TREE-RING DATES AND NAVAJO SETTLEMENT PATTERNS IN ARIZONA

2017 ◽  
Vol 82 (1) ◽  
pp. 25-49 ◽  
Author(s):  
Chip Colwell ◽  
T. J. Ferguson
Keyword(s):  
Tree Ring ◽  
Settlement Patterns ◽  
Colorado River ◽  
High Confidence ◽  
New Approach ◽  
River Watershed ◽  
Northern Arizona ◽  
Black Mesa ◽  
Tree Ring Data ◽  
The U.S

The historical timing and movement of Navajo communities in the U.S. Southwest continue to be key, but unresolved, issues. This paper analyzes tree-ring data to consider initial Navajo settlement patterns in the Little Colorado River watershed, Black Mesa, and nearby regions in northern Arizona. We are critical of previous studies that deem all tree-ring dates to be equally valid, so we present a new approach to systematically identify potential early Navajo sites. After analyzing hundreds of tree-ring specimens from 774 sites, we conclude that dendrochronological evidence offers moderate-to-high confidence that 18 Navajo sites in the study area were settled prior to 1882. These dendrochronological data support the hypothesis of a westward Navajo migration from the Dinétah, reaching Black Mesa in Arizona about 1840, other areas north and east of the Hopi Mesas in the 1850s, and land west of Hopi in the 1870s after the release of Navajos from Fort Sumner in 1868.

scholarly journals How Long Does a 15-Year Drought Last? On the Correlation of Rare Events

2019 ◽  
Vol 32 (5) ◽  
pp. 1345-1359 ◽  
Author(s):  
George Rhee ◽  
Jimmy Salazar ◽  
Corwin Grigg
Keyword(s):  
Water Supply ◽  
Tree Ring ◽  
Colorado River ◽  
River System ◽  
Past Century ◽  
Water Shortages ◽  
Tree Ring Data ◽  
Supply Problem ◽  
Quantitative Understanding ◽  
Streamflow Statistics

Abstract Communities reliant upon the Colorado River system are at risk of water shortages because of fluctuations of the river’s streamflows. The solution to the water supply problem for the Colorado River system lies within a quantitative understanding of these fluctuations during droughts. Streamflow data (direct and inferred) for the Colorado River extend back approximately 1200 years through the analysis of tree-ring records (Meko et al.; Woodhouse et al.). We further analyze these data using a mathematical model to present estimates for the future water supply of the Colorado River by comparing measured streamflows of the past century with the yearly tree-ring data of the Colorado River. We estimate that the Colorado River system’s reservoirs lack enough stored water reserves to last through the current drought, which has been ongoing since 2000. If true, it is essential to reevaluate the way water is used and stored for the Colorado River. The methods presented are relevant to any river system whose streamflow statistics are Gaussian.

Back to the Drawing Board

2017 ◽  
Author(s):  
Bruno Verdini Trejo
Keyword(s):  
Colorado River ◽  
Window Of Opportunity ◽  
New Approach ◽  
Critical Window ◽  
Cooperative Process ◽  
Drawing Board ◽  
First Time ◽  
Two Sides ◽  
The U.S ◽  
Colorado River Water

Explores how, in the context of drought, the parties were able to move From Litigation to Cooperation. After a serious diplomatic confrontation and ensuing lawsuit in which both countries ended up worse off than before, leaders on both sides of the border set out to frame a new mandate. With this new approach, the two sides sought to redefine their relations on the Colorado River and begin negotiations from a constructive, mutual gains mindset. Turning Crisis into Opportunity examines the ways in which the two sides seized a critical window of opportunity to move the negotiations forward following the devastating 2010 earthquake in Mexico’s Mexicali Valley, which weakened the alternatives of several domestic constituencies in Mexico who were opposed to a cooperative process with the U.S. No Negotiation without Representation explains how the U.S. was able to break the traditional diplomatic protocol to allow the seven U.S. states that own the rights to the Colorado River water to be appropriately represented and have a seat at the negotiating table. Involved for the first time as co-sovereigns with the U.S. and Mexican federal authorities, the contributions of the Upper Basin and Lower Basin states were critical to shaping an implementable agreement.

