Isoprene emission in central Amazonia - from measurements to model estimates

2020 ◽  
Author(s):  
Eliane Gomes-Alves ◽  
Tyeen Taylor ◽  
Pedro Assis ◽  
Giordane Martins ◽  
Rodrigo Souza ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Plant Traits ◽  
Leaf Age ◽  
Environmental Drivers ◽  
Good Representation ◽  
Leaf Demography ◽  
Isoprene Emission ◽  
Environmental Controls ◽  
Central Amazonia ◽  
Emission Capacity

<p>Isoprene regulates large-scale biogeochemical cycles by influencing atmospheric chemical and physical processes, and its dominant sources to the global atmosphere are the tropical forests. Although global and regional model estimates of isoprene emission have been optimized in the last decades, modeled emissions from tropical vegetation still carry high uncertainty due to a poor understanding of the biological and environmental controls on emissions. It is already known that isoprene emission quantities may vary significantly with plant traits, such as leaf phenology, and with the environment; however, current models still lack of good representation for tropical plant species due to the very few observations available. In order to create a predictive framework for the isoprene emission capacity of tropical forests, it is necessary an improved mechanistic understanding on how the magnitude of emissions varies with plant traits and the environment in such ecosystems. In this light, we aimed to quantify the isoprene emission capacity of different tree species across leaf ages, and combine these leaf measurements with long-term canopy measurements of isoprene and its biological and environmental drivers; then, use these results to better parameterize isoprene emissions estimated by MEGAN. We measured at the Amazon Tall Tower Observatory (ATTO) site, central Amazonia: (1) isoprene emission capacity at different leaf ages of 21 trees species; (2) isoprene canopy mixing ratios during six campaigns from 2013 to 2015; (3) isoprene tower flux during the dry season of 2015 (El-Niño year); (3) environmental factors – air temperature and photosynthetic active radiation (PAR) - from 2013 to 2018; and (4) biological factors – leaf demography and phenology (tower based measurements) from 2013 to 2018. We then parameterized the leaf age algorithm of MEGAN with the measurements of isoprene emission capacity at different leaf ages and the tower-based measurements of leaf demography and phenology. Modeling estimates were later compared with measurements (canopy level) and five years of satellite-derived isoprene emission (OMI) from the ATTO domain (2013-2017). Leaf level of isoprene emission capacity showed lower values for old leaves (> 6 months) and young leaves (< 2 months), compared to mature leaves (2-6 months); and our model results suggested that this affects seasonal ecosystem isoprene emission capacity, since the demography of the different leaf age classes varied a long of the year. We will present more results on how changes in leaf demography and phenology and in temperature and PAR affect seasonal ecosystem isoprene emission, and how modeling can be improved with the optimization of the leaf age algorithm. In addition, we will present a comparison of ecosystem isoprene emission of normal years (2013, 2014, 2017 years) and anomalous years (2015 - El-Niño; and 2016 - post El-Niño), and discuss how a strong El-Niño year can influence plant functional strategies that can be carried over to the consecutive year and potentially affect isoprene emission.</p>

scholarly journals Leaf phenology as one important driver of seasonal changes in isoprene emissions in central Amazonia

2018 ◽  
Vol 15 (13) ◽  
pp. 4019-4032 ◽  
Author(s):  
Eliane G. Alves ◽  
Julio Tóta ◽  
Andrew Turnipseed ◽  
Alex B. Guenther ◽  
José Oscar W. Vega Bustillos ◽  
...  
Keyword(s):  
Leaf Age ◽  
Leaf Phenology ◽  
Evergreen Forest ◽  
Forest Site ◽  
Area Index ◽  
Isoprene Emission ◽  
Evergreen Forests ◽  
Central Amazonia ◽  
Meteorological Observations ◽  
Emission Capacity

Abstract. Isoprene fluxes vary seasonally with changes in environmental factors (e.g., solar radiation and temperature) and biological factors (e.g., leaf phenology). However, our understanding of the seasonal patterns of isoprene fluxes and the associated mechanistic controls is still limited, especially in Amazonian evergreen forests. In this paper, we aim to connect intensive, field-based measurements of canopy isoprene flux over a central Amazonian evergreen forest site with meteorological observations and with tower-mounted camera leaf phenology to improve our understanding of patterns and causes of isoprene flux seasonality. Our results demonstrate that the highest isoprene emissions are observed during the dry and dry-to-wet transition seasons, whereas the lowest emissions were found during the wet-to-dry transition season. Our results also indicate that light and temperature cannot totally explain isoprene flux seasonality. Instead, the camera-derived leaf area index (LAI) of recently mature leaf age class (e.g., leaf ages of 3–5 months) exhibits the highest correlation with observed isoprene flux seasonality (R2=0.59, p<0.05). Attempting to better represent leaf phenology in the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1), we improved the leaf age algorithm by utilizing results from the camera-derived leaf phenology that provided LAI categorized into three different leaf ages. The model results show that the observations of age-dependent isoprene emission capacity, in conjunction with camera-derived leaf age demography, significantly improved simulations in terms of seasonal variations in isoprene fluxes (R2=0.52, p<0.05). This study highlights the importance of accounting for differences in isoprene emission capacity across canopy leaf age classes and identifying forest adaptive mechanisms that underlie seasonal variation in isoprene emissions in Amazonia.

scholarly journals Edge Growth Form of European Buckthorn Increases Isoprene Emissions From Urban Forests

2021 ◽  
Vol 3 ◽  
Author(s):  
Aarti P. Mistry ◽  
Adam W. T. Steffeck ◽  
Mark J. Potosnak
Keyword(s):  
Invasive Species ◽  
Air Quality ◽  
Species Composition ◽  
Tree Species ◽  
Urban Forests ◽  
Google Earth ◽  
Urban Trees ◽  
Emission Rates ◽  
Isoprene Emission ◽  
Environmental Controls

Urban trees provide numerous benefits, such as cooling from transpiration, carbon sequestration, and street aesthetics. But volatile organic compound emissions from trees can combine with anthropogenic nitrogen oxide emissions to form ozone, a harmful air pollutant. The most commonly-emitted of these compounds, isoprene, negatively impacts air quality and hence is detrimental to human health. In addition to environmental controls such as light and temperature, the quantity of isoprene emitted from a leaf is a genus-specific trait. Leaf isoprene emission is enzymatically controlled, and species are typically classified as emitters or non-emitters (near-zero emission rates). Therefore, the species composition of urban forests affects whole-system isoprene production. The process of plant invasion alters species composition, and invasive tree species can be either emitters or non-emitters. If an invasive, isoprene-emitting tree species displaces native, non-emitting species, then isoprene emission rates from urban forests will increase, with a concomitant deterioration of air quality. We tested a hypothesis that invasive species have higher isoprene emission rates than native species. Using existing tree species inventory data for the Chicago region, leaf-level isoprene emission rates of the six most common invasive and native tree species were measured and compared. The difference was not statistically significant, but this could be due to the variability associated with making a sufficient number of measurements to quantify species isoprene emission rates. The most common invasive species European buckthorn (Rhamnus cathartica, L.) was an emitter. Because European buckthorn often invades the disturbed edges common in urban forests, we tested a second hypothesis that edge-effect isoprene emissions would significantly increase whole-system modeled isoprene emissions. Using Google Earth satellite imagery to estimate forested area and edge length in the LaBagh Woods Forest Preserve of Cook County (Chicago, IL, USA), edge isoprene emission contributed 8.1% compared to conventionally modeled forest emissions. Our results show that the invasion of European buckthorn has increased isoprene emissions from urban forests. This implies that ecological restoration efforts to remove European buckthorn have the additional benefit of improving air quality.

scholarly journals Ecosystem-level carbon storage and its links to diversity, structural and environmental drivers in tropical forests of Western Ghats, India

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Subashree Kothandaraman ◽  
Javid Ahmad Dar ◽  
Somaiah Sundarapandian ◽  
Selvadurai Dayanandan ◽  
Mohammed Latif Khan
Keyword(s):  
Carbon Storage ◽  
Tropical Forests ◽  
Western Ghats ◽  
Environmental Drivers ◽  
Ecosystem Level

Enhanced isoprene emission capacity and altered light responsiveness in aspen grown under elevated atmospheric CO2concentration

2012 ◽  
Vol 18 (11) ◽  
pp. 3423-3440 ◽  
Author(s):  
Zhihong Sun ◽  
Ülo Niinemets ◽  
Katja Hüve ◽  
Steffen M. Noe ◽  
Bahtijor Rasulov ◽  
...  
Keyword(s):  
Isoprene Emission ◽  
Emission Capacity

scholarly journals Seasonal coupling of canopy structure and function in African tropical forests and its environmental controls

Ecosphere ◽  
2013 ◽  
Vol 4 (3) ◽  
pp. art35 ◽  
Author(s):  
Kaiyu Guan ◽  
Adam Wolf ◽  
David Medvigy ◽  
Kelly K. Caylor ◽  
Ming Pan ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Canopy Structure ◽  
Structure And Function ◽  
Environmental Controls ◽  
And Function

scholarly journals Influence of tree size, taxonomy, and edaphic conditions on heart rot in mixed-dipterocarp Bornean rainforests: implications for aboveground biomass estimates

2015 ◽  
Vol 12 (9) ◽  
pp. 6821-6861 ◽  
Author(s):  
K. D. Heineman ◽  
S. E. Russo ◽  
I. C. Baillie ◽  
J. D. Mamit ◽  
P. P.-K. Chai ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Wood Density ◽  
Aboveground Biomass ◽  
Tree Size ◽  
Stem Volume ◽  
Mixed Effect ◽  
Edaphic Conditions ◽  
Environmental Controls ◽  
Dipterocarp Forests ◽  
Source Of Error

