scholarly journals Stem Carbon Dioxide Efflux of Lignophytes Exceeds That of Cycads and Arborescent Monocots

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 159
Author(s):  
Thomas E. Marler
Keyword(s):  
Carbon Cycle ◽  
Tree Species ◽  
Common Garden ◽  
Stem Growth ◽  
Co2 Efflux ◽  
Growth Forms ◽  
Carbon Dioxide Efflux ◽  
Ecosystem Level ◽  
Stem Co2 Efflux ◽  
Co2 Dynamics

Tree stem CO2 efflux (Es) can be substantial and the factors controlling ecosystem-level Es are required to fully understand the carbon cycle and construct models that predict atmospheric CO2 dynamics. The majority of Es studies used woody lignophyte trees as the model species. Applying these lignophyte data to represent all tree forms can be inaccurate. The Es of 318 arborescent species was quantified in a common garden setting and the results were sorted into four stem growth forms: cycads, palms, monocot trees that were not palms, and woody lignophyte trees. The woody trees were comprised of gymnosperm and eudicot species. The Es did not differ among the cycads, palms, and non-palm monocots. Lignophyte trees exhibited Es that was 40% greater than that of the other stem growth forms. The Es of lignophyte gymnosperm trees was similar to that of lignophyte eudicot trees. This extensive species survey indicates that the Es from lignophyte tree species do not align with the Es from other tree growth forms. Use of Es estimates from the literature can be inaccurate for understanding the carbon cycle in tropical forests, which contain numerous non-lignophyte tree species.

Warming effects on soil CO2 efflux in the tropical Andes: Insights from an experimental thermosequence with dominant tree species.

2021 ◽  
Author(s):  
Elizabeth Ocampo Montoya ◽  
Andrew T. Nottingham ◽  
Juan Camilo Villegas Palacio ◽  
Lina M. Mercado ◽  
Zorayda Restrepo ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Carbon Cycle ◽  
Environmental Change ◽  
Temperature Coefficient ◽  
Tropical Forests ◽  
Tree Species ◽  
Thermal Sensitivity ◽  
Co2 Efflux ◽  
Tropical Andes ◽  
Increased Temperature

<p>Tropical forests, while only occupying 12% to 15% of the Earth's surface, contain about 25% of the world's carbon biomass, with soils representing the second largest reservoir. Yet, recent studies have suggested that, in response to changing environmental conditions, in future decades tropical forests can switch from carbon sinks to carbon sources, with profound implications for the global carbon cycle. Most of these conclusions result from studies in lowland humid forests. However, other tropical forests, such as those occurring in the Andes are also important determinants of regional-to-global biogeochemical functioning, and their sensitivity to future warming has been less studied than in lowland forests. In this study, we explore intra and interspecific thermal sensitivity of soil respiration and its components (autotrophic and heterotrophic) in 15 dominant tree species in the tropical Andes, through an experimental thermosecuence in the Colombian Andes that uses elevation as a proxy for warming. In this thermosequence, a common garden experiment was set up and individuals from 15 dominant species were planted in three sites that represent a temperature gradient: the higher elevation site (2452 masl) corresponds to the base condition; the mid-elevation site (1326 masl) represents a warming of 8°C; and the lower site (575 masl) and it represents a warming of 12°C. Our results indicate consistently higher respiration values with increased temperature both within and between tree species. We used 𝑸<sub>10</sub> values (the factor by which soil respiration increases for every 10-degree rise in temperature) to determine the temperature sensitivity of soil respiration. More specifically, for a warming of 5°C there is a temperature coefficient of 𝑸<strong><sub>10</sub></strong> = 2 and for a warming of 9°C and there is a temperature coefficient 𝑸<sub>10</sub> = 3, this means that for the greater increase temperature the soil respiration can increase faster. Notably, our results show that not all species respond equally to augmented temperatures, highlighting the potential for differential effects of increased temperature and more generally, of environmental change in the compositions and function of these strategic ecosystems. Collectively, our results are relevant for the management and adaptation of ecosystems, particularly tropical Andean forest, and for the refinement of ecological models that support projections of global environmental change and carbon cycle. </p>

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 > 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.

Corticolous Lichen Species Diversity on Dominant Trees in Selected Sacred Groves of Paschim Medinipur District, West Bengal, India

2021 ◽  
Vol 63 (3-4) ◽  
pp. 447-464
Author(s):  
U. K. Sen ◽  
R. K. Bhakat
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
West Bengal ◽  
Lichen Species ◽  
Growth Forms ◽  
Sacred Groves ◽  
Community Based ◽  
Shorea Robusta ◽  
Lichen Diversity ◽  
Community Based Conservation

Sacred groves are the fairly well-protected system of community-based conservation of tree patches on account of their association with village gods, and repository of many rare and threatened elements of biodiversity. There are, however, few publications on lichens of sacred groves. The lichens have long been regarded as sensitive indicators for monitoring environmental state. The present study reports one hundred and sixteen species of lichens from forty-four genera of nineteen families in four selected sacred groves of Paschim Medinipur district, West Bengal. These lichens represent two different growth forms, i.e. crustose (105 species) and foliose (11 species). Shorea robusta, a dominant tree species in two sacred groves bears the highest lichen diversity with seventy-four species. To better understand the related biodiversity and climate, this work is likely to promote further studies on lichen diversity in other regions of West Bengal.

