Annual Sapling Growth Data

for the Walker Branch Throughfall Displacement Experiment (TDE)

1.1 Document Title: TDE annual sapling growth data
1.2 Revision Date:  January 9, 2001
1.3 Document Summary:  Tree basal area growth for 1994, 1995, 1996, 1997, 1998, 1999, 2000
1.4 Sponsor: Office of Biological and Environmental Research, U. S. DOE

2.1 Investigator and data set contact:

P.J. Hanson (
Research Staff Member
Environmental Sciences Division
Oak Ridge National Laboratory
P.O. Box 2008, Building 1059
Oak Ridge, TN 37831-6422
2.2 Title Of Investigation:
Walker Branch Throughfall Displacement Experiment (TDE)

Caliper based, annual grwoth data for the two most common on the TDE site:  Acer rubrum and Cornus florida.

In February and March of 1994, 10 transects for observations of sapling growth and mortality were established across the three plots from lower- to upper-slope positions. Although other species were considered for these measurements, only Acer rubrum and Cornus florida were distributed across the TDE in sufficient numbers for inclusion. Saplings ranged from 10 to 60 mm dbh with the majority from 10 to 40 mm. Height measurements were not included because the crowns were broad without predominant main shoots and because height growth was minimal in the low light understory environment of our closed canopy stand. Starting at the time of spring leafout each year, biweekly measurements of stem diameter at a permanently marked location on each saplingís main stem (typically between 1 and 1.5 meters above the ground) were conducted until sapling growth had ceased for that year. Each stem caliper measurement was the mean of three replicate diameter measurements made with a digital caliper (0.01 mm resolution) from three different angles around the marked point of measurement. The mean of replicate measures from different angles was required to minimize the impact of noncircular stem cross sections. Sapling stem diameters were converted to basal area to express mean daily sapling growth rates per plant in mm2 day-1, or integrated annual sapling growth in mm2 year-1.

Incremental growth of saplings that died in a given year were included in the calculation of that years mean growth rate, but excluded in all subsequent estimates of annual growth.  Additonal randomly chosen saplings were added to the measurement pool after the 1994, 1995, and 1996 growing seasons (to make up for mortality losses), but no additional plants were added to this observation set after that time.

Data are provided in comma delimeted text files where the first line includes the variable names and subsequent lines include the following data by year.

6.1 Variable, Definition, and Units

6.2 Number of Records: 392 saplings
6.3 Missing data: Missing data is represented by empty cells.
6.4 Related Data Sets:  Intra-annual sapling growth data at approximately biweekly resolution are also available for some years.

Negative values can occur and should not be thrown out.

8.1 Limitations of the data:     None.
8.2 Known Problems With The Data:     None.
8.3 Usage Guidance:     None.


Hanson, P.J. , D.E.Todd and J.S. Amthor.   (in press)  A six year study of sapling and large-tree growth and mortality responses to natural and induced variability in precipitation and throughfall.   Tree Physiology (in press).

Hanson, P.J., D.E. Todd, M.A. Huston, J.D. Joslin, Jennifer Croker, and R. M. Augé. 1998.  Description and field performance of the Walker Branch Throughfall Displacement Experiment: 1993-1996, ORNL/TM-13586, Oak Ridge National Laboratory, Oak Ridge, Tennessee.


Click on the following to view data for the listed year.
Once open the files can exported as text files with the 'Save As' command.

Annual sapling growth file