Table 18.2--Estimates of ambient O3 effects on growth of forest tree species occurring in the South

Species	% Growth Reduction	Conditions		Source
Seedling/Sapling Studies
Multiple species	0-10	Shoot growth		Chappelka and Samuelson 1998
Southern pines	2-5	Summary estimate of 19 field-chamber studies		Teskey 1996
Loblolly pine	0-3	Mean response to 50-200 ppm-hr		Taylor 1994 (synthesis- whole tree biomass)
	1-10	Sensitive family response to 50-200 ppm-hr
Hardwoods	13	Values derived from response		Reich and others 1988
Conifers	3	surface at 20 ppm-hr
Black cherry	10-24			Hogsett and others 1997
Yellow poplar	5-13	Values derived from O3 exposure-
Sugar maple	0-9	response functions and model-
Red maple	0-1	simulated tree and stand
Loblolly pine	2-5	response
E. White pine	4-8
Virginia pine	0-1
Mature Tree Studies
Loblolly pine	2-9		Whole tree carbon model using branch chamber data (GA)	Dougherty and others 1992
	3		Mean response
	0-13		Mean annual weekly responses to O3 and interactions of O3 and moisture stress, 5 years (TN)	McLaughlin and Downing 1996
	0-5		Annual O3 effect - no water stress
	0-30		Annual O3 effect - moderate water stress
Hardwoods	3-16		Regional simulation with canopy-stand model across moisture gradients. Highest reductions occurred in areas with highest O3 levels and on soils with high water holding capacity where drought stress was absent.	Ollinger and others 1997