15 research outputs found
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Characterization of the woody biomass feedstock potential resulting from California's drought.
Regional tree die-off events generate large quantities of standing dead wood, raising concern over catastrophic wildfire and other hazards. Governmental responses to tree die-off have often focused on incentivizing biomass energy production that utilizes standing dead trees removed for safety concerns. However, the full distribution of potential woody bioenergy feedstock after tree die-off has not been evaluated due to the complexities of surveying and precisely measuring large forested areas. In this paper, we present a novel method for estimating standing dead biomass at a fine spatial resolution that combines aerial survey data with forest structure maps. Using this method, we quantify biomass generated by the unprecedented tree die-off that occurred in California following a 4-year drought and widespread pest outbreaks. The results are used to estimate feasibly recoverable feedstock for energy production. We find that approximately 95.1 million bone-dry tons (BDT) of dead biomass resulted from 2012-2017 mortality, with a lower bound of 26.2 million BDT. In other words, of the aboveground live tree biomass in 2012, ~1.3-4.8% died by 2017. Of the standing dead biomass, 29% meets minimum constraints for potential cost-effective bioenergy feedstock. This proportion drops to as low as 15% in the most affected areas due to terrain slope, wilderness status, and other factors, highlighting the need to complement disposal via biomass energy with other strategies to mitigate the risks of the tree mortality crisis, which is likely to only become more severe over time due to climate change
Characterization of the woody biomass feedstock potential resulting from California's drought.
Recommended from our members
Post-fire tree regeneration in an altered disturbance regime: community dynamics and interactions with land management
Fire has long shaped forests across the globe. Anthropogenic forces are reshaping fire regimes, leading to unprecedented forest conditions and unknown long-term consequences. Land management can help mitigate undesired effects of altered fire regimes, but effective management requires information about tree species’ responses to disturbances both historical and modern. In my dissertation, I add to a body of literature examining how novel fire patterns affect tree regeneration and whether forest management strategies can mitigate any undesired effects. I focus on mixed-conifer forests of the Sierra Nevada, where logging, fire exclusion, and climate change have shifted the fire regime from frequent, heterogenous fire to infrequent fire with greater high severity. The tree species that have long comprised these forests are not well adapted to regenerate in large, homogenous fire patches. My dissertation investigates three main questions in three chapters: 1) Can forest management prevent large fire patches and promote post-fire recovery? 2) Will the novel fire regime shift overall species composition toward firs and away from pines? 3) What is the role of post-fire shrub dynamics in determining ecological succession in novel-type fire patches? In Chapter 1, I show that strategically placed fuel reduction treatments effectively reduced fire severity and promoted recovery when burned in a wildfire. In Chapter 2, I explore the idea that the shifting fire regime may lead to regional fir enrichment. I focus on plant interactions following severe wildfire and show that shrub competition affects ponderosa pine more strongly than it affects white fir. However, simulation modeling results in Chapter 3 show that, on net, shrub neighborhood dynamics do not produce an ecological filter favoring firs, though patterns are sensitive to shrub species. These three chapters together illustrate the importance of forest patch dynamics for wildfire resistance and recovery
Recommended from our members
Post-fire tree regeneration in an altered disturbance regime: community dynamics and interactions with land management
Fire has long shaped forests across the globe. Anthropogenic forces are reshaping fire regimes, leading to unprecedented forest conditions and unknown long-term consequences. Land management can help mitigate undesired effects of altered fire regimes, but effective management requires information about tree species’ responses to disturbances both historical and modern. In my dissertation, I add to a body of literature examining how novel fire patterns affect tree regeneration and whether forest management strategies can mitigate any undesired effects. I focus on mixed-conifer forests of the Sierra Nevada, where logging, fire exclusion, and climate change have shifted the fire regime from frequent, heterogenous fire to infrequent fire with greater high severity. The tree species that have long comprised these forests are not well adapted to regenerate in large, homogenous fire patches. My dissertation investigates three main questions in three chapters: 1) Can forest management prevent large fire patches and promote post-fire recovery? 2) Will the novel fire regime shift overall species composition toward firs and away from pines? 3) What is the role of post-fire shrub dynamics in determining ecological succession in novel-type fire patches? In Chapter 1, I show that strategically placed fuel reduction treatments effectively reduced fire severity and promoted recovery when burned in a wildfire. In Chapter 2, I explore the idea that the shifting fire regime may lead to regional fir enrichment. I focus on plant interactions following severe wildfire and show that shrub competition affects ponderosa pine more strongly than it affects white fir. However, simulation modeling results in Chapter 3 show that, on net, shrub neighborhood dynamics do not produce an ecological filter favoring firs, though patterns are sensitive to shrub species. These three chapters together illustrate the importance of forest patch dynamics for wildfire resistance and recovery
Native Bees Associated with Isolated Aspen Stands in Pacific Northwest Bunchgrass Prairie
Recommended from our members
Characterization of the woody biomass feedstock potential resulting from California's drought.
Regional tree die-off events generate large quantities of standing dead wood, raising concern over catastrophic wildfire and other hazards. Governmental responses to tree die-off have often focused on incentivizing biomass energy production that utilizes standing dead trees removed for safety concerns. However, the full distribution of potential woody bioenergy feedstock after tree die-off has not been evaluated due to the complexities of surveying and precisely measuring large forested areas. In this paper, we present a novel method for estimating standing dead biomass at a fine spatial resolution that combines aerial survey data with forest structure maps. Using this method, we quantify biomass generated by the unprecedented tree die-off that occurred in California following a 4-year drought and widespread pest outbreaks. The results are used to estimate feasibly recoverable feedstock for energy production. We find that approximately 95.1 million bone-dry tons (BDT) of dead biomass resulted from 2012-2017 mortality, with a lower bound of 26.2 million BDT. In other words, of the aboveground live tree biomass in 2012, ~1.3-4.8% died by 2017. Of the standing dead biomass, 29% meets minimum constraints for potential cost-effective bioenergy feedstock. This proportion drops to as low as 15% in the most affected areas due to terrain slope, wilderness status, and other factors, highlighting the need to complement disposal via biomass energy with other strategies to mitigate the risks of the tree mortality crisis, which is likely to only become more severe over time due to climate change
Data from: The fate of phosphorus fertilizer in Amazon soya bean fields
Fertilizer-intensive soya bean agriculture has recently expanded in southeastern AmazĂ´nia, and whereas intensive fertilizer use in the temperate zone has led to widespread eutrophication of freshwater ecosystems, the effects in tropical systems are less well understood. We examined the fate of fertilizer P by comparing P forms and budgets across a chronosequence of soya bean fields (converted to soya beans between 2003 and 2008) and forests on an 800 km2 soya bean farm in Mato Grosso, Brazil. Soya bean fields were fertilized with 50 kg P ha-1 yr-1 (30 kg P ha-1 y-1 above what is removed in crops). We used modified Hedley fractionation to quantify soil P pools and found increases in less-plant-available inorganic pools and decreases in organic pools in agricultural soils compared with forest. Fertilizer P did not move below 20 cm. Measurements of P sorption capacity suggest that while fertilizer inputs quench close to half of the sorption capacity of fast-reacting pools, most added P is bound in more slowly reacting pools. Our data suggest that this agricultural system currently has a low risk of P losses to waterways and that long time-scales are required to reach critical soil thresholds that would allow continued high yields with reduced fertilizer inputs