Table 1. Quality factors and predictors to be measured in the main stages of forest regeneration.
Stage Quality factors and predictors to be measured
Soil preparation Number of prepared spots ha–1
Length, width and height of prepared spot (cm)
Soil type (coarse – fine – peat)
Stoniness (yes – no)
Logging debris (yes – no)
Planting Number of planted seedlings ha–1
Planting depth (cm)
Seedlings distance from unprepared soil (cm)
Seedling anchor (yes – no)
Young stand management Number of crop trees ha–1
Composition of stand (number of pines, spruces and birches)
Stand height, average (m)
Stand diameter, average (cm)
Number of stumps ha–1
Stump diameter, average (cm)
Table 2. Number of independent-assessment sites according to service provider, stage of chain and year.
Variable Soil preparation Planting Young stand management Total
Service provider
1 27 16 10 53
2 59 21 16 96
3 1 - 2 3
4 7 20 4 31
5 - 7 13 20
6 - 4 - 4
7 - - 4 4
Total 94 68 49 211
Year
2011 6 - 3 9
2012 35 24 33 92
2013 33 35 4 72
2014 20 9 9 38
Total 94 68 49 211
1

Fig. 1. Schematic of the study design and sequence.

Table 3. Number of sample plots to be measured in self-control.
Regeneration area (ha) Number of sample plots
0.50 – 1.99 5
2.00 – 3.99 6
4.00 – 5.99 7
6.00 – 7.99 8
8.00 – 9.99 9
10 or bigger 10
Table 4. Description of self-control (SC) and independent-assessment (IA) datasets in each stage.
Variable No. of sites Area (ha) Sample plots
N Min (per site) Max (per site) Mean (per site)
Soil preparation
SC 94 180 510 2 10 5.4
IA 94 180 1501 4 23 16.4
Planting
SC 68 153 376 2 15 5.5
IA 68 153 1111 2 27 16.3
Young stand management
SC 49 99 276 2 12 5.7
IA 49 99 658 3 21 14.6
Table 5. Main characteristics of soil preparation sites in independent-assessment.
Class variable No. of sites % of sites Area (ha) No. of sample plots % of sample plots
Soil type
Coarse mineral 48 51.1 84 748 49.8
Fine mineral 33 35.1 62 509 33.9
Peat 7 7.4 15 183 12.2
No dominant 6 6.4 19 - -
Unknown 61 4.1
Stony soil 10 10.6 16 98 6.6
Disruptive logging debris 3 3.2 4 72 4.9
Soil preparation
Spot mounding 87 92.6 160 1295 86.3
Ditch mounding 6 6.3 17 188 12.5
Patching - - - 12 0.8
No dominant 1 1.1 3 6 0.4
Site type (*)
OMaT - - - - -
OMT 16 17 22 255 17
MT 52 55.3 102 859 57.2
VT 8 8.5 20 118 7.9
CT - - - - -
CIT - - - - -
No dominant 3 3.2 5 - -
Unknown 15 16 31 269 17.9
Target density
1600 1 1.1 1.4 20 1.3
1800 16 17 32.7 269 17.9
1900 8 8.5 19.2 122 8.1
2000 36 38.3 53.3 537 35.8
Unknown 33 35.1 73.2 553 36.8
Soil preparation equipment
Mounding plate 50 53.2 88 766 54
Digger shovel 31 33 70 514 34.3
Both 8 8.5 11 132 8.8
Unknown 5 5.3 11 89 5.9
Work period
Spring 53 56.4 103 838 55.8
Autumn 40 42.5 76 643 42.8
Unknown 1 1.1 1 20 1.3
(*) Site type according to Cajander (1949).
Table 6. Main characteristics of modelling data set for soil preparation.
