scholarly journals Stem CO2 Efflux as an Indicator of Forests’ Productivity in Relict Juniper Woodlands (Juniperus thurifera L.) of Southern Spain

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1340
Author(s):  
Francisco Antonio García Morote ◽  
Manuela Andrés Abellán ◽  
Eva Rubio ◽  
Iván Pérez Anta ◽  
Francisco García Saucedo ◽  
...  
Keyword(s):  
Exponential Model ◽  
Joint Effect ◽  
Arid Ecosystems ◽  
Co2 Efflux ◽  
Stem Respiration ◽  
C Cycle ◽  
Stem Temperature ◽  
Juniper Woodland ◽  
Stem Co2 Efflux ◽  
Semi Arid

There are considerable uncertainties about the C cycle in semi-arid ecosystems. Hence, studies that have focused on Juniperus in Mediterranean woodlands are non-existent. This study provides a survey of the effect of the juniper woodland type (young and mature woodlands; joint effect of maturity and forest productivity) on stem respiration. We checked the seasonal variation of stem respiration, evaluating the effects of stem temperature on stem CO2 efflux. For this, we measured the stem CO2 efflux (µmol CO2 m−2 s−1) over the four seasons on 16 junipers using LI-6400 equipment. The results showed that in the more productive site (young woodland), the stem CO2 efflux was higher. This variable followed a clear seasonal trend, being higher during the spring and progressively decreasing in cold periods. In both juniper woodlands, and especially in the older forests, the Q10 coefficients were low (<2), typical of cold forests and slow-growing species. The exponential model also confirmed that the Q10 was significantly higher in young juniper trees. Thus, stem CO2 efflux was an indicator of the growth in this juniper woodland that is well adapted to a semi-arid climate.

A new automated stem CO2 efflux chamber based on industrial ultra-low-cost sensors

2019 ◽  
Author(s):  
Johannes Brändle ◽  
Norbert Kunert
Keyword(s):  
Gas Exchange ◽  
Low Cost ◽  
Climatic Conditions ◽  
Co2 Efflux ◽  
Diurnal Changes ◽  
Lowland Forest ◽  
Stem Respiration ◽  
Stem Co2 Efflux ◽  
Gas Exchange System ◽  
Controlling Processes

Abstract Tree autotrophic respiratory processes, especially stem respiration or stem CO2 efflux (Estem), are important components of the forest carbon budget. Despite the efforts to investigate the controlling processes of Estem in the last years a considerable lack in our knowledge remains on the abiotic and biotic drivers affecting Estem dynamics. It has been strongly advocated that long-term measurements would shed light into those processes. The expensive scientific instruments needed to measure gas exchange has prevented from applying Estem measurements on a larger temporal and spatial scale. Here, we present an automated closed dynamic chamber system based on inexpensive and industrially broadly applied CO2 sensors reducing the costs for the sensing system to a minimum. The CO2 sensor was cross-calibrated with a commonly used gas exchange system in the laboratory and in the field, and we found very good accordance of these sensors. We tested the system under harsh tropical climatic conditions, characterized by heavy tropical rainfall events, extreme humidity, and temperatures, in a moist lowland forest in Malaysia. We recorded Estem of three Dyera costulata trees with our prototype over various days. The variation of Estem was large among the three tree individuals and varied by 7.5-fold. However, clear diurnal changes in Estem were present in all three tree individuals. One tree showed high diurnal variation in Estem and the relationship between Estem and temperature was characterized by a strong hysteresis. The large variations found within one single tree species highlights the importance of continuous measurement to quantify ecosystem carbon fluxes.

scholarly journals Low-cost chamber design for simultaneous CO2 and O2 flux measurements between tree stems and the atmosphere

2021 ◽  
Author(s):  
Juliane Helm ◽  
Henrik Hartmann ◽  
Martin Göbel ◽  
Boaz Hilman ◽  
David Herrera ◽  
...  
Keyword(s):  
Low Cost ◽  
Co2 Flux ◽  
Co2 Efflux ◽  
Stem Respiration ◽  
Ecosystem Carbon ◽  
O2 Concentration ◽  
Flux Measurements ◽  
Stem Co2 Efflux ◽  
Tree Stem

