Forest Inventory of a Northern Hardwood Forest: Watershed 6, 2012, Hubbard Brook Experimental Forest
TITLE
Forest Inventory of a Northern Hardwood Forest: Watershed 6, 2012, Hubbard Brook Experimental Forest
PRINCIPAL INVESTIGATOR(s)
John J. Battles
University of California, Berkeley
Environmental Science, Policy, and Management
137 Mulford Hall
Berkeley, CA 94720-3114
USA

Phone: (510) 643-0684
Chris Johnson
Department of Civil and Environmental Engineering, Syracuse University
151 Link Hall
Syracuse, NY 13244
USA
Steven Hamburg
Environmental Defense Fund
18 Tremont Street, Suite 850
Boston, MA 02108
USA
Tim Fahey
Department of Natural Resources, Cornell University
104A Bruckner Hall
Ithaca, NY 14853
USA
Charles Driscoll
Department of Civil and Environmental Engineering, Syracuse University
151 Link Hall
Syracuse, NY 13244
USA
Gene Likens
Institute of Ecosystem Studies
Box AB
Millbrook, NY 12545
USA
OTHERS INVOLVED
Natalie van Doorn
ABSTRACT:
Forest inventory surveys were initiated in 1965, repeated in 1977, and repeated at 5 year intervals after that; this data set was collected in summer of 2012. The inventory consists of a total inventory of all trees >=10 cm diameter-at-breast-height (dbh) on the whole of the watershed (13.23 ha), as measured in each of the 208 25 m x 25 m plots. Trees >=2 to <=10 cm dbh were subsampled using a 3 meter wide strip along one edge of each 25 m x 25 m plot. With the addition of tree tags in 2002 on all trees >=10 cm dbh, tracking of individual trees is now possible.
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
biomass, diameter breast height, forests, HBEF Watershed 6, HBR, Hubbard Brook LTER, inventory, trees, vegetation, watersheds.
KEYWORD SET: LTER Core Research Areas
primary production.
BEGIN DATE
2012
END DATE
2012
LOCATION
Watershed 6 is a 13.23 ha watershed extending from the weir at 560m to the ridge at 790m.
West bounding coordinate: -71.743462
East bounding coordinate: -71.735649
North bounding coordinate: 43.957001
South bounding coordinate: 43.949928
Elevation
Minimum: 560
Maximum: 790
(Unit: meter)
SAMPLING BACKGROUND
The forest was first sampled in 1965. The hydrology has been monitored since 1963. Surveys were initiated in 1965, repeated in 1977, and repeated at 5 year intervals after that. These data were collected in the summer of 2012. The stream water chemistry has been monitored since 1963. The watershed is forested by typical northern hardwood species (sugar maple, beech and yellow birch) on the lower 90% of its area and by a montane boreal transition forest of red spruce, balsam fir and white birch on the highest 10%. Surveying techniques were used in 1965 to install a grid system of 208 grid cells, each 25 x 25 m square. These grid units serve as the plot system. See the following links for more information:
http://hubbardbrook.org/overview/maps/w6_zone_map.shtml
http://hubbardbrook.org/watersheds/w6_grid_elevations.shtml
SAMPLING DESIGN
The inventory consists of a total inventory of all trees >=10 cm dbh on the whole of the watershed (13.23 ha), as measured in each of the 208 25 m x 25 m plots. Trees >=2 to <=10 cm dbh were subsampled using a 3 meter wide strip along one edge of each 25 m x 25 m plot (see plot layout). The lengths of these strips are not always exactly 25 meters, due to drift or imprecise replacement of the corner stakes. The actual measured length of the strip is used to calculate the area of the plot (as given in the data) for the smaller trees. For the larger trees, plot area was not adjusted for drift and is assumed to be 625 sq. meters.
DATA DESCRIPTION
The data consist of the diameters (dbh) of all trees >=10 cm dbh, live and dead, in the whole of the watershed (10714 individual stems). Dead trees were recorded as standing dead trees (trees dead but retaining most of their fine branches) and as snags (trees broken off above dbh or with only their major large branches still intact). Live trees were noted "sick" if they had very sparse foliage or yellowing foliage in the mid summer sampling. A subsample of trees >=2 cm dbh and <10cm dbh were measured at the same time (3870 individual stems). All stems that met the size criteria were measured individually, and in some years it was noted whether a stem was part of a group of stems from the same tree (i.e. multiple stems that split from a single trunk below breast height). In 2002, uniquely numbered aluminum tags were nailed to each stem >10 cm dbh to allow for tracking of individual stems from survey to survey.
