Silva Fennica

Fig. 1. Schematic figure of silver birch seedlings in climate-controlled closed-top chambers in 2002. A) randomized placement of seedling-trays in each chamber; B) location of chambers in the field.

Fig. 2. Placement of differently treated silver birch seedlings in the built environments in 2003 (figure is not drawn to scale). Within each climate treatment, all the seedlings were located randomly, and their positions re-randomized each week. The distance between the seedlings was 20 cm.

Table 1. Summary of cross tabulations for survived and dead seedlings. The term “survived” refers to overwintered seedlings and “dead” to seedlings that were winterkilled or suffered from broken stems. The percentage (%) of each group indicates the proportion of all the 384 seedlings in the 2003 experiment.
Treatment
	Amb. T and amb. CO₂		Amb. T and elev. CO₂		Elev. T and amb. CO₂		Elev. T and elev. CO₂		Total
	Number	%	Number	%	Number	%	Number	%	Number	%
Survived	32	8.3	46	12.0	41	10.7	47	12.2	166	43.2
Dead	64	16.7	50	13.0	55	14.3	49	12.8	218	56.8
Total	96	25.0	96	25.0	96	25.0	96	25.0	384	100.0

	Fertilized				Unfertilized				Total
	Number	%			Number	%			Number	%
Survived	90	23.4			76	19.8			166	43.2
Dead	102	26.6			116	30.2			218	56.8
Total	192	50.0			192	50.0			384	100.0

	Control		25% defoliated		50% defoliated		75% defoliated		Total
	Number	%	Number	%	Number	%	Number	%	Number	%
Survived	49	12.8	41	10.7	40	10.4	36	9.4	166	43.2
Dead	47	12.2	55	14.3	56	14.6	60	15.6	218	56.8
Total	96	25.0	96	25.0	96	25.0	96	25.0	384	100.0

Fig. 3. Absolute height increment (cm) of silver birch seedlings during the growing season 2003. The plot results are based on untransformed data, where mean values of different treatment combinations with the standard errors are presented. The trend line is based on the least squares means (LS means) provided by SAS/MIXED. Abbreviations: Amb. T = ambient temperature; Elev. T = elevated temperature; Amb. CO₂ = ambient CO₂; Elev. CO₂ = elevated CO₂.

Fig. 4. Root: shoot ratios (biomass of roots in proportion to biomass of stems + leaves) of silver birch seedlings in different treatment combinations at the end of the experiment. The plot results are based on untransformed data, where mean values of different treatment combinations with the standard errors are presented. The trend line is based on the least squares means (LS means) provided by SAS/MIXED. Abbreviations: Amb. T = ambient temperature; Elev. T = elevated temperature; Amb. CO₂ = ambient CO₂; Elev. CO₂ = elevated CO₂.