Leaf area index following the ice storm of January 1998 at the Hubbard Brook Experimental Forest
Leaf area index following the ice storm of January 1998 at the Hubbard Brook Experimental Forest
Steven Hamburg
Environmental Defense Fund
18 Tremont Street, Suite 850
Boston, MA 02108
Anne G. Rhoads
Matt Vadeboncoeur
University of New Hampshire
8 College Road
Durham, NH 03824
Tom Siccama
Tim Fahey
Geoff Wilson
Brian Weeks
This dataset includes measurements of changes in Leaf Area Index (LAI) collected as part of a long-term study of the recovery of the forest canopy following the ice storm of January 1998. Measurements were taken in Watershed 1 and Watershed 6 between July 1998 and July 2006.
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
biomass, canopy, diameter breast height, foliage, forests, HBEF Watershed 6, HBR, Hubbard Brook LTER, inventory, leaf, tree, vegetation, watersheds.
KEYWORD SET: LTER Core Research Areas
primary production.
Watershed 1
West bounding coordinate: -71.730866
East bounding coordinate: -71.725832
North bounding coordinate: 43.959356
South bounding coordinate: 43.952121
Watershed 6
West bounding coordinate: -71.742990
East bounding coordinate: -71.735175
North bounding coordinate: 43.957070
South bounding coordinate: 43.949996
We began a long-term study of the recovery of the forest canopy following the ice storm of January 1998. Qualitative assessment of canopy damage began in May of 1998, and quantitative measures of damage based on leaf area index (LAI, leaf area per unit of ground area) began in July of 1998, and continued (not every year) through 2006. Both watersheds 1 and 6 (WS1, WS6) were sampled within the area that is subdivided into 25 X 25 m permanent plots.
Twenty-two damaged plots were selected for long-term monitoring of LAI from middle and upper elevational plots (elevations acc. to Whittaker et al. 1974) impacted by the ice storm on WS1 (10 plots) and WS6 (12 plots) using a stratified random design. All measured damaged plots were first stratified by weighted mean damage class (0-<1, 1-<2, and 2-<3), then by elevation. The long-term monitoring plots were then selected from these groupings in proportion to the damage class/elevational distribution. Five plots below 560 m on WS1 and five below 624 m on WS6 were also established to serve as undamaged references.
In July of 1998 the LAI measurements were taken in the 32 plots using a leaf area meter . A 15 X 15 m subplot was delineated within the center of each pre-selected 25 X 25 m plot. Ten points were randomly chosen within each of these subplots. Two horizontal LAI readings (sensor held at 0 degrees) were taken at each of these points, one measuring the LAI of the shrub plus tree canopy (1 m off the ground), and the other measuring that of only the tree canopy (2.5 m off the ground). The LAI-2000's optical sensor was attached to a telescoping pole to maintain consistent heights between points. The readings of the two outer rings were eliminated, decreasing the area viewed by the optical sensor (from 0 to 43 degrees of zenith) and reducing the influence of trees outside of the plots. Readings were taken at dawn and dusk to meet the diffuse light requirement of the LAI-2000. Measurements were repeated in July 1999, 2000, 2001, 2005, on both watersheds, and in 2006 on W6 only.
LAI readings were taken at two levels in the forest in order to measure the LAI of the understory and overstory canopies. Overstory or tree LAI readings were taken at 2.5 m from the ground and understory or shrub LAI readings were based on measurements taken at 1 m off the ground. To obtain shrub LAI values, the overstory LAI readings were subtracted from the readings taken at 1 m from the ground since these measurements also included the upper canopy. The ten readings taken in each plot were averaged to obtain a mean tree LAI and a mean shrub LAI value for that plot. The units for LAI are m2 of leaves/m2 of forest floor.
  • Rhoads, A.G., Hamburg, S.P., Fahey, T.J., Siccama, T.G., Hane, E.H., Battles, J., Cogbill, C., Randall, J., and Wilson, G. 2002. Effects of an intense ice storm on the structure of a northern hardwood forest. Canadian Journal of Forest Research 32:1763-1775.
  • Rhoads, A.G., Hamburg, S.P., Fahey, T.J., Siccama, T.G., and Kobe, R. 2004. Comparing direct and indirect methods of assessing canopy structure in a northern hardwood forest. Canadian Journal of Forest Research 34:584-591.
  • Welles, J.M. 1990. Some indirect methods of estimating canopy structure. Remote Sensing Rev. 5:31-43.
  • Welles, J.M., and Norman, J.M. 1991. Instrument for indirect measurement of canopy architecture. Agron. J. 83:818-825.
  • Whittaker, R.H., Bormann, F.H., Likens, G.E., and Siccama, T.G. 1974. The Hubbard Brook Ecosystem Study: Forest Biomass and Production. Ecol. Mon. 44:233-252.
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]. http://hubbardbrook.org/data/dataset.php?id=81 (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
Email: hbr-im@lternet.edu

Data file: lai.txt
Description: Leaf area index measurements from 1998 - 2006 at the Hubbard Brook LTER site.
ColumnVariableDescriptionUnitsCoded?Missing value label
1YEARYear data was collectedYYYYnnone
2WSWatershed numbernoneynone
3PLOTPlot numbernoneynone
4ELEVATION_BANDElevation bandnoneynone
6LAITLeaf area index (trees)meterSquaredPerMeterSquaredn
7LAISLeaf area index (trees and shrubs)meterSquaredPerMeterSquaredn


Variable: WS
Watershed 1
Watershed 6
Variable: PLOT
> 0 integer id corresponding to an existent plot
within the low elevation band
within the mid elevation band
within the high elevation band

Missing Value Code
Code Explanation
Data missing or not taken
Data missing or not taken