy scenarios compared to fossil fuel scenarios. Outputs can facilitate dialog between land managers, planners, community members and decision-makers. © 2014 Elsevier B.V.


Lydersen J.M.,U.S. Department of Agriculture | Collins B.M.,U.S. Department of Agriculture | Ewell C.M.,U.S. Department of Agriculture | Reiner A.L.,U.S. Department of Agriculture | And 6 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2014

Inventories of greenhouse gas (GHG) emissions from wildfire provide essential information to the state of California, USA, and other governments that have enacted emission reductions. Wildfires can release a substantial amount of GHGs and other compounds to the atmosphere, so recent increases in fire activity may be increasing GHG emissions. Quantifying wildfire emissions however can be difficult due to inherent variability in fuel loads and consumption and a lack of field data of fuel consumption by wildfire. We compare a unique set of fuel data collected immediately before and after six wildfires in coniferous forests of California to fuel consumption predictions of the first-order fire effects model (FOFEM), based on two different available fuel characterizations. We found strong regional differences in the performance of different fuel characterizations, with FOFEM overestimating the fuel consumption to a greater extent in the Klamath Mountains than in the Sierra Nevada. Inaccurate fuel load inputs caused the largest differences between predicted and observed fuel consumption. Fuel classifications tended to overestimate duff load and underestimate litter load, leading to differences in predicted emissions for some pollutants. When considering total ground and surface fuels, modeled consumption was fairly accurate on average, although the range of error in estimates of plot level consumption was very large. These results highlight the importance of fuel load input to the accuracy of modeled fuel consumption and GHG emissions from wildfires in coniferous forests. ©2014. American Geophysical Union. All Rights Reserved.


Hurteau M.D.,Pennsylvania State University | Robards T.A.,Spatial Informatics Group LLC | Stevens D.,Northern Arizona University | Saah D.,Spatial Informatics Group LLC | And 3 more authors.
Forest Ecology and Management | Year: 2014

Quantifying the impacts of changing climatic conditions on forest growth is integral to estimating future forest carbon balance. We used a growth-and-yield model, modified for climate sensitivity, to quantify the effects of altered climate on mixed-conifer forest growth in the Lake Tahoe Basin, California. Estimates of forest growth and live tree carbon stocks were made for low and high emission scenarios using four downscaled general circulation model (GCM) projections. The climate scenarios were coupled with a range of commonly-used fuels reduction treatments to quantify the combined effects of these factors on live tree carbon stocks. We compared mid- (2020-2049) and late-21st (2070-2099) century carbon stock estimates with a baseline period of 1970-1999 using common input data across time periods. Recursive partitioning analysis indicates that GCM, forest composition, and simulation period most influence live tree carbon stock changes. Comparison with the late 20th century baseline period shows mixed carbon stock responses across scenarios. Growth varied by species, often with compensatory responses among dominant species that limited changes in total live tree carbon. The influence of wildfire mitigation treatments was relatively consistent with each GCM by emission scenario combination. Treatments that included prescribed fire had greater live tree carbon gains relative to baseline under the scenarios that had overall live tree carbon gains. However, across GCMs the influence of treatments varied considerably among GCM projections, indicating that further refinement of regional climate projections will be required to improve model estimates of fuel manipulations on forest carbon stocks. Additionally, had out simulations included the effects of projected climate changes on increasing wildfire probability, the effects of management treatments on carbon stocks may have been more pronounced because of the influence of treatment on fire severity. © 2013 Elsevier B.V.


Buchholz T.,Spatial Informatics Group LLC | Buchholz T.,University of Vermont | Hurteau M.D.,Pennsylvania State University | Gunn J.,Spatial Informatics Group | And 2 more authors.
GCB Bioenergy | Year: 2016

The potential greenhouse gas benefits of displacing fossil energy with biofuels are driving policy development in the absence of complete information. The potential carbon neutrality of forest biomass is a source of considerable scientific debate because of the complexity of dynamic forest ecosystems, varied feedstock types, and multiple energy production pathways. The lack of scientific consensus leaves decision makers struggling with contradicting technical advice. Analyzing previously published studies, our goal was to identify and prioritize those attributes of bioenergy greenhouse gas (GHG) emissions analysis that are most influential on length of carbon payback period. We investigated outcomes of 59 previously published forest biomass greenhouse gas emissions research studies published between 1991 and 2014. We identified attributes for each study and classified study cases by attributes. Using classification and regression tree analysis, we identified those attributes that are strong predictors of carbon payback period (e.g. the time required by the forest to recover through sequestration the carbon dioxide from biomass combusted for energy). The inclusion of wildfire dynamics proved to be the most influential in determining carbon payback period length compared to other factors such as feedstock type, baseline choice, and the incorporation of leakage calculations. Additionally, we demonstrate that evaluation criteria consistency is required to facilitate equitable comparison between projects. For carbon payback period calculations to provide operational insights to decision makers, future research should focus on creating common accounting principles for the most influential factors including temporal scale, natural disturbances, system boundaries, GHG emission metrics, and baselines. © 2016 John Wiley & Sons Ltd.


