Belowground Growth 2001
PI: 	Jeff Welker
Natural Resource Ecology Laboratory
Natural and Environmental Science Building
Fort Collins, CO 80523
Office Phone: (970) 491-1796
E-Mail: jwelker@nrel.colostate.edu

co-PI:	Jace Fahnestock
Natural Resource Ecology Laboratory
Natural and Environmental Science Building
Fort Collins, CO 80523
Office Phone: (970) 491-5262
E-Mail: jace@nrel.colostate.edu

Contact: Paddy Sullivan
Natural Resource Ecology Laboratory
Natural and Environmental Science Building
Fort Collins, CO 80523
Office Phone: (970) 491-5630
E-Mail: paddy@nrel.colostate.edu

Funding Source
	NSF (OPP-019643)

Overview
	Belowground growth data were collected from June 9-August 15, 2001, with
an additional sampling date on October 12, 2001, at the Toolik Lake LTER (68º 
38'N, 149º 43'W) ITEX moist tussock snowfence site.  Measurements were taken at
a mean interval of 7.7 days in plots treated with elevated winter snow (7th year 
of treatment - ~3m drift), warming (1st year of treatment - ITEX open-top 
chambers) and fertilization (1st year of treatment - 2 applications: June 5 and 
July 9, 2001, each @ 15g N m-2).

Instrument Description
Cellulose acetate butyrate (CAB) minirhizotron tubes with a 2-inch inside 
diameter were installed at approximately 45( to the soil surface in July 2000.  
Digital minirhizotron images were taken in 2001 with a BTC-2 Minirhizotron Camera 
System (Bartz Technology Corporation, Santa Barbara, CA). 

Data Collection and Processing
Digital minirhizotron images were captured as a continuous series of adjoining 
frames from the soil surface to a maximum depth of 64 cm with the ICAP software 
package (Bartz Technology Corporation, Santa Barbara, CA).  Image analysis, 
which included the quantification of root dimension and color, was conducted 
with the PC-Based MSU ROOTs software package (Enslin et al. 1994).  Roots were 
identified only when a root length greater than 1.5 mm was visible within the 
image.  Root dimensions (i.e., length and width) were traced manually and 
exported to a database.  Root color, from which we inferred root age, was 
classified as white (new production), brown (suberized), gray (non-functional and 
of varying degrees of decomposition) and missing, with additional categories of 
moved and obscured to further the precision of standing biomass estimates. 

Data Format 
	Missing data: None
	Column Headers 
		Julian Date	
Actual Depth (vertical depth, rather than angular depth)
Root Area (root length (mm) x root diameter (mm))	
Daily Root Area Production (root area/days since previous sample)	
Image Volume (image height (mm) x image width (mm) x image depth 
(1 mm)	
RA Pro (root area production/image volume (mm3))

Data Remarks
	These are preliminary data.  Root area production will probably be 
converted into root biomass production when our methods are refined.

References Cited
Enslin, W.R., K.S. Pregitzer and R.L. Hendrick. 1994. MSU ROOTs: A PC-Based 
Program toQuantify Plant Roots. Center for Remote Sensing, Michigan State 
University, 115 ManlyMiles Building, 1405 S. Harrison Rd., East Landing, MI 
48823-5243.