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Fig. 1. Time schedule of the experimental short day treatments, with starting dates and durations as indicated.

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Fig. 2. Height (A) and root collar diameter (B) growth from start of the experimental treatments on 20 June until termination of the experiment on 1 September in Picea abies seedlings exposed to SD treatment with different starting dates and durations as indicated.

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Fig. 3. Seedling height in Picea abies seedlings exposed to SD treatment with different starting dates as indicated.

Table 1. Dry mass of shoots and roots of Picea abies seedlings exposed to short day treatment with different starting dates and durations. Values followed by the same letter are not significantly different (p > 0.05).
Starting date Duration (days) Dry weight shoots
(g seedling–1) 		Dry weight roots
(g seedling–1)
20 June 10 2.74 ad 0.98 a
20 June 17 2.47 a 1.00 a
27 June 10 2.62 a 1.02 a
27 June 17 2.57 a 0.97 a
4 July 10 2.81 ad 1.01 a
4 July 17 2.82 ad 1.03 a
11 July 10 3.29 b 1.07 a
11 July 17 3.07 bd 0.98 a
Control 0 3.95 c 1.20 a
Note: Dry weight was only determined for seedlings SD-treated for 10 and 17 days.
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Fig. 4. Amount of Picea abies seedlings with second bud flush following SD treatment with different durations and starting dates as indicated. Only dates and durations leading to second bud flush are shown.