Chen Q.,University of Hawaii at Manoa | Vaglio Laurin G.,University of Rome Tor Vergata | Vaglio Laurin G.,CMCC Centro Mediterraneo per i Cambiamenti Climatici | Battles J.J.,University of California at Berkeley | And 2 more authors.
Remote Sensing of Environment | Year: 2012

The relationship between lidar-derived metrics and biomass could vary across different vegetation types. However, in many studies, there are usually a limited number of field plots associated with each vegetation type, making it difficult to fit reliable statistical models for each vegetation type. To address this problem, this study used mixed-effects modeling to integrate airborne lidar data and vegetation types derived from aerial photographs for biomass mapping over a forest site in the Sierra Nevada mountain range in California, USA. It was found that the incorporation of vegetation types via mixed-effects models can improve biomass estimation from sparse samples. Compared to the use of lidar data alone in multiplicative models, the mixed-effects models could increase the R 2 from 0.77 to 0.83 with RMSE (root mean square error) reduced by 10% (from 80.8 to 72.2Mg/ha) when the lidar metrics derived from all returns were used. It was also found that the SAF (Society of American Forest) cover types are as powerful as the NVC (National Vegetation Classification) alliance-level vegetation types in the mixed-effects modeling of biomass, implying that the future mapping of vegetation classes could focus on dominant species. This research can be extended to investigate the synergistic use of high spatial resolution satellite imagery, digital image classification, and airborne lidar data for more automatic mapping of vegetation types, biomass, and carbon. © 2012 Elsevier Inc.


Gunn J.S.,Initiative Capital | Saah D.S.,Spatial Informatics Group LLC | Fernholz K.,Dovetail | Ganz D.J.,Nature Conservancy
Forest Science | Year: 2011

We evaluated the implications of area regulation of harvest on eligible carbon under both the Voluntary Carbon Standard (VCS) and the Chicago Climate Exchange (CCX) for public forest lands in north central Minnesota (89,840 ha total). We used data from the carbon submodel of the US Forest Service Forest Vegetation Simulator (Lake States variant) to evaluate changes in forest carbon stocks under different management scenarios. Baseline harvest intensity was defined by considering the manager's short-range tactical plans and the distribution of harvests by cover type and intensity class then became the "business as usual" (BAU) for use in the calculation of eligible carbon under the VCS and CCX. Under VCS, the most effective way to increase carbon stocks while meeting other management objectives was to shift harvest practices to lower intensity entries and retain higher residual basal areas. The carbon stock change rates for each manager varied significantly under the BAU scenario and resulted in a mean annual net decrease. Because CCX carbon credit eligibility requires a net increase of carbon stocking from the base year, area regulation may create periods of time where there is no eligible carbon volume. An alternate management strategy that uses the area regulation method, reduces harvest intensity, and decreases overall acreage harvested was able to provide higher postharvest carbon stocks versus the BAU scenario under VCS. © 2011 by the Society of American Foresters.


Alix-Garcia J.,University of Wisconsin - Madison | Bartlett A.,University of San Francisco | Saah D.,University of San Francisco | Saah D.,Spatial Informatics Group LLC.
Journal of Economic Geography | Year: 2013

This article examines spatial changes in production in the presence of civil conflict. A simple model predicts land abandonment which increases with proximity to insecurity, and welfare losses to rural land owners. The model also predicts that food aid can buffer the land-use change impacts generated by war. Spatial data on land use, violent events, displaced populations and aid from 2001-2007 corroborate these predictions in Darfur, Sudan. The results suggest large disruptions in short-term production, with abandonment of agriculture far from the cities, and intensification of land use on their periphery. © The Author (2013). Published by Oxford University Press. All rights reserved.


York R.A.,University of California at Berkeley | Battles J.J.,University of California at Berkeley | Wenk R.C.,University of California at Berkeley | Saah D.,Spatial Informatics Group LLC
Forestry | Year: 2012

Multi-aged stands in a mixed conifer forest of California were treated to mitigate harvest-related increases in surface fuels and to prepare sites for natural regeneration of Pinus species. The study was designed to (1) assess effectiveness of small gap fuel treatments (piling and burning in 0.04 ha gaps) on surface fuel and modelled fire behaviour; (2) test the effect of substrate quality on germination of Pinus species; (3) measure the influence of gap creation on light availability and stand-level light heterogeneity. While the fuel treatment only covered 10 per cent of stand area, it was effective in avoiding increases in stand-level surface fuel following harvests. Fire behaviour was predicted to be moderate following the treatments. The harvest coupled with the gap surface fuel treatments did not change predicted fire behaviour compared with the pretreatment stands. There was a significant but variable increase in germination of Pinus ponderosa seed when sowed on ash substrates compared with bare soil. No substrate effect was detected for Pinus lambertiana. The 0.04-ha gaps created distinct pockets of light and greatly increased stand-level light heterogeneity. This gap-based approach to regenerating multi-aged stands coupled with small-scale fuel treatments is promising for reducing fire hazard and regenerating shade-intolerant species. © Institute of Chartered Foresters, 2011. All rights reserved.

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