The following data sets are currently available on the Harvard Forest web page (see http://harvardforest.fas.harvard.edu/data/archive.html). Starting dates for active projects begun before 1992 are indicated in brackets. Recent projects for which complete data are not yet posted are marked with an asterisk.

• Environmental Measurement Site (EMS) [1989]
• Methane Data at EMS
• Soil Respiration, Temperature, and Moisture at EMS
• Meteorological Back Trajectories for EMS
• Canopy Chemistry Study
• CO₂ Exchange by Hemlock Forests in Central New England*

• Harvard Forest Climate Data [1964]
• Phenology of Woody Species [1990]

• N Saturation Amendment Experiment [1988]
• Simulated Hurricane Experiment [1990]
• Trace Gas Fluxes & Soil N Dynamics in Simulated Hurricane Experiment
• Microsite Environments in Simulated Hurricane Experiment
• DIRT Experiment (Litter Manipulation) [1990]
• Soil Warming Experiment [1991]
• Phenology and Growth of Vegetation at Soil Warming Experiment

• Forest Change and Human Populations in New England
• Land Use and Forest Dynamics in Central Massachusetts
• Land Use and Forest Dynamics at Harvard Forest
• Vegetation Patterns of a New England Sand Plain (Montague, MA)
• Demography and Morphology of Ericaceous Species on Montague Sand Plain
• Plant Life History and Land-Use History (Montague, MA and Harvard Forest)*
• Dynamics of Old-Growth Forests on Wachusett Mountain (Princeton, MA)*
• Forest Ecosystem Response to Hemlock woolly Adelgid in Southern New England
• North Quabbin MA Conservation Study
• North Quabbin MA Timber Harvesting Study*
• Land Use and Land Cover Change on the Massachusetts Coast*
• Land Use and Land Cover Change in the Yucatan (Mexico)*
• Landscape-Scale Forest Dynamics in the Luquillo Experimental Forest (PR)

• Forest Damage Patterns in the 1938 Hurricane
• Reconstruction of 1938 Hurricane (New England) and Hurricane Hugo (Puerto Rico)
• Landscape and Regional Impacts of Hurricanes in New England*
• Landscape and Regional Impacts of Hurricanes in Puerto Rico*

• Hemlock Mapped Tree Plot [1990]
• Lyford Mapped Tree Plot [1962]
• Overstory Mapped Tree Plots [1990]
• Hurricane Recovery Plots (Harvard Forest) [1940]
• Hurricane Recovery Plots (Pisgah Forest) [1984]
• Regeneration Following Clearcut Study [1990]
• 1937 Vegetation Inventory (3000 acres)
• 1986 Vegetation Inventory (3000 acres)

• PnET: Modeling Carbon, Water, and Nitrogen Dynamics
• INTERPNT: Mapping Trees Using Distance Measurements
• EXPOS: Modeling Topographic Exposure to Wind
• HURRECON: Modeling Hurricane Wind Speed, Direction, and Damage

• Vegetation Patterns Over Recent Centuries in Northeastern North America
• Long-term Dynamics of Vegetation and Environment in Central Massachusetts
• Long-term Stand Dynamics in Central Massachusetts
• Paleolimnology of Lakes in Central New England*

• Gap Partitioning Among Maples in Central New England
• Canopy Photosynthesis Study
• Fern Understory as an Ecological Filter
• Leaf Display Flexibility in Forest Trees*
• Linking Community Dynamics and Ecosystem Function*
• Plant Functional Pools of C and N for Ecosystem Carbon Cycling*

• Vascular Plants
• Bryophytes
• Breeding Birds

• History of Wildlife in Massachusetts
• Bird Nest Predation in Eastern Oak Forest*
• Vertical Activity of White-Footed Mouse in Oak Forest*
• Effects of Acorn Production on White-Footed Mouse Populations
• Influence of Abandoned Stonewalls on Small Mammal Distributions*

At the present time, downloading of Harvard Forest data sets is not recorded electronically, and prospective users (though encouraged) are not required to notify us of their intended or actual use of our data. We are able to track some uses through the questions and acknowledgements that we receive. Several projects also actively submit their data to regional and national databases. Below are examples of use of our on-line data by other scientists.

• Environmental Measurement Site. Data from the EMS project are ntegrated into the NIGEC and AmeriFlux data systems via hot links at the CDIAC and NIGEC web sites. There have been hundreds of hits and several modeling papers using these data. The data structure has been adapted for widespread use in the AmeriFlux network. The Harvard Forest EMS site and data set were also a component of the NARSTO-NE regional air quality study sponsored by a consortium of EPA, state agencies and industry.
• N-Saturation Data. Foliary chemistry, soil chemistry, litter decomposition, and PnET-predicted N deposition data have been downloaded and used by scientists from NIWOT LTER, Inst. Of Arctic Biology, Syracuse University, Marshall University, and Mt. Holyoke College; and a joint publication is in review with scientists from the Swedish University of Agricultural Sciences.
• Climate Data. The Harvard Forest climate data set has been used in numerous modeling studies and is probably the most frequently downloaded data set. Recently we prepared and submitted our data for inclusion in the LTER Network ClimDB project (http://sql.lternet.edu/climdb/climdb.html), which provides tools for data selection and reduction.
• Pollen Data. Pollen data sets from several projects (Datasets HF026, HF027, HF029) have been submitted to the North American Pollen Database (http://www.museum.state.il.us/research/napd/), where they are easily accessible to other paleoecologists and have been used by many European and North American scientists. For example the IGBP Biome 300 project will continue to use these and other historical data regularly
• Models & Software. Numerous acknowledgments have been received for the Interpnt and Expos programs, along with some requests for source code.
• There has been wide international use of results and data from the DIRT and Soil Warming Experiments.

In addition the following data sets, recently posted, are expected to attract users in the coming year: Phenology of Woody Species (10-year record), North Quabbin Timber Harvesting Study (15-year record), and various long-term Mapped Tree Plots(HF031, HF032, HF036, HF002).