Abstract Tree stem CO2 efflux is an important component of ecosystem carbon fluxes and has been the focus of many studies. While CO2 efflux can easily be measured, a growing number of studies have shown that it is not identical with actual in situ respiration. Complementing measurements of CO2 flux with simultaneous measurements of O2 flux provides an additional proxy for respiration, and the combination of both fluxes can potentially help getting closer to actual measures of respiratory fluxes. To date, however, the technical challenge to measure relatively small changes in O2 concentration against its high atmospheric background has prevented routine O2 measurements in field applications. Here we present a new and low-cost field-tested device for autonomous real-time and quasi-continuous long-term measurements of stem respiration by combining CO2 (NDIR based) and O2 (quenching based) sensors in a tree stem chamber. Our device operates as a cyclic closed system and measures changes in both CO2 and O2 concentration within the chamber over time. The device is battery-powered with a &gt; 1 week power independence and data acquisition is conveniently achieved by an internal logger. Results from both field and laboratory tests document that our sensors provide reproducible measurements of CO2 and O2 exchange fluxes under varying environmental conditions.

scholarly journals Internal respiration of Amazon tree stems greatly exceeds external CO<sub>2</sub> efflux

2012 ◽  
Vol 9 (12) ◽  
pp. 4979-4991 ◽  
Author(s):  
A. Angert ◽  
J. Muhr ◽  
R. Negron Juarez ◽  
W. Alegria Muñoz ◽  
G. Kraemer ◽  
...  
Keyword(s):  
Tropical Trees ◽  
Co2 Efflux ◽  
Water Stream ◽  
New Approach ◽  
Stem Respiration ◽  
Internal Flux ◽  
Stem Co2 Efflux ◽  
Internal Co2 ◽  
Global Carbon ◽  
Net Release

Abstract. Respiration in tree stems is an important component of forest carbon balance. The rate of CO2 efflux from the stem has often been assumed to be a measure of stem respiration. However, recent work in temperate forests has demonstrated that stem CO2 efflux can either overestimate or underestimate respiration rate because of emission or removal of CO2 by transport in xylem water. Here, we studied gas exchange from stems of tropical forest trees using a new approach to better understand respiration in an ecosystem that plays a key role in the global carbon cycle. Our main questions were (1) is internal CO2 transport important in tropical trees, and, if so, (2) does this transport result in net release of CO2 respired in the roots at the stem, or does it cause the opposite effect of net removal of stem-respired CO2? To answer these questions, we measured the ratio of stem CO2 efflux to O2 influx. This ratio, defined here as apparent respiratory quotient (ARQ), is expected to equal 1.0 if carbohydrates are the substrate for respiration, and the net transport of CO2 in the xylem water is negligible. Using a stem chamber approach to quantifying ARQ, we found values of 0.66 ± 0.18. These low ARQ values indicate that a large portion of respired CO2 (~ 35%) is not emitted locally, and is probably transported upward in the stem. ARQ values of 0.21 ± 0.10 were found for the steady-state gas concentration within the stem, sampled by in-stem equilibration probes. These lower values may result from the proximity to the xylem water stream. In contrast, we found ARQ values of 1.00 ± 0.13 for soil respiration. Our results indicate the existence of a considerable internal flux of CO2 in the stems of tropical trees. If the transported CO2 is used in the canopy as a substrate for photosynthesis, it could account for up to 10% of the C fixed by the tree, and perhaps serve as a mechanism that buffers the response of the tree to changing CO2 levels. Our results also indicate, in agreement with previous work, that the widely used CO2 efflux approach for determining stem respiration is unreliable. We demonstrate here a field applicable approach for measuring the O2 uptake rate, which we suggest to be a more appropriate method to estimate stem respiration rates.

Relationship between stem CO2 efflux and stem temperature at different measuring depths in Pinus massoniana trees

2016 ◽  
Vol 36 (4) ◽  
pp. 229-235 ◽  
Author(s):  
Qingpeng Yang ◽  
Ming Xu ◽  
Yonggang Chi ◽  
Yunpu Zheng
Keyword(s):  
Pinus Massoniana ◽  
Co2 Efflux ◽  
Stem Temperature ◽  
Stem Co2 Efflux

Estimation of whole-stem respiration, incorporating vertical and seasonal variations in stem CO2 efflux rate, of Chamaecyparis obtusa trees

2010 ◽  
Vol 15 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Masatake G. Araki ◽  
Hajime Utsugi ◽  
Takuya Kajimoto ◽  
Qingmin Han ◽  
Tatsuro Kawasaki ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Chamaecyparis Obtusa ◽  
Co2 Efflux ◽  
Efflux Rate ◽  
Stem Respiration ◽  
Stem Co2 Efflux

scholarly journals Internal respiration of Amazon tree stems greatly exceeds external CO<sub>2</sub> efflux

