Michael Stambaugh
University of Missouri Columbia, Forestry Department, Faculty Member
- Associate Professoredit
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Climate has a primary influence on the occurrence and rate of combustion in ecosystems with carbon-based fuels such as forests and grasslands. Society will be confronted with the effects of climate change on fire in future forests. There... more
Climate has a primary influence on the occurrence and rate of combustion in ecosystems with carbon-based fuels such as forests and grasslands. Society will be confronted with the effects of climate change on fire in future forests. There are, however, few quantitative appraisals of how climate will affect wildland fire in the United States. We demonstrated a method for estimating changes in fire probability based on future climate simulations of temperature and precipitation. The probability of a fire occurring in a particular climate was extracted from the Physical Chemistry Fire Frequency Model (PC2FM) and represented the rate of change in fire due to climate. Climate output data from two global climate models (GCMs) were applied to the PC2FM to estimate changes in fire probability. We calculated change in fire frequency and probabilities from the difference between current and future climates and mapped climate-forced percentage change in fire probability under each GCM for the n...
The Eck Memorial Natural Area is the largest old-growth shortleaf pine ( Pinus echinata Mill.) forest in Missouri, USA. The objectives of this study were to characterize vegetation, examine historic and contemporary disturbances, and... more
The Eck Memorial Natural Area is the largest old-growth shortleaf pine ( Pinus echinata Mill.) forest in Missouri, USA. The objectives of this study were to characterize vegetation, examine historic and contemporary disturbances, and describe potential vegetation changes for this natural area. Shortleaf pine was the most important tree species at the site and had the highest single species basal area (8.1 m 2 ha -1 ). Old-growth shortleaf pines averaged 230 years in age and ranged from approximately 120 to 325 years. Canopy gaps (< 6 years old) constituted 4% of the total area, and average expanded and actual gap sizes were 421 m2 and 210 m2, respectively. The uneven-aged structure of shortleaf pine suggests that the species has continually regenerated and recruited to the overstory despite the relatively low fire frequency of 44 years. Results of this study suggest that although canopy gaps are important in allowing understory trees to recruit to overstory positions, they are no...
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Background Vegetation of the Cumberland Plateau (USA) has undergone dramatic transitions since the last glaciation and particularly since the onset of widespread logging and twentieth century fire exclusion. Shortleaf pine (Pinus echinata... more
Background Vegetation of the Cumberland Plateau (USA) has undergone dramatic transitions since the last glaciation and particularly since the onset of widespread logging and twentieth century fire exclusion. Shortleaf pine (Pinus echinata Mill.), one of the most fire-dependent conifers in the US, occurs throughout the Cumberland Plateau, but its abundance has declined dramatically since Euro-American settlement and continues to decline. To better understand the historical ecology of fire within the natural range of shortleaf pine, we reconstructed fire regimes at three new sites throughout the central and southern Cumberland Plateau region based on fire scars on shortleaf pine trees. Results Fire event chronologies extended back to the seventeenth century and revealed historical fire regimes that were frequent and dominated by dormant-season and low-severity events. Fires occurred on average every 4.4 to 5.3 years at the study sites before widespread Euro-American settlement, and we...
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Research Interests: Geography, Fire Ecology, Ecology, Forest Ecology, Wildlife, and 4 moreEcosystem, Woodland, Ecotone, and Fire regime
An amendment to this paper has been published and can be accessed via the original article.
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Understanding the effects of fire on advance regeneration of oak (Quercus L.) species and their competitors is an important step in determining the role of prescribed fire in regenerating and restoring upland oak ecosystems. Our study... more
Understanding the effects of fire on advance regeneration of oak (Quercus L.) species and their competitors is an important step in determining the role of prescribed fire in regenerating and restoring upland oak ecosystems. Our study aimed to understand how dormant-season prescribed fire affects advance regeneration of chinkapin oak (Quercus muehlenbergii Engelm.), black oak (Quercus velutina Lam.), and their major competitors at sites targeted for woodland restoration and management. We analyzed relationships between stem size and survival probability; determined the effect of fire temperature on survival probability; and compared how mortality, sprouting, and survival differed among species. For chinkapin oak, black oak, and bitternut hickory (Carya cordiformis (Wangenh.) K. Koch), mortality was low and rate of sprouting was high after shoot dieback. Initial basal diameter was significantly related to survival probability after one fire for all species except chinkapin oak and bl...
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Fire management is increasingly used to manage forest stand structure and dynamics. Relatively intense fires can injure the tree stem and induce fire scar formation, affecting subsequent tree growth and wood quality. Here, we consider the... more
Fire management is increasingly used to manage forest stand structure and dynamics. Relatively intense fires can injure the tree stem and induce fire scar formation, affecting subsequent tree growth and wood quality. Here, we consider the physiological effects of fire scarring in white oak. Potential hydraulic conductivity, estimated from the mean vessel area and vessel number, was determined for growth rings formed before, during, and after the year of injury. We measured vessel anatomy using the ROXAS image analysis tool on the cross-sections of 14 white oaks of various ages with fire scars originating in different years through the late 19th and early 20th century. We found that the mean vessel area and potential hydraulic conductivity were significantly reduced for the year of and the year immediately following fire injury. After this two-year period, mean vessel area returned to levels present in wood formed prior to the injury. Age when scarred, radius from the pith when scarr...
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Rising atmospheric [CO2 ], ca , is expected to affect stomatal regulation of leaf gas-exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water and nutrient cycling of forests. Researchers have proposed various... more
Rising atmospheric [CO2 ], ca , is expected to affect stomatal regulation of leaf gas-exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water and nutrient cycling of forests. Researchers have proposed various strategies for stomatal regulation of leaf gas-exchange that include maintaining a constant leaf internal [CO2 ], ci , a constant drawdown in CO2 (ca - ci ), and a constant ci /ca . These strategies can result in drastically different consequences for leaf gas-exchange. The accuracy of Earth systems models depends in part on assumptions about generalizable patterns in leaf gas-exchange responses to varying ca . The concept of optimal stomatal behavior, exemplified by woody plants shifting along a continuum of these strategies, provides a unifying framework for understanding leaf gas-exchange responses to ca . To assess leaf gas-exchange regulation strategies, we analyzed patterns in ci inferred from studies reporting C stable isotope ratios (δ(13) ...
Research Interests: Paleoclimatology, Carbon Dioxide, Photosynthesis, Biology, Carbon Cycle, and 15 moreGlobal Change Biology, Medicine, Biological Sciences, Plant Physiology, Environmental Sciences, Carbon Isotopes, Stable Isotopes and Palaeoenvironment, Trees, Gymnosperms, Carbon Isotope, Angiosperms, Woody Plants, Plant Leaves, Stomatal Conductance, and Leaf Gas Exchange
Tree-ring dated fire scars provide long-term records of fire frequency, giving land managers valuable baseline information about the fire regimes that existed prior to Euro-American settlement. However, for the East, fire history data... more
Tree-ring dated fire scars provide long-term records of fire frequency, giving land managers valuable baseline information about the fire regimes that existed prior to Euro-American settlement. However, for the East, fire history data prove difficult to acquire because the generally moister climate of the region causes rapid decay of wood. In an endeavor to fill data gaps, the research team collected fire scar data in the states of Alabama, Louisiana, Kentucky, Tennessee, Iowa, Wisconsin, and Michigan. The second part of the project used this newly collected fire history data combined with previously collected records to parameterize and calibrate a continental fire frequency model based on climate. The purpose of this model is to aid in understanding how climate constrains and drives fire regimes across the U.S. Large temporal and spatial gaps exist in our knowledge of continental fire regimes, but the new Physical Chemistry Fire Frequency Model (PC2FM) can assign a fire frequency ...
During the last deglaciation temperatures over midcontinental North America warmed dramatically through the Bølling-Allerød, underwent a cool period associated with the Younger-Dryas and then reverted to warmer, near modern temperatures... more
During the last deglaciation temperatures over midcontinental North America warmed dramatically through the Bølling-Allerød, underwent a cool period associated with the Younger-Dryas and then reverted to warmer, near modern temperatures during the early Holocene. However, paleo proxy records of the hydroclimate of this period have presented divergent evidence. We reconstruct summer relative humidity (RH) across the last deglacial period using a mechanistic model of cellulose and leaf water δ18O and δD combined with a pollen-based temperature proxy to interpret stable isotopes of sub-fossil wood. Midcontinental RH was similar to modern conditions during the Last Glacial Maximum, progressively increased during the Bølling-Allerød, peaked during the Younger-Dryas, and declined sharply during the early Holocene. This RH record suggests deglacial summers were cooler and characterized by greater advection of moisture-laden air-masses from the Gulf of Mexico and subsequent entrainment over...
