The North American tree-ring fire-scar network

Fire regimes in North American forests are diverse and modern fire records are often too short to capture important patterns, trends, feedbacks, and drivers of variability. Tree-ring fire scars provide valuable perspectives on fire regimes, including centuries-long records of fire year, season, frequency, severity, and size. Here, we introduce the newly compiled North American tree-ring fire-scar network (NAFSN), which contains 2562 sites, >37,000 fire-scarred trees, and covers large parts of North America. We investigate the NAFSN in terms of geography, sample depth, vegetation, topography, climate, and human land use. Fire scars are found in most ecoregions, from boreal forests in northern Alaska and Canada to subtropical forests in southern Florida and Mexico. The network includes 91 tree species, but is dominated by gymnosperms in the genus Pinus. Fire scars are found from sea level to >4000-m elevation and across a range of topographic settings that vary by ecoregion. Multiple regions are densely sampled (e.g., >1000 fire-scarred trees), enabling new spatial analyses such as reconstructions of area burned. To demonstrate the potential of the network, we compared the climate space of the NAFSN to those of modern fires and forests; the NAFSN spans a climate space largely representative of the forested areas in North America, with notable gaps in warmer tropical climates. Modern fires are burning in similar climate spaces as historical fires, but disproportionately in warmer regions compared to the historical record, possibly related to under-sampling of warm subtropical forests or supporting observations of changing fire regimes. The historical influence of Indigenous and non-Indigenous human land use on fire regimes varies in space and time. A 20th century fire deficit associated with human activities is evident in many regions, yet fire regimes characterized by frequent surface fires are still active in some areas (e.g., Mexico and the southeastern United States). These analyses provide a foundation and framework for future studies using the hundreds of thousands of annually- to sub-annually-resolved tree-ring records of fire spanning centuries, which will further advance our understanding of the interactions among fire, climate, topography, vegetation, and humans across North America

Tropical tree growth driven by dry-season climate variability

Interannual variability in the global land carbon sink is strongly related to variations in tropical temperature and rainfall. This association suggests an important role for moisture-driven fluctuations in tropical vegetation productivity, but empirical evidence to quantify the responsible ecological processes is missing. Such evidence can be obtained from tree-ring data that quantify variability in a major vegetation productivity component: woody biomass growth. Here we compile a pantropical tree-ring network to show that annual woody biomass growth increases primarily with dry-season precipitation and decreases with dry-season maximum temperature. The strength of these dry-season climate responses varies among sites, as reflected in four robust and distinct climate response groups of tropical tree growth derived from clustering. Using cluster and regression analyses, we find that dry-season climate responses are amplified in regions that are drier, hotter and more climatically variable. These amplification patterns suggest that projected global warming will probably aggravate drought-induced declines in annual tropical vegetation productivity. Our study reveals a previously underappreciated role of dry-season climate variability in driving the dynamics of tropical vegetation productivity and consequently in influencing the land carbon sink.We acknowledge financial support to the co-authors provided by Agencia Nacional de Promoción Científica y Tecnológica, Argentina (PICT 2014-2797) to M.E.F.; Alberta Mennega Stichting to P.G.; BBVA Foundation to H.A.M. and J.J.C.; Belspo BRAIN project: BR/143/A3/HERBAXYLAREDD to H.B.; Confederação da Agricultura e Pecuária do Brasil - CNA to C.F.; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES, Brazil (PDSE 15011/13-5 to M.A.P.; 88881.135931/2016-01 to C.F.; 88887.199858/2018-00 to G.A.-P.; Finance Code 001 for all Brazilian collaborators); Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq, Brazil (ENV 42 to O.D.; 1009/4785031-2 to G.C.; 311874/2017-7 to J.S.); CONACYT-CB-2016-283134 to J.V.-D.; CONICET to F.A.R.; CUOMO FOUNDATION (IPCC scholarship) to M.M.; Deutsche Forschungsgemeinschaft - DFG (BR 1895/15-1 to A.B.; BR 1895/23-1 to A.B.; BR 1895/29-1 to A.B.; BR 1895/24-1 to M.M.); DGD-RMCA PilotMAB to B.T.; Dirección General de Asuntos del Personal Académico of the UNAM (Mexico) to R.B.; Elsa-Neumann-Scholarship of the Federal State of Berlin to F.S.; EMBRAPA Brazilian Agricultural Research Corporation to C.F.; Equatorian Dirección de Investigación UNL (21-DI-FARNR-2019) to D.P.-C.; São Paulo Research Foundation FAPESP (2009/53951-7 to M.T.-F.; 2012/50457-4 to G.C.; 2018/01847‐0 to P.G.; 2018/24514-7 to J.R.V.A.; 2019/08783-0 to G.M.L.; 2019/27110-7 to C.F.); FAPESP-NERC 18/50080-4 to G.C.; FAPITEC/SE/FUNTEC no. 01/2011 to M.A.P.; Fulbright Fellowship to B.J.E.; German Academic Exchange Service (DAAD) to M.I. and M.R.; German Ministry of Education, Science, Research, and Technology (FRG 0339638) to O.D.; ICRAF through the Forests, Trees, and Agroforestry research programme of the CGIAR to M.M.; Inter-American Institute for Global Change Research (IAI-SGP-CRA 2047) to J.V.-D.; International Foundation for Science (D/5466-1) to M.I.; Lamont Climate Center to B.M.B.; Miquelfonds to P.G.; National Geographic Global Exploration Fund (GEFNE80-13) to I.R.; USA’s National Science Foundation NSF (IBN-9801287 to A.J.L.; GER 9553623 and a postdoctoral fellowship to B.J.E.); NSF P2C2 (AGS-1501321) to A.C.B., D.G.-S. and G.A.-P.; NSF-FAPESP PIRE 2017/50085-3 to M.T.-F., G.C. and G.M.L.; NUFFIC-NICHE programme (HEART project) to B.K., E.M., J.H.S., J.N. and R. Vinya; Peru ‘s CONCYTEC and World Bank (043-2019-FONDECYT-BM-INC.INV.) to J.G.I.; Peru’s Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT-BM-INC.INV 039-2019) to E.J.R.-R. and M.E.F.; Programa Bosques Andinos - HELVETAS Swiss Intercooperation to M.E.F.; Programa Nacional de Becas y Crédito Educativo - PRONABEC to J.G.I.; Schlumberger Foundation Faculty for the Future to J.N.; Sigma Xi to A.J.L.; Smithsonian Tropical Research Institute to R. Alfaro-Sánchez.; Spanish Ministry of Foreign Affairs AECID (11-CAP2-1730) to H.A.M. and J.J.C.; UK NERC grant NE/K01353X/1 to E.G.Peer reviewe

Reconstrucción de 350 años de precipitación para el suroeste de Chihuahua, México

En el suroeste del estado de Chihuahua, México, en la reserva “Cerro El Mohinora” se desarrollaron series de tiempo dendrocronológicas de madera temprana, tardía y anillo total de Pseudotsuga menziesii con una longitud de tres siglos y medio (1657-2005), con el objetivo de analizar la variabilidad hidroclimática histórica de la región. La reconstrucción de precipitación invierno-primavera indica gran variabilidad interanual, decenal y multidecenal de los patrones de precipitación para la región. Sequías severas se reconstruyeron para los periodos 1695-1715, 1753-1760, 1785-1792, 1798-1806, 1819-1830, 1841-1870, 1890-1897, 1906-1912, 1924-1941, 1971-1977 y 1994-2005, aunque las sequías más prolongadas ocurrieron en los periodos 1695-1715, 1841-1870 y 1924-1941. Las últimas tres décadas del siglo XX y los años corrientes de la primera década del siglo XXI (1971-2005) indican un periodo de intensa sequía para la región, con impactos en lo ecológico y socioeconómico aun no cuantificados

Historic Variability of the Water Inflow to the Lazaro Cardenas Dam and Water Allocation in the Irrigation District 017, Comarca Lagunera, Mexico

An assemblage of tree-ring chronologies for the Nazas (NZW) in the Western Sierra Madre (WSM), Mexico was developed to determine water inflow at the Lazaro Cardenas Dam (LCD), the main source of water for surface irrigation in the Irrigation District 017 (DDR 017), Comarca Lagunera. A Principal Component Analysis of the ring-width chronologies was conducted to determine a common climate signal, and a stepwise model based on selected chronologies of the PC1 (CBA, COC) and PC2 (ARN) were used to develop a water inflow reconstruction to the Lazaro Cardenas Dam (LCD) extending from 1753 to 2003 (251 years), resulting in the following significant findings: the warm phase of the El Niño Southern Oscillation (ENSO) in the winter-spring season had a significant influence (SOI; Dec–Feb = −0.24, p < 0.01), but the North American Monsoon System (NAMS) was the most important in determining the water yield in the summer season (r = 0.48, p < 0.01). Water gauge inflow records (77 years) at the LCD used to determine the annual allocation of water for agriculture in the irrigation district 017 was an average of 1676 × 106 m3, where the maximum annual water outflow allowed of 1100 × 106 m3 for safety reasons, the dam infrastructure was released in 74% of the years and increasing to 78% when considering the reconstructed inflow. Prolonged drought episodes lasting more than 10 consecutive years were detected in the reconstructed inflow, information that could be used by decision makers to establish proper irrigation management strategies to ameliorate the economic and social impact when these extreme hydroclimatic events may occur. © 2022 by the authors.Open access journalThis 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]

Nuorrutetun teräsaihion kovuusjakauman määrittäminen

Sierra de Manantlán Biosphere Reserve (RBSM) in Jalisco is the most important reserve in western Mexico, where fres are one of the main forest disturbances. In order to reconstruct historical fre regimes, partial sections of Pinus douglasiana with fre scars were collected. Using dendrochronological techniques, the exact dating of 293 scars from 51 trees allowed the reconstruction of fre frequency for the period 1867-2010. We reconstructed mean fre interval of 5.5 years (MFI: all scars) and 3.6 years for the Weibull mean probability interval (WMPI). The MFI (≥ 25% scarred) was 8.9 years and WMPI was 6.9 years. The seasonal patterns of fre occurrence showed that most fres (68.3%) were formed in middle earlywood, 30% in early earlywood and 1.7% in late earlywood. Considering the phenology of the species, it was determined that 98.3% of fres occurred in spring and 1.7% at the beginning of summer. The fres were recorded in dry years, but the relationship was not statistically significant. A strong relationship between droughts and widespread fres was observed. Likewise, it was determined that climate variability was strongly related to ENSO; fres reconstructed from 1956 to 2010 correspond with both El Niño and La Niña events

Pacific and Atlantic influences on Mesoamerican climate over the past millennium

A new tree-ring reconstruction of the Palmer Drought Severity Index (PDSI) for Mesoamerica from AD 771 to 2008 identifies megadroughts more severe and sustained than any witnessed during the twentieth century. Correlation analyses indicate strong forcing of instrumental and reconstructed June PDSI over Mesoamerica from the El Niño/Southern Oscillation (ENSO). Spectral analyses of the 1,238-year reconstruction indicate significant concentrations of variance at ENSO, sub-decadal, bi-decadal, and multidecadal timescales. Instrumental and model-based analyses indicate that the Atlantic Multidecadal Oscillation is important to warm season climate variability over Mexico. Ocean-atmospheric variability in the Atlantic is not strongly correlated with the June PDSI reconstruction during the instrumental era, but may be responsible for the strong multidecadal variance detected in the reconstruction episodically over the past millennium. June drought indices in Mesoamerica are negatively correlated with gridded June PDSI over the United States from 1950 to 2005, based on both instrumental and reconstructed data. Interannual variability in this latitudinal moisture gradient is due in part to ENSO forcing, where warm events favor wet June PDSI conditions over the southern US and northern Mexico, but dryness over central and southern Mexico (Mesoamerica). Strong anti-phasing between multidecadal regimes of tree-ring reconstructed June PDSI over Mesoamerica and reconstructed summer (JJA) PDSI over the Southwest has also been detected episodically over the past millennium, including the 1950-1960s when La Niña and warm Atlantic SSTs prevailed, and the 1980-1990s when El Niño and cold Atlantic SSTs prevailed. Several Mesoamerican megadroughts are reconstructed when wetness prevailed over the Southwest, including the early tenth century Terminal Classic Drought, implicating El Niño and Atlantic SSTs in this intense and widespread drought that may have contributed to social changes in ancient Mexico. © 2011 Springer-Verlag

Major Mesoamerican droughts of the past millennium

Ancient Montezuma baldcypress (Taxodium mucronatum) trees found in Barranca de Amealco, Queretaro, have been used to develop a 1,238-year tree-ring chronology that is correlated with precipitation, temperature, drought indices, and crop yields in central Mexico. This chronology has been used to reconstruct the spring-early summer soil moisture balance over the heartland of the Mesoamerican cultural province, and is the first exactly dated, annually resolved paleoclimatic record for Mesoamerica spanning the Late Classic, Post Classic, Colonial, and modern eras. The reconstruction indicates that the Terminal Classic drought extended into central Mexico, supporting other sedimentary and speleothem evidence for this early 10th century drought in Mesoamerica. The reconstruction also documents severe and sustained drought during the decline of the Toltec state (1149-1167) and during the Spanish conquest of the Aztec state (1514-1539), providing a new precisely dated climate framework for Mesoamerican cultural change. Copyright 2011 by the American Geophysical Union

Feeding ecology of the catfish Ictalurus punctatus(Siluriformes: Ictaluridae) in a reservoir in Northeast Mexico

Objective: To determine the main food of the catfish according to seasonal variability and the sex of the organism in the Venustiano Carranza Dam, Coahuila, Mexico. Methodology: In total, 143 catfish stomachs from different seasons were examined. In the analysis of the stomach content, the detected organisms were determined until the taxonomic order rank. The seasonal and sex feeding variability were also analyzed. The Relative Importance Index and the Alimentary Index were applied. Non-parametric tests were carried out to compare stomach content between seasons and sexes. Results: The total annual trophic spectrum for catfish consisted of 13 items, of which only the order Ephemeroptera was categorized as a frequent food. In the winter season the catfish consumed significantly more food compared to the other seasons, but there was no difference in the amount consumed by females and males (p0.05). Implications: This information is relevant to highlight the importance of the biological integrity of the terrestrial site which surrounds the reservoir as a source of food for the catfish. Conclusions: Catfish channel in the Venustiano Carranza Dam is a generalist species (13 alimentary items). There was a difference in food consumed during the different seasons of the year. However, there was no difference between the sexe

Tropical tree growth driven by dry-season climate variability

Interannual variability in the global land carbon sink is strongly related to variations in tropical temperature and rainfall. This association suggests an important role for moisture-driven fluctuations in tropical vegetation productivity, but empirical evidence to quantify the responsible ecological processes is missing. Such evidence can be obtained from tree-ring data that quantify variability in a major vegetation productivity component: woody biomass growth. Here we compile a pantropical tree-ring network to show that annual woody biomass growth increases primarily with dry-season precipitation and decreases with dry-season maximum temperature. The strength of these dry-season climate responses varies among sites, as reflected in four robust and distinct climate response groups of tropical tree growth derived from clustering. Using cluster and regression analyses, we find that dry-season climate responses are amplified in regions that are drier, hotter and more climatically variable. These amplification patterns suggest that projected global warming will probably aggravate drought-induced declines in annual tropical vegetation productivity. Our study reveals a previously underappreciated role of dry-season climate variability in driving the dynamics of tropical vegetation productivity and consequently in influencing the land carbon sink.Fil: Zuidema, Pieter A.. University of Agriculture Wageningen; Países BajosFil: Babst, Flurin. University of Arizona; Estados UnidosFil: Groenendijk, Peter. Universidade Estadual de Campinas; BrasilFil: Trouet, Valerie. University of Arizona; Estados UnidosFil: Abiyu, Abrham. World Agroforestry Centre; KeniaFil: Acuña Soto, Rodolfo. Universidad Nacional Autónoma de México; MéxicoFil: Adenesky Filho, Eduardo. Universidade Regional de Blumenau; BrasilFil: Alfaro Sánchez, Raquel. Wilfrid Laurier University; CanadáFil: Aragão, José Roberto Vieira. Universidade Estadual de Campinas; BrasilFil: Assis Pereira, Gabriel. Universidade de Sao Paulo; Brasil. Universidad Federal de Lavras; BrasilFil: Bai, Xue. Chinese Academy of Sciences; República de ChinaFil: Barbosa, Ana Carolina. Universidad Federal de Lavras; BrasilFil: Battipaglia, Giovanna. Seconda Universita Degli Studi Di Napoli; ItaliaFil: Beeckman, Hans. Royal Museum For Central Africa; BélgicaFil: Botosso, Paulo Cesar. Embrapa Forestry; BrasilFil: Bradley, Tim. U.S. Department of Agriculture; Estados UnidosFil: Bräuning, Achim. Universitat Erlangen Nuremberg; AlemaniaFil: Brienen, Roel. University of Leeds; Reino UnidoFil: Buckley, Brendan M.. Columbia University; Estados UnidosFil: Camarero, J. Julio. Instituto Pirenaico de Ecología; EspañaFil: Carvalho, Ana. Universidad de Coimbra; PortugalFil: Ceccantini, Gregório. Universidade de Sao Paulo; BrasilFil: Centeno Erguera, Librado R.. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias; MéxicoFil: Cerano Paredes, Julián. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias; MéxicoFil: Chávez-Durán, Álvaro Agustín. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias; MéxicoFil: Cintra, Bruno Barçante Ladvocat. Universidade de Sao Paulo; BrasilFil: Cleaveland, Malcolm K.. University of Arkansas for Medical Sciences; Estados UnidosFil: Couralet, Camille. Royal Museum For Central Africa; BélgicaFil: D?Arrigo, Rosanne. Columbia University; Estados UnidosFil: del Valle, Jorge Ignacio. Universidad Nacional de Colombia; ColombiaFil: Ferrero, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lopez Callejas, Lidio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Mayor; Chil