Stem respiration in SAFE intensive GEM carbon plots

Description

SAFE Intensive Carbon Plots, part of the Global Ecosystem Monitoring (GEM) network, see http://gem.tropicalforests.ox.ac.uk/Stem respiration is measured on approximately 50 stems pre plot (typically two stems per subplot, but varies), using 11 cm diameter PVC collars glued on the stem at 140 cm height.The collars often fall or leak, or the trees die, so the number of measurements per day is almost always <50.The aim is to measure monthly, but in practice the measurement interval is almost always longer (problems with access, staffing and instruments)Data from late 2011 or early 2012, except from the two Danum plots (DC1 and DC2), which were set up in March 2015.The values represent the flux per unit stem area (not scaled to the whole tree).EGM-4 infrared CO2 analyser and SRC-1 respiration chamber (PP Systems).Chamber closure time is 124 seconds, CO2 concentration inside the chamber is recorded every 5 s. Flux is calculated from the linear change in concentration in the chamber headspace, and corrected for collar height (5 cm) and air temperature.The stem respiration data can be linked to other data (census, species, traits) collected from the same stems by the stem tag number.Constants for calculating fluxes 0.106 Collar diameter, m 0.008824734 Collar area, m2 0.05 Collar height, m 0.0012287 Chamber volume, incl. top part of the adapter (as in GEM manual) 0.000441237 Extra airspace of the collar, m3 0.001669937 Total chamber headspace, m3 101,325 pressure 8.314472 R 273.15 Temperature to Kelvins 12.01 Molar mass of carbon 2592000 seconds --> months pV=nRT ideal gas law n=pV/(RT) n=m/M mass mole m=n*M m=MpV/(RT)

Projects

This dataset was collected as part of the following projects:

https://safeproject.net/projects/project_view/113

Funding

These data were collected as part of research funded by:

Sime Darby Foundation (Grant , SAFE Core data
)

European Research Council Advanced Investigator Grant, GEM-TRAIT (Grant , Grant number 321131
)

NERC Human-Modified Tropical Forests Programme: Biodiversity And Land-use Impacts on tropical ecosystem function (BALI) Project (Grant , NE/K016369/1
)

NERC standard grant: The multi-year impacts of the 2015/2016 El Niño on the carbon cycle of tropical forests worldwide (Grant , NE/P001092/1
)

HSBC Malaysia (Grant
)

The University of Zurich (Grant
)

This dataset is released under the CC-BY 4.0 licence, requiring that you cite the dataset in any outputs, but has
the additional condition that you acknowledge the contribution of these funders in any
outputs.

Permits

These data were collected under permit from the following authorities:

Sabah Biodiversity Centre (SABC) ( Research licence JKM/MBs.1000-2/2 JLD.6 (76))

Files

This dataset consists of 1 file:
SAFE_StemRespiration_SAFEdatabase_2024-07-22.xlsx

SAFE_StemRespiration_SAFEdatabase_2024-07-22.xlsx

This file contains dataset metadata and 1 data tables:

Stem respiration flux data

Worksheet: data

Description: Stem respiration flux data

Number of fields: 18

Number of data rows: 10414

ForestType: Old-growth or Logged (type: categorical)

SAFEPlotName: SAFE plot name, as in the SAFE Gazetteer (type: location)

Plot: Plot name used in field wrok (type: id)

ForestPlotsCode: Plot code in the ForestPlots database (this should be used in publications, instead of plot name). (type: id)

Date: Date of measurement (type: date)

Observers: Observers (type: comments)

Subplot: Subplot number within each plot, 1-25 (type: id)

StemTagNumber: Stem tag number (ID), unique within plot but NOT across plots (type: id)

EGM_RecordNumber: EGM record number in raw flux file (type: id)

AirT: Air temperature (type: numeric)

Remarks: Comments reguarding measurements. This includes collar quality, if measurements are repeated, or if tree is dead (type: comments)

Slope: Slope of the linear regression between time (seconds) from the chamber closure and CO2 concentration (parts per million, ppm) in the chamber headspace. (type: numeric)

AirT_Use: Air temperature (type: numeric)

Flux_g_C_m2ofStemArea_month: Flux corverted from ppm s-1 to Mg carbon per hectare per month. See conversion below. (type: numeric)

Quality: 1 - good flux; 0 - missing data or bad measurement; 2 - outlier (type: numeric)

Year: Year of measurement (type: id)

Month: Month of measurement (type: id)

Day: Day of measurement (type: id)

Extents

Date range: 2011-08-26 to 2019-09-11

Latitudinal extent: 4.5° to 5.07°

Longitudinal extent: 116.75° to 117.82°