uid=HFR,o=lter,dc=ecoinformatics,dc=org all public read doi:10.6073/pasta/ed73b2b6a0bf3475001f2d6bf35f80a6 David Orwig https://orcid.org/0000-0001-7822-3560 Julian Hadley Mark VanScoy Researcher Liza Nicoll Researcher 2024 English

Leaf area index (LAI) measurements are made to detect changes in forest leaf area that are important in understanding forests’ carbon dioxide (CO2) uptake and water use. Measurements of LAI in different forest types are useful understanding differences between forests in CO2 uptake and water use, while variation in LAI in the same forest type over time helps to explain interannual variation and long-term trends in carbon storage and water use. Within a single year, especially for deciduous forests, seasonal changes in LAI are very important in determining the forest’s cycle of CO2 uptake and water use. LAI measurements at Harvard Forest were begun in the old-growth hemlock stand in 1998 in order to understand and develop a predictive model for its carbon exchange, and were begun at the Little Prospect Hill site in 2002 to better understand CO2 uptake and carbon storage at this site, which were measured by the eddy-covariance method beginning in 2002. Due to a lack of personnel, multiple annual measurements of LAI to examine seasonal change in leaf area did not begin until 2007.

canopy cover leaf area index leaves LTER controlled vocabulary primary production 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=hf150 Prospect Hill Tract (Harvard Forest). Coordinates based on WGS84 datum. -72.185 -72.180 +42.542 +42.539 355 380 meter 1998 2024 ongoing 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

Leaf area index is measured with the LAI-2000 canopy analyzer (Licor, Inc., Lincoln, NE, USA). Data are collected under diffuse-light conditions, either around the time of sunrise or in cloudy weather, with one LAI sensor continuously logging data above the canopy on an eddy flux tower, and measurements with the other sensor made at multiple plots within each forest type - usually 12 plots within the old-growth hemlock forest, and 36 plots on Little Prospect Hill. For details on the positions of plots, see HF148. Data collected in Hemlock stand in November 1998, August 2009, and November 2009 (planned). Data collected annually at LPH stand during September 2002, 2003, 2004, 2005 and 2007, and multiple times in 2008 and 2009.

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. hf150-01-hem-lai.csv Hemlock leaf area index hf150-01-hem-lai.csv 19422 8b84acef06bfa1aa74857f55ee438c6f 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p15/hf150/hf150-01-hem-lai.csv datetime date and time YYYY-MM-DDThh:mm:ss date date YYYY-MM-DD doy day of year nominalDay 1 whole time time hh:mm:ss distance distance from tower meter 1 whole NA missing value transect compass direction from Hemlock tower from geographic north degree 1 whole NA missing value lai_masked leaf area index measurement with the 5th ring masked dimensionless 0.01 real NA missing value sel standard error of mean dimensionless 0.01 real NA missing value 310 hf150-02-lph-lai.csv Little Prospect Hill leaf area index hf150-02-lph-lai.csv 93212 3101c1833d3838cd0783d981f8076c92 1 \r\n column , https://harvardforest.fas.harvard.edu/data/p15/hf150/hf150-02-lph-lai.csv datetime date and time YYYY-MM-DDThh:mm:ss date date YYYY-MM-DD doy day of year nominalDay 1 whole time time hh:mm:ss distance distance from tower meter 1 whole NA missing value transect compass direction from LPH tower from geographic north degree 1 whole NA missing value lai_unmasked unmasked leaf area index measurement dimensionless 0.01 real NA missing value sel_unmasked standard error of mean of unmasked measurement dimensionless 0.01 real NA missing value lai_masked leaf area index measurement with the 5th ring masked dimensionless 0.01 real NA missing value sel_masked standard error of mean of masked measurement dimensionless 0.01 real NA missing value 1353 plot long-term measurement https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf103 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf063 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf148 https://harvardforest.fas.harvard.edu/exist/apps/datasets/showData.html?id=hf072