Understory Vegetative Diversity of Post-Thinned Pine Plantations Treated with Fertilizer, Fire and Herbicide in East Texas

Table 6

Change in importance values (IV) of herbaceous and shrub species at cherokee ridge and sweet union research sites, east Texas, USA between 1999 (pretreatment) and 2001 (2 years posttreatment. *significantly different at P = .1 from analysis of various test proc GLM (SAS, ver 8).

	Sweet union		Cherokee ridge
Species	1999	2001	1999	2001
American beautyberry	4	10*	6	24*
Poison Ivy	8	7	6	0
Grape	5	13*	2	1
Ragweed	5	13*	3	0
Smilax	4	2	5	1
Yellow wood-sorrell	2	6*	3	8*
Yaupon	4	7*	2	1
Mulberry	2	1	—	—
Blackberry	—	—	2	0
Virginia creeper	—	—	2	1
Bitterweed	—	—	2	0