The role of waterlogging and sand accretion in modulating the morphology of the dune slack plant Scirpus americanus

1990 ◽  
Vol 68 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Denise M. Seliskar
Keyword(s):  
Sand Dune ◽  
Plant Morphology ◽  
Common Garden ◽  
Stem Growth ◽  
Reciprocal Transplant ◽  
Dune Slack ◽  
Coastal Sand Dune ◽  
Scirpus Americanus ◽  
Common Garden Experiments

Scirpus americanus Pers., a major dune slack plant in coastal sand dune ecosystems, differs in height along transects ranging between the lowest and highest elevational areas of slacks located along the coast of Delaware, U.S.A. Using reciprocal transplant and common garden experiments, results suggest that environmental factors rather than hereditary traits are more important in accounting for the differences in plant morphology expressed in the field. Dune slack plants are exposed to stresses of waterlogging and sand accretion in their natural environment. In controlled greenhouse experiments waterlogging was shown to inhibit stem growth and cause an increase in aerenchymatous tissue, whereas periodic sand deposition caused an increase in the plant height of Scirpus.

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.

scholarly journals Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest in decadal scale

2009 ◽  
Vol 6 (5) ◽  
pp. 8633-8660
Author(s):  
B. Koehler ◽  
M. D. Corre ◽  
E. Veldkamp ◽  
J. P. Sueta
Keyword(s):  
Growth Period ◽  
Montane Forest ◽  
Stem Growth ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
N Addition ◽  
Soil Co2 ◽  
Lowland Forest ◽  
Soil Carbon Dioxide ◽  
Decadal Scale

Abstract. Atmospheric nitrogen (N) deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide CO2 efflux to long-term experimental N-addition (125 kg N ha−1 yr-1) in mature lowland and montane forests in Panamá. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In the montane forest, on soils with low nutrient supplying capacity and an organic layer, fine litterfall and stem-growth were N-limited. Our objectives were to 1) explore the influence of soil temperature and moisture on the dynamics of soil CO2 efflux and 2) determine the responses of soil CO2 efflux from an N-rich and N-limited forest to elevated N input. Annual soil CO2-C efflux was larger from the lowland (15.20±1.25 Mg C ha−1) than the montane forest (9.36±0.29 Mg C ha−1). In the lowland forest, soil moisture explained the largest fraction of the variance in soil CO2 efflux while soil temperature was the main explanatory variable in the montane forest. Soil CO2 efflux in the lowland forest did not differ between the control and 9–11 yr N-addition plots, suggesting that chronic N input to nutrient-rich tropical lowland forests on well-buffered soils may not change their C balance in decadal scale. In the montane forest, first year N addition did not affect soil CO2 efflux but annual CO2 efflux was reduced by 14% and 8% in the 2- and 3 yr N-addition plots, respectively, compared to the control. This reduction was caused by a decrease in soil CO2 efflux during the high stem-growth period of the year, suggesting a shift in carbon partitioning from below- to aboveground in the N-addition plots where stem diameter growth was promoted.

scholarly journals Light and propagule pressure affect invasion intensity of Prunus serotina in a 14-tree species forest common garden experiment

NeoBiota ◽  
2019 ◽  
Vol 46 ◽  
pp. 1-21 ◽  
Author(s):  
Andrzej M. Jagodziński ◽  
Marcin K. Dyderski ◽  
Paweł Horodecki ◽  
Kathleen S. Knight ◽  
Katarzyna Rawlik ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Tree Species ◽  
Propagule Pressure ◽  
Light Availability ◽  
Common Garden ◽  
Additive Models ◽  
Common Garden Experiment ◽  
Tree Stand ◽  
Biomass Increment ◽  
The Impact

Experiments testing multiple factors that affect the rate of invasions in forests are scarce. We aimed to assess how the biomass of invasive Prunusserotina changed over eight years and how this change was affected by light availability, tree stand growth, and propagule pressure. The study was conducted in Siemianice Experimental Forest (W Poland), a common garden forest experiment with 14 tree species. We investigated aboveground biomass and density of P.serotina within 53 experimental plots with initial measurements in 2005 and repeated in 2013. We also measured light availability and distance from seed sources. We used generalized additive models to assess the impact of particular predictors on P.serotina biomass in 2013 and its relative change over eight years. The relative biomass increments of P.serotina ranged from 0 to 22,000-fold. The success of P.serotina, expressed as aboveground biomass and biomass increment, varied among different tree species stands, but was greater under conifers. Total biomass of P.serotina depended on light and propagule availability while biomass increment depended on the change in tree stand biomass, a metric corresponding to tree stand maturation. Our study quantified the range of invasion intensity, expressed as biomass increment, in a forest common garden experiment with 14 tree species. Canopy cover was the most important variable to reduce susceptibility to invasion by P.serotina. Even a modest decrease of overstory biomass, e.g. caused by dieback of coniferous species, may be risky in areas with high propagule pressure from invasive tree species. Thus, P.serotina control may include maintaining high canopy closure and supporting natural regeneration of tree species with high leaf area index, which shade the understory.

scholarly journals Effects of litter traits, soil biota, and soil chemistry on soil carbon stocks at a common garden with 14 tree species

2015 ◽  
Vol 123 (3) ◽  
pp. 313-327 ◽  
Author(s):  
Kevin E. Mueller ◽  
Sarah E. Hobbie ◽  
Jon Chorover ◽  
Peter B. Reich ◽  
Nico Eisenhauer ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Tree Species ◽  
Soil Chemistry ◽  
Common Garden ◽  
Carbon Stocks ◽  
Soil Biota ◽  
Litter Traits ◽  
Soil Carbon Stocks
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