Abstract. Fungal decay of heartwood creates hollows and areas of reduced wood density within the stems of living trees known as heart rot. Although heart rot is acknowledged as a source of error in forest aboveground biomass estimates, there are few datasets available to evaluate the environmental controls over heart rot infection and severity in tropical forests. Using legacy and recent data from drilled, felled, and cored stems in mixed dipterocarp forests in Sarawak, Malaysian Borneo, we quantified the frequency and severity of heart rot, and used generalized linear mixed effect models to characterize the association of heart rot with tree size, wood density, taxonomy, and edaphic conditions. Heart rot was detected in 55% of felled stems > 30 cm DBH, while the detection frequency was lower for stems of the same size evaluated by non-destructive drilling (45%) and coring (23%) methods. Heart rot severity, defined as the percent stem volume lost in infected stems, ranged widely from 0.1–82.8%. Tree taxonomy explained the greatest proportion of variance in heart rot frequency and severity among the fixed and random effects evaluated in our models. Heart rot frequency, but not severity, increased sharply with tree diameter, ranging from 56% infection across all datasets in stems > 50 cm DBH to 11% in trees 10–30 cm DBH. The frequency and severity of heart rot increased significantly in soils with low pH and cation concentrations in topsoil, and heart rot was more common in tree species associated with dystrophic sandy soils than with nutrient-rich clays. When scaled to forest stands, the percent of stem biomass lost to heart rot varied significantly with soil properties, and we estimate that 7% of the forest biomass is in some stage of heart rot decay. This study demonstrates not only that heart rot is a significant source of error in forest carbon estimates, but also that it strongly covaries with soil resources, underscoring the need to account for edaphic variation in estimating carbon storage in tropical forests.

scholarly journals Climate and environmental drivers of berry productivity from the forest–tundra ecotone to the high Arctic in Canada

2020 ◽  
Vol 6 (4) ◽  
pp. 529-544
Author(s):  
Noémie Boulanger-Lapointe ◽  
Greg H.R. Henry ◽  
Esther Lévesque ◽  
Alain Cuerrier ◽  
Sarah Desrosiers ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Growing Season ◽  
High Arctic ◽  
Environmental Drivers ◽  
Climate Variables ◽  
Vaccinium Uliginosum ◽  
Forest Tundra ◽  
Environmental Controls ◽  
Circumpolar North ◽  
Northern Edge

Berry shrubs are found across the circumpolar North where they are an important source of food for people and animals. However, the environmental controls on berry productivity in these regions is poorly understood. This study presents the results of an ongoing berry productivity monitoring program for Empetrum nigrum L., Vaccinium uliginosum L., and Vaccinium vitis-idaea L. from the forest–tundra ecotone to the high Arctic in Canada. Berry productivity was the highest recorded for these species with up to 119 berries/m2 (E. nigrum) and 661 berries/m2 (V. uliginosum) measured at one plot in Pangnirtung. On average, berry productivity for E. nigrum and V. uliginosum was higher toward the northern edge of the species distribution range. The climate variables important for the productivity of V. uliginosum in high Arctic sites were closely associated with the onset of the growing season and water availability during the growing season, whereas those important in the low Arctic sites reflected conditions during the growing season. None of the climate variables used were associated with the productivity of E. nigrum and V. vitis-idaea, likely due to complex responses and length of the time-series, thus highlighting the importance of continued monitoring in partnership with northern people and institutions.

scholarly journals Patterns of above-ground biomass and its environmental drivers: an analysis based on plot-based surveys in the dry tropical forests and woodlands of southern Africa

2018 ◽  
Vol 6 ◽  
pp. 309-316
Author(s):  
Priscilla Sichone ◽  
Vera De Cauwer ◽  
António Valter Chisingui ◽  
Francisco Maiato P. Gonçalves ◽  
Manfred Finckh ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Southern Africa ◽  
Environmental Drivers ◽  
Above Ground Biomass ◽  
Ground Biomass ◽  
Dry Tropical Forests

scholarly journals Climatic and soil factors explain the two-dimensional spectrum of global plant trait variation

2021 ◽  
Author(s):  
Julia S. Joswig ◽  
Christian Wirth ◽  
Meredith C. Schuman ◽  
Jens Kattge ◽  
Björn Reu ◽  
...  
Keyword(s):  
Plant Traits ◽  
Global Analysis ◽  
Size Variation ◽  
Climate Change Impacts ◽  
Joint Effect ◽  
Growth Potential ◽  
Environmental Drivers ◽  
Trait Variation ◽  
Plant Trait ◽  
Energy Limitation

AbstractPlant functional traits can predict community assembly and ecosystem functioning and are thus widely used in global models of vegetation dynamics and land–climate feedbacks. Still, we lack a global understanding of how land and climate affect plant traits. A previous global analysis of six traits observed two main axes of variation: (1) size variation at the organ and plant level and (2) leaf economics balancing leaf persistence against plant growth potential. The orthogonality of these two axes suggests they are differently influenced by environmental drivers. We find that these axes persist in a global dataset of 17 traits across more than 20,000 species. We find a dominant joint effect of climate and soil on trait variation. Additional independent climate effects are also observed across most traits, whereas independent soil effects are almost exclusively observed for economics traits. Variation in size traits correlates well with a latitudinal gradient related to water or energy limitation. In contrast, variation in economics traits is better explained by interactions of climate with soil fertility. These findings have the potential to improve our understanding of biodiversity patterns and our predictions of climate change impacts on biogeochemical cycles.

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