PR Papers by Malcolm K Cleaveland
Estado Actual De La Dendrocronologìa en México
The status of dendrochronology in Mexico
Eos, Transactions American Geophysical Union, 2000
Journal of Geophysical Research, 2002
Ancient Austrocedrus Tree-Ring Chronologies Used to Reconstruct Central Chile Precipitation Variability from a.d. 1200 to 2000
Journal of Climate, 2006
... Jonathan Barichivich ... 5), which includes La Sequía de San Juan de Mañosca from 1636 to 1... more ... Jonathan Barichivich ... 5), which includes La Sequía de San Juan de Mañosca from 1636 to 1639 (VicunaMackenna 1877; Bonilla 1999; Piwonka 1999) when three of the four years are estimated to have had below-average precipitation (ie, 285.5, 313.4, 335.9, and 421.0 mm ...
Fems Microbiology Letters, 2004
During the 16th century, Mexico suffered a demographic catastrophe with few parallels in worldÕs ... more During the 16th century, Mexico suffered a demographic catastrophe with few parallels in worldÕs history. In 1519, the year of the arrival of the Spaniards, the population in Mexico was estimated to be between 15 and 30 million inhabitants. Eighty-one years later, in 1600, only two million remained. Epidemics (smallpox, measles, mumps), together with war, and famine have been considered to be the main causes of this enormous population loss. However, re-evaluation of historical data suggests that approximately 60-70% of the death toll was caused by a series of epidemics of hemorrhagic fevers of unknown origin. In order to estimate the impact of the 1576 epidemic of hemorrhagic fevers on the population we analyzed the historical record and data from the 1570 and 1580 censuses of 157 districts. The results identified several remarkable aspects of this epidemic: First, overall, the population loss for these 157 districts was 51.36%. Second, there was a clear ethnic preference of the disease, the Spanish population was minimally affected whereas native population had high mortality rate. Third, the outbreak originated in the valleys of central Mexico whence it evolved as an expansive wave. Fourth, a positive correlation between altitude and mortality in central Mexico was found. Fifth, a specific climatic sequence of events was associated with the initiation and dissemination of the hemorrhagic fevers. Although the last epidemic of hemorrhagic fevers in Mexico ended in 1815, many questions remain to be answered. Perhaps the most relevant ones are whether there is a possible reemergence of the hemorrhagic fevers and how vulnerable we are to the disease.
Dendrochronologia, 2005
Earlywood ring-width chronologies derived primarily from Douglas-fir trees were used to reconstru... more Earlywood ring-width chronologies derived primarily from Douglas-fir trees were used to reconstruct winter-spring (November-May) precipitation and fall-spring (September-June) streamflow volumes for the period 1765-1993 in the forested upper Nazas watershed in Durango, Mexico. The tree-ring data were obtained from mixed conifer stands within or adjacent to the upper Nazas watershed. Precipitation data were derived from one of the longest regional records. The streamflow data were obtained from a guage located in the upper Nazas watershed. The Principal Component 1 (PC1) of nine residual earlywood chronologies accounted for 73% of the variance in November-May precipitation 1967-1993, and 64% for the total period with available data 1941-1993. The mean of three residual earlywood chronologies from Douglas-fir explained 51% of the normalized streamflow at Sardinas from 1971-1992. The 20th century was characterized by severe droughts, especially between 1950 and 1963 that also affected other regions of Mexico and the southwestern United States. Additional droughts of similar or greater magnitude occurred in the 1790s, 1810s, 1860-1870s and 1890-1910s. Similar periods of low flow occur in the September-June streamflow reconstruction between 1765 and 1993. These results indicate that tree-ring chronologies from this region document a high percentage of the precipitation and streamflow variance. Spectral analysis detected significant high periodicities in both records at peaks of 4 and 7 years that could be related to the ENSO frequency bands (approximately 4.0 and 6.25 years). Analysis of the reconstructed records show strong influence of ENSO on precipitation and streamflow amounts on an interannual basis. These results can provide significant inputs to decisions regarding management of water resources that are used to irrigate land in the Comarca Lagunera: specifically they indicate that water budgeting should be managed over longer time periods to account for this ENSO-related variability rather than on the year-to-year basis that is presently used.