CALCULATIONS
Aboveground and belowground biomass was estimated for each stem in the inventory and is included in the data. Estimates were based on species-specific allometric equations developed at Hubbard Brook. Phytosociology or biomass summaries can be obtained by using our interactive calculators. Phytosociology summaries include basal area, density and frequency of each species for the watershed as a whole or for smaller units as chosen by the user. Diameter distributions for a specific species can also be selected. Biomass summaries include biomass estimates by plant part for each species for the watershed as a whole or for smaller units as chosen by the user. Options to estimate productivity and total nutrient pools in the vegetation are also available. To access the calculators or for extensive details about how these calculations are made, see link in ADDITIONAL RESOURCES below.
NOTES
For surveys prior to 2002 (when stems where first tagged), it is not possible to compare the data between sampling years on a plot by plot basis, since trees were not individually tagged and plot corners have shifted slightly over time. At the time of the 1977 and 1982 inventories, many of the aluminum rods marking plot corners had come out and were replaced but not resurveyed. Also, trees on the lines between plots can "drift" between plots between years depending on the observers line of sight or decision as to whether the center of the base of a tree is in one plot or the adjoining plot. In 1989 we prepared maps of each plot on which we outlined edge trees and assigned them to one plot or another. These maps have been copied on the backs of the field data collection sheets in the more recent years such that problem trees can be assigned consistently. For extensive notes about the details of these surveys and subsequent calculations, see link in ADDITIONAL RESOURCES below.
With the addition of tree tags in 2002, tracking of individual trees is now possible. Subsequent surveys of tagged trees allow for corrections to be made. For example, it is possible to tag trees that had clearly been missed in the previous survey (trees >19.5 cm dbh as measured in 2012 – the cutoff was based on observed maximum 5-year increment from tree rings). Another benefit of tagged tree inventories is that it is possible to catch field blunders as defined by extraordinary negative or positive diameter growth. Such examples are coded in the dataset under the variable AnalysisCode, where an “I” signifies that the dbh from that year was interpolated by regression from subsequent survey data. It is not recommended that these trees be used for demographic analyses since the growth has been estimated. DBH note: Tagged trees <10cm dbh were kept in the inventory as long as they were >10cm at the time of the initial tagging.
Vigor codes 1 and 2 (beech bark disease assessment) are deprecated for 2002 and later data with overall beech health recorded using codes 3 - 6.
ADDITIONAL RESOURCES
REFERENCES
  • Whittaker, R.H., Likens, G.E., Bormann, F.H., Eaton, J.S., and Siccama, T.G. 1979. Hubbard Brook Ecosystem Study: forest nutrient cycling and element behavior. Ecology 60(1):203-220.
  • Whittaker, R.H., Bormann, F.H., Likens, G.E., and Siccama, T.G. 1974. The Hubbard Brook Ecosystem Study: forest biomass and production. Ecol. Monogr. 44(2):233-254.
  • Bormann, F.H., Siccama, T.G., Likens, G.E., and Whittaker, R.H. 1970. Hubbard Brook Ecosystem Study: composition and dynamics of the tree stratum. Ecol. Monogr. 40(4):373-388.
DATA ACCESS GUIDELINES
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.

