Table 3.

Wood anatomy in lower stems of hybrid poplar grown for 60 d under different conditions

Treatment	Cambium cell layers (number)		Fibre cell wall thickness (μm)
	Opposite wood	Tension wood	Opposite wood	Tension wood
Control	6.14±0.25 a	6.36±0.51 a	3.59±0.16 a,b	5.17±0.24 a
Elevated CO2	6.31±0.45 a	8.56±0.80 b	3.63±0.23 a	5.35±0.10 a
Elevated CO2 and ozone	5.48±0.28 a	5.68±0.24 a	2.99±0.22 b,c	4.32±0.13 b
Ozone	3.06±0.51 b	3.38±0.32 c	2.73±0.21 c	3.74±0.10 c

Values are mean ±SE (n=3 biological replicates). Mean values not sharing the same letter are significantly different at P <0.05.