Variable N Mean SD Min Max
Self-control 2011–2014
No. of spot mounds 510 8.40 3.67 0 20
No. of ditch mounds 510 1.21 3.23 0 17
No. of inverted mounds 510 0.05 0.67 0 11
No. of patches 510 0.24 1.21 0 11
No. of preparation spots 510 9.90 1.73 6 20
Height of mound, cm 446 16.82 5.32 9 35
Footprint preparation spot, m2 468 0.37 0.13 0.05 0.9
Independent-assessment 2012–2014
No. of spot mounds 1501 7.9 3.59 0 18
No. of ditch mounds 1501 1.1 2.83 0 16
No. of inverted mounds 1501 0.0 0.00 0 0
No. of patches 1501 0.1 0.67 0 11
No. of preparation spots 1501 9.1 2.18 1 18
Height of mound, cm 1478 16.7 6.30 5 60
Footprint of preparation spot, m2 1501 0.5 0.29 0.07 2.56
N = number of sample plots.
Note: variation among N occurs due to the removal of incomplete or illogical measurements.
Table 7. Main characteristics of planting sites in independent-assessment.
Class variable No. of sites % of sites Area (ha) No. of sample plots % of sample plots
Seedling
Pine 8 11.8 13.6 162 14.6
Spruce 52 76.5 120.1 949 85.4
Pine + spruce 8 11.8 19.2
Soil preparation
Mounding 63 92.6 136.5 1023 92
Disc trenching 2 2.9 1.6 28 2.5
Stump removal 3 4.4 14.8 60 5.5
Target density
1800 17 25 44.4 300 27
1900 1 1.5 1.1 15 1.4
2000 37 54.4 71.9 560 50.4
Unknown 13 19.1 35.5 236 21.2
Site type (*)
OMaT - - - - -
OMT 11 16.2 27.2 192 17.3
MT 28 41.2 55.2 483 43.5
VT 13 19.1 26.3 210 18.9
CT - - - - -
CIT - - - - -
Unknown 16 23.5 44.2 226 20.3
(*) Site type according to Cajander (1949).
Table 8. Main characteristics of modelling data set for planting.
Variable N Mean SD Min Max
Self-control 2011–2014
No. of seedlings planted to prepared spot 376 9.51 2.19 0 15
No. of seedlings planted to unprepared soil 376 0.49 1.25 0 9
No. of seedlings planted overall 376 10.00 1.58 4 15
Planting depth, cm 371 4.58 1.41 1 10
Distance from humus edge, cm 289 32.78 16.86 0 130
Independent-assessment 2012–2014
No. of seedlings planted to prepared spot 1111 8.09 2.61 0 18
No. of seedlings planted to unprepared soil 1111 0.95 1.87 0 13
No. of seedlings planted overall 1111 9.03 2.37 0 22
Planting depth, cm 1111 6.21 2.38 0 10
Distance from humus edge, cm 1073 23.45 13.28 0 70
N = number of sample plots.
Note: variation among N occurs due to the removal of incomplete or illogical measurements.
Table 9. Main characteristics of young stand management sites in independent-assessment.
Class variable No. of stands % of stands Area (ha) No. of sample plots % of sample plots
Site type (*)
OMaT - - - - -
OMT 6 12.2 13.5 82 12.5
MT 11 22.4 21.5 175 26.6
VT 6 12.2 11.5 102 15.5
CT - - - 11 1.7
CIT - - - - -
No dominant 1 2 1.2 - -
Unknown 25 51 51.1 288 43.8
Dominant tree
Pine 19 38.8 45.3 276 41.9
Spruce 14 28.6 30.7 189 28.7
Birch 8 16.3 10 143 21.7
No dominant 8 16.3 12.8 50 7.6
Method
Early clearing 7 14.3 17.8 85 12.9
Normal tending 35 71.4 72.9 428 65
Later tending 7 14.3 8.1 145 22
(*) Site type according to Cajander (1949).
Table 10. Main characteristics of modelling data set for young stand management.
Variable N Mean SD Min Max
Self-control 2011–2014
No. of spruces 276 3.29 3.63 0 11
No. of pines 276 4.57 5.14 0 16
No. of birches 276 2.49 2.91 0 11
No. of other broadleaf trees 276 0.00 0.00 0 0
No. of trees overall 276 10.34 2.21 3 16
Dominant height of trees, m 276 4.43 1.73 2 10
Diameter of trees, cm 276 5.04 2.23 2 13
No. of stumps 276 24.18 13.21 0 69
Diameter of stumps, cm 225 3.08 1.06 1 6
Independent-assessment 2012–2014
No. of spruces 658 3.27 3.78 0 16
No. of pines 658 4.67 4.94 0 20
No. of birches 658 2.78 3.29 0 18
No. of other broadleaf trees 658 0.02 0.16 0 2
No. of trees overall 658 10.74 3.21 2 25
Dominant height of trees, m 658 5.00 2.27 2 15
Diameter of trees, cm 658 5.10 2.44 1 13
No. of stumps 649 15.07 12.26 0 100
Diameter of stumps, cm 635 2.48 1.11 0.5 8.5
N = number of sample plots.
Note: variation among N occurs due to the removal of incomplete or illogical measurement.
2

Fig. 2. Means and standard deviations of the assessed variables in different stages of the regeneration process (SC = Self-control, IA = Independent assessment).

3

Fig. 3. Comparison of self-control and independent-assessment results. Each point of the scatter plot displays individual working site.

Table 11. Multivariate multilevel model for soil preparation. Parameter estimates and variance components of equations for number, height and footprint of prepared spots. The most common values of the class variables were used as a reference class.
Predictor No. of prepared spots Height of mound (cm) Footprint of prepared spot (m2)
Estimate SE χ2-value Estimate SE χ2-value Estimate SE χ2-value
Intercept 9.76 0.29 1103.3 *** 16.16 0.50 1053.8 *** 0.56 0.04 235.9 ***
Discrepancy 0.55 0.34 2.6 ns –0.68 1.03 0.4 ns –0.18 0.04 19.1 ***
Soil texture
 Fine mineral
  IA 0.13 0.14 0.9 ns 0.60 0.45 1.8 ns 0.00 0.02 0.1 ns
  SC 0.00 0.24 1.55 0.77 4.0 ** 0.01 0.02 0.3 ns
 Peat
  IA –0.59 0.18 11.1 *** 1.92 0.58 10.9 *** –0.02 0.02 0.8 ns
  SC 0.46 0.28 2.7 * 2.57 0.90 8.3 ** 0.07 0.03 6.9 **
 Stony soil
  IA –1.92 0.21 86.9 *** –0.97 0.70 1.9 ns –0.06 0.03 5.2 *
  SC 1.04 0.27 14.3 *** –0.12 0.90 0.0 ns 0.02 0.03 0.7 ns
 Logging debris
  IA –1.82 0.21 72.9 *** –2.08 0.74 7.9 ** –0.04 0.03 2.7 ns
  SC 1.16 0.28 16.9 *** 0.81 0.97 0.7 ns 0.02 0.03 0.4 ns
Random part
 SD (uk)
  IA 1.05 0.4721 - 1.41 1.1733 - 0.12 0.0071 -
  SC 0.81 0.3097 - 3.26 4.667 - 0.08 0.0027 -
 SD (ukj)
  IA 0.78 0.1276 - 2.01 0.9953 - 0.15 0.0041 -
  SC 0.68 0.1149 - 2.11 1.138 - 0.04 0.0005 -
 SD (ekji)
  IA 1.65 0.1032 - 5.79 1.2801 - 0.20 0.0016 -
  SC 1.06 0.0826 - 3.12 0.765 - 0.08 0.0005 -
Discrepancy = difference between self-control (SC) and independent-assessment (IA), SE = Standard error, SD = Standard deviation.
* significant at 0.05, ** significant at 0.01 and *** significant at 0.001 level. “ns” = non-significant at 0.1 level.
Subscripts i, j and k refer to sample plot, regeneration area and combined contractor and year.
Table 12. Multivariate multilevel model for soil preparation. Variance explained at different hierarchical levels for number, height and footprint of prepared spots. Fixed effects are the same as in Table 11.