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CONTACT PERSON

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

Phone: (603) 726-8902
Email: hbr-im@lternet.edu

Data file: w62012veg.txt
Description: Tree inventory data for Watershed 6, 2012, at the Hubbard Brook LTER. Data variable names and descriptions have been updated from those used in pre-2002 data tables for simplification purposes. The current variables TwoToTen and TwoToTenArea are equivalent to 2-10 and 2-10Area, respectively. Vigor codes 1 and 2 (beech bark disease assessment) are deprecated for 2002 and later data with overall beech health recorded using codes 3 - 6. A separate variable was added in 2012 to specifically code for stage of Beech bark disease
Notes on Data: The data is physically located at the Battles Laboratory, Environmental Science, Policy, and Management, University of California, Berkeley and was last updated in July 2013.
ColumnVariableDescriptionUnitsCoded?Missing value label
1Plotplot numbernoneynone
2Zonevegetation zonenoneynone
3Speciesspecies acronymnoneynone
4SppNumspecies numbernoneynone
5SeqSequence number. Unique number for each tree.noneynone
6TagTree tag numbernoney
0
7Dbhdiameter at breast height, in cmcentimeternnone
8Vigorvigor codenoneynone
9AbvBmssaboveground biomass in kilograms estimated for each stemkilogramnnone
10BlwBmssbelowground biomass in kilograms estimated for each stemkilogramnnone
11TwotoTenpresence (1) or absence (0) of measured trees in the 2 - 10 cm diameter class for that plot (in some years, not all plots were measured)noneynone
1210AreaArea of plot on which trees >10 cm dbh were measured (m-2)meterSquaredn
0
13TwotoTenAreaArea of plot on which trees 2-10 cm dbh were measured (m-2)meterSquaredn
0
14ElevBNew category of elevation zone used for 2002 and later collectionsnoneynone
15AnalysisCodeDbh interpolated from later data; not applicable for this data set at this timenoneynone
16bbdBeech bark disease (bbd) codenoneynone

CODES

Variable: Plot
Description:
An integer representing the plot
Variable: Zone
Code
Description
1
primarily spruce/fir forest on the ridge top - 26 plots
2
high hardwoods - 26 plots
3
slightly lower high hardwoods - 29 plots (can be combined with zone 2)
4
middle elevation hardwoods - 90 plots
5
lower elevation hardwoods - 37 plots
Variable: Species, SppNum
SppNum
Species Code
Species/SppNum description
1
ACSA
Sugar maple (Acer saccharum)
2
FAGR
American beech (Fagus grandifolia)
3
BEAL
Yellow birch (Betula alleghaniensis)
4
FRAM
White ash (Fraxinus americana)
5
ACSP
Mountain maple (Acer spicatum)
6
ACPE
Striped maple or moose wood (Acer pensylvanicum)
7
PRPE
Pin or fire cherry (Prunus pensylvanica)
8
PRVI
Choke cherry (Prunus virginiana)
9
ABBA
Balsam fir (Abies balsamea)
10
PIRU
Red spruce (Picea rubens)
11
BEPA
White or paper birch (Betula papyrifera)
12
SOAM
Mountain ash (Sorbus americana)
13
ACRU
Red maple (Acer rubrum)
14
TSCA
Eastern hemlock (Tsuga canadensis)
15
UNKN
unknown, used for unidentifiable rotten snags
16
POTR
Quaking aspen (Populus tremuloides)
17
PRSE
Black cherry (Prunus serotina)
18
AMSP
Shadbush (Amelanchier sp.)
19
POGR
Big-tooth aspen (Populus grandidentata)
20
SASP
Willow (Salix sp.)
21
COAL
Alternate-leaved dogwood (Cornus alternifolia)
22
PRSP
Cherry (unspecified) (Prunus sp.)
23
SARA
Red elderberry (Sambucus racemosa)
Variable: Seq
Description:
A positive number representing the sequence number of an individual tree
Variable: Tag
Description:
A positive number or number-letter combination representing an individual tree tag
Variable: Vigor
Code
Description
0
healthy
3
sick (trees with crown in decline)
4
standing dead tree
5
standing dead snag (no limbs left)
6
a downed dead tree including any dead tree that is broken or detached below dbh
Variable: TwotoTen
Code
Description
1
Presence
0
Absence
Variable: ElevB
Code
Description
H
High elevation, >710 meters
M
Mid elevation, 630 - 710 meters
L
Low elevation, <630 meters
Variable: AnalysisCode
Description:
I indicates dbh is interpolated by regression from later measurements. Not applicable for this dataset at this time
Variable: bbd
Code
Description
0
No bbd present
1
bbd present on trunk, but did not affect dbh area and measure
2
bbd affected the dbh area and measure, but not severely (usually only at 1-2 points)
3
bbd affected the dbh area and measure severely (on many points/sides)

MISSING VALUE CODES
Variable
Missing Value Code
Code Explanation
Tag
0
Tree did not have a tag
10Area
0
Area does not apply to the current sample
TwotoTenArea
0
Area does not apply to the current sample