scholarly journals Evaluation of O3 Effects on Cumulative Photosynthetic CO2 Uptake in Seedlings of Four Japanese Deciduous Broad-Leaved Forest Tree Species Based on Stomatal O3 Uptake

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 556 ◽  
Author(s):  
Masahiro Yamaguchi ◽  
Yoshiyuki Kinose ◽  
Hideyuki Matsumura ◽  
Takeshi Izuta
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Net Primary Production ◽  
Forest Tree ◽  
Co2 Uptake ◽  
Growing Seasons ◽  
Whole Plant ◽  
Broad Leaved Forest ◽  
Leaf Level ◽  
Species Specific

The current level of tropospheric ozone (O3) is expected to reduce the net primary production of forest trees. Here, we evaluated the negative effects of O3 on the photosynthetic CO2 uptake of Japanese forest trees species based on their cumulative stomatal O3 uptake, defined as the phytotoxic O3 dose (POD). Seedlings of four representative Japanese deciduous broad-leaved forest tree species (Fagus crenata, Quercus serrata, Quercus mongolica var. crispula and Betula platyphylla var. japonica) were exposed to different O3 concentrations in open-top chambers for two growing seasons. The photosynthesis–light response curves (A-light curves) and stomatal conductance were measured to estimate the leaf-level cumulative photosynthetic CO2 uptake (ΣPn_est) and POD, respectively. The whole-plant-level ΣPn_est were highly correlated with the whole-plant dry mass increments over the two growing seasons. Because whole-plant growth is largely determined by the amount of leaf area per plant and net photosynthetic rate per leaf area, this result suggests that leaf-level ΣPn_est, which was estimated from the monthly A-light curves and hourly PPFD, could reflect the cumulative photosynthetic CO2 uptake of the seedlings per unit leaf area. Although the O3-induced reductions in the leaf-level ΣPn_est were well explained by POD in all four tree species, species-specific responses of leaf-level ΣPn_est to POD were observed. In addition, the flux threshold appropriate for the linear regression of the responses of relative leaf-level ΣPn_est to POD was also species-specific. Therefore, species-specific responses of cumulative photosynthetic CO2 uptake to POD could be used to accurately evaluate O3 impact on the net primary production of deciduous broad-leaved trees.

scholarly journals Leaf Area Index identified as a major source of variability in modelled CO<sub>2</sub> fertilization

2018 ◽  
Author(s):  
Qianyu Li ◽  
Xingjie Lu ◽  
Yingping Wang ◽  
Xin Huang ◽  
Peter M. Cox ◽  
...  
Keyword(s):  
Primary Production ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Vegetation Types ◽  
Cable Model ◽  
Co2 Fertilization ◽  
Area Index ◽  
Leaf Level

Abstract. The concentration-carbon feedback factor (β), also called the CO2 fertilization effect, is a key unknown in climate-carbon cycle projections. A better understanding of model mechanisms that govern terrestrial ecosystem responses to elevated CO2 is urgently needed to enable a more accurate prediction of future terrestrial carbon sink. We calculated CO2 fertilization effects at various hierarchical levels from leaf biochemical reaction, leaf photosynthesis, canopy gross primary production (GPP), net primary production (NPP), to ecosystem carbon storage (cpool), for seven C3 vegetation types in response to increasing CO2 under RCP 8.5 scenario, using the Community Atmosphere Biosphere Land Exchange model (CABLE). Our results show that coefficient of variation (CV) for the CABLE model among the seven vegetation types is 0.15–0.13 for the biochemical level β, 0.13–0.16 for the leaf-level β, 0.48 for the βGPP, 0.45 for the βNPP, and 0.58 for the βcpool. The low variation of the leaf-level β is consistent with a theoretical analysis that leaf photosynthetic sensitivity to increasing CO2 concentration is almost an invariant function. In CABLE, the major jump in CV of β values from leaf- to canopy- and ecosystem-levels results from divergence in modelled leaf area index (LAI) within and among the vegetation types. The correlations of βGPP, βNPP, or βcpool with βLAI are very high in CABLE. Overall, our results indicate that modelled LAI is a key factor causing the divergence in β values in CABLE model. It is therefore urgent to constrain processes that regulate LAI dynamics in order to better represent the response of ecosystem productivity to increasing CO2 in Earth System Models.

scholarly journals A bottom-up quantification of foliar mercury uptake fluxes across Europe

2020 ◽  
Vol 17 (24) ◽  
pp. 6441-6456 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Carl Joseph ◽  
Ansgar Kahmen ◽  
Günter Hoch ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Growing Season ◽  
Deposition Flux ◽  
Foliar Uptake ◽  
Bottom Up ◽  
Needle Age ◽  
Uptake Rates ◽  
Mercury Uptake ◽  
Species Specific

Abstract. The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multiyear-old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m−2 for beech, 26 ± 5 µg Hg m−2 for oak, 4 ± 1 µg Hg m−2 for pine and 11 ± 1 µg Hg m−2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m−2, which was 4 times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m−2. Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom-up approach provides a promising method to quantify foliar Hg uptake fluxes on an ecosystem scale.

scholarly journals Active layer depth and soil properties impact specific leaf area variation and ecosystem productivity in a boreal forest

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0232506
Author(s):  
Carolyn G. Anderson ◽  
Ben Bond-Lamberty ◽  
James C. Stegen
Keyword(s):  
Boreal Forest ◽  
Leaf Area ◽  
Active Layer ◽  
Specific Leaf Area ◽  
Tree Species ◽  
Net Primary Production ◽  
Process Models ◽  
Ecosystem Productivity ◽  
Layer Depth ◽  
Extensive Evaluation

Specific leaf area (SLA, leaf area per unit dry mass) is a key canopy structural characteristic, a measure of photosynthetic capacity, and an important input into many terrestrial process models. Although many studies have examined SLA variation, relatively few data exist from high latitude, climate-sensitive permafrost regions. We measured SLA and soil and topographic properties across a boreal forest permafrost transition, in which dominant tree species changed as permafrost deepened from 54 to >150 cm over 75 m hillslope transects in Caribou-Poker Creeks Research Watershed, Alaska. We characterized both linear and threshold relationships between topographic and edaphic variables and SLA and developed a conceptual model of these relationships. We found that the depth of the soil active layer above permafrost was significantly and positively correlated with SLA for both coniferous and deciduous boreal tree species. Intraspecific SLA variation was associated with a fivefold increase in net primary production, suggesting that changes in active layer depth due to permafrost thaw could strongly influence ecosystem productivity. While this is an exploratory study to begin understanding SLA variation in a non-contiguous permafrost system, our results indicate the need for more extensive evaluation across larger spatial domains. These empirical relationships and associated uncertainty can be incorporated into ecosystem models that use dynamic traits, improving our ability to predict ecosystem-level carbon cycling responses to ongoing climate change.

A bottom up approach to quantify foliar uptake of gaseous elemental mercury by European forests during the 2018 growing season

2020 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Günter Hoch ◽  
Christine Alewell ◽  
Martin Jiskra
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Elemental Mercury ◽  
Growing Season ◽  
Accumulation Rates ◽  
Bottom Up ◽  
Deposition Fluxes ◽  
Gaseous Elemental Mercury ◽  
Species Specific ◽  
Hg Accumulation

&lt;p&gt;The deposition of gaseous elemental mercury, Hg(0), from the atmosphere to terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. However, there is emerging evidence that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. We will present a novel bottom up approach to calculate Hg(0) deposition fluxes to aboveground foliage by combining foliar Hg accumulation rates on the basis of leaf area with species-specific leaf area indices. We analyzed Hg content in 583 foliage samples from major tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to Northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all tree species at all sites. We found that foliar Hg accumulation rates normalized to leaf area increased with crown height and decreased with the age of multi-year old needles. We did not detect a clear latitudinal gradient in foliar Hg accumulation rates.&lt;/p&gt;&lt;p&gt;On an ecosystem scale we developed a simple bottom up approach for foliar Hg(0) uptake considering the systematic variations in crown height, needle age and tree species. We calculated species-specific average foliar Hg(0) dry deposition rates for the 2018 growing season of 22 &amp;#177; 4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for beech, 16 &amp;#177; 8 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for oak, 3 &amp;#177; 0.4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for birch, 18 &amp;#177; 10 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for spruce and 8 &amp;#177; 4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for pine. For comparison, the average Hg wet deposition flux measured at 4 of our 10 research sites during the same time period was 2.5 &amp;#177; 0.2 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;Scaling up site-specific deposition rates to the forested area of Europe (EU28) resulted in a total aboveground Hg(0) deposition to foliage of approximately 20 Mg during the 2018 growing season. Our results confirm that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. The bottom up approach we used is a promising method to quantify Hg(0) deposition fluxes based on easy-to-do Hg concentration measurements in foliage.&lt;/p&gt;

scholarly journals Irradiance-induced plasticity in the hydraulic properties of saplings of different temperate broad-leaved forest tree species

2006 ◽  
Vol 26 (12) ◽  
pp. 1505-1516 ◽  
Author(s):  
T. S. Barigah ◽  
T. Ibrahim ◽  
A. Bogard ◽  
B. Faivre-Vuillin ◽  
L. A. Lagneau ◽  
...  
Keyword(s):  
Tree Species ◽  
Hydraulic Properties ◽  
Forest Tree ◽  
Forest Tree Species ◽  
Broad Leaved Forest ◽  
Leaved Forest

scholarly journals Species-specific water use by forest tree species: From the tree to the stand

2012 ◽  
Vol 114 ◽  
pp. 67-77 ◽  
Author(s):  
Ismael Aranda ◽  
Alicia Forner ◽  
Barbara Cuesta ◽  
Fernando Valladares
Keyword(s):  
Water Use ◽  
Tree Species ◽  
Forest Tree ◽  
Forest Tree Species ◽  
Species Specific

scholarly journals Impact Assessment of Ozone Absorbed through Stomata on Photosynthetic Carbon Dioxide Uptake by Japanese Deciduous Forest Trees: Implications for Ozone Mitigation Policies

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 137
Author(s):  
Yoshiyuki Kinose ◽  
Masahiro Yamaguchi ◽  
Hideyuki Matsumura ◽  
Takeshi Izuta
Keyword(s):  
Carbon Dioxide ◽  
Impact Assessment ◽  
Deciduous Forest ◽  
Forest Tree ◽  
Mitigation Measures ◽  
Co2 Uptake ◽  
Forest Trees ◽  
Photosynthetic Carbon ◽  
Species Specific ◽  
The Impact

Photosynthesis by trees is expected to contribute to preventing climate change including global warming. However, the current levels of tropospheric ozone (O3) reduce the uptake of photosynthetic carbon dioxide (CO2) by forest trees in Japan, which is a concern. Furthermore, it is unknown how much O3 should be reduced to prevent plants’ O3-induced damage. The objective of the present study was to assess the negative effects of the current levels of O3 absorbed via stomata and the impact of its mitigation on the CO2 uptake by trees in Japanese forests. Impact assessment, targeted in 2011–2015, was performed for four deciduous broad-leaved trees: Fagus crenata, Quercus serrata, Q. mongolica var. crispula, and Betula platyphylla var. japonica. The assessment was based on species-specific cumulative stomatal O3 uptake (COU) and species-specific responses of annual photosynthetic CO2 uptake to COU. Annual COU differed between the four trees; the average COU of F. crenata, Q. serrata, Q. mongolica var. crispula, and B. platyphylla var. japonica across Japan was 41.7, 26.5, 33.0, and 29.1 mmol m−2, respectively, and the reductions in CO2 uptake by the four trees were 14.0%, 10.6%, 8.6%, and 15.4%, respectively. Further analysis revealed that reducing the atmospheric O3 concentration by approximately 28%, 20%, 17%, and 49% decreased the O3-induced reductions in photosynthetic CO2 uptake to 5% in F. crenata, Q. serrata, Q. mongolica var. crispula, and B. platyphylla var. japonica, respectively. In the near future, implementing mitigation measures for the O3 damage in plants is expected to enhance the photosynthetic capacity of Japanese forest tree species.

scholarly journals A bottom-up quantification of foliar mercury uptake fluxes across Europe

2020 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Carl Joseph ◽  
Ansgar Kahmen ◽  
Günter Hoch ◽  
...  
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Growing Season ◽  
Deposition Flux ◽  
Foliar Uptake ◽  
Bottom Up ◽  
Needle Age ◽  
Uptake Rates ◽  
Mercury Uptake ◽  
Species Specific

Abstract. The exchange of gaseous elemental mercury, Hg(0), between the atmosphere and terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. Emerging evidence suggests foliar uptake of atmospheric Hg(0) to be a major deposition pathway to terrestrial surfaces. Here, we present a bottom-up approach to calculate Hg(0) uptake fluxes to aboveground foliage by combining foliar Hg uptake rates normalized to leaf area with species-specific leaf area indices. This bottom-up approach incorporates systematic variations in crown height and needle age. We analyzed Hg content in 583 foliage samples from six tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to Northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all six tree species at all sites. We found that foliar Hg uptake rates normalized to leaf area were highest at the top of the tree crown. Foliar Hg uptake rates decreased with needle age of multi-year old conifers (spruce and pine). Average species-specific foliar Hg uptake fluxes during the 2018 growing season were 18 ± 3 µg Hg m−2 for beech, 26 ± 5 µg Hg m−2 for oak, 4 ± 1 µg Hg m−2 for pine and 11 ± 1 µg Hg m−2 for spruce. For comparison, the average Hg(II) wet deposition flux measured at 5 of the 10 research sites during the same period was 2.3 ± 0.3 µg Hg m−2, which was four times lower than the site-averaged foliar uptake flux of 10 ± 3 µg Hg m−2. Scaling up site-specific foliar uptake rates to the forested area of Europe resulted in a total foliar Hg uptake flux of approximately 20 ± 3 Mg during the 2018 growing season. Considering that the same flux applies to the global land area of temperate forests, we estimate a foliar Hg uptake flux of 108 ± 18 Mg. Our data indicate that foliar Hg uptake is a major deposition pathway to terrestrial surfaces in Europe. The bottom up approach provides a promising method to quantify foliar Hg uptake fluxes on an ecosystem scale.

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