Black Mesa Black on White

1941 ◽  
Vol 7 (2Part1) ◽  
pp. 164-165
Author(s):  
Harold S. Colton
Keyword(s):  
Tree Ring ◽  
Original Description ◽  
American Archaeology ◽  
Northern Arizona ◽  
Black Mesa ◽  
Peabody Museum

A very important southwestern pottery type, well dated by tree ring studies, is called Deadmans Black-on-white by Colton, and Black Mesa Pueblo II Black-on-white by Morss. When the Handbook of Northern Arizona Pottery Wares (Colton and Hargrave, 1937) was being written, and there were two descriptions of the type, the question arose which name to choose. The original description of Deadmans Black-on-white appeared in Bulletin 104 of the Bureau of American Ethnology, which carried a printed authorization date of Feb. 17, 1931, and which appeared in 1932. Morss published his description of the same type in 1931, calling it Black Mesa Pueblo II Black-on-white (Papers of the Peabody Museum of American Archaeology and Ethnology).

scholarly journals Supporting Restoration Decisions through Integration of Tree-Ring and Modeling Data: Reconstructing Flow and Salinity in the San Francisco Estuary over the Past Millennium

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2139
Author(s):  
Paul H. Hutton ◽  
David M. Meko ◽  
Sujoy B. Roy
Keyword(s):  
San Francisco ◽  
Tree Ring ◽  
San Francisco Estuary ◽  
Salinity Intrusion ◽  
Estuarine Ecosystem ◽  
Freshwater Flow ◽  
The Past ◽  
Decadal Scale ◽  
Tree Ring Data ◽  
Past Millennium

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.

scholarly journals Cariaco Basin Calibration Update: Revisions to Calendar and 14C Chronologies for Core Pl07-58Pc

Radiocarbon ◽  
2004 ◽  
Vol 46 (3) ◽  
pp. 1161-1187 ◽  
Author(s):  
Konrad A Hughen ◽  
John R Southon ◽  
Chanda J H Bertrand ◽  
Brian Frantz ◽  
Paula Zermeño
Keyword(s):  
Tree Ring ◽  
Cariaco Basin ◽  
Calibration Data ◽  
Data Set ◽  
Varve Chronology ◽  
Pine Tree ◽  
Tree Ring Data ◽  
Calibration Data Set ◽  
Recent Version ◽  
Radiocarbon Calibration

This paper describes the methods used to develop the Cariaco Basin PL07-58PC marine radiocarbon calibration data set. Background measurements are provided for the period when Cariaco samples were run, as well as revisions leading to the most recent version of the floating varve chronology. The floating Cariaco chronology has been anchored to an updated and expanded Preboreal pine tree-ring data set, with better estimates of uncertainty in the wiggle-match. Pending any further changes to the dendrochronology, these results represent the final Cariaco 58PC calibration data set.

Tree growth across the Nepal Himalaya during the last four centuries

2017 ◽  
Vol 41 (4) ◽  
pp. 478-495 ◽  
Author(s):  
UK Thapa ◽  
S St. George ◽  
DK Kharal ◽  
NP Gaire
Keyword(s):  
Tree Ring ◽  
Tree Growth ◽  
Environmental Changes ◽  
Ring Width ◽  
High Elevation ◽  
Forest Growth ◽  
Tree Ring Width ◽  
Early 19Th Century ◽  
Tree Ring Data ◽  
Instrumental Records

The climate of Nepal has changed rapidly over the recent decades, but most instrumental records of weather and hydrology only extend back to the 1980s. Tree rings can provide a longer perspective on recent environmental changes, and since the early 2000s, a new round of field initiatives by international researchers and Nepali scientists have more than doubled the size of the country’s tree-ring network. In this paper, we present a comprehensive analysis of the current tree-ring width network for Nepal, and use this network to estimate changes in forest growth nation-wide during the last four centuries. Ring-width chronologies in Nepal have been developed from 11 tree species, and half of the records span at least 290 years. The Nepal tree-ring width network provides a robust estimate of annual forest growth over roughly the last four centuries, but prior to this point, our mean ring-width composite fluctuates wildly due to low sample replication. Over the last four centuries, two major events are prominent in the all-Nepal composite: (i) a prolonged and widespread growth suppression during the early 1800s; and (ii) heightened growth during the most recent decade. The early 19th century decline in tree growth coincides with two major Indonesian eruptions, and suggests that short-term disturbances related to climate extremes can exert a lasting influence on the vigor of Nepal’s forests. Growth increases since AD 2000 are mainly apparent in high-elevation fir, which may be a consequence of the observed trend towards warmer temperatures, particularly during winter. This synthesis effort should be useful to establish baselines for tree-ring data in Nepal and provide a broader context to evaluate the sensitivity or behavior of this proxy in the central Himalayas.

Strength of cold-formed steel shear diaphragms

1979 ◽  
Vol 6 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Paul Fazio ◽  
Kinh Ha ◽  
S. Chockalingam
Keyword(s):  
Air Force ◽  
Test Data ◽  
Seismic Design ◽  
Shear Capacity ◽  
Rational Method ◽  
New Approach ◽  
Iron And Steel ◽  
Cold Formed Steel ◽  
The U.S ◽  
Steel Institute

The design of light-gage steel corrugated shear diaphragms is not yet covered by the structural codes of many countries, including Canada. The shear capacity of steel diaphragms may be predicted by various approaches currently available, namely, those proposed by: (1) the American Iron and Steel Institute; (2) the Manual of seismic design of buildings, published by the U.S. Departments of the Army, Navy, and Air Force; and (3) the recommendations outlined in the current British code. In this paper, a rational method is proposed and the application of all the above methods is illustrated with reference to a specific example. Finally, the shear strengths of many diaphragms are predicted by the new approach developed by the authors and the results are compared to test data.

Developing a triple tree-ring constraint for tree growth and physiology in a global land surface model

2021 ◽  
Author(s):  
Jonathan Barichivich ◽  
Philippe Peylin ◽  
Valérie Daux ◽  
Camille Risi ◽  
Jina Jeong ◽  
...  
Keyword(s):  
Tree Ring ◽  
Land Surface ◽  
Forest Ecosystems ◽  
Ring Width ◽  
Land Surface Model ◽  
Surface Model ◽  
Growth Variability ◽  
Tree Ring Data ◽  
Surface Models ◽  
Global Land

<p>Gradual anthropogenic warming and parallel changes in the major global biogeochemical cycles are slowly pushing forest ecosystems into novel growing conditions, with uncertain consequences for ecosystem dynamics and climate. Short-term forest responses (i.e., years to a decade) to global change factors are relatively well understood and skilfully simulated by land surface models (LSMs). However, confidence on model projections weaken towards longer time scales and to the future, mainly because the long-term responses (i.e., decade to century) of these models remain unconstrained. This issue limits confidence on climate model projections. Annually-resolved tree-ring records, extending back to pre-industrial conditions, have the potential to constrain model responses at interannual to centennial time scales. Here, we constrain the representation of tree growth and physiology in the ORCHIDEE global land surface model using the simulated interannual variability of tree-ring width and carbon (Δ<sup>13</sup>C) and oxygen (δ<sup>18</sup>O) stable isotopes in six sites in boreal and temperate Europe.  The model simulates Δ<sup>13</sup>C (r = 0.31-0.80) and δ<sup>18</sup>O (r = 0.36-0.74) variability better than tree-ring width variability (r < 0.55), with an overall skill similar to that of other state-of-the-art models such as MAIDENiso and LPX-Bern. These results show that growth variability is not well represented, and that the parameterization of leaf-level physiological responses to drought stress in the temperate region can be improved with tree-ring data. The representation of carbon storage and remobilization dynamics is critical to improve the realism of simulated growth variability, temporal carrying over and recovery of forest ecosystems after climate extremes. The simulated physiological response to rising CO2 over the 20th century is consistent with tree-ring data in the temperate region, despite an overestimation of seasonal drought stress and stomatal control on photosynthesis. Photosynthesis correlates directly with isotopic variability, but correlations with δ<sup>18</sup>O combine physiological effects and climate variability impacts on source water signatures. The integration of tree-ring data (i.e. the triple constraint: width, Δ<sup>13</sup>C and δ<sup>18</sup>O) and land surface models as demonstrated here should contribute towards reducing current uncertainties in forest carbon and water cycling.</p>

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