Plastic adjustments in xylem vessel traits to drought events in three Cedrela species from Peruvian Tropical Andean forests

Cedrela species occur within the Tropical montane cloud forest (TMCF) and rainforest in North America (Mexico), Central and South America. We assessed the hypothesis that functional xylem hydraulic architecture might be influenced by specific climatic variations. We investigated the effect of climate on tree-ring width and vessel traits (diameter, vessel density, vulnerability index and hydraulic diameter) of three relict-endemic and threatened Cedrela species (Cedrela fissilis, C. nebulosa and C. angustifolia) inhabiting Peruvian Tropical Andean cloud forests. All Cedrela species showed a significant reduction in radial growth and adjusted vessel trait linked with temperature, precipitation, and evapotranspiration. Ring-width and vessel traits showed adaptation within Cedrela species, crucial to understanding a rough indication of the plant’s ability to withstand drought-induced embolism or cavitation. Our results provide evidence for hydraulic mechanisms that determine specific wood anatomical functionality to climatic variation and drought responses. Therefore, changing the frequency or intensity of future drought events might exceed the adaptive limits of TMCF tree species, resulting in a substantial reduction of hydraulic functionality in Peruvian Cedrela species.Fil: Rodríguez Ramírez, Ernesto C.. Universidad Continental; PerúFil: 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: Acevedo-Vega, Ingrith. Universidad Continental; PerúFil: Crispin DelaCruz, Doris B.. Universidad Continental; Perú. Universidade Federal de Pernambuco; BrasilFil: Ticse Otarola, Ginette Vilma Alicia. Universidad Continental; Perú. Asociación ANDINUS; PerúFil: Requena Rojas, Edilson Jimmy. Universidad Continental; Per

Revealing Polylepis microphylla as a suitable tree species for dendrochronology and quantitative wood anatomy in the Andean montane forests

In the tropical Andes climate change is expected to increase temperatures and change precipitation patterns. To overcome the lack of systematic weather records that limits the performance of climate models in this region, the use of the environmental information contained in tree rings from tropical Andean species have been found useful to reconstruct spatio-temporal climate variability. Because classical dendrochronology based on ring-width patterns is often challenging in the tropics, alternative approaches such as Quantitative Wood Anatomy (QWA) based on the measurement and quantification of anatomical traits within tree rings can be a significant advance in the field. Here we assess the dendrochronological potential of Polylepis microphylla and its climate sensitivity by using i) classic dendrochronological methods to generate the first Tree-ring Width (TRW) chronology for this tree species spanning from 1965 to 2018; ii) radiocarbon (¹⁴C) analyses as an independent validation method to assess the annual periodicity of the tree growth layers; and iii) QWA to generate tree-ring annual records of the number (VN) and size (VS) of vessels to investigate the climate sensitivity of these anatomical traits. The annual periodicity in P. microphylla radial growth was confirmed by both dendrochronological and ¹⁴C analyses. We found that VN and VS are promising new proxies to reconstruct climate variability in this region and that they provide different information than TRW. While TRW provides information at inter-annual resolution (i.e., year-to-year variability), VN and VS generated with sectorial QWA provide intra-annual resolution for each stage of the growing process. The TRW and the anatomical traits (i.e., VN and VS) showed strong positive correlation with maximum temperature for different periods of the growing season: while VS is higher with warmer conditions prior to the growing season onset, tree-rings are wider and present higher number of vessels when warmer conditions occur during the current growing season. Our findings pointed out the suitability of P. microphylla for dendrochronological studies and may suggest a good performance of this species under the significant warming expected according to future projections for the tropical Andes.Fil: Rodríguez Morata, C.. Columbia University; Estados UnidosFil: Pacheco Solana, A.. Columbia University; Estados UnidosFil: Ticse Otarola, Ginette Vilma Alicia. Universidad Continental; Perú. Asociación ANDINUS; PerúFil: Boza Espinoza, T. E.. Pontificia Universidad Católica de Perú; PerúFil: Crispín-DelaCruz, D.B.. Universidad Federal Rural Pernambuco; Brasil. Universidad Continental; PerúFil: Santos, G. M.. University of California; Estados UnidosFil: Morales, Mariano Santos. 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 Continental; PerúFil: Requena Rojas, Edilson Jimmy. Universidad Continental; PerúFil: Andreu Hayles, Laia. Institució Catalana de Recerca I Estudis Avançats; España. Consejo Superior de Investigaciones Científicas. Centre de Recerca Ecológica I Aplicacions Forestals; España. Columbia University; Estados Unido

Forçamento radiativo direto devido a propriedades de aerossóis na estação antártica peruana e na área metropolitana de Huancayo

We describe the results of the study of aerosol optical depth (AOD) and Direct Radiative Forcing (DRF) in Top Of Atmosphere (TOA), obtained from the measurement and monitoring campaign carried out during the XXI Antarctic Peruvian Expedition in the months of January and February 2013 and in the Metropolitan Huancayo Area in the months of June and July 2019. In the Scientific Peruvian Station at Antarctic “Machu Picchu” our used a SP02-L sun photometer, which is within the instrumental framework of the International Polar Year. This instrument has 4 channels: 412 nm, 500 nm, 675 nm and 862 nm, thus allowing direct radiation spectra measurements. And in the MHA we used the BF5 sensor. This instrument measured Direct, Diffuse and Global Radiation in low wavelength. The results calculated of AOD in polar latitudes varied between 0.0646 to 0.1061, in relation to AOD in MHA, presents the value maximum that is 0.58 (11 of June) and minimum that is 0.19 (12 June). The Angstrom coefficient was determined have values ranging from 0 to 0.07, these values also indicates the presence of big particles. Also to the MHA presents the mean value varied from 0 to 1.8, that indicated the presence the aerosols types biomass burning and industrial. Recorded optical properties used to estimate the direct aerosol radiative forcing (DARF) at the top of the atmosphere. The results indicates that on King George Island site the DARF is between [-2 4] W/m2; also, the direct aerosol radiative forcing in MHA is between [0 20] W/m2.Descrevemos os resultados do estudo da profundidade ótica do aerossol (POA) e do Forçamento Radiativo Direto (FRD) no topo da atmosfera (TOA), obtidos durante a campanha de medição e monitoramento, XXI Expedição Antártica do Peru, entre os meses de janeiro e fevereiro de 2013, e na área metropolitana de Huancayo (AMH) entre os meses de junho e julho de 2019. Na Estação Antártica Peruana Machu Picchu utilizou-se um fotômetro solar SP02-L. Tal instrumento possui 4 canais: 412 nm, 500 nm, 675 nm e 862 nm, permitindo realizar medições diretas do espectro de radiação visível. Na AMH usamos o sensor BF5, que mede a radiação direta, difusa e global em comprimento de onda curta. Os cálculos de AOD em latitudes polares variaram entre 0,0646 e 0,1061. Na AMH apresenta valor máximo de 0,58 (11 de junho) e mínimo de 0,19 (12 de junho). Determinou-se o coeficiente de Angstrom variando de 0 a 0,07, esses valores indicam a presença de partículas grandes. Na AMH varia de 0 a 1,8, que indica a presença de aerossóis de fonte de queima de biomassa e industrial. As propriedades óticas observadas foram usadas para estimar a forçante radiativa direta por aerossóis (FRDA) no topo da atmosfera. Os resultados indicam que no King George Island, o FRDA, está entre -2 e 4 W/m2; já para a AMH a forçante radiativa direta de aerossol está entre 0 e 20 W/m2.Revisión por paresCampus Huancay

The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

Dendroclimatological assessment of Polylepis rodolfo-vasquezii: a novel Polylepis species in the Peru highlands

In spite of enormous diversity in tree species, dendrochronological records in the tropical Andes are very scarce. Therefore, it is necessary to increase the search for new tree species with high dendrochronological characteristics in the tropical Andes, including the humid Puna of Peru. We present the first tree-ring chronology from Polylepis rodolfo-vasquezii, a recently described tree species in the Central Andes of Peru between 4000 and 4400 m elevation. Fifty trees were sampled in the district of Comas, Peru. After establishing the anatomical characteristics that delimit the annual growth rings, we developed a ring-width chronology by applying conventional dendrochronological techniques. The chronology covers the period 1869–2015 (157 years) and is well replicated from 1920 to present (> 20 samples). The statistics used to evaluate the quality of the chronology indicate that the P. rodolfo-vasquezii has similar values of MS, RBAR and EPS to those shown by other Polylepis spp chronologies. To determine the main climatic factors controlling the growth of P. rodolfo-vasquezii, we compared our chronology with local and regional temperature and precipitation records. Growth season temperature (November to May) seems to be the main climatic factor modulating inter-annual variations in the growth of this species. The sensitivity to inter-annual temperature variations highlights the potential of P. rodolfo-vasquezii to provide climatically sensitive dendrochronological records in the Central Andes. To our knowledge, this is the first tree-ring record in South America displaying significant relationships with temperature over the tropical Atlantic Ocean.Fil: Requena Rojas, Edilson Jimmy. Universidad Continental; PerúFil: Morales, Mariano Santos. 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: Villalba, Ricardo. 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; Argentin

Assessing dendrochronological potential of Escallonia myrtilloides in the high Andes of Peru

There is a significant dendrochronological gap in the Puna of the central Andes of Peru, which motivates research on new species. In this study, we present the first tree-ring chronologies of Escallonia myrtilloides. We collected samples at San Pedro Saño and Sapallanga in Peru, analyzed the anatomical characteristics that delimit the annual growth rings, and developed two tree-ring chronologies through conventional dendrochronological techniques. The tree-ring chronologies cover the period 1940-2015 (76 years) for San Pedro Saño and 1960-2015 (56 years) for Sapallanga. The E. myrtilloides chronologies presented similar values of mean sensitivity, Rbar and EPS to those recorded for Polylepis tarapacana, Polylepis pepei, and Polylepis rugulosa in the Puna region. The analysis of the climate-growth relationships indicated positive correlations with precipitation and negative correlations with temperature in particular months of the current growing season (October-April). This precipitation/temperature-sensitive record highlights the high value of E. myrtilloides for future studies on the influence of climate on tree growth in the central Andes. ©Fil: Requena Rojas, Edilson Jimmy. Universidad Continental; PerúFil: Amoroso, Mariano Martin. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Ticse Otarola, Ginette. Universidad Continental; PerúFil: Crispin Delacruz, Doris B.. Universidad Continental; Per

Assessing dendrochronological potential of escallonia myrtilloides in the high Andes of Peru

There is a significant dendrochronological gap in the Puna of the central Andes of Peru, which motivates research on new species. In this study, we present the first tree-ring chronologies of Escallonia myrtilloides. We collected samples at San Pedro Saño and Sapallanga in Peru, analyzed the anatomical characteristics that delimit the annual growth rings, and developed two tree-ring chronologies through conventional dendrochronological techniques. The tree-ring chronologies cover the period 1940–2015 (76 years) for San Pedro Saño and 1960–2015 (56 years) for Sapallanga. The E. myrtilloides chronologies presented similar values of mean sensitivity, Rbar and EPS to those recorded for Polylepis tarapacana, Polylepis pepei, and Polylepis rugulosa in the Puna region. The analysis of the climate-growth relationships indicated positive correlations with precipitation and negative correlations with temperature in particular months of the current growing season (October–April). This precipitation/temperature-sensitive record highlights the high value of E. myrtilloides for future studies on the influence of climate on tree growth in the central Andes

Assessing the Hydric Deficit on Two <i>Polylepis</i> Species from the Peruvian Andean Mountains: Xylem Vessel Anatomic Adjusting

The impact of drought on vessel architecture and function has been broadly assessed for a variety of tree species in the last decades, but the hydraulic plasticity under temperature increase has scarcely been studied. The effect of drought on tree-ring width and specific hydraulic conductivity depends on relict-tree species resilience to climatic adaptability and its wood anatomical responses to climatic oscillations. We assessed the vessel architecture adaptation of two threatened Peruvian Andean Polylepis species (P. rodolfo-vasquezii and P. tarapacana). We found that historical Peruvian drought years differentially affected Polylepis species, where P. rodolfo-vasquezii showed vessel anatomical features significantly sensitive to drought events when contrasted with P. tarapacana. The drought effect influenced the capacity of Polylepis species to adjust the tree-ring width and vessel anatomical traits of their hydraulic system. Our results suggest that drought events influence Polylepis species’ adaptability and resilience to dry periods and could also restrict them from remaining as a part of the Peruvian Andean puna and mountain ecosystems

Assessing the Hydric Deficit on Two Polylepis Species from the Peruvian Andean Mountains: Xylem Vessel Anatomic Adjusting

The impact of drought on vessel architecture and function has been broadly assessed for a variety of tree species in the last decades, but the hydraulic plasticity under temperature increase has scarcely been studied. The effect of drought on tree-ring width and specific hydraulic conductivity depends on relict-tree species resilience to climatic adaptability and its wood anatomical responses to climatic oscillations. We assessed the vessel architecture adaptation of two threatened Peruvian Andean Polylepis species (P. rodolfo-vasquezii and P. tarapacana). We found that historical Peruvian drought years differentially affected Polylepis species, where P. rodolfo-vasquezii showed vessel anatomical features significantly sensitive to drought events when contrasted with P. tarapacana. The drought effect influenced the capacity of Polylepis species to adjust the tree-ring width and vessel anatomical traits of their hydraulic system. Our results suggest that drought events influence Polylepis species&rsquo; adaptability and resilience to dry periods and could also restrict them from remaining as a part of the Peruvian Andean puna and mountain ecosystems