Table 3.

Tension wood to opposite wood density ratio of hybrid poplar stem after 46 d of fumigation with different ozone concentrations

Level	Treatment	Wood density (TW/OW)
Lower stem	Control	1.209±0.007
	Ozone, 50 nl l−1	1.145±0.013
	Ozone, 100 nl l−1	1.111±0.032*
	Ozone, 200 nl l−1	1.075±0.010*
	Ozone, 300 nl l−1	1.089±0.018*
Middle stem	Control	1.088±0.032
	Ozone, 50 nl l−1	1.050±0.005
	Ozone, 100 nl l−1	1.033±0.037*
	Ozone, 200 nl l−1	1.039±0.017*
	Ozone, 300 nl l−1	1.037±0.007*

Data are mean values ±SD (n=3, individual replicates).

*Significant differences (P <0.05) between control and ozone treatments.

TW/OW, tension wood to opposite wood ratio.