2012 ◽  
Vol 9 (8) ◽  
pp. 11443-11477 ◽  
Author(s):  
A. Angert ◽  
J. Muhr ◽  
R. Negron Juarez ◽  
W. Alegria Muñoz ◽  
G. Kraemer ◽  
...  
Keyword(s):  
Carbon Balance ◽  
Co2 Efflux ◽  
Water Stream ◽  
Stem Respiration ◽  
Gas Concentration ◽  
Respiration Rates ◽  
Internal Flux ◽  
Stem Co2 Efflux ◽  
First Time ◽  
Global Carbon

Abstract. Respiration in tree stems is an important component of forest carbon balance. The rate of CO2 efflux from the stem has often been assumed to be a measure of stem respiration. However, recent work in temperate forests has demonstrated that stem CO2 efflux can either overestimate or underestimate respiration rate, because of emission or removal of CO2 by transport in xylem water. Here we used the ratio between CO2 efflux and O2 influx in stems of tropical forest trees to better understand respiration in an ecosystem that plays a key role in the global carbon cycle. This ratio, which we defined here as apparent respiratory quotient (ARQ), is expected to equal 1.0 if carbohydrates are the substrate for respiration, and the net transport of CO2 in the xylem water is negligible. However, using a stem chamber approach to quantifying ARQ we found values of 0.66 ± 0.18. These low ARQ values indicate that a large portion of respired CO2 (~35%) is not emitted locally, and is probably transported upward in the stem. ARQ values of 0.21 ± 0.10 were found for the steady-state gas concentration within the tree, sampled by in-stem equilibration probes. These lower values may result from the proximity to the xylem water stream. In contrast, we found ARQ values of 1.00 ± 0.13 for soil respiration. Our results indicate, for the first time, the existence of a~considerable internal flux of CO2in the stem of tropical trees. If the transported CO2 is used in the canopy as a substrate for photosynthesis, it could account for several percent of the C fixed by the tree, and perhaps serve as a mechanism that buffers the response of the tree to changing CO2 levels. Our results also indicate, in agreement with previous work, that the widely used CO2 efflux approach for determining stem respiration is unreliable. We demonstrate here a field applicable approach for measuring the O2 uptake rate, which we suggest to be a more appropriate method to estimate stem respiration rates.

scholarly journals Dynamics of temperature normalized stem CO2 efflux in Norway spruce stand

2011 ◽  
Vol 59 (6) ◽  
pp. 121-126
Author(s):  
Eva Dařenová ◽  
M. Pavelka ◽  
D. Janouš
Keyword(s):  
Norway Spruce ◽  
Growing Season ◽  
Automated System ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Co2 Efflux ◽  
Factors Affecting ◽  
Factor Effect ◽  
Stem Temperature ◽  
Stem Co2 Efflux

Respiration of stems contributes approximately 8 to 13 % to the total respiration of forest ecosystem, which is not negligible, and it has to be included in carbon flux estimates. The aim of this study was to determine dynamics of stem CO2 efflux during the growing season in Norway spruce stand and factors affecting this efflux. Continuous measurements of stem CO2 efflux were carried out by an automated system during the growing season in 2006–2009. Further measured characteristics were stem temperature, stem increment and precipitations. Stem CO2 efflux was in tight relationship with changes in temperature with the mean coefficient of determination of 0.76. This infers that temperature was the main factor driving changes in CO2 efflux during the season. To eliminate effect of temperature and determine other factors influencing stem CO2 efflux, CO2 efflux was normalized for temperature of 10 °C (R10). Basic seasonal course of R10 followed the pattern of stem growth rate with its maxima in June and July. The other factor effect, which was possible to determine, was presence of rainfall. Rainfall strong enough caused mostly increase in R10. This effect was the most significant when the R10 course had a decreasing trend in the second part of the growing season.

scholarly journals Individual- and stand-level Stem CO<sub>2</sub> efflux in a subtropical <i>Schima superba</i> plantation

2012 ◽  
Vol 9 (3) ◽  
pp. 3289-3315
Author(s):  
L. W. Zhu ◽  
P. Zhao ◽  
G. Y. Ni ◽  
Q. P. Cao ◽  
C. M. Zhou ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Temperature Response ◽  
Stem Volume ◽  
Co2 Efflux ◽  
Vertical Variation ◽  
Schima Superba ◽  
Stem Temperature ◽  
Stem Co2 Efflux ◽  
Q10 Values ◽  
Gas Exchange System

Abstract. Stem CO2 efflux was investigated with an open gas exchange system while stand microclimate and stem temperature were continuously monitored in a Schima superba plantation in South China for several days in August and December, 2010. The temperature response of respiration over the different seasons, the vertical variation in stem CO2 efflux along the stem and the stand-level stem CO2 efflux were examined. Stem volume was identified as the better correlate for stem CO2 efflux and was used as scaling scalar for the stand-level estimates of stem CO2 efflux in this S. superba plantation. Volume-based stem CO2 efflux was higher at 2 m than at 1.3 m. Mean stem CO2 efflux was 268.9 and 104.6 μmol m−3 s−1 in August and December, respectively, indicating a dramatic seasonal variation of stem CO2 efflux. The temperature response of stem CO2 efflux was constant during our study period with Q10 values of 1.9 and 1.8. In this subtropical S. superba plantation, the averaged stem CO2 efflux per unit ground area was 3.36 and 1.26 μmol m−2 s−1 in August and December, respectively, which was underestimated due to the vertical variation of stem CO2 efflux along the stem. Our results suggest that stem CO2 efflux has a constant temperature response on the stand scale, and the seasonal variation in stem CO2 efflux is mainly controlled by stem temperature, and the vertical variation in stem CO2 efflux needs to be considered at the stand-level estimation.

scholarly journals Individual- and stand-level stem CO<sub>2</sub> efflux in a subtropical <I>Schima superba</I> plantation

2012 ◽  
Vol 9 (10) ◽  
pp. 3729-3737 ◽  
Author(s):  
L. W. Zhu ◽  
P. Zhao ◽  
G. Y. Ni ◽  
Q. P. Cao ◽  
C. M. Zhou ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Ecosystem Respiration ◽  
Temperature Response ◽  
Stem Volume ◽  
Co2 Efflux ◽  
Vertical Variation ◽  
Schima Superba ◽  
Stem Temperature ◽  
Stem Co2 Efflux ◽  
Gas Exchange System

Abstract. Stem respiration is an important, but poorly studied component of total forest ecosystem respiration. Stem CO2 efflux was investigated with an open gas exchange system while stand microclimate and stem temperature were continuously monitored in a Schima superba plantation in South China for several days in August and December 2010. The temperature response of respiration in the different seasons, the vertical variation in stem CO2 efflux along the stem, and the stand-level stem CO2 efflux were examined. Stem volume was identified as the better correlate for stem CO2 efflux and was used as the scalar for the stand-level estimates of stem CO2 efflux in this S. superba plantation. Volume-based stem CO2 efflux was higher at 2 m than at 1.3 m. Mean stem CO2 efflux was 268.9 and 104.6 μmol m−3 s−1 in August and December, respectively, indicating a dramatic seasonal variation of stem CO2 efflux. The temperature response of stem CO2 efflux remained constant during our study period with Q10 values of 1.9 and 1.8. In this subtropical S. superba plantation, stem CO2 efflux per unit ground area averaged 3.36 and 1.26 μmol m−2 s−1 based on the measurement data at 1.3-m height of the stem in August and December, respectively. Our results suggest that stem CO2 efflux has a constant temperature response, and the seasonal variation in stem CO2 efflux is mainly controlled by stem temperature, and the vertical variation in stem CO2 efflux needs to be considered in the stand-level estimation.

scholarly journals Controlling factors of ecosystem and soil respiration in a xeric shrubland in the Chihuahuan Desert, Mexico

2021 ◽  
Vol 39 ◽  
Author(s):  
Dulce Yaahid Flores-Rentería
Keyword(s):  
Structural Equation ◽  
Chihuahuan Desert ◽  
Equation Model ◽  
Arid Ecosystems ◽  
Shortwave Radiation ◽  
Co2 Efflux ◽  
C Cycle ◽  
Wide Variability ◽  
Negative Effect ◽  
Annual Scale

In the terrestrial carbon cycle is very relevant to identify the influence of soil in the CO2 released to the atmosphere, which is linked to multiple biotic and abiotic drivers. Arid ecosystems dominate the trend and interannual variability of the land CO2 sink. This pattern is mainly controlled by temperature, precipitation, and shortwave radiation. Thus, these environments are characterized by a wide variability of water availability, which causes the CO2 efflux to be highly variable in time, challenging our model capacities. This study aims to understand the ecosystem CO2 fluxes and their controlling mechanisms from the Chihuahuan Desert in Northeast Mexico. We explore the average contribution of the Rsoil (1.30 mmol m-2 s‑1) to Reco (1.76 mmol m-2 s‑1), while identifying the controlling mechanisms of both on an annual scale. The structural equation model constructed showed a good f it for the data, explaining 50% and 93% of the annual variance of Rsoil and Reco, respectively. According to this model, Rsoil was mainly controlled by the air temperature, and Reco by soil water content. Unexpectedly, vapor pressure def icit was the most weight variable with a direct negative effect on Reco, supporting the idea that the vegetation component has a crucial role in the CO2 efflux of this ecosystem. This study highlights the importance of include multiple factors in the models of the C cycle.

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