uid=HFR,o=lter,dc=ecoinformatics,dc=org all public read doi:10.6073/pasta/124bf598c954e022e021be305adfc5d4 Timothy Sipe Richard Bowden Charles McClaugherty https://orcid.org/0000-0001-5884-0756 Kirsten Bixler Researcher 2023 English

Hemispherical photos were taken at 35 interior grid corners in each land use site’s 30 m x 50 m permanent plot on uniformly overcast days during summer 1998. A Canon A-1 35 mm camera with a 7.5 mm lens was mounted on a tripod, positioned so the film plane was 0.5 m above ground, oriented N-S with a compass, and leveled. Ektachrome 100 slide film was used. Two exposures were made for each location. The slides were processed and digitized in jpeg format by Kodak, Inc. at a resolution of 1536 x 1024 dpi. The jpeg images were screened for nearground obstructions. Fifteen of the 35 photo locations per site were used in subsequent analysis. Hemiview software (v. 2.0, Delta-T Devices Ltd., Cambridge, UK) was used to process the images and calculate indirect, direct, and global (= indirect + direct) sky factors for each sample location, plus the proportion of global sky factor represented by direct beam radiation. Several images spanning a wide range of canopy density were used to develop protocols for setting optimal thresholds in converting from color to black and white images. Each B/W image was then analyzed at three threshold levels, the optimum level plus 5 threshold units (~ 2.5%) above and below the optimum. The results were averaged across the three threshold levels to provide one set of sky factor data per sample location. Above-canopy incident radiation was calculated daily for the June-September growing season based on (1) latitude and longitude, (2) average atmospheric transmission, and (3) monthly averages for fractions of the day in diffuse radiation due to cloud cover for the Harvard Forest area. Data for 2 and 3 above were provided by researchers at the State University of New York at Albany. Below-canopy radiation was estimated daily across half-hour intervals as the sum of diffuse and direct beam components. Sky factors were then calculated from the above- and below-canopy radiation values and averaged both monthly and across the growing season.

canopy cover imagery land use radiation LTER controlled vocabulary 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=hf135 Prospect Hill Tract (Harvard Forest). Coordinates based on WGS84 datum. -72.20 -72.17 +42.55 +42.53 335 357 meter 1998 1998 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

Plot locations: Plow #1 Site: Prospect Hill Tract, Compartment # III, southern end. Plow #2 Site: Prospect Hill Tract, Compartment # III, southern end. Pasture #1 Site: Prospect Hill Tract, Compartment # I, southeastern edge. Pasture #2 Site: Prospect Hill Tract, Compartment # VIII, central edge. Woodlot #1 Site: Prospect Hill Tract, Compartment # VIII, northeastern edge. Woodlot #2 Site: Prospect Hill Tract, Compartment # VII, central.

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. hf135-01-sky.csv canopy sky factors hf135-01-sky.csv 3001 a818ccd74ef8ab170f15f364ce6c59c5 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p13/hf135/hf135-01-sky.csv category level of pooling All Sites all 6 sites combined By Legacy plow vs. pasture vs. woodlot, with data averaged across the two replicates of each legacy By Site by individual site sky.factor sky factor ISF indirect sky factor DSF direct sky factor GSF global sky factor (ISF+DSF) DSF/GSF ratio of direct and global sky factors legacy.site for legacy or site comparisons P plow S pasture W woodlot P1 plow replicate 1 P2 plow replicate 2 S1 pasture replicate 1 S2 pasture replicate 2 W1 woodlot replicate 1 W2 woodlot replicate 2 n sample size, number of hemispherical photos analyzed for all sites combined, per legacy and per site number 1 whole NA missing value mean mean for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value std.dev standard deviation for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value std.error standard error for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value range range for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value max maximum for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value min minimum for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value median median for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value ci.25 25% CI for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value ci.75 75% CI for photos analyzed across all sites, per legacy, and per site number 0.001 real NA missing value 40 historical plot community short-term measurement https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf133 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf134 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf136 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf137 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf138 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf139 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf140 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf141 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf142 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf143 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf144