Table 2.

Cross-sectional and conducting xylem element parameters for roots of Populus angulata x plantierensis whips for each of the root wire girdling treatments

Parameter	No girdle		Full girdle		Partial girdle
Cross-sectional surface area (μm²)	25556a^z	+2152*	21132ab	±2152	15322b	±2152
Number of functional vessels	8206a	±507	4547b	±507	4895b	±594
Xylem vessel diameter (μm)^x	.293ab	±0.045	.360a	±0.045	.239b	±0.045
Total functional xylem area (μm²)^w	2429a	±338	I642ab	±338	1110b	±396
Conductive area (%)^v	9.4a		8.8a		8.0a

↵^zvalues are the mean of seven independent replications, mean separation in rows at the 5% level.
^ystandard error
↵^xvalues are an average of 20 vessels in each of four quadrants.
↵^wnumber of functional xylem x xylem vessel diameter.
↵^vtotal functional xylem area cross sectional