A History and Definition of Green Roof Technology with Recommendations for Future Research

Green roof technology has a history that predates the modern era. Many functions of green roofs utilized during human history are analogous to contemporary functions. The justification of the use of green roof technology based on a review of literature shows the multiple and documented benefits that these systems can impart to the urban environment. A case study of the installation of the Southern Illinois University Carbondale green roof, showed the actual process of constructing the system. The maintenance and observation of this system gives firsthand experience. Interviews with green roof professionals allow greater understanding of current research needs. Finally, from these resources, recommendations for future research can be identified. This could ensure cogent direction in future research

Megadrought and Megadeath in 16th Century Mexico

The native population collapse in 16th century Mexico was a demographic catastrophe with one of the highest death rates in history. Recently developed tree-ring evidence has allowed the levels of precipitation to be reconstructed for north central Mexico, adding to the growing body of epidemiologic evidence and indicating that the 1545 and 1576 epidemics of cocoliztli (Nahuatl for "pest”) were indigenous hemorrhagic fevers transmitted by rodent hosts and aggravated by extreme drought conditions

The Longleaf Tree-Ring Network: Reviewing and expanding the utility of Pinus palustris Mill. Dendrochronological data

The longleaf pine (Pinus palustris Mill.) and related ecosystem is an icon of the southeastern United States (US). Once covering an estimated 37 million ha from Texas to Florida to Virginia, the near-extirpation of, and subsequent restoration efforts for, the species has been well-documented over the past ca. 100 years. Although longleaf pine is one of the longest-lived tree species in the southeastern US—with documented ages of over 400 years—its use has not been reviewed in the field of dendrochronology. In this paper, we review the utility of longleaf pine tree-ring data within the applications of four primary, topical research areas: climatology and paleoclimate reconstruction, fire history, ecology, and archeology/cultural studies. Further, we highlight knowledge gaps in these topical areas, for which we introduce the Longleaf Tree-Ring Network (LTRN). The overarching purpose of the LTRN is to coalesce partners and data to expand the scientific use of longleaf pine tree-ring data across the southeastern US. As a first example of LTRN analytics, we show that the development of seasonwood chronologies (earlywood width, latewood width, and total width) enhances the utility of longleaf pine tree-ring data, indicating the value of these seasonwood metrics for future studies. We find that at 21 sites distributed across the species’ range, latewood width chronologies outperform both their earlywood and total width counterparts in mean correlation coefficient (RBAR = 0.55, 0.46, 0.52, respectively). Strategic plans for increasing the utility of longleaf pine dendrochronology in the southeastern US include [1] saving remnant material (e.g., stumps, logs, and building construction timbers) from decay, extraction, and fire consumption to help extend tree-ring records, and [2] developing new chronologies in LTRN spatial gaps to facilitate broad-scale analyses of longleaf pine ecosystems within the context of the topical groups presented

A record of flooding on the White River, Arkansas derived from tree-ring anatomical variability and vessel width

Tree rings preserve important records of past flooding. We present the results of an examination of inter-annual tree-ring anatomical variability and vessel width in overcup oak (Quercus lyrata) and river flooding at a bottomland hardwood forest site near the confluence of the White and Mississippi Rivers. We developed two flood chronologies based on (1) visual identification of ?flood-ring? anatomical anomalies and (2) a simple method for quantitative measurements of earlywood vessel width (VW). Using visual flood rings, we have developed a response index (RI) chronology of floods from 1780?2013 and, using the VW measurements, we have developed a quantitative reconstruction of spring river levels from 1800?2013. Both the RI and VW chronologies are strongly related to spring river flooding and indicate that major floods such as those in 1805, 1826, 1844, 1852, 1858, occurred in the period prior to the systematic collection of stage data, and that the frequency of extreme events has greatly varied over the past two centuries. These chronologies provide important new information about Lower Mississippi River flooding in past centuries, and our simple method of measuring VW is a potentially useful new approach to the development of tree-ring records of flooding.U.S National Science Foundation Geography and Spatial Sciences Program [BSC 1359801]; University of Alabama Department of Geography; University of Alabama Graduate School12 month embargo; published online: 13 October 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Climate and the mfecane (with erratum)

The mfecane is thought to be a massive upheaval and devastation of Nguni tribal chiefdoms in the second decade of the 19th century in what is now KwaZulu-Natal and the Eastern Cape of South Africa. Other historians have challenged this extreme interpretation suggesting that the use of the term mfecane be discontinued. We show that pervasive cycles of drought and cold periods in southern Africa are significantly amplified and extended by volcanic eruptions and that, in particular, the eruption of Tambora in 1815 triggered a prolonged and extreme climatic event which bears all of the characteristics ascribed to the mfecane. These findings are supported by a coupled ocean–atmosphere numerical model and by tree-ring rainfall and sea surface temperature analyses, suggesting that the term mfecane is an appropriate description of a singular climatic event. Erratu

Future Streamflow in a Southeastern US watershed from a Paleo Perspective: A case study of St. Marys River, Florida

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The effects of geographical distribution on the reliability of wind energy

We examine the effects of geographic distribution of wind power plants (WPPs) on the reliability of electrical output within the Midwestern United States. North American Regional Reanalysis (NARR) data are extrapolated to 80 m using the power law and used to characterize the wind resource at 108 NARR grid points corresponding to existing WPPs. These sites are then organized, on the basis of nearest neighbors, into networks ranging from single WPPs to the full network of 108 WPPs. For each network, a suite of statistics is computed and used to characterize energy reliability as it relates to the number of WPPs within, and the area enclosed by, the network. The results demonstrate that WPP dispersion reduces variability and thereby improves the reliability of electrical output from WPPs. As scale increases, marginal improvements in reliability diminish, but there is no saturation of benefits on the scales considered here. The results are combined with wind resource information to identify sites that can further improve reliability for aggregated wind power in the study region

Tree-ring anatomical variability and flooding near the White River-Mississippi River confluence

I explored the relationship between inter-annual tree-ring anatomical variability of overcup oak (Quercus lyrata) and river flooding at a floodplain forest site near the confluence of the White River and Mississippi River, developing chronologies of anatomical variability from quantitative measurement series and also from the visual identification of presence or absence of “flood-ring” anatomical anomalies. A chronology developed from measured widths of the first rank of earlywood vessels (VR1W) in each growth increment displayed a strong signal related to spring river levels, and a VR1W-based model of spring river levels explains 37 percent of the variance of the 67 years of mean March-April-May stage height with which it was calibrated. The flood-related signal present in the VR1W chronology provides quantitative evidence supporting the continued study of past floods using tree rings, but does not capture relative magnitude of floods better than a chronology of flood response based on visual identification of flood-ring anatomical anomalies. Further investigation of the tree-ring flood record necessitates the development of chronologies from carefully selected sites, as well as continued exploration of methods of quantifying anatomical variability. (Published By University of Alabama Libraries