Climatic Change, 2006
Maize was domesticated more than 6,000 years ago in central Mexico, and remains a vital staple fo... more Maize was domesticated more than 6,000 years ago in central Mexico, and remains a vital staple food and cultural symbol in Mesoamerica. Maize yield in the central highlands is strongly dependant on adequate rainfall early in the growing season (April-June) because late maturation of the crop may result in damage from autumn frost. Climate-induced crop failures with profound socioeconomic impacts have punctuated Mexican history. However, reliable records of maize harvest have not been available until very recently, and historical records of crop yield and price are discontinuous and can be difficult to interpret. We have developed a continuous, exactly dated, tree-ring reconstruction of maize yield variability in central Mexico from 1474 to 2001 that provides new insight into the history of climate and food availability in the heartland of the Mesoamerican cultural province. The reconstruction indicates that seven of the most severe agricultural crises in Mexican history occurred during decadal-scale episodes of reconstructed maize shortfalls.
Climate Research, 2002
The state of Chihuahua lies in an arid to semiarid zone in the NW central plain of Mexico. Its ag... more The state of Chihuahua lies in an arid to semiarid zone in the NW central plain of Mexico. Its agricultural economy is highly vulnerable to frequent droughts. In this study, we reconstruct winter-spring precipitation from 1647-1992 using 6 earlywood width chronologies of Douglas fir from around Chihuahua. The tree-ring data explain 56% of the winter-spring precipitation variance in a linear regression for 1949-1992, and there is strong correlation between the tree-ring reconstructed precipitation data and the observed precipitation data not used for calibration (r = 0.74, p < 0.01). The 5 driest years in the reconstructed precipitation record were 1974, 1954, 1742, 1980, and 1820 in order of severity, and the longest dry period in the 346 yr record lasted about 17 yr (1948)(1949)(1950)(1951)(1952)(1953)(1954)(1955)(1956)(1957)(1958)(1959)(1960)(1961)(1962)(1963)(1964) during the severe 1950s drought that also affected the SW United States. The reconstructed precipitation record has a statistically significant 4 yr spectral peak in the El Niño/Southern Oscillation (ENSO) frequency band and is significantly correlated with indices of ENSO (tropical rainfall index; r = 0.58, p = 0.001). The correlation between the ENSO and Chihuahuan reconstructed precipitation varied in strength when computed for non-overlapping 18 yr sub-periods (ranging from r = 0.43 to r = 0.68), which may reflect changes in the ENSO teleconnection to climate in northern Mexico.
Bulletin of The American Meteorological Society, 1998
Exactly dated tree-ring chronologies from ENSO-sensitive regions in subtropical North America and... more Exactly dated tree-ring chronologies from ENSO-sensitive regions in subtropical North America and Indonesia together register the strongest ENSO signal yet detected in tree-ring data worldwide and have been used to reconstruct the winter Southern Oscillation index (SOI) from 1706 to 1977. This reconstruction explains 53% of the variance in the instrumental winter SOI during the boreal cool season (December-February) and was verified in the time, space, and frequency domains by comparisons with independent instrumental SOI and sea surface temperature (SST) data. The large-scale SST anomaly patterns associated with ENSO in the equatorial and North Pacific during the 1879-1977 calibration period are reproduced in detail by this reconstruction. Cross-spectral analyses indicate that the reconstruction reproduces over 70% of the instrumental winter SOI variance at periods between 3.5 and 5.6 yr, and over 88% in the 4-yr frequency band. Oscillatory modes of variance identified with singular spectrum analysis at ~3.5, 4.0, and 5.8 yr in both the instrumental and reconstructed series exhibit regimelike behavior over the 272-yr reconstruction. The tree-ring estimates also suggest a statistically significant increase in the interannual variability of winter SOI, more frequent cold events, and a slightly stronger sea level pressure gradient across the equatorial Pacific from the mid-nineteenth to twentieth centuries. Some of the variability in this reconstruction must be associated with background climate influences affecting the ENSO teleconnection to subtropical North America and may not arise solely from equatorial ENSO forcing. However, there is some limited independent support for the nineteenth to twentieth century changes in tropical Pacific climate identified in this reconstruction and, if substantiated, it will have important implications to the low-frequency dynamics of ENSO.
POTENCIAL DENDROCRONOLÓGICO DE Taxodium mucronatum Ten Y ACCIONES PARA SU CONSERVACIÓN
Climatic Change, 2003
Earlywood width chronologies from Douglas-fir tree rings were used to reconstruct winter (Novembe... more Earlywood width chronologies from Douglas-fir tree rings were used to reconstruct winter (November–March) precipitation for more than 600 years over Durango, Mexico. The tree-ring data were obtained from two sites of long-lived Douglas-fir in northern and southern Durango and the seasonal climatic precipitation data were regionally averaged from five weather stations well distributed across the state. The averaged earlywood chronology accounted for 56% of the variance in instrumental November–March precipitation 1942–1983. We validated the reconstruction against independent precipitation records. The worst winter drought of the 20th century in Durango occurred 1950–1965. However, the reconstruction indicates droughts more severe than any witnessed in the 20th century, e.g., the 1850s–1860s, and the megadrought in the mid- to late-16th century. Reconstructed winter precipitation 1540–1579 shows 33 of 40 years were dry. Persistent drought may be linked to extended La Niña episodes. The Tropical Rainfall Index (TRI) correlates well with instrumental and reconstructed winter precipitation (r = 0.49 and 0.55, respectively), reflecting the strong ENSO modulation of cool season climate over northern Mexico. The ENSO teleconnection varies through time, with TRI-reconstructed precipitation correlations ranging from 0.78 to 0.27 in five periods 1895–1993. The 1942–1983 winter observed and reconstructed Durango data correlate well with the corresponding seasonalization of the All-Mexico Rainfall Index (AMRI; r=0.68, P<0.0001 and r=0.70, P<0.001, respectively), indicating that both the observed and the reconstructed precipitation often reflect broad-scale precipitation anomalies across Mexico. New long Douglas-fir and baldcypress tree-ring chronologies are now available for central and southern Mexico near major population centers, allowing the exploration of relationships between drought, food scarcity, and social and political upheaval in Mexican history.
Science, 1998
10. The data we report were obtained from the following typical experimental procedures. All data... more 10. The data we report were obtained from the following typical experimental procedures. All data has been shown to be reproducible with an error of ϳ5%. The oxidation of methane was conducted in a 300-ml high-pressure, stirred autoclave from Autoclave Engineers. The reactor was modified so that all the internal parts were either glass-lined or made from tantalum. The reactor was equipped with baffles, a hollow shaft/impeller, and was stirred at 1500 rpm to insure thorough gas-liquid mixing during the reaction. The reactor was loaded with the Pt catalyst (typically 20 to 50 mM) along with 80 to 120 ml H 2 SO 4 (at desired concentration), and the system was degassed with N. The reactor was heated to the desired reaction temperature (typically between 180°and 220°C), and a mixture of 97% methane and 3% neon was added to a total pressure of 500 psig. The methane/neon feed was added to the reactor from a known-volume reservoir in which the temperature and pressure of the gas was measured before and after addition so that the total moles of methane/neon added to the reactor could be accurately determined. The reaction was typically allowed to proceed for 1 to 3 hours. Cooling to near room temperature with an external, water-cooled line stopped the reaction, and the gas phase was vented into a 20-liter pressure vessel. After allowing several hours for thorough gas mixing, the vented gas was analyzed with a Hewlett-Packard 5880 GC equipped with a Hayesep D column and a thermal conductivity detector. The molar composition in the vented gas (primarily CH 4 , CO 2 , SO 2 , and CH 3 Cl) was determined on the basis of the reference neon internal standard; molar ratios of the gases; and the temperature, pressures, and volume of the vented gas. The liquid phase remaining in the 300-ml high-pressure reactor was analyzed by 1 H and 13 C NMR and highpressure liquid chromatography (HPLC) analyses. For NMR analysis, a known amount of acetic acid was added to an aliquot of the reaction solution as an internal standard. Methyl bisulfate (and any free methanol) was determined from the ratio of the 1 H NMR methyl resonances of methyl bisulfate (3.4 ppm) to acetic acid (2.02 ppm). The methyl products were also quantified by HPLC analysis of the liquid phase. Known volume aliquots of reaction solution were first hydrolyzed by the addition of three parts water to one part crude reaction solution and heated to 90°C for 4 hours in a sealed vial. The hydrolyzed solution was analyzed with a Hewlett-Packard 1050 HPLC equipped with an HPX-87H column (Bio-Rad) and a refractive index detector. The eluent was 0.1 volume % H 2 SO 4 in water. Methanol eluted at 16.2 min. The gas phase (CH 4 , CO 2 and CH 3 Cl) and liquid phase (CH 3 OSO 3 H and CH 3 OH) analyses allowed Ͼ90 to 95% mass balance on methane. 11. Oxidation of the Pt(II) center to Pt(IV ) occurs as evidenced by changes in the solution NMR spectra. Free ligand is generated, but no reaction at the C-H bonds is observed. 12. Calculated volumetric productivity based on the liquid phase for this reaction is ϳ10 -7 mol ml -1 s -1 ; Catalyst turnover number (ϳ20) and catalyst TOF (ϳ10 -3 s -1 ) were values obtained over the integrated reaction time. 13. The catalyst was still active after 500 turnovers. The reaction was stopped at this point. The actual number of turnovers before the regeneration would be required has not been determined. 14. The exact value depends on the value for the solubility of methane in H 2 SO 4 used in the calculations. 15. M. W. Holtcamp, J. A. Labinger, J. E. Bercaw, J. Am.
Papers by Malcolm K Cleaveland
Tree rings in hydrological studiesin hydrological studies
Springer eBooks, Sep 2, 2006
The 8th Century Megadrought Across North America
The 8th Century Megadrought Across North America, 2002
The 8th Century Megadrought Across North America
• Stahle, D. W. ;
• Therrell, M. D. ;
• Cl... more The 8th Century Megadrought Across North America
• Stahle, D. W. ;
• Therrell, M. D. ;
• Cleaveland, M. K. ;
• Fye, F. K. ;
• Cook, E. R. ;
• Grissino-Mayer, H. D. ;
• Acuna-Soto, R.
Abstract
Tree-ring data suggest that the 8th and 16th century megadroughts may have been the most severe and sustained droughts to impact North America in the past 1500 years. The 16th century megadrought may have persisted for up to 40 years, and extended from the tropics to the boreal forest and from the Pacific to Atlantic coasts. Evidence for the 8th century drought is sparse, but tree-ring and lake sediment data indicate that this drought extended from the northern Great Plains, across the southwestern United States, and into central Mexico and the Yucatan peninsula. Tree-ring data from Colorado and New Mexico document severe drought from A.D. 735-765, and may provide accurate and precise dating for the onset of the epic droughts reconstructed during the late first millennium A.D. with sedimentary data from Elk Lake, Minnesota; Moon Lake, South Dakota; La Piscina de Yuriria, Guanajuato; and Lake Chichancanab, Yucatan. If these chronological refinements are correct, then the sedimentary records suggest much greater persistence to the 8th century megadrought than indicated by the very high resolution tree-ring data, and a strong second pulse of prolonged drought late in the first millennium. Analyses of instrumental precipitation and drought indices during the 20th century, along with tree-ring reconstructions of climate in Mexico and the Southwest, indicate that annual and decadal droughts can both simultaneously impact the entire region from New Mexico and Texas down into central Mexico. The intensity and large-scale impact of drought across this region seem to be greatest when La Nina conditions and the low phase of the North Pacific oscillation prevail. The tree-ring dated 8th century megadrought occurred near the decline of the Classic Period civilizations at Teotihuacan in central Mexico and in the Mayan region of the Yucatan. The 8th century megadrought may have interacted with anthropogenic environmental degradation, epidemic disease, and social upheaval to contribute to the collapse of the Classic Period in Mesoamerica.
Publication:
American Geophysical Union, Fall Meeting 2002, abstract id.PP71C-04
Pub Date:
December 2002
Bibcode:
Keywords:
• 1812 Drought;
• 3344 Paleoclimatology;
• 4221 Dendrochronology
Water resources research, 1992
Tree ring indices from an expanded network of 17 white oak (Quercus alba) sites in eastern and ce... more Tree ring indices from an expanded network of 17 white oak (Quercus alba) sites in eastern and central Iowa were used to reconstruct state average July Palmer hydrological drought index (PHDI), annual precipitation (previous August to current July), and other climate variables for 1640-1982. We removed nonclimatic variance trends caused by changing sample size and senescent growth. July PHDI correlated better with tree growth than annual precipitation. Occurrence of prolonged droughts throughout the reconstruction suggests that decades like the 1930s occur about twice per century in Iowa. Iowa climate is correlated with the Southern Oscillation Index (SO1) from June in the year of El Nifio onset (Yr0) through the next February (Yr+ 1), with negative SO1 (El Nifio) associated with wetter conditions. When the June (Yr0) to February (Yr+ 1) average SOI reaches extremes >+ 1.0 or-<-1.0, it correlates significantly with observed and reconstructed July PHDI (r =-0.37 and-0.56, respectively). Climate during solar cycles centered on sunspot minima alternates between wet and dry regimes that differ by an average of 1.21 units of observed July PHDI and 46.7 mm of annual precipitation for 1877-1982. The solar relationship has been stable since 1640. Combining solar and SO1 influences in forecasts may improve prediction of Iowa climate. 1. INTRODUCTION Iowa agriculture suffers major losses from drought. For example, the average annual value of Iowa's corn and soybean crops from 1978 to 1987 was $5.3 billion [U.S. Department of Agriculture, 1979-1989], and the 1988 drought caused combined losses of about $1.35 billion in corn and soybean yields at those prices. Knowledge of the long-term frequency and magnitude of growing season drought would help determine the likelihood of future crop losses and could improve drought prediction and contingency planning. Although statewide precipitation records begin in 1873 and contain several drought years comparable to 1988, a much longer record is required to draw conclusions about the frequency of such rare drought occurrences. Tree rings that respond to soil moisture changes provide a means of investigating climate before weather observations become available [Fritts, 1976] and of exploring possible long-term changes in frequency of extreme events [Stahle and Cleaveland, 1988]. In an initial study, Duvick and Blasing [1981] related ring widths of white oak (Quercus alba L.) to annual precipitation ending in July of the growing season. Ring width indices from three sites in central Iowa yielded estimates of annual (August-July) precipitation from 1680 to 1979. Six decades comparable to the 1930s in dryness were found, and 12 consecutive years of subnormal precipitation appeared to have occurred in the early 1800s. Blasing and Duvick [1984] used tree ring indices from seven sites in Iowa plus seven sites in Illinois to produce a 300-year (1680-1979) series of annual precipitation estimates for the two-state region. The 10-year running averages for this series indicated a poorly defined cycle of about 20 years which was most evident before 1800 but accounted for no more than 10% of the variance.
A 963-year reconstruction of summer (JJA) stream flow in the White River, Arkansas, USA, from tree-rings
The Holocene, 2000
An average of three baldcypress ( Taxodium distichum) ring-width chronologies was used to recon s... more An average of three baldcypress ( Taxodium distichum) ring-width chronologies was used to recon struct total summer (JJA) mean daily flow of the White River at Clarendon, Arkansas, for years 1023–1985. A quadratic transformation of the tree-ring data accounted for 68% (R2 adjusted for degrees of freedom lost) when regressed against total summer flow 1931–1985. The distribution of the quadratic reconstruction matched the gauged distribution much better than a simple linear model which only accounted for 62% of the variance. The model was validated by comparing regression estimates against independent data. Years with summer flow below the 25th percentile occur nonrandomly, i.e., they tend to cluster, in both the reconstructed and gauged data. Hydrologic regimes have apparently varied considerably in the past on annual to century time-scales, with extended dry and wet periods that exceeded anything in the modern record. The frequency of both wet and dry extremes has varied considerably over the last millennium. The eleventh through thirteenth cen turies were not analysed due to reduced replication, but the well-replicated fourteenth and twentieth centuries both have large numbers of extremes. The twentieth century appears to have more extreme low flows than the previous centuries and also to have a large number of high flows. The practical consequences for society of variation in extremes and persistence of low flows may be considerable. Climatic change or anthropogenic changes to the watershed (e.g., widespread upland clearing for agriculture and logging of bottomland forests) may be responsible for the change in hydrologic regime during the twentieth century.
Forest Ecology and Management, Dec 1, 1999
Dendrochronological analyses indicate that Pterocarpus angolensis produces anatomically distincti... more Dendrochronological analyses indicate that Pterocarpus angolensis produces anatomically distinctive annual growth rings in the indigenous forests of western Zimbabwe. Annual growth rings in P. angolensis can be identi®ed on highly polished crosssectional surfaces on the basis of the semi-ring porous tree rings; the reasonably continuous band of initial parenchyma; and by smaller changes in vessel diameter, wood density, and color from the early-wood to late-wood portion of the growth rings. Together, four lines of evidence indicate that these growth bands are annual: P. angolensis is strongly deciduous and the phenology of this species is tightly synchronized with the seasonality of rainfall in western Zimbabwe; the growth rings are semi-ring porous; ring-width time series are highly correlated between trees at a single forest location, and between forests separated by >100 km; and also because the mean ring-width chronologies derived from these trees are signi®cantly correlated with regional rainfall totals during the wet season from 1901±1990. P. angolensis is one of the most valuable timber species in south tropical Africa, and the discovery of exactly annual growth rings will allow detailed analyses of the growth and yield under different ecological and management settings. It may also be possible to develop centuries-long tree-ring chronologies from P. angolensis, which would be useful for the reconstruction of past climate and stream¯ow.
Atlantic and Pacific Influences on Mesoamerican Climate Over the Past Millennium (Invited)
AGUFM, Dec 1, 2010
Montezuma baldcypress (Taxodium mucronatum) trees in Queretaro have been used to develop the firs... more Montezuma baldcypress (Taxodium mucronatum) trees in Queretaro have been used to develop the first exactly dated millennium-long tree-ring chronology in central Mexico. The chronology is sensitive to both precipitation and temperature, and has been used to reconstruct the Palmer Drought Severity Index (PDSI) for June from AD 771-2008 for a large sector of Mesoamerica (most of central and southern Mexico).
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PR Papers by Malcolm K Cleaveland
Papers by Malcolm K Cleaveland
• Stahle, D. W. ;
• Therrell, M. D. ;
• Cleaveland, M. K. ;
• Fye, F. K. ;
• Cook, E. R. ;
• Grissino-Mayer, H. D. ;
• Acuna-Soto, R.
Abstract
Tree-ring data suggest that the 8th and 16th century megadroughts may have been the most severe and sustained droughts to impact North America in the past 1500 years. The 16th century megadrought may have persisted for up to 40 years, and extended from the tropics to the boreal forest and from the Pacific to Atlantic coasts. Evidence for the 8th century drought is sparse, but tree-ring and lake sediment data indicate that this drought extended from the northern Great Plains, across the southwestern United States, and into central Mexico and the Yucatan peninsula. Tree-ring data from Colorado and New Mexico document severe drought from A.D. 735-765, and may provide accurate and precise dating for the onset of the epic droughts reconstructed during the late first millennium A.D. with sedimentary data from Elk Lake, Minnesota; Moon Lake, South Dakota; La Piscina de Yuriria, Guanajuato; and Lake Chichancanab, Yucatan. If these chronological refinements are correct, then the sedimentary records suggest much greater persistence to the 8th century megadrought than indicated by the very high resolution tree-ring data, and a strong second pulse of prolonged drought late in the first millennium. Analyses of instrumental precipitation and drought indices during the 20th century, along with tree-ring reconstructions of climate in Mexico and the Southwest, indicate that annual and decadal droughts can both simultaneously impact the entire region from New Mexico and Texas down into central Mexico. The intensity and large-scale impact of drought across this region seem to be greatest when La Nina conditions and the low phase of the North Pacific oscillation prevail. The tree-ring dated 8th century megadrought occurred near the decline of the Classic Period civilizations at Teotihuacan in central Mexico and in the Mayan region of the Yucatan. The 8th century megadrought may have interacted with anthropogenic environmental degradation, epidemic disease, and social upheaval to contribute to the collapse of the Classic Period in Mesoamerica.
Publication:
American Geophysical Union, Fall Meeting 2002, abstract id.PP71C-04
Pub Date:
December 2002
Bibcode:
Keywords:
• 1812 Drought;
• 3344 Paleoclimatology;
• 4221 Dendrochronology