## Gedan Lab Sap Flux Dataset

Efforts are (still) underway to validate the raw data and provide appropriate corrections & documentation where applicable. This resource is discoverable as a placeholder. In the meantime, please contact Riley Leff (rileyleff@gwmail.gwu.edu or rileyleff@gmail.com) with specific requests or questions.

Data Structures

Sapflux Data

Data will be made available as .csv files and equivalent .parquet files.

Parquet is a high-performance columnar storage format with strongly-enforced rules regarding data types.

Columns:

ts: POSIX-formatted timestamp set to Eastern Standard Time.

a: alpha, the log of the ratio of the average temperature change in the downstream needle to the average temperature change in the downstream needle between 60 and 80 seconds after the onset of the heat pulse.

b: beta, the log of the ratio of the maximum temperature change in the downstream needle to the maximum temperature change in the upstream needle.

t: time since the onset of the heat pulse to reach maximum temperature change in the downstream needle

depth: stored as continuous numeric but can be considered categorical as well. 10mm or 20mm probe depth.

vh: estimated heat velocity (calculated)

j: estimated sap flux density (calculated)

Metadata

Specific metadata, including probe misalignment, hardware details, and supporting physiological measurements will be made available as a .toml file

TOML is a simple configuration format that is both human-readable and broadly supported in many programming languages..

These attributes are necessary to contextualize the measurements, calculate sap flux rates from raw temperature changes, correct for errors, and scale water usage estimates to the plant or ecosystem level.

The data are organized around a structure that we call a “deployment”. A deployment consists of a unique hardware interface assigned to a particular measurement context over a defined timeframe.

hardware.toml defines hardware characteristics.

sample: hardware.toml toml [301] id = "301" make = "campbell_scientific" model = "CR200X" protocols.sdi12.addresses = ["0", "1"] context.toml defines an individual, its features, and its context in the study.

sample: context.toml toml [brnv_H5_10] site = "BRNV" zone = "high_forest" plot = "5" tree = "10" genus = "Nyssa" species = "sylvatica" classif = "angiosperm"

deployments.toml assigns a timeframe to a combination of a hardware interface and a context.

sample: deployments.toml toml [1] hw_interface = "304_sdi12_1" context = "brnv_H7_891" start_ts = "2021-01-30 00:00:00-05:00" end_ts = "2022-06-11 11:30:00-05:00" interval = "30m"