Fig. 1. Overview of seed orchard FP-512 Målilla, Sweden (57.37 latitude, 15.85 longitude) with the location of the three trials, each with nine blocks. Trial A was active throughout the studied period, Trial B was active until 2016, and Trial C began in 2017.

2

Fig. 2. Thinning trials in the Picea abies seed orchard FP-512 Målilla, Sweden. I. – Layout of the plots in three blocks (of nine) each in Trials A and B. II. – Layout of the plots in three blocks (of nine) in Trial C.

Table 1. Treatments in the three thinning trials in the Picea abies seed orchard FP-512 Målilla in Sweden (57.37 latitude, 15.85 longitude).
Trial Treatments Cone data for years
Trial A Not thinned 667 stems ha–1 2011, 2016, 2017, 2019–2022
Thinned 333 stems ha–1
Trial B Not thinned 800 stems ha–1 2011, 2016
Thinned 400 stems ha–1
Trial C Not thinned 400 stems ha–1 2019–2022
Thinned 200 stems ha–1
Table 2. In the thinning trials A and B in the Picea abies seed orchard FP-512 Målilla, data collection 2011. Scoring classes for number of cones per tree and the number used for each class in the statistical analyses.
Cone scoring class Number used Cone scoring class Number used
0 0 41–80 60
1–10 5 81–160 120
11–20 15 161–320 240
21–40 30 >320 480
3

Fig. 3. In thinning Trial A in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of fresh cones per tree (l tree–1) in Trial A. Significance levels above the bars: ns – not statistically significant (p < 0.05); * – statistically significant (p < 0.05).

Fig. 4. In thinning Trial A in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of fresh cones per hectare (hl ha–1) in Trial A. Significance levels above the bars: ns – not statistically significant (p < 0.05); *** – statistically significant (p < 0.001).

5

Fig. 5. In thinning Trial A in the Picea abies seed orchard FP-512 Målilla, Sweden. The total volume cones per tree (l tree–1) divided into good and bad cones in Trial A for the years 2020–2022.

6

Fig. 6. In thinning Trial A in the Picea abies seed orchard FP-512 Målilla, Sweden. The total volume of cones per hectare (hl ha–1) divided into good and bad cones in Trial A for the years 2020–2022.

7

Fig. 7. In thinning Trial B in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of cones per tree (l tree–1) in Trial B. Significance levels above the bars: ns – not statistically significant (p < 0.05).

8

Fig. 8. In thinning Trial B in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of cones per hectare (hl ha–1) in Trial B. Significance levels above the bars: ns – not statistically significant (p < 0.05); ** – statistically significant (p < 0.01) ; *** – statistically significant (p < 0.001).

9

Fig. 9. In thinning Trial C in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of cones per tree (l tree–1) in Trial C. Significance levels above the bars: ns – not statistically significant (p < 0.05).

10

Fig. 10. In thinning Trial C in the Picea abies seed orchard FP-512 Målilla, Sweden. The volume of cones per hectare (hl ha–1) in Trial C. Significance levels above the bars: ns – not statistically significant (p < 0.05); *** – statistically significant (p < 0.001).

11

Fig. 11. In thinning Trial C in the Picea abies seed orchard FP-512 Målilla, Sweden. The total volume cones per tree (l tree–1) divided into good and bad cones in Trial C for the years 2020–2022.

12

Fig. 12. In thinning Trial C in the Picea abies seed orchard FP-512 Målilla, Sweden. The total volume of fresh cones per hectare (hl ha–1) divided into good and bad cones in Trial C for the years 2020–2022.

Table 3. In the thinning trials A and C in the Picea abies seed orchard FP-512 Målilla. Cone and seed quality data. Cones collected in autumn 2022. Traits with statistically significant differences (p < 0.05) are marked in bold.
Trial Treatment Cones per liter Cone lenght (cm) Seeds damaged by insects (%) Empty seeds (%) Filled seeds (%) 1000 seeds weight (gr) AP (%) (1) Filled seeds per cone Seeds per Kg
A Thinned 7.3 11.8 0.3 0.5 99.2 7.34 96 179 138 787
A Not thinned 7.7 11.7 0.9 1.7 97.4 7.43 97 185 135 088
C Thinned 8.0 11.5 0.9 1.0 98.1 7.09 96 174 141 142
C Not thinned 7.7 11.5 0.6 1.4 98.0 6.82 97 196 146 642
(1) AP – anatomic potential, a value corresponding to germination capacity (Simak 1980).