---

Annual Sapling Growth Data

for the Walker Branch Throughfall Displacement Experiment (TDE)

1.0 DOCUMENT INFORMATION
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

 2.0 INVESTIGATOR
2.1 Investigator and data set contact:

P.J. Hanson (hansonpj@ornl.gov)
Research Staff Member
Environmental Sciences Division
Oak Ridge National Laboratory
P.O. Box 2008, Building 1059
Oak Ridge, TN 37831-6422

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

 4.0 PROCEDURES
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.
 
 

 5.0 OBSERVATION NOTES
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.
 

6.0 DATA ORGANIZATION
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

Column 1 = PlantID
Arbitrary individual tree identification number


Column 2 = SPC

Species identification code
AR = Acer rubrum
CF = Cornus florida


Column 3 = TRT

Treatment of the TDE experiment
W = wet
A = ambient
D = dry


Column 4 = SLP

Slope position on the TDE site
U = upper
M = middle
B = bottom


Column 5 = Y

Y coordinate of the XY corrdinate system of the TDE experiment (Values range from 1 to 10)


Column 6 = X

X coordinate of the XY corrdinate system of the TDE experiment (Values range from 1 to 30)


Column 7 = G1994

Basal area growth rate per tree for 1994 in mm2 y-1


Column 8 = G1995

Basal area growth rate per tree for 1995 in mm2 y-1


Column 9 = G1996

Basal area growth rate per tree for 1996 in mm2 y-1


 Column 10 = G1997

Basal area growth rate per tree for 1997 in mm2 y-1


 Column 11 = G1998

Basal area growth rate per tree for 1998 in mm2 y-1


 Column 12 = G1999

Basal area growth rate per tree for 1999 in mm2 y-1


Column 13 = G2000

Basal area growth rate per tree for 2000 in mm2 y-1

7.0 KNOWN ERRORS AND QUALITY ASSESSMENT
Negative values can occur and should not be thrown out.

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

 9.0 REFERENCES:

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.
None

 10.0 DATA LISTING

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