About the Forest
About the Forest
Vertical tree air temperature measurements within the canopy of the HJ Andrews Experimental Forest, 2011-2019
CREATOR(S): Sarah J. K. Frey, Julia A. Jones
PRINCIPAL INVESTIGATOR(S): Julia A. Jones
ORIGINATOR(S): Sarah J. K. Frey
OTHER RESEARCHER(S): Mark D Schulze, Adam Scott Hadley, Matthew G Betts, Adam M Kennedy
DATA SET CONTACT PERSON: Sarah J. K. Frey
TOOL CONTACT: Matthew J. Gregory
METADATA CREATION DATE:
3 Oct 2017
MOST RECENT METADATA REVIEW DATE:
18 Feb 2020
air temperature, forests
This study is intended to understand vertical temperature profiles and their spatial patterns in relation to forest structure and landscape context.
Experimental Design - MV008:
Eleven sites (of the 184 existing sites where temperature and bird data are collected) were chosen for instrumentation of HOBO temperature loggers up through the canopy. Site selection was based on elevation, landscape position, and forest type. Six of the 11 sites are located in old-growth forest and five are located in plantation forest. Loggers were spaced at 5-m intervals starting at 6.5 m, which is 5 m higher than the original 1.5 m logger at these sites. The tallest logger at each site depended on the forest canopy height and the height of the individual tree that the loggers were placed in (ranges from 11.5 m to 46.5 m). Sites are grouped into low elevation (487, 556, 567, 622, 687 m) and high elevation (979, 1082, 1184, 1301, 1301, 1339 m).
Field Methods - MV008:
Each of the 11 trees selected were rigged to set up temperature and light sensors up through the canopy. Loggers were installed using a pulley system and parachute cord so that downloading data and changing batteries is easily accomplished. Half of a 3-inch diameter schedule 40 PVC pipe, cut to 6-in in length for a sun shield was used at each HOBO sensor. All temperature loggers were oriented to face south using a compass (and within what was physically possible based on the parachute cord). Temperature was programmed to be recorded every 20 minutes. The 1.5 meter sensor data is from data collected in MS045 study where temperature resolution is every 20 minutes at the bird sites and every 15 minutes at the vegetation sites. Data is download from the units 1-2 times a year (May - August) and change of batteries once a year based on sampling frequency (generally on the second offload session of each year).
Models/Algorithms - MV008:
A Python workflow, which includes instructions on how the Python code is run, including the yaml and wheel file to be used in the Python code, which can be adjusted by the user to change the flagging of the data, and the definition of flags used in the Python QAQC file.
Processing Procedures - MV008:
There is a version of the data offline, but available, that have had a light-adjustment applied based on the illumination values in order to account for bias in the temperature measurements created by light hitting the sensor shield. The light adjustment is based on paired light and temperature measurements, from the Discovery Tree (see document hobo_correction_181012.pdf). It is Corrected air T = 0.2267*(lux/1000) + 0.04955 or y = 0.1987x + 0.0726. This light adjustment was applied to the cleaned version of the dataset.
Quality Assurance - MV008:
These data are run through a locally developed Python program QAQC procedure. These data have only been flagged and include extreme values, gaps, spikes and possible snow indication. Some visual inspection of the data using a visualization tool occurred. The Python program can create cleaned and filled versions of the data based on specified parameters. More information on this is found in the supplementary documents (Python workflow, Python flag definitions).
See related files.
Geographic Extent: H. J. Andrews Experimental Forest, Western Cascades, Oregon
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