Variable and hierarchy level Variance Proportion % Error variance of self-control Correlation r Error
proportion %
Without fixed effects With fixed effects Difference
% 		Without fixed effects With fixed effects Without fixed effects With fixed effects Difference
%
No. of prepared spots
Contractor 1.104 1.100 0.4 22.2 24.8 1.51 1.15 23.8 –0.71 105
Regeneration area 0.886 0.615 30.6 17.8 13.9 1.03 0.71 31.3 –0.65 115
Sample plot 2.992 2.720 9.1 60.1 61.3 - - - - -
Mound height (cm)
Contractor 1.754 1.982 –13.0 4.4 5.0 17.19 10.38 39.6 –0.19 523
Regeneration area 4.047 4.058 –0.3 10.1 10.3 5.46 4.21 23.0 –0.46 104
Sample plot 34.106 33.468 1.9 85.5 84.7 - - - - -
Footprint of prepared spot (m2)
Contractor 0.022 0.014 38.4 25.1 17.6 0.03 0.02 37.2 –0.80 121
Regeneration area 0.024 0.023 2.5 26.5 29.5 0.03 0.03 –3.6 –0.96 112
Sample plot 0.043 0.042 3.9 48.4 52.9 - - - - -
Table 13. Multivariate multilevel model for planting. Parameter estimates and variance components of the equations for the number of planted seedlings, planting depth, and distance from humus edge. The most common values of the class variables were used as a reference class.
Predictor   Planted seedlings Planting depth (cm) Distance from humus (cm)
Estimate SE χ2-value Estimate SE χ2-value Estimate SE χ2-value
Intercept 8.88 0.23 1520.8 *** 6.32 0.31 416.6 *** 23.11 1.60 209.3 ***
Discrepancy 0.79 0.21 14.01 *** –1.63 0.32 26.2 *** 8.94 3.16 8.0 **
Seedling species
 Pine
  IA 0.40 0.31 1.65 ns 0.19 0.30 0.4 ns –1.65 1.84 0.8 ns
  SC 0.08 0.33 0.06 ns –1.48 0.36 16.9 *** 4.23 3.76 1.3 ns
 Mixed
  IA 1.07 0.58 3.38 ns –0.28 0.65 0.2 ns 0.00 0.00 0.0
  SC 0.00 0.00 0.00 0.00 0.00 0.0 0.00 0.00 0.0
Random part
 SD (uk)
  IA 0.83 0.3385 - 1.30 0.6402 - 6.21 16.5823 -
  SC 0.95 0.33 - 0.80 0.2557 - 11.64 54.0982 -
 SD (ukj)
  IA 0.91 0.2303 - 0.91 0.2185 - 5.59 8.2111 -
  SC 0.39 0.0954 - 0.49 0.0904 - 4.29 10.7414 -
 SD (ekji)
  IA 2.07 0.1884 - 1.83 0.1472 - 10.81 5.2042 -
  SC 1.25 0.1273 - 0.95 0.0747 - 11.69 12.7362 -
Discrepancy = difference between self-control (SC) and independent-assessment (IA). SE = Standard error, SD = Standard deviation.
* significant at 0.05, ** significant at 0.01 and *** significant at 0.001 level. “ns” = non-significant at 0.1 level.
Subscripts i, j and k refer to sample plot, regeneration area and worker.
Table 14. Multivariate multilevel model for planting. Variances explained at different hierarchical levels for the number of planted seedlings, planting depth, and distance from humus edge. Fixed effects are the same as in Table 13.
Variable and
hierarchy level 		Variance Proportion % Error variance of self-control Correlation
r 		Error
proportion
%
Without fixed effects With
fixed effects 		Difference
% 		Without fixed effects With
fixed effects 		Without fixed effects With
fixed effects 		Difference
%
No. of planted seedlings
Worker + year 0.835 0.690 17.4 14.1 11.8 0.42 0.52 –24 –0.26 75
Regeneration area 0.804 0.835 –3.9 13.5 14.3 0.34 0.32 6 –0.97 39
Sample plot 4.301 4.304 –0.1 72.4 73.8 - - - - -
Planting depth (cm)
Worker + year 1.698 1.699 1.0 28.8 28.9 1.63 1.65 –1 –0.81 97
Regeneration area 0.834 0.821 1.9 14.2 14.0 0.92 0.69 25 –0.84 84
Sample plot 3.358 3.361 –0.2 57.0 57.1 - - - - -
Distance from humus edge (cm)
Worker + year 38.892 38.522 –0.1 20.8 20.6 121.74 133.48 –10 –0.25 347
Regeneration area 31.891 31.270 1.6 17.0 16.8 69.02 62.65 9 –0.85 200
Sample plot 116.575 116.808 –0.1 62.2 62.6 - - - - -
Table 15. Multivariate multilevