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Higuchi, Niro

Publications and source records attributed to Higuchi, Niro.

At least 37 records · Page 2
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DOE OSTI2020

Convergent evolution of tree hydraulic traits in Amazonian habitats: implications for community assemblage and vulnerability to drought

Amazonian droughts are increasing in frequency and severity. However, little is known about how this may influence species-specific vulnerability to drought across different ecosystem types. We measured 16 functional traits for 16 congeneric species from six families and eight genera restricted to floodplain, swamp, white-sand or plateau forests of Central Amazonia. We investigated whether habitat distributions can be explained by species hydraulic strategies, and if habitat specialists differ in their vulnerability to embolism that would make water transport difficult during drought periods. We found strong functional differences among species. Nonflooded species had higher wood specific gravity and lower stomatal density, whereas flooded species had wider vessels, and higher leaf and xylem hydraulic conductivity. The P 50 values (water potential at 50% loss of hydraulic conductivity) of nonflooded species were significantly more negative than flooded species. However, we found no differences in hydraulic safety margin among species, suggesting that all trees may be equally likely to experience hydraulic failure during severe droughts. Water availability imposes a strong selection leading to differentiation of plant hydraulic strategies among species and may underlie patterns of adaptive radiation in many tropical tree genera. Our results have important implications for modeling species distribution and resilience under future climate scenarios.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Leaf isoprene and monoterpene emission distribution across hyperdominant tree genera in the Amazon basin

Tropical forests are acknowledged to be the largest global source of isoprene (C 5 H 8 ) and monoterpenes (C 10 H 16 ) emissions, with current synthesis studies suggesting few tropical species emit isoprenoids (20-38%) and do so with highly variable emission capacities, including within the same genera. This apparent lack of a clear phylogenetic thread has created difficulties both in linking isoprenoid function with evolution and for the development of accurate biosphere-atmosphere models. In this work, we present a systematic emission study of "hyperdominant" tree species in the Amazon Basin. Across 162 individuals, distributed among 25 botanical families and 113 species, isoprenoid emissions were widespread among both early and late successional species (isoprene: 61.9% of the species; monoterpenes: 15.0%; both isoprene and monoterpenes: 9.7%). The hyperdominant species (69) across the top five most abundant genera, which make up about 50% of all individuals in the Basin, had a similar abundance of isoprenoid emitters (isoprene: 63.8%; monoterpenes: 17.4%; both 11.6%). Among the abundant genera, only Pouteria had a low frequency of isoprene emitting species (15.8% of 19 species). In contrast, Protium, Licania, Inga, and Eschweilera were rich in isoprene emitting species (83.3% of 12 species, 61.1% of 18 species, 100% of 8 species, and 100% of 12 species, respectively). Light response curves of individuals in each of the five genera showed light-dependent, photosynthesis-linked emission rates of isoprene and monoterpenes. Importantly, in every genus, we observed species with light-dependent isoprene emissions together with monoterpenes including β-ocimene. These observations support the emerging view of the evolution of isoprene synthases from β-ocimene synthases. Our results have important implications for understanding isoprenoid function-evolution relationships and the development of more accurate Earth System Models.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Stomatal conductance and leaf temperature raw data from Aug 2016-Nov 2017 at the B34 tower in Manaus, Brazil

This data package contains raw data from stomatal conductance and leaf temperature measurements from the B34 tower in Manaus, Brazil. The attached zip file contains two data files and two metadata files. Additional metadata, such as site information and equipment manuals, are included in the data package listed under Dataset Reference(s). Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Stomatal conductance and leaf temperature raw data from Aug 2016-Nov 2017 at the K34 tower in Manaus, Brazil

These are raw data from stomatal conductance and leaf temperature measurements from the NGEE-Tropics K34 tower in Manaus, Brazil. The attached zip file contains two data files and two metadata files. Related data packages, including additional metadata such as site information and equipment manuals, are included in the data package listed under Dataset Reference(s). Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Stomatal conductance and leaf temperature raw data from Aug 2016-Nov 2017 at the B34 tower in Manaus, Brazil

This data package contains raw data from stomatal conductance and leaf temperature measurements from the B34 tower in Manaus, Brazil. The attached zip file contains two data files and two metadata files. Additional metadata, such as site information and equipment manuals, are included in the data package listed under Dataset Reference(s). Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Raw leaf temperature data from May 2017- Aug 2017 at the B34 and K34 towers in Manaus, Brazil

This data package contains raw data from leaf temperature measurements. Additional metadata, such as site information and equipment manuals, are included in the data package listed under Dataset Reference(s) along with all related data packages. Leaf temperature measurements were made using Teflon insulated type T thermocouples (OM-CP-OCTTEMP-A Nomad®, Omega Engineering) directly attached to the abaxial side of the leaf using a breathable white tape and configured to register measurements every 15 s. No data processing or QA/QC was done on the raw datasets. Processed datasets will be uploaded separately. Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Air temperature and relative humidity raw data from June 2016-Jan2018 at the K34 tower in Manaus, Brazil

This data package contains raw data from stomatal conductance and leaf temperature measurements from the K34 tower in Manaus, Brazil. The attached zip file contains one data file and two metadata files. Related data packages, including additional metadata such as site information and equipment manuals, are listed under Dataset Reference(s). Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Air temperature and relative humidity raw data from June 2017-Oct 2018 at the B34 tower in Manaus, Brazil

This data package contains raw data from stomatal conductance and leaf temperature measurements from the B34 tower at the NGEE Tropics site in Manaus, Brazil. Related data packages, including additional metadata such as site information and equipment manuals, are included in the data package listed under Dataset Reference(s). Air temperature and relative humidity data were obtained using a thermohygrometer (HC2S3, Campbell Scientific®) installed in tower K34 making a profile of (HR_: 7m, HR_2: 14m, HR_3: 21m). Data files are included in CSV and Excel file formats. No data processing or QA/QC was done on the raw datasets. Processed datasets will be uploaded separately. Contact israelmdt@gmail.com if you need to use this dataset for additional information.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015–2016 El Niño Event in the Amazon Forest

Current climate change scenarios indicate warmer temperatures and the potential for more extreme droughts in the tropics, such that a mechanistic understanding of the water cycle from individual trees to landscapes is needed to adequately predict future changes in forest structure and function. In this study, we contrasted physiological responses of tropical trees during a normal dry season with the extreme dry season due to the 2015–2016 El Niño-Southern Oscillation (ENSO) event. We quantified high resolution temporal dynamics of sap velocity (V s ), stomatal conductance (g s ) and leaf water potential (Ψ L ) of multiple canopy trees, and their correlations with leaf temperature (T leaf ) and environmental conditions [direct solar radiation, air temperature (T air ) and vapor pressure deficit (VPD)]. The experiment leveraged canopy access towers to measure adjacent trees at the ZF2 and Tapajós tropical forest research (near the cities of Manaus and Santarém). The temporal difference between the peak of g s (late morning) and the peak of VPD (early afternoon) is one of the major regulators of sap velocity hysteresis patterns. Sap velocity displayed species-specific diurnal hysteresis patterns reflected by changes in T leaf . In the morning, T leaf and sap velocity displayed a sigmoidal relationship. In the afternoon, stomatal conductance declined as T leaf approached a daily peak, allowing Ψ L to begin recovery, while sap velocity declined with an exponential relationship with Tleaf. In Manaus, hysteresis indices of the variables T leaf -T air and Ψ L -T leaf were calculated for different species and a significant difference (p < 0.01, α = 0.05) was observed when the 2015 dry season (ENSO period) was compared with the 2017 dry season (“control scenario”). In some days during the 2015 ENSO event, T leaf approached 40°C for all studied species and the differences between T leaf and T air reached as high at 8°C (average difference: 1.65 ± 1.07°C). Generally, T leaf was higher than T air during the middle morning to early afternoon, and lower than T air during the early morning, late afternoon and night. Our results support the hypothesis that partial stomatal closure allows for a recovery in Ψ L during the afternoon period giving an observed counterclockwise hysteresis pattern between Ψ L and T leaf .

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Critical wind speeds suggest wind could be an important disturbance agent in Amazonian forests

Abstract Recent research in the central Amazon suggests that wind is a major agent of disturbance, however, a mechanistic understanding of how wind may lead to tree mortality in Amazonian forests remains unclear. Here we estimated wind speeds necessary to topple central Amazon trees by linking both static and dynamic versions of two wind speed estimation methods (four methods total) to field data on tree failure derived from a static winching study. Static versions of these methods assumed invariant wind characteristics as more trees failed, while dynamic versions updated tree spacing, leaf area index and wind profiles progressively after each tree failure. First, we used a profile method which estimates wind force on individual trees by segments. We calculated drag on each segment and converted drag into basal turning moment, and compared the summed turning moments to the critical turning moment measured in the winching study. Estimated critical wind speeds from the static profile method varied greatly, from 10.75 m s−1 to >120.0 m s−1 with a mean of 45.70 m s−1. Critical wind speeds estimated with static approaches decreased with tree size but were not significantly different between two focal genera. Primary drivers of variation in critical wind speed were tree height and crown size. Second, we used the turning moment coefficient method of Hale, S.E., Gardiner, B., Peace, A., Nicoll, B., Taylor, P. and Pizzirani, S. 2015 Comparison and validation of three versions of a forest wind risk model. Environ. Model. Softw.68, 27–41. doi:10.1016/j.envsoft.2015.01.016.; the static version of this method yielded less-variable estimates, ranging from 18.98 to 52.01 m s−1, with a mean of 30.88 m s−1. Notably, the two static methods for estimating critical wind speeds differed in the trees they identified as having the highest and lowest critical wind speeds. Dynamic variants of the above two methods produced greatly reduced ranges in CWS estimates for our study trees, because after the early tree failures, remaining trees were subject to greater wind penetration into the stand and thus greater loading for a given above-canopy wind speed. CWS estimated with dynamic approaches differed significantly between the focal taxa. Nevertheless, both estimates suggest that wind speeds commonly observed during Amazon storms are sufficient to produce widespread tree damage and mortality.

Peterson, Chris J.↗
DOE OSTI2019

Volatile monoterpene ‘fingerprints’ of resinous Protium tree species in the Amazon rainforest

Volatile terpenoid resins represent a diverse group of plant defense chemicals involved in defense against herbivory, abiotic stress, and communication. However, their composition in tropical forests remains poorly characterized. As a part of tree identification, the 'smell' of damaged trunks is widely used, but is highly subjective. Here, we analyzed trunk volatile monoterpene emissions from 15 species of the genus Protium in the central Amazon. By normalizing the abundances of 28 monoterpenes, 9 monoterpene 'fingerprint' patterns emerged, characterized by a distinct dominant monoterpene. While 4 of the 'fingerprint' patterns were composed of multiple species, 5 were composed of a single species. Moreover, among individuals of the same species, 6 species had a single 'fingerprint' pattern, while 9 species had two or more 'fingerprint' patterns among individuals. A comparison of 'fingerprints' between 2015 and 2017 from 15 individuals generally showed excellent agreement, demonstrating a strong dependence on species identity, but not time of collection. The results are consistent with a previous study that found multiple divergent copies of monoterpene synthase enzymes in Protium. We conclude that the monoterpene 'fingerprint' database has important implications for constraining Protium species identification and phylogenetic relationships and enhancing understanding of physiological and ecological functions of resins and their potential commercial applications.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Raw/Translated data and metadata from sensor and leaf sample measurements at Manaus, Brazil, 24 May 2016 -16 March 2017

Raw and processed data from K34 tower site on a plateau near Manaus, Brazil including automated and manually collected time series data on leaf surface temperature (thermocouples, IR radiometer, thermocamera), leaf gas exchange fluxes of CO2, isoprene emissions, and H2O, sap flow, leaf water potential, soil moisture, and ambient concentrations of volatile organic compounds. IR radiometer data from the B34 tower in the nearby valley is also included.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Leaf surface temperature and sapflow raw data, 11 March 2016 - 13 June 2016, Santarem Brazil, Km67 tower

This data package contains raw, unprocessed leaf surface temperature data for five trees and sap velocity data for four trees near the Km67 flux tower in Santarem, Brazil. Data was collected over the course of three months. Datalogger output from sapflow ICT sensors was translated using ICT software and is included in the attached zip file. Raw data is in .csv and .xls formats. Leaf surface temperature sensor photos, sensor manual PDFs, and three file-level metadata excel files are also included in the attached file.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Sap Velocity, Leaf-level Measurements, and Meteorological Data in Manaus and Santarem, Plant Science, Brazil: 2015-2017

These datasets were used in the paper Gimenez et al., 2019 (Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015–2016 El Niño Event in the Amazon Forest) published in Frontiers in Plant Science, special issue: Water-Use Efficiency: Advances and Challenges in a Changing Climate. This data package contains data from ICT sap flow sensors, leaf temperature (Infrared Sensors), leaf gas exchange, leaf water potential and leaf thermocouple data used for some experiments of the NGEE-Tropics project in the Amazon Forest (sites: BR-Ma2 and BR-Sa1). The data package also includes environmental data (Relative humidity, air temperature, and VPD) collected using thermo-hygrometers installed in K-34 tower vertical profile (Manaus - BR-Ma2).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Dry and hot: the hydraulic consequences of a climate change-type drought for Amazonian trees

How plants respond physiologically to leaf warming and low water availability may determine how they will perform under future climate change. In 2015-2016 an unprecedented drought occurred across Amazonia with record-breaking high temperatures and low soil moisture, offering a unique opportunity to evaluate the performances of Amazonian trees to a severe climatic event. We quantified the responses of leaf water potential, sap velocity, whole-tree hydraulic conductance (Kwt), turgor loss and xylem embolism, during and after the 2015-2016 El Niño for five canopy-tree species. Leaf/xylem safety margins (SM), sap velocity and Kwt showed a sharp drop during warm periods. SMs were negatively correlated with vapor pressure deficit but had no significant relationship with soil water storage. Based on our calculations of canopy stomatal and xylem resistances, the decrease in sap velocity and Kwt was due to a combination of xylem cavitation, and stomatal closure. Our results suggest extremely warm droughts greatly amplify the degree of trees’ physiological stress and can lead to mortality. Given the extreme nature of the 2015-2016 El Niño and that temperatures are predicted to increase, this work can serve as a case study of the possible impact climate warming can have on tropical trees.

Fontes, Clarissa G.↗
DOE OSTI2018

Recognizing Amazonian tree species in the field using bark tissues spectra

The identification of tree species in the field is often a subjective process and misidentifications cause many problems for forest management in the Amazon Forest. Near infrared spectra from dried leaves of herbarium specimens are able to distinguish species in tropical forests. However, tools to improve species identification directly in the field are needed. In this study, we tested whether spectral reflectance of bark tissues (rhytidome and phloem) collected with a portable spectrometer in the field can be used for the discrimination of tree species. Spectral data was collected for 254 trees of 8 families, 10 genera and 11 species from terra firme forests in Central Amazon with an ASD field spectrometer. Data consisted of reflectance values within 350–2500 nm wavelengths. We compared the rate of correct species recognition for different datasets using linear discriminant models. The rate of correct species assignment using this technique was 98% when using spectra from the inner bark (phloem) and 94% with outer bark (rhytidome) spectra. We suggest that the application of this technique can improve the quality of species identification directly during field inventories, fostering better forest management practices.

54 ENVIRONMENTAL SCIENCES↗