Table 1. Linear mixed effects model results of eucalypt productivity (total, aboveground and belowground; TB, AGB, and BGB, respectively) and biomass allocation (root to shoot ratio; R∶S) across CO₂, soil N, species pair type (monoculture vs. mixture with the non-native E. nitens) treatments and native species subgenus (N = 190).

		Variable
		δTB		AGB		BGB		R∶S
Treatment	Df	Chisq	p	Chisq	p	Chisq	p	Chisq	p
S	1	2.63	0.105	2.458	0.117	3.42	0.064	3.78	0.052
M	1	19.995	1*10−5	19.428	1*10−5	17.966	2*10−5	2.851	0.091
C	1	2.191	0.139	1.78	0.182	3.518	0.061	1.789	0.181
N	1	14.749	1.2*10−4	15.782	7*10−5	7.952	0.005	0.141	0.707
S*M	1	1.377	0.241	1.102	0.294	1.686	0.194	0.084	0.773
S*C	1	0.205	0.65	0.151	0.698	0.494	0.482	0.358	0.55
M*C	1	5.207	0.022	5.722	0.017	3.375	0.066	0.616	0.433
S*N	1	9.377	0.002	10.188	0.001	5.427	0.02	0.071	0.79
M*N	1	2.4*10−4	0.988	0.002	0.965	9*10−5	0.992	0.013	0.908
C*N	1	5.513	0.019	5.234	0.022	4.803	0.028	0.915	0.339
S*M*C	1	0.781	0.377	0.813	0.367	0.533	0.465	0.125	0.724
S*M*N	1	0.075	0.785	0.115	0.734	0.006	0.939	0.005	0.945
S*C*N	1	0.284	0.594	0.384	0.536	0.015	0.904	0.878	0.349
M*C*N	1	0.719	0.396	0.869	0.351	0.169	0.681	0.296	0.587
S*M*C*N	1	4.215	0.04	4.131	0.042	3.364	0.067	0.785	0.376

In a greenhouse experiment, 28 native Tasmanian eucalypt species within two subgenera (S), Symphyomyrtus and Eucalyptus, were treated with factorial combinations of ambient or elevated CO₂ (C; 420 or 700 ppm, respectively) and low or high soil N (N; 3 or 30 kg/ha/mo), and paired with a conspecific or a non-native (E. nitens) individual (M). In these models, whole-pot biomass measurements and ratios of root to shoot biomass were averaged for each native species in each treatment combination, cube root transformed, and blocked by species. P values are shown in bold and are significant at α≤0.05.

^δTB, total biomass; AGB, aboveground biomass; BGB, belowground biomass; R∶S, root to shoot ratio; M, species pair type (native species monoculture vs. mixture with E. nitens); C, CO₂ treatment (420 or 700 ppm); N, nitrogen treatment (3 or 30 kg ha⁻¹ mo⁻¹).