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Dendroecology is the science that dates tree rings to their exact calendar year of formation to study processes that influence forest ecology (e.g., Speer 2010 [1], Amoroso et al., 2017 [2]). Reconstruction of past fire regimes is a core... more
Dendroecology is the science that dates tree rings to their exact calendar year of formation to study processes that influence forest ecology (e.g., Speer 2010 [1], Amoroso et al., 2017 [2]). Reconstruction of past fire regimes is a core application of dendroecology, linking fire history to population dynamics and climate effects on tree growth and survivorship. Since the early 20th century when dendrochronologists recognized that tree rings retained fire scars (e.g., Figure 1), and hence a record of past fires, they have conducted studies worldwide to reconstruct [2] the historical range and variability of fire regimes (e.g., frequency, severity, seasonality, spatial extent), [3] the influence of fire regimes on forest structure
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To test tree growth sensitivity to temperature under different ambient CO2 concentrations, we determined stem radial growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern... more
To test tree growth sensitivity to temperature under different ambient CO2 concentrations, we determined stem radial growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatial variation in temperature across the modern species distributional range. Paleo oaks were sampled from Northern Missouri, USA and compared to a pollen-based, high-resolution paleo temperature reconstruction from Northern Illinois, USA. Growth data were from 53 paleo bur oak log cross sections collected in Missouri. These oaks were preserved in river and stream sediments and were radiocarbon-dated to a period of rapid climate change during the last deglaciation (10.5 and 13.3 cal kyr BP). Growth data from modern bur oaks were obtained from increment core collections paired with USDA Forest Service Forest Inventory and Analysis data collected across the Great Plains, Midwest, and Upper Great Lakes regions. For m...
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Rising atmospheric [CO2], ca, is expected to affect stomatal regulation of leaf gas- exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water and nutrient cycling of forests. Researchers have proposed various... more
Rising atmospheric [CO2], ca, is expected to affect stomatal regulation of leaf gas- exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water and nutrient cycling of forests. Researchers have proposed various strategies for stomatal regulation of leaf gas-exchange that include maintaining a constant leaf internal [CO2], ci, a constant drawdown in CO2 (ca - ci), and a constant ci/ca. These strategies can result in drastically different consequences for leaf gas-exchange. The accuracy of Earth systems models depends in part on assumptions about generalizable patterns in leaf gas-exchange responses to varying ca. The concept of optimal stomatal behavior, exemplified by woody plants shifting along a continuum of these strategies, provides a unifying framework for understanding leaf gas-exchange responses to ca. To assess leaf gas-exchange regulation strategies, we analyzed patterns in ci inferred from studies reporting C stable isotope ratios (δ13C) or photosynthetic discrimination (∆) in woody angiosperms and gymnosperms that grew across a range of ca spanning at least 100 ppm. Our results suggest that much of the ca-induced changes in ci/ca occurred across ca spanning 200 to 400 ppm. These patterns imply that ca - ci will eventually approach a constant level at high ca because assimilation rates will reach a maximum and stomatal conductance of each species should be constrained to some minimum level. These analyses are not consistent with canalization towards any single strategy, particularly maintaining a constant ci. Rather, the results are consistent with the existence of a broadly conserved pattern of stomatal optimization in woody angiosperms and gymnosperms. This results in trees being profligate water users at low ca, when additional water loss is small for each unit of C gain, and increasingly water- conservative at high ca, when photosystems are saturated and water loss is large for each unit C gain.
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Page 1. FIRE RISK ASSESSMENT OF THE WESTERN PORTION OF THE CENTRAL HARDWOODS FOREST REGION A Dissertation presented to the Faculty of the Graduate School University of Missouri-Columbia In Partial Fulfillment of the Requirements for the... more
Page 1. FIRE RISK ASSESSMENT OF THE WESTERN PORTION OF THE CENTRAL HARDWOODS FOREST REGION A Dissertation presented to the Faculty of the Graduate School University of Missouri-Columbia In Partial Fulfillment of the Requirements for the Degree ...
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Shortleaf pine (Pinus echinata) is one of the most of important conifers in the Central Hardwood region both ecologically and economically. In the Ozark Highlands of Missouri and Arkansas, the presence of shortleaf pine provides an... more
Shortleaf pine (Pinus echinata) is one of the most of important conifers in the Central Hardwood region both ecologically and economically. In the Ozark Highlands of Missouri and Arkansas, the presence of shortleaf pine provides an important conifer component in otherwise hardwood dominated forest types. Regional forest health issues such as oak decline and red oak borer as well as