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Abstract Tree stems exchange CO2, CH4and N2O with the atmosphere but the magnitudes, patterns and drivers of these greenhouse gas (GHG) fluxes remain poorly understood. Our understanding mainly comes from static-manual measurements, which provide limited information on the temporal variability and magnitude of these fluxes. We measured hourly CO2, CH4and N2O fluxes at two stem heights and adjacent soils within an upland temperate forest. We analyzed diurnal and seasonal variability of fluxes and biophysical drivers (i.e., temperature, soil moisture, sap flux). Tree stems were a net source of CO2(3.80 ± 0.18 µmol m−2s−1; mean ± 95% CI) and CH4(0.37 ± 0.18 nmol m−2s−1), but a sink for N2O (−0.016 ± 0.008 nmol m−2s−1). Time series analysis showed diurnal temporal correlations between these gases with temperature or sap flux for certain days. CO2and CH4showed a clear seasonal pattern explained by temperature, soil water content and sap flux. Relationships between stem, soil fluxes and their drivers suggest that CH4for stem emissions could be partially produced belowground. High-frequency measurements demonstrate that: a) tree stems exchange GHGs with the atmosphere at multiple time scales; and b) are needed to better estimate fluxes magnitudes and understand underlying mechanisms of GHG stem emissions.
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Dataset: Spatiotemporal variability and origin of CO2 and CH4 tree stem fluxes in an upland forest
The exchange of multiple greenhouse gases (i.e., CO2 </sub>and CH4</sub>) between tree stems and the atmosphere represents a knowledge gap in the global carbon cycle. Stem CO2</sub> and CH4</sub> fluxes vary across time and space and is unclear which are their individual or shared drivers. This dataset contains information of CO2</sub> and CH4</sub> fluxes at different stem heights combining manual (biweekly; n=678) and automated (hourly; n>38,000) measurements in a temperate upland forest.</div>This study was performed in an upland forested area at the St. Jones Reserve [39°5’20”N, 75°26’21”W], a component of the Delaware National Estuarine Research Reserve (DNERR).</div></div>The dominant vegetation species are bitternut hickory (Carya cordiformis</i>), eastern red cedar (Juniperus virginiana</i> L.), American holly (Ilex opaca</i> (Ashe)), sweet gum (Liquidambar styraciflua</i> L.) and black gum (Nyssa sylvatica</i> (Marshall)), with an overall tree density of 678 stems ha-1</sup> and mean diameter at breast height (DBH) of 25.7±13.9 cm (mean±sd). We studied bitternut hickory, which is one of the most important species in the study site, accounting for 24.9% of the total basal area.</div></div>For code </div>
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- Award ID(s):
- 1652594
- PAR ID:
- 10395725
- Publisher / Repository:
- figshare
- Date Published:
- Subject(s) / Keyword(s):
- 50301 Carbon Sequestration Science 40104 Climate Change Processes 50101 Ecological Impacts of Climate Change 50102 Ecosystem Function 50206 Environmental Monitoring Environmental Science 70599 Forestry Sciences not elsewhere classified 70508 Tree Nutrition and Physiology
- Format(s):
- Medium: X Size: 9579835 Bytes
- Size(s):
- 9579835 Bytes
- Sponsoring Org:
- National Science Foundation
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