Fine root production and mortality from minirhizotrons at the Hubbard Brook Experimental Forest
Fine root production and mortality from minirhizotrons at the Hubbard Brook Experimental Forest
Tim Fahey
Department of Natural Resources, Cornell University
12 Fernow Hall
Ithaca, NY 14853

Phone: (607)-255-5470
Geri Tierney
This data set reports observations of fine root growth, mortality and lifespan in the mature forest. The lifespan data can be combined with fine root biomass data to estimate fine root production in the forests (Fahey et al. 2005). This data set was from reference plots for a snow manipulation experiment and the results are summarized in Tierney et al. (2001).
KEYWORD SET: Hubbard Brook Ecosystem Study LTER
HBEF Snow Removal Study, HBR, Hubbard Brook LTER, root, tree, vegetation.
KEYWORD SET: LTER Core Research Areas
primary production.
Snow manipulation plots at HBEF. These data are from the reference plots only.
West bounding coordinate: -71.804985
East bounding coordinate: -71.697350
North bounding coordinate: 43.962128
South bounding coordinate: 43.915932
Plot SM1
West bounding coordinate: -71.741392
East bounding coordinate: -71.741392
North bounding coordinate: 43.950408
South bounding coordinate: 43.950408
Plot SM2
West bounding coordinate: -71.747275
East bounding coordinate: -71.747275
North bounding coordinate: 43.939433
South bounding coordinate: 43.939433
Plot YB1
West bounding coordinate: -71.735058
East bounding coordinate: -71.735058
North bounding coordinate: 43.936356
South bounding coordinate: 43.936356
Plot YB2
West bounding coordinate: -71.746986
East bounding coordinate: -71.746986
North bounding coordinate: 43.928469
South bounding coordinate: 43.928469
The sites are 10 x 10 m plots selected for a snow manipulation study; however data reported herein are from reference plots only. Two sites are dominated (>80%) by sugar maple (SM1 and SM2) and two are dominated by yellow birch (YB1 and YB2). In the fall and winter of 1996, understory was removed from these plots, and equipment was installed. SM1 is a south-facing site which lies west of W6 at 648 m asl. SM2 is a south-facing site which lies northwest of W101 at 564 m asl. YB1 is a southeast-facing site which likes west of W101 at 472 m asl. YB2 is a north-facing site which lies near W7 at 640 m asl. Slope at SM1, SM2 and YB1 is moderate (about 20%), and slope is steeper (27%) at YB2.
For a complete description of the snow study, see
Dynamics of fine roots (<1 mm diameter) were monitored using minirhizotrons. Four clear plastic minirhizotron tubes (5 cm diameter) were installed at a 45 angle in each of the four reference plots during fall 1996 and spring 1997. Tubes were installed to depth of obstruction by rocks, which varied from site to site with a mean of 21 +/- 5 cm standard error. Styrofoam insulation was placed in each tube to minimize temperature differences between the tube environment and the bulk soil. Images were collected at 25-mm intervals along each tube approximately monthly during the snow-free season from November 1997 to September 1999. Winter conditions prevented measurements from late November until mid-April; thus, overwinter mortality and production are reflected in data from April, the first collection after snowmelt. On each date, about 40 images were collected from each tube along four axes filmed at about 45 from vertical along the upper and lower surfaces of each tube.
Images were analyzed using RooTracker software. Each month, the location, length, diameter and appearance of all new roots growing within each frame were recorded. Changes in size and morphology of each root were tracked through successive intervals. A root was classified "dead" when it became very faint or discontinuous with indistinct edges, shriveled to a fraction of its previous width, or completely disappeared. Dead roots were subsequently tracked until disappearance, and apparently dead roots which later grew or appeared restored were returned to the live category. Roots which became obstructed from view by other roots, condensation, debris, or subtle shifts in MR tube position were classified "obscured" and watched for subsequent reappearance; those that did not reappear were not included in calculations of root mortality.
From these data, fine root length density, production and mortality for each plot were calculated for each interval by pooling data from all four tubes within each plot. Root length density (mm cm-2) was calculated by summing live fine root length and dividing by total minirhizotron tube viewing area. Mean daily fine root production rate (mm cm-2 day-1) was calculated as new root length visible during an observation interval divided by total tube viewing area and the number of days since the previous filming. Because fine root mortality was highly dependent upon the amount of fine root length visible, we calculated a proportional daily fine root mortality rate (% day-1), as root length mortality divided by live root length in the previous interval, and divided by the number of days since the previous filming.
  • Fahey, T.J., Tierney, G.L., Fitzhugh, R.D., Wilson, G.F., and Siccama, T.G. 2005. Soil respiration and soil carbon balance in a northern hardwood forest ecosystem. Canadian Journal of Forest Research 35(2):244-253.
  • Hardy, J.P., Groffman, P.M., Fitzhugh, R.D., Henry, K.S., Welman, A.T., Demers, J.D., Fahey, T.J., Driscoll, C.T., Tierney, G.L., and Nolan, S.N. 2001. Snow depth manipulation and its influence on soil frost and water dynamics in a northern hardwood forest. Biogeochemistry 56:151-174.
  • Tierney, G.L., Fahey, T.J., Groffman, P.M., Hardy, J.P., Fitzhugh, R.D., and Driscoll, C.T. 2001. Soil freezing alters fine root dynamics in a northern hardwood forest. Biogeochemistry 56:175-190.
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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)

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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.

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

Phone: (603) 726-8902

Data file: fineroots.txt
Description: Fine root data from minirhizotrons on the snow removal study at Hubbard Brook LTER
ColumnVariableDescriptionUnitsCoded?Missing value label
1DateSample dateYYYYMMDDnnone
2SiteSample sitenoneynone
3ProductionProduction ratemillimeterPerCentimeterSquaredPerDaynnone
4MortalityMortality ratepercentPerDaynnone
5RLDRoot Length DensitymillimeterPerCentimeterSquarednnone
6IntervalSample intervaldimensionlessnnone


Variable: Site
Sugar Maple Plot 1
Sugar Maple Plot 2
Yellow Birch Plot 1
Yellow Birch Plot 2