A Note on SAP pH in Eastern Redcedar (Juniperus Virginiana L.)

Twelve eastern redcedar (Juniperus virginiana L.) trees were sampled for the sap pH of the sapwood at three locations along the bole and one location on the roots. Soil pH measurements were taken at each tree site for comparison with sap pH. Sap pH was positively correlated with soil pH. A regression model using mean soil pH as the independent variable accounted for 71% of the variation of the mean sap pH. There was a decreasing gradient in sap pH from crown to stump

Developing and Using Fire Scar Histories in the Southern and Eastern United States

Land managers developing fire management plans in the eastern and southern United States lack quantitative information on historic fire regimes. Twelve new fire histories were developed from dated fire scars on trees from regions where no fire scar history data had existed before in the states of Alabama, Louisiana, Kentucky, Iowa, Wisconsin, and Michigan. Sites represent highly variable climates from extreme cold (with long snow cover duration) to subtropical. All sites utilized oak or pine recorder species that were collected from closed forest to open savanna structures. Pre-industrial mean fire intervals ranged from 3 to more than 35 years at sites that typically encompassed less than 2 km2 in area. The most frequent fire regime was found in Louisiana‟s Kisatchie National Forest (MFI = 3 yrs) while the longest fire intervals were at inland sites near the shore of Lake Superior (MFI \u3e 35 yrs) some 1900 kilometers to the north. The subtropical site in Louisiana is perhaps the only site in the U.S. where fires are documented to have occurred more than once a year. The history of fire at sites in Wisconsin, Louisiana, and Michigan showed distinct temporal progressions in changes in fire frequency that we attributed to changing human population. Sites in Wisconsin showed potential for very large fires associated with drought years. Fire history data analyses and summaries were presented at multiple venues (workshops, conferences) and have been published in scientific journals and reports to regional land managers. Fire history data has also been made publicly available through the International Multiproxy Paleofire Databank (IMPD). New fire history data from this project combined with previously collected fire history data from the Missouri Tree-Ring Laboratory and published fire histories in North America were used to parameterize and calibrate a continental fire frequency model based on climate. The most important contribution of this model is towards understanding climate forcing of fire regimes across the continental U.S. We have developed a suite of climate-based fire frequency models for the continental U.S. that show to be highly robust. Models and calibrations were validated with empirical fire history data during pre-industrial periods so to minimize non-climate influences associated with U.S. settlement (land conversion, changing cultures). Fire frequency models follow theoretical concepts from physical chemistry, utilize spatially-explicit fire and climate data, and were parameterized and validated using statistical methods. Data from fire history studies were accumulated from 37 states and include data based on fire scars (n = 168), expert estimates (n = 7) and charcoal (n = 3). Historic mean fire interval (MFI) models were parameterized using mean maximum temperature, precipitation, their interaction, and estimated population density (anthropogenic ignitions). Models are being used to: assess the role of climate in forcing fire frequency, map coarse-scale historic fire frequency for the continental U.S., and assess departures in fire regimes and smoke emissions

The Age and Density of Ancient and Modern Oak Wood in Streams and Sediments

Large wood of oak trees (Quercus spp.) has resided in the streams and sediments of north Missouri, USA for many thousands of years. This wood affords the opportunity to compare a chronosequence of differences in wood density over a very long period. We analyzed the relationship between the age (residence time) and density of heartwood from oak boles using tree-ring and 14C dating methods and discuss their implications. The residence time of large oak wood (> 25 cm diameter) sampled in the streams and sediments ranged from less than 14 years to more than 12,320 years. The oak wood ranged in density from 0.82 g cm-3 for a tree that had recently fallen into the stream to 0.14 g cm-3 for ancient oak wood. Two regression equations relate age (residence time) and density of oak wood and explain 88 percent of the variance in the dependent variables. Equation 1, heartwood density = age, can be used for studies in carbon cycling, wood as invertebrate habitat, or other questions related to the density and ecology of wood in streams such as wood retention and export. Equation 2, age = heartwood density, can be used for estimating when oak wood was formed on a very coarse scale over many thousands of years

Developing and Using Fire Scar Histories in the Southern and Eastern United States

Land managers developing fire management plans in the eastern and southern United States lack quantitative information on historic fire regimes. Twelve new fire histories were developed from dated fire scars on trees from regions where no fire scar history data had existed before in the states of Alabama, Louisiana, Kentucky, Iowa, Wisconsin, and Michigan. Sites represent highly variable climates from extreme cold (with long snow cover duration) to subtropical. All sites utilized oak or pine recorder species that were collected from closed forest to open savanna structures. Pre-industrial mean fire intervals ranged from 3 to more than 35 years at sites that typically encompassed less than 2 km2 in area. The most frequent fire regime was found in Louisiana‟s Kisatchie National Forest (MFI = 3 yrs) while the longest fire intervals were at inland sites near the shore of Lake Superior (MFI \u3e 35 yrs) some 1900 kilometers to the north. The subtropical site in Louisiana is perhaps the only site in the U.S. where fires are documented to have occurred more than once a year. The history of fire at sites in Wisconsin, Louisiana, and Michigan showed distinct temporal progressions in changes in fire frequency that we attributed to changing human population. Sites in Wisconsin showed potential for very large fires associated with drought years. Fire history data analyses and summaries were presented at multiple venues (workshops, conferences) and have been published in scientific journals and reports to regional land managers. Fire history data has also been made publicly available through the International Multiproxy Paleofire Databank (IMPD). New fire history data from this project combined with previously collected fire history data from the Missouri Tree-Ring Laboratory and published fire histories in North America were used to parameterize and calibrate a continental fire frequency model based on climate. The most important contribution of this model is towards understanding climate forcing of fire regimes across the continental U.S. We have developed a suite of climate-based fire frequency models for the continental U.S. that show to be highly robust. Models and calibrations were validated with empirical fire history data during pre-industrial periods so to minimize non-climate influences associated with U.S. settlement (land conversion, changing cultures). Fire frequency models follow theoretical concepts from physical chemistry, utilize spatially-explicit fire and climate data, and were parameterized and validated using statistical methods. Data from fire history studies were accumulated from 37 states and include data based on fire scars (n = 168), expert estimates (n = 7) and charcoal (n = 3). Historic mean fire interval (MFI) models were parameterized using mean maximum temperature, precipitation, their interaction, and estimated population density (anthropogenic ignitions). Models are being used to: assess the role of climate in forcing fire frequency, map coarse-scale historic fire frequency for the continental U.S., and assess departures in fire regimes and smoke emissions

Inorganic Concentrations in the Wood of Eastern Redcedar Grown on Different Sites

Samples of eastern redcedar (Juniperus virginiana L.) growing on soils derived from five parent materials—rhyolite, dolomite, limestone, sandstone, and chert—were analyzed for levels of inorganics in sapwood and heartwood. Eighteen elements were detected in sapwood using inductively coupled plasma optical emission spectroscopy. Neutron activation analysis was also used to determine concentrations of an additional six elements in heartwood. No difference was found between results obtained by the two analytical methods. Conventional wet chemistry techniques were used to determine nitrogen and sulfur concentrations in some samples

Spring temperature responses of oaks are synchronous with North Atlantic conditions during the last deglaciation

Paleoclimate proxies based on the measurement of xylem cell anatomy have rarely been developed across the temperature range of a species or applied to wood predating the most recent millennium. Here we describe wood anatomy-based proxies for spring temperatures in central North America from modern bur oaks (Quercus macrocarpa Michx.). The strong coherence of temperature signals across the species range supports the use of these proxies across thousands of years of climatic change. We also used 79 subfossil oak log cross sections from northern Missouri, ¹⁴C-dated to 9.9-13.63 ka (ka is 1000 cal yr BP), to assess the frequency of oak deposition into alluvial sediments and a subset of these oaks for a wood anatomy-based reconstruction of spring paleotemperatures. Temperatures during the Younger Dryas cold period (YD) were up to 3.5 degrees C lower than modern temperatures for that region, equivalent to or lower than those experienced at the northern edge of the modern species range. Compared to extant oaks growing at much higher [CO₂], subfossil oaks had greater vessel frequencies. Besides very low theoretical (or estimated) xylem conductivity near the beginning of the oak record near 13.6 ka, vessel frequencies greater than modern trees compensated for reduced vessel dimensions so that theoretical xylem conductivity was consistently above that of modern trees at the cold northern sites. Significant correlations were found between the frequency of ¹⁴C-dated oaks and either delta δ¹⁸O from the NGRIP (North Greenland Ice Core Project) ice core or from the Cariaco grayscale marine-sediment record from the southern Caribbean sea. Oak deposition into alluvial sediments during the YD was significantly lower than expected given the average sample depth of oaks from 9.9 to 13.6 ka. Reduced oak deposition during the YD suggests that an abrupt shift in climate reduced oak populations across the region and/or changed the rates of channel movement across drainages.Keywords: Pleistocene, Quercus macrocarpa, Holocene, Pre-Boreal, Younger Dryas, Radiocarbon, Wood anatomy, Great Plains\, USA, Phenology, Bolling-Allerod, Xylem, Bur oa

A dynamic leaf gas-exchange strategy is conserved in woody plants under changing ambient CO2: evidence from carbon isotope discrimination in paleo and CO2 enrichment studies

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) C) 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. This article is protected by copyright. All rights reserved.Rising atmospheric [CO2], c(a), 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], c(i), a constant drawdown in CO2 (c(a)-c(i)), and a constant c(i)/c(a). 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 c(a). 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 c(a). To assess leaf gas-exchange regulation strategies, we analyzed patterns in c(i) inferred from studies reporting C stable isotope ratios (C-13) or photosynthetic discrimination () in woody angiosperms and gymnosperms that grew across a range of c(a) spanning at least 100ppm. Our results suggest that much of the c(a)-induced changes in c(i)/c(a) occurred across c(a) spanning 200 to 400ppm. These patterns imply that c(a)-c(i) will eventually approach a constant level at high c(a) 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 toward any single strategy, particularly maintaining a constant c(i). 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 c(a), when additional water loss is small for each unit of C gain, and increasingly water-conservative at high c(a), when photosystems are saturated and water loss is large for each unit C gain

Multi-omic analysis in injured humans: Patterns align with outcomes and treatment responses

Trauma is a leading cause of death and morbidity worldwide. Here, we present the analysis of a longitudinal multi-omic dataset comprising clinical, cytokine, endotheliopathy biomarker, lipidome, metabolome, and proteome data from severely injured humans. A "systemic storm" pattern with release of 1,061 markers, together with a pattern suggestive of the "massive consumption" of 892 constitutive circulating markers, is identified in the acute phase post-trauma. Data integration reveals two human injury response endotypes, which align with clinical trajectory. Prehospital thawed plasma rescues only endotype 2 patients with traumatic brain injury (30-day mortality: 30.3 versus 75.0%; p = 0.0015). Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) was identified as the most predictive circulating biomarker to identify endotype 2-traumatic brain injury (TBI) patients. These response patterns refine the paradigm for human injury, while the datasets provide a resource for the study of critical illness, trauma, and human stress responses

Archival of eastern U.S. fire scar history data

Fire scar histories are a critical fire data source because they form a foundation for defining fire regimes. The objective of this project was to properly archive the data (fire scar event chronologies, tree-ring chronologies) and metadata of eastern U.S. fire scar study sites developed under project #06-3-1-16, “Developing and Using Fire Scar Histories in the Southern and Eastern United States”, PI: Richard Guyette. Datasets to be archived included tree-ring chronologies (annual resolution), fire event chronologies (annual to seasonal resolution), and wood samples. Crossdated tree-ring measurements used to date fire scars have been submitted to the International Tree-Ring Databank. All fire history datasets, including metadata, have been submitted to NOAA’s International Multiproxy Paleofire Databank. Metadata describing tree species, spatial attributes, and access were entered into Metavist. The management implications of these data pertain to applications to forest ecosystem conservation and restoration through the design of fire management programs. Additional work is needed to complete archival of over 50 additional datasets completed by the Missouri Tree-Ring Laboratory

Progress In Constructing A Long Oak Chronology From The Central United States

We describe methods and progress in developing the American Long Oak Chronology (ALOC), an effort to construct an oak tree-ring chronology from the Central US that spans the Holocene. Since 2000, we have collected and measured ring widths on over 550 pieces of subfossil oak (Quercus) wood. Over 330 oak samples have been radiocarbon dated, with ages ranging up to 14,000 cal yr B.P. A 1,093- year-long tree-ring record has been constructed from live and subfossil bur oaks (Q. macrocarpa Michx.) and swamp white oaks (Q. bicolor Willd.) growing along and buried in sediments of streams that flow through northern Missouri and southern Iowa, USA. Here we describe the ALOC for the period A.D. 912–2004 to demonstrate its dendrochronological value, display the material quality, and emphasize the importance of chronology construction. We also report on progress in developing older floating chronologies. The development of more long, multi-millennium chronologies will be an important contribution to dendroclimatology. These chronologies will be particularly useful to the Central US, a region with a continental climate and limited temporal depth of annually resolved paleorecords. Perhaps more critical is its location in the middle of one of the most important agricultural regions in the world.This item is part of the Tree-Ring Research (formerly Tree-Ring Bulletin) archive. For more information about this peer-reviewed scholarly journal, please email the Editor of Tree-Ring Research at [email protected]