uid=HFR,o=lter,dc=ecoinformatics,dc=org
all
public
read
doi:10.6073/pasta/a5aa971918bf932201bf9fe9404fb36e
Photosynthetically Active Radiation in the Clearcut Site at Harvard Forest 2013
Christopher
Williams
https://orcid.org/0000-0002-5047-0639
Myroslava
Khomik
https://orcid.org/0000-0002-0377-8833
Researcher
Richard
MacLean
Researcher
2023
English
The purpose of these measurements was to capture the light attenuation of the canopy throughout the growing season, which can help in determining leaf area/canopy openness at the site. Measurements were done along a 50-m-long transect (one of the ones used for line-intercept vegetation surveys, on the side of the EC-tower). Eight measurement locations were established along the transect, equidistant, and marked with a bright orange flag. Measurements were taken with a LI-COR LI-191 Line quantum sensor as described below. Before and after measurements along the transect, PAR-readings were taken in an open area (away from canopy cover) either at a log along the access road to the site or up on the fire tower nearby. At each location along the transect, two measurements were taken – one at the ground surface and one at a height of 1.3m (diameter at breast height).
canopy cover
irradiance
leaves
light
photosynthetically active radiation
LTER controlled vocabulary
primary production
disturbance
LTER core area
Harvard Forest
HFR
LTER
USA
HFR default
This dataset is released to the public under Creative Commons CC0 1.0 (No Rights Reserved). Please keep the dataset creators informed of any plans to use the dataset. Consultation with the original investigators is strongly encouraged. Publications and data products that make use of the dataset should include proper acknowledgement.
Creative Commons Zero v1.0 Universal
https://spdx.org/licenses/CC0-1.0.html
CC0-1.0
https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf231
Prospect Hill Tract (Harvard Forest). Coordinates based on WGS84 datum.
-72.174
-72.174
+42.546
+42.546
403
403
meter
2013
2013
complete
Information Manager
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
hf-im@lists.fas.harvard.edu
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
(978) 724-3595
https://harvardforest.fas.harvard.edu
Study Site
The study site occupies roughly a 200 m x 400 m area (8 ha) near the top of Prospect Hill, within the Harvard Forest Long Term Ecological Research Site.
Measuring Light Interception with the LI-Quantum Bar Sensor
MEASUREMENTS TO BE DONE ON A CLEAR DAY AROUND NOON (i.e. 11:45-12:15pm). Note: Calibration coefficient should read -159.5.
1. Attach the cable and the logger to the bar. (all should be in the black-gun case).
2. Be gentle with the bar-sensor, especially the white-sensor strip – don’t scratch it.
3. Place the bar onto the log out by the main road, in the open. Locate the bar to be parallel with the main road and pointing its tip down the road – away from the tower. This will be our initial measurement of PAR in the open. All measurements after should be at or below this number.
4. Level the bar.
5. Turn on the logger. Make sure it is reading in mircomoles (µmol).
6. Make sure nothing is shading the white-sensor part of the instrument.
7. When ready, press “Ave” and keep the bar level and steady for 15 seconds.
8. The instrument will be measuring PAR over 15 seconds and will return the computed average on the screen.
9. Record that number in the associated log book. Record also the time of the reading.
10. Press “hold” to make the log go back to instant readings.
11. Move onto one of eight measurement points. These are located along transect 2, marked with orange flags (labeled “PAR1- PAR8”, on your left.
12. Take measurements within our forest: (a) One by placing the bar near the ground (facing the same direction and orientation, as was on the log). Level it. Make sure you are not shadowing the bar. Take a reading as in steps 3-7 above. Record that in the log book. Record also the time of your reading. (b) Next bring the bar to your shoulder level (about 1.3 m – DBH – above the ground) and take a reading, as before in point a. This one will tend to be higher compared to the ground reading. (c) Move onto the next flag.
13. Once you’re done with all eight locations, go back to the log in the open, by the road.
14. Take a final reading on the log, as in steps 3-7.
15. Make notes of the cloud conditions and weather in the log book.
16. Transfer data from log book into digital format for storage.
Harvard Forest Long-Term Ecological Research
Harvard Forest
324 North Main Street
Petersham
MA
01366
USA
(978) 724-3302
(978) 724-3595
https://harvardforest.fas.harvard.edu
https://ror.org/059cpzx98
pointOfContact
The Harvard Forest Long-Term Ecological Research (LTER) program examines ecological dynamics in the New England region resulting from natural disturbances, environmental change, and human impacts.
National Science Foundation LTER grants: DEB-8811764, DEB-9411975, DEB-0080592, DEB-0620443, DEB-1237491, DEB-1832210.
hf231-01-par.csv
par data
hf231-01-par.csv
23402
cca92ae033093e939707860c956fff74
1
\r\n
column
,
https://harvardforest.fas.harvard.edu/data/p23/hf231/hf231-01-par.csv
id
unique data identifier
unique data identifier
NA
missing value
datetime
date and time when the measurement was taken
YYYY-MM-DDThh:mm
NA
missing value
date
date when the measurement was taken
YYYY-MM-DD
NA
missing value
time
time of day when the measurement was taken (eastern time zone, local
time)
hh:mm
1 minute
NA
missing value
location
whether measurements were taken in the open or along a transect within the
forest stand
whether measurements were taken in the open or along a transect within the
forest stand
NA
missing value
location.id
location identification
location identification
NA
missing value
par
par measurement in micromoles per mole
dimensionless
0.01
real
NA
missing value
open
whether or not the measurement was taken in the open
0
measurement was not taken in the open
1
measurement was taken in the open
NA
missing value
dbh
whether or not the measurement was taken at a height of
DBH
0
measurement was not taken at a height of DBH
1
measurement was taken at a height of DBH
NA
missing value
ground
whether or not the measurement was taken at the
surface/ground
0
the measurement was not taken at the surface/ground
1
the measurement was taken at the surface/ground
NA
missing value
378
informatics
atmosphere
community
short-term measurement
modeling
https://wordpress.clarku.edu/cwilliams/
https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf224
https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf222