Tree inventory data for the Hubbard Brook Valley Plots, baseline data collected 1995 - 1998
Tree inventory data for the Hubbard Brook Valley Plots, baseline data collected 1995 - 1998
John J. Battles
University of California, Berkeley
Environmental Science, Policy, and Management
137 Mulford Hall
Berkeley, CA 94720-3114
Tim Fahey
Department of Natural Resources, Cornell University
104A Bruckner Hall
Ithaca, NY 14853
Thomas G. Siccama
Yale School of Forestry and Environmental Studies
Paul Schwarz
Suzanne Wapner
The valley-wide plots are a grid of 431 sites along fifteen N–S transects established at 500-m intervals spanning the entire Hubbard Brook Valley. Multiple above- and below- ground attributes were measured between 1995 and 1998. This dataset includes forest inventory data; soil data and other measurements are presented in separate datasets.
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
biomass, diameter breast height, forests, HBEF Valleywide Plots, HBR, Hubbard Brook LTER, inventory, schwarz, trees, vegetation, watersheds.
KEYWORD SET: LTER Core Research Areas
primary production.
The valley-wide plots are a grid of 431 sites along fifteen N–S transects established at 500-m intervals spanning the entire Hubbard Brook Valley.
West bounding coordinate: -71.80620
East bounding coordinate: -71.70220
North bounding coordinate: 43.9590
South bounding coordinate: 43.9140
The 431 sites are located across the entire Hubbard Brook Valley. Fifteen N–S transects were established at 500-m intervals to span the entire Hubbard Brook Valley. Along the transects, a regular array of 431 500-m2 circular plots was established at distance intervals of either 25 m, 100 m, or 200 m. UTM coordinates of all plots are included in this dataset. A map of the plot locations can be found in: Schwarz et al, 2003.
This dataset contains the tree inventory of 431 plots that Paul Schwarz and others established between 1995-1998. Data collected on these plots led to the following two publications (1,2) and a doctoral thesis (3). The dataset includes tree tag number, diameter breast height (DBH), crown status (4 classes), and tree status (4 classes) of all trees > 10cm DBH during the sampling period of 1995-1998. It also contains UTM coordinates for each plot. Physical plot attributes are posted in a different dataset on this website. Soils data (soil chemistry, depth, exchangeable cations, and texture) and a tree recruitment inventory were also taken on these plots. Soils data and tree recruitment data are also posted separately on this website.
Plot establishment - The following methods related to plot establishment are excerpted from Schwarz et al 2003 (see below for reference): Fifteen North–South transects were established at 500-m intervals to span the entire Hubbard Brook Valley. Along the transects, a regular array of 431 500-m2 circular plots was established at distance intervals of either 25 m, 100 m, or 200 m. The sampling layout and spacing of the plots was designed to facilitate the analysis of spatial patterns in the forest vegetation by utilizing a wide range of distance intervals between plots (Fortin et al. 1989). A map of the plots can be found here:
The intention was that each plot would contain 50 to 60 canopy-sized trees. Some forest stands were considerably more dense than this (usually they were spruce/fir stands), and under these circumstances the plot radius was reduced to 10 m (314 m2). Each plot was identified with a gray PVC pipe placed in the center of the plot with a round aluminum ID tag and UTM coordinates. UTM coordinates were taken at plot center. The plots were arranged along N-S transects originating at the Forest Service road along Hubbard Brook.
Adult tree inventory - Within each plot, all trees (both alive and dead) greater than or equal to 10 cm at breast height (BH, 1.37 m) were measured and tagged with a rectangular, numbered aluminum tag secured with a 3 inch aluminum nail. DBH was measured to the nearest 0.1 cm, and measurements were made from the uphill side of a tree. Trees were tagged sequentially from the inside to the outside edge of the plot and in a clockwise direction around the plot. The first tree tagged in each plot should be a tree uphill from the plot center growing along (or near) the painted N-S transect line. The tags should all face the plot’s center.
After a tree was measured and tagged, it was identified to species (using the appropriate species code). A tree’s crown status was assigned to one of four categories: dominant (D), codominant (C), intermediate (I), or suppressed (S). A dominant rating implies that the top of the tree’s canopy was above its neighbors and was in no way competing for light. A codominant rating implies that the tree was sharing the top of the forest canopy with one adjacent neighboring tree and was competing with that neighbor for light. An intermediate rating implies that the tree’s canopy was at the level of the forest canopy but was sharing the canopy with two or more adjacent neighboring trees. A suppressed rating implies that the tree’s canopy was below the forest canopy and was light limited. Its crown condition was rated as either (I), if 80–100% of the tree’s potential foliage was intact; (2), if 50–80%; (3), if 10–50%; or (4), if less than 10% of the potential foliage was intact. Any unusual characteristics of the tree were also noted e.g., tree was leaning, roots growing around a boulder, etc. Assessing a tree’s crown status and condition tends to be the most difficult measurement because it is so subjective. Occasionally there are legitimate differences of opinion. However, the purpose of assessing a tree’s crown status and condition was to relate its canopy position to its potential growth rate. This purpose was kept in mind when assessing trees.
Special cases - Wounded trees: If a tree had a wound at breast height, then was measured either above or below BH and noted as such. The DBH measurements were used to calculate forest basal area and biomass, so the most representative measurement of the tree was used.
Clumped trees: If there was more than one stem originating from the same root system, then each stem that was 10 cm DBH or larger was measured as a separate tree and given a unique tag. These clumps were noted on the data sheet.
  • Fortin, M.-J., Drapeau, P., and Legendre, P. 1989. Spatial autocorrelation and sampling design in plant ecology. Vegetation 83:209–222.
  • Schwarz, P.A. 2001. Spatial patterns of abundance of northern hardwood-conifer tree species in a forested valley in the White Mountains, New Hampshire, USA. PhD Disseration, Cornell University.
  • Schwarz, P.A., Fahey, T.J., Martin, C.W., Siccama, T.G., and Bailey, A.S. 2001. Structure and composition of three northern hardwood-conifer forests with differing disturbance histories. Forest Ecology and Management 144:201-212.
  • Schwarz, P.A., Fahey, T.J., and McCulloch, C.E. 2003. Factors controlling spatial variation of tree species abundance in a forested landscape. Ecology 84(7):1862-1878.
Data Use Policy

The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, government or other not-for-profit professional purposes.

2) Redistribution. The data and metadata are provided for use by the Data User. The Data User will not redistribute the original Data Set or metadata to others without the explicit permission of the Principal Investigator.

3) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly attribute the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier.

Citation example: Holmes, R.T. 2012. Bird Abundances at Hubbard Brook (1969-2010) and on three replicate plots (1986-2000) in the White Mountain National Forest. Durham, NH. Hubbard Brook Data Archive [Database]. (23 July 2012)

4) Acknowledgment: The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed to its content. Acknowledgments should identify the supporting party, the party that received the support, and any identifying information such as grant numbers.

Acknowledgment example: Data on [topic] were provided by [name of PI] on [date]. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station, Newtown Square, PA. Significant funding for collection of these data was provided by [agency]-[grant number], [agency]-[grant number], etc.

5) Consultation and questions. Data users are strongly encouraged to consult with the Principal Investigator(s) who collected these data for further information. Also, when appropriate, Data Users should consider including the Principal Investigator as a collaborator and/or co-author in the use of these data.

6) Notification. The Data User will notify the Principal Investigator of any publication or derivative work based on the Data Set. The Data User will also provide the Principal Investigator and/or the administrator of the Hubbard Brook Ecosystem Study with a pdf or two reprints of any publication(s) resulting from use of the Data Set.

7) Disclaimer. While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

8) Terms of Agreement. By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.


Information Manager, Hubbard Brook LTER
234 Mirror Lake Road
North Woodstock, NH 03262

Phone: (603) 726-8902

Data file: valley_tree_inventory.txt
Description: Tree inventory data for the Hubbard Brook Valley Plots, initial survey measured between 1995 and 1998.
ColumnVariableDescriptionUnitsCoded?Missing value label
1PLOTPlot ID numbernoneynone
2UTM_EASTINGUTM Easting of plot locationmeternnone
3UTM_NORTHINGUTM Northing of plot locationmeternnone
4DATEDate of inventoryYYYY-MM-DDn
5DATE_NOTENotes about the Datenoneynone
6TREE_TAGTree tagnoneynone
7PLOT_AREAArea of the plothectarennone
8SPECIESSpecies codenoneynone
9DBHDiameter at breast heightmeternnone
10CROWN_STATUSRelative dominance of tree crownnoneynone
11TREE_STATUS1Tree statusnoneynone
12TREE_STATUS2Tree status divided into numerical categoriesnoneynone
13COMMENTSTree commentsnoneynone


Variable: PLOT
Plot number
Variable: DATE_NOTE
Notes about the Date
Variable: TREE_TAG
Tree tag ID
Variable: SPECIES
Fagus grandifolia
Populus grandidentata
Prunus serotina
Abies balsamea
Fraxinus nigra
Tilia americana
Tsuga canadensis
Betula populifolia
Amelanchier spp
Sorbus americana
Betula papyrifera
Prunus pensylvanica
Populus tremuloides
Acer rubrum
Picea rubens
Acer saccharum
Acer pensylvanicum
Fraxinus americana
Betula alleghaniensis (formerly Betula lutea)
dead or broken
Variable: TREE_STATUS1
Tree status alive or dead (see methods for dead descriptions)
Variable: TREE_STATUS2
standing dead
dead on ground
Variable: COMMENTS
Comments about tree sampling

Missing Value Code
Code Explanation
Unkown date