Dr. James H. Speer is a Professor of Geography and Geology at Indiana State University. He received his bachelors and master’s degree from the University of Arizona in Geosciences and his PhD from the University of Tennessee in Geography. He is a biogeographer who uses tree-ring to reconstruct environmental variables such as fire history, insect outbreaks, and climate. Through his years of studying environmental history he has realized that humans are operating outside the natural range of variability for most natural systems which has motivated him to give back to society by being a champion for sustainability at Indiana State University and in the Wabash Valley. Dr. Speer was the lead PI and is a Senior Scholar for the Institute for Community Sustainability which was established in February 2012. He is the President for Our Green Valley Alliance for Sustainability, chairs the steering committee for the Terre Foods Cooperative Market, on the Tree Advisory Board for ISU, is the chair of the President’s Council on Sustainability, is a past president of the Geography Educator’s Network of Indiana, and is a past president of the Tree-Ring Society. He lives in Terre Haute with his wife and two sons. Supervisors: Dr. Thomas W. Swetnam and Dr. Kenneth H. Orvis
ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation ... more ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation records across Nepal are too short to place the recent drought in a longer context to understand the full range of natural variability in the climate system. In the present study we have collected tree core samples of Tsuga dumosa from two sites, Chhetti and Ranghadi, in the Api Nampa Conservation Area of the western Nepal Himalayas to understand drought variation for the past three centuries. We have developed a 357-year (AD 1657–2013) tree-ring chronology. The tree growth-climate response analysis revealed a stronger positive correlation with spring (March-May) standardized precipitation evapotranspiration index (SPEI01) (r = 0.523, p < 0.01) than precipitation (r = 0.459, p < 0.01), self-calibrating Palmer drought severity index (scPDSI) (r = 0.250, p < 0.01), or temperature (r = -0.486, p < 0.01). Stronger positive correlation with SPEI01 indicates moisture availability is the limiting factor for the growth of this species on these sites. Based on this growth-climate response we reconstructed spring SPEI from AD 1707 to 2013 for the region. The reconstruction showed several dry and wet episodes indicating no persistent climate trend within the past three centuries. The current drought is one of the four most severe in our 307-year record.
International Journal of Sustainability in Higher Education, 2020
Purpose The purpose of this study was to explore college students’ understanding of sustainabilit... more Purpose The purpose of this study was to explore college students’ understanding of sustainability and, specifically, the extent to which students see social justice as being integral to sustainability. Design/methodology/approach Between fall 2015 and 2017, an online survey study was deployed to students at a Midwestern University in the USA to assess attitudes and concerns about environmental issues and awareness of the university’s activities related to these issues. This analysis included ten assessment items from a larger study, of which 1,929 participants were included in the final sample. A chi-square goodness-of-fit and variable cluster analysis were performed on the included items. Findings Items such as “recycling,” “economic viability” and “fair treatment of all” were identified as integral to the concept of sustainability, while items such as “growing organic vegetables” and “reducing meat consumption” had high levels of “not applicable” and “don’t know” responses, with ...
Ahstrnct: The climatic response of trees that occupy closed canopy forests in the eastern United ... more Ahstrnct: The climatic response of trees that occupy closed canopy forests in the eastern United States (US) is important to understanding the possible trajectory these forests may lake in response to a warming climate. Ollr study examined trce
The creation of chronologies from intra-annual features in tree rings is increasingly utilized in... more The creation of chronologies from intra-annual features in tree rings is increasingly utilized in dendrochronology to create season-specific climate histories, among other applications. A conifer latewood-width network has recently been developed for the southwestern United States, but considerable uncertainty remains in understanding site and species differences in signal strength and sample depth requirements. As part of the 22nd annual North American Dendroecological Fieldweek, the first Pinus ponderosa earlywood-width (EW) and latewood-width (LW) chronologies were developed for the Jemez Mountains in northern New Mexico. The aim was to extend an existing total ring-width (TW) chronology and to assess the potential for creating long LW chronologies. Analysis of chronology signal strength suggests that large sample size requirements remain a considerable hurdle for creating P. ponderosa LW chronologies longer than 400 years. At the Cat Mesa site, twenty-three sample trees were req...
Abstract Coarse woody debris (CWD; i.e. downed limbs and boles) serves numerous ecosystem functio... more Abstract Coarse woody debris (CWD; i.e. downed limbs and boles) serves numerous ecosystem functions, which vary according to the degree of decay. CWD decay is often described using five categories based on readily observed physical characteristics ranging from freshly fallen (Class I) to advanced decay with little structural integrity (Class V). Though useful in categorizing downed wood in a forest, these categories do not necessarily provide information about time since death or the decay process. Dendrochronology can be used to assign death dates to CWD and begin to provide a temporal description of the decay process. We used standard dendrochronological techniques to determine the death dates of 94 CWD samples from five common hardwood taxa in southern Indiana. Across taxa, the time since death of Class I (1.4 ± 1.7 years; mean ± SD; least decayed class) was significantly shorter than Class II (5.2 ± 3.6 years), which was shorter than the more decayed classes (Class III: 11.5 ± 4.9, and Class IV: 11.2 ± 5.6 years). Within this general trend, time since death within a decay class varied greatly among taxa. Combining dendrochronology techniques with visual decay characteristics can improve our understanding of CWD's role and provide a more precise timeline for biomass and nutrient turnover within forested systems.
The original version of this Article contained an error in the Data Availability section, which i... more The original version of this Article contained an error in the Data Availability section, which incorrectly read 'All data will be freely available via https://www.ams.ethz.ch/research.html .' The correct version states ' http://www.ams.ethz.ch/research/published-data.html ' in place of ' https://www.ams.ethz.ch/research.html '. This has been corrected in both the PDF and HTML versions of the Article.
Though tree-ring chronologies are annually resolved, their dating has never been independently va... more Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the C content in 484 individual tree rings formed in the periods 770-780 and 990-1000 CE. Distinct C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved C...
This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The... more This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (< 5 cm DBH) trees. We further presented Root-to-Shoot Ratios of uprooted trees. Data on the importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection...
Although there are other scientific means of dating climatic and environmental events, dendrochro... more Although there are other scientific means of dating climatic and environmental events, dendrochronology provides the most reliable of all palaeorecords. This comprehensive text addresses all of the subjects that a reader who is new to the field will need to know and will be a welcome reference for practitioners at all levels. It includes a history of the discipline, biological and ecological background, principles of the field, basic scientific information on the structure and growth of trees, the complete range of dendrochronology methods, and a full description of each of the relevant subdisciplines.
The Bridger Antelope Trap is an archaeological site listed on the National Register of Historic p... more The Bridger Antelope Trap is an archaeological site listed on the National Register of Historic places in southwestern Wyoming that was used by American Indians while hunting antelope as described by early settlers. The trap is a large corral that was constructed from juniper (Juniperus osteosperma) and covers approximately 26 acres (110,000 m2). This study's goal is to demonstrate the trap's age of construction, its use and maintenance, and its time depth based on tree rings. As part of dating the archaeological wood, we also built a living chronology from the surrounding trees. Over the course of two field seasons, we collected wood samples from living juniper trees, ax-cut stumps, and the trap itself. The juniper wood was difficult and contained numerous micro and locally absent rings, but we successfully built a living chronology by crossdating with skeleton plots. The wood from the trap was largely eroded and weathered, and samples taken with an archaeological drill wer...
The Dendrochronology and Biogeography Laboratory at Indiana State University was established in 2... more The Dendrochronology and Biogeography Laboratory at Indiana State University was established in 2001. In the last 13 years, we have had 3 PhD, 12 Masters, and 6 undergraduate students work on theses that involved dendrochronology. This work has been completed under the supervision of Dr. Jim Speer and Dr. Karla Hansen-Speer who worked as a lab manager at the lab for three years. Most of this work focuses on disturbance ecology, but we have also branched out to archaeology and climate response. The focus of this presentation will be our three most recent research projects which examined pandora moth outbreaks across their entire range using chronologies from the International Tree-Ring Databank, developing a chronology in a new tree species to dendrochronology (Juniperus osteosperma) to date the Bridger Antelope Trap archaeological site in Wyoming, and examining the effect of fire on sixteen arboreal species in the Eastern Deciduous Forest. Throughout his career as a dendrochronologi...
ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation ... more ABSTRACT Western Nepal has experienced a severe drought in the past two decades, but observation records across Nepal are too short to place the recent drought in a longer context to understand the full range of natural variability in the climate system. In the present study we have collected tree core samples of Tsuga dumosa from two sites, Chhetti and Ranghadi, in the Api Nampa Conservation Area of the western Nepal Himalayas to understand drought variation for the past three centuries. We have developed a 357-year (AD 1657–2013) tree-ring chronology. The tree growth-climate response analysis revealed a stronger positive correlation with spring (March-May) standardized precipitation evapotranspiration index (SPEI01) (r = 0.523, p < 0.01) than precipitation (r = 0.459, p < 0.01), self-calibrating Palmer drought severity index (scPDSI) (r = 0.250, p < 0.01), or temperature (r = -0.486, p < 0.01). Stronger positive correlation with SPEI01 indicates moisture availability is the limiting factor for the growth of this species on these sites. Based on this growth-climate response we reconstructed spring SPEI from AD 1707 to 2013 for the region. The reconstruction showed several dry and wet episodes indicating no persistent climate trend within the past three centuries. The current drought is one of the four most severe in our 307-year record.
International Journal of Sustainability in Higher Education, 2020
Purpose The purpose of this study was to explore college students’ understanding of sustainabilit... more Purpose The purpose of this study was to explore college students’ understanding of sustainability and, specifically, the extent to which students see social justice as being integral to sustainability. Design/methodology/approach Between fall 2015 and 2017, an online survey study was deployed to students at a Midwestern University in the USA to assess attitudes and concerns about environmental issues and awareness of the university’s activities related to these issues. This analysis included ten assessment items from a larger study, of which 1,929 participants were included in the final sample. A chi-square goodness-of-fit and variable cluster analysis were performed on the included items. Findings Items such as “recycling,” “economic viability” and “fair treatment of all” were identified as integral to the concept of sustainability, while items such as “growing organic vegetables” and “reducing meat consumption” had high levels of “not applicable” and “don’t know” responses, with ...
Ahstrnct: The climatic response of trees that occupy closed canopy forests in the eastern United ... more Ahstrnct: The climatic response of trees that occupy closed canopy forests in the eastern United States (US) is important to understanding the possible trajectory these forests may lake in response to a warming climate. Ollr study examined trce
The creation of chronologies from intra-annual features in tree rings is increasingly utilized in... more The creation of chronologies from intra-annual features in tree rings is increasingly utilized in dendrochronology to create season-specific climate histories, among other applications. A conifer latewood-width network has recently been developed for the southwestern United States, but considerable uncertainty remains in understanding site and species differences in signal strength and sample depth requirements. As part of the 22nd annual North American Dendroecological Fieldweek, the first Pinus ponderosa earlywood-width (EW) and latewood-width (LW) chronologies were developed for the Jemez Mountains in northern New Mexico. The aim was to extend an existing total ring-width (TW) chronology and to assess the potential for creating long LW chronologies. Analysis of chronology signal strength suggests that large sample size requirements remain a considerable hurdle for creating P. ponderosa LW chronologies longer than 400 years. At the Cat Mesa site, twenty-three sample trees were req...
Abstract Coarse woody debris (CWD; i.e. downed limbs and boles) serves numerous ecosystem functio... more Abstract Coarse woody debris (CWD; i.e. downed limbs and boles) serves numerous ecosystem functions, which vary according to the degree of decay. CWD decay is often described using five categories based on readily observed physical characteristics ranging from freshly fallen (Class I) to advanced decay with little structural integrity (Class V). Though useful in categorizing downed wood in a forest, these categories do not necessarily provide information about time since death or the decay process. Dendrochronology can be used to assign death dates to CWD and begin to provide a temporal description of the decay process. We used standard dendrochronological techniques to determine the death dates of 94 CWD samples from five common hardwood taxa in southern Indiana. Across taxa, the time since death of Class I (1.4 ± 1.7 years; mean ± SD; least decayed class) was significantly shorter than Class II (5.2 ± 3.6 years), which was shorter than the more decayed classes (Class III: 11.5 ± 4.9, and Class IV: 11.2 ± 5.6 years). Within this general trend, time since death within a decay class varied greatly among taxa. Combining dendrochronology techniques with visual decay characteristics can improve our understanding of CWD's role and provide a more precise timeline for biomass and nutrient turnover within forested systems.
The original version of this Article contained an error in the Data Availability section, which i... more The original version of this Article contained an error in the Data Availability section, which incorrectly read 'All data will be freely available via https://www.ams.ethz.ch/research.html .' The correct version states ' http://www.ams.ethz.ch/research/published-data.html ' in place of ' https://www.ams.ethz.ch/research.html '. This has been corrected in both the PDF and HTML versions of the Article.
Though tree-ring chronologies are annually resolved, their dating has never been independently va... more Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the C content in 484 individual tree rings formed in the periods 770-780 and 990-1000 CE. Distinct C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved C...
This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The... more This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (< 5 cm DBH) trees. We further presented Root-to-Shoot Ratios of uprooted trees. Data on the importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection...
Although there are other scientific means of dating climatic and environmental events, dendrochro... more Although there are other scientific means of dating climatic and environmental events, dendrochronology provides the most reliable of all palaeorecords. This comprehensive text addresses all of the subjects that a reader who is new to the field will need to know and will be a welcome reference for practitioners at all levels. It includes a history of the discipline, biological and ecological background, principles of the field, basic scientific information on the structure and growth of trees, the complete range of dendrochronology methods, and a full description of each of the relevant subdisciplines.
The Bridger Antelope Trap is an archaeological site listed on the National Register of Historic p... more The Bridger Antelope Trap is an archaeological site listed on the National Register of Historic places in southwestern Wyoming that was used by American Indians while hunting antelope as described by early settlers. The trap is a large corral that was constructed from juniper (Juniperus osteosperma) and covers approximately 26 acres (110,000 m2). This study's goal is to demonstrate the trap's age of construction, its use and maintenance, and its time depth based on tree rings. As part of dating the archaeological wood, we also built a living chronology from the surrounding trees. Over the course of two field seasons, we collected wood samples from living juniper trees, ax-cut stumps, and the trap itself. The juniper wood was difficult and contained numerous micro and locally absent rings, but we successfully built a living chronology by crossdating with skeleton plots. The wood from the trap was largely eroded and weathered, and samples taken with an archaeological drill wer...
The Dendrochronology and Biogeography Laboratory at Indiana State University was established in 2... more The Dendrochronology and Biogeography Laboratory at Indiana State University was established in 2001. In the last 13 years, we have had 3 PhD, 12 Masters, and 6 undergraduate students work on theses that involved dendrochronology. This work has been completed under the supervision of Dr. Jim Speer and Dr. Karla Hansen-Speer who worked as a lab manager at the lab for three years. Most of this work focuses on disturbance ecology, but we have also branched out to archaeology and climate response. The focus of this presentation will be our three most recent research projects which examined pandora moth outbreaks across their entire range using chronologies from the International Tree-Ring Databank, developing a chronology in a new tree species to dendrochronology (Juniperus osteosperma) to date the Bridger Antelope Trap archaeological site in Wyoming, and examining the effect of fire on sixteen arboreal species in the Eastern Deciduous Forest. Throughout his career as a dendrochronologi...
The main objective of this research was to develop a technique for mast reconstruction using dend... more The main objective of this research was to develop a technique for mast reconstruction using dendrochronology. During this work I collected cores from 845 individual trees from white (Quercus alba), chestnut (Q. prinus), northern red (Q. rubra), black (Q. velutina), and scarlet oaks (Q. coccinea), at 17 sites in the southern Appalachians. I identified five basic steps that are necessary for mast reconstruction. 1) Crossdate the tree-ring series; 2) Standardize the series with a flexible cubic smoothing spline; 3) Use multiple regression to remove climate; 4) Use simple linear regression between the climate residuals and a known mast record to define a regression equation; 5) Use the regression equation to reconstruct mast beyond the scope of the known mast record. From climate analysis of these five oak species grown under closed-canopy conditions, I determined that four of the five species were adequate recorders Palmer Drought Severity Index and temperature. I developed five mast reconstructions on the stand-level explaining from 20% to 47% of the remaining variance in the chronology after climate was removed. At most, 25% of the site-species chronologies showed a reduction in ring width in known years of heavy mast production, which has implications for the theories of mast fruiting. The evolved strategies hypothesis predicts that a tradeoff should be evident between incremental growth and reproductive effort and the lack of a consistent tradeoff brings this theory into question. I explored the application of mast reconstructions to a problem in wildlife management by comparing two of my reconstructions to a black bear population estimate and black bear harvest records. I found that acorn production from three years prior and the current year correlated significantly with these respective records. This work demonstrates a new technique for dendrochronology, which I call dendromastecology. It can be applied to other genera and localities around the world to provide information to tree biologists, wildlife ecologists, and mast ecologists. Whether or not future mast reconstructions are successful, they will continue to provide evidence about the tradeoff between incremental growth and reproductive effort.
Pandora moth (Coloradia pandora Blake) is a phytophagous insect, defoliating ponderosa pine trees... more Pandora moth (Coloradia pandora Blake) is a phytophagous insect, defoliating ponderosa pine trees in the western United States. However, long-term studies of this insect and its effects on the forest ecosystem have not been conducted. Using dendrochronological techniques, I examined past timing and intensity of defoliation through its effects on radial growth of trees in the forests of south central Oregon. Pandora moth leaves a distinctive ring-width “signature” that was easily identifiable in the wood. The growth for the first year of the signature was half the normal ring-width with narrow latewood. The following two years produced extremely narrow rings, with the entire suppression lasting from 4 to 18 years. Twenty-two individual outbreaks were reconstructed from this 620 year chronology. I found that pandora moth outbreaks were episodic on individual sites, with a return interval of 9 to 156 years. Conversely, on the regional scale of south central Oregon, outbreaks demonstrated a 37-year periodicity. On average, pandora moth defoliation caused a 29% mean periodic growth reduction in defoliated ponderosa pine trees. Spread maps of the first year that sites demonstrated suppression were plotted revealing an apparent annual spread of the outbreaks. Examination of a fire history on one pandora moth outbreak site suggested that pandora moth outbreaks delay fire by interrupting the needle fall needed for fire spread. Superposed epoch analysis showed that the year that the outbreak was first recorded was significantly dry and the fourth year prior was significantly wet. Therefore, climate may be a triggering factor in pandora moth outbreaks. The stem analysis demonstrated that the percent volume reduction was greatest at the base of the tree and declined further up the bole. The percent volume reduction in the canopy of the trees was variable with outlying high and low values. The mean volume reduction per outbreak was .053 m3 per tree. Although this insect is considered a forest pest and causes inconvenience for people living nearby, pandora moth is not as widespread and damaging as some other phytophagous insects. However, its very distinctive ring-width signature and the length of the ponderosa pine record enables reconstruction of very long outbreak histories, which may deepen our understanding of the interaction between defoliating insects and their ecosystem.
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Papers by James H Speer
1) Crossdate the tree-ring series;
2) Standardize the series with a flexible cubic smoothing spline;
3) Use multiple regression to remove climate;
4) Use simple linear regression between the climate residuals and a known mast record to define a regression equation;
5) Use the regression equation to reconstruct mast beyond the scope of the known mast record.
From climate analysis of these five oak species grown under closed-canopy conditions, I determined that four of the five species were adequate recorders Palmer Drought Severity Index and temperature. I developed five mast reconstructions on the stand-level explaining from 20% to 47% of the remaining variance in the chronology after climate was removed. At most, 25% of the site-species chronologies showed a reduction in ring width in known years of heavy mast production, which has implications for the theories of mast fruiting. The evolved strategies hypothesis predicts that a tradeoff should be evident between incremental growth and reproductive effort and the lack of a consistent tradeoff brings this theory into question. I explored the application of mast reconstructions to a problem in wildlife management by comparing two of my reconstructions to a black bear population estimate and black bear harvest records. I found that acorn production from three years prior and the current year correlated significantly with these respective records.
This work demonstrates a new technique for dendrochronology, which I call dendromastecology. It can be applied to other genera and localities around the world to provide information to tree biologists, wildlife ecologists, and mast ecologists. Whether or not future mast reconstructions are successful, they will continue to provide evidence about the tradeoff between incremental growth and reproductive effort.
Twenty-two individual outbreaks were reconstructed from this 620 year chronology. I found that pandora moth outbreaks were episodic on individual sites, with a return interval of 9 to 156 years. Conversely, on the regional scale of south central Oregon, outbreaks demonstrated a 37-year periodicity. On average, pandora moth defoliation caused a 29% mean periodic growth reduction in defoliated ponderosa pine trees. Spread maps of the first year that sites demonstrated suppression were plotted revealing an apparent annual spread of the outbreaks. Examination of a fire history on one pandora moth outbreak site suggested that pandora moth outbreaks delay fire by interrupting the needle fall needed for fire spread. Superposed epoch analysis showed that the year that the outbreak was first recorded was significantly dry and the fourth year prior was significantly wet. Therefore, climate may be a triggering factor in pandora moth outbreaks. The stem analysis demonstrated that the percent volume reduction was greatest at the base of the tree and declined further up the bole. The percent volume reduction in the canopy of the trees was variable with outlying high and low values. The mean volume reduction per outbreak was .053 m3 per tree.
Although this insect is considered a forest pest and causes inconvenience for people living nearby, pandora moth is not as widespread and damaging as some other phytophagous insects. However, its very distinctive ring-width signature and the length of the ponderosa pine record enables reconstruction of very long outbreak histories, which may deepen our understanding of the interaction between defoliating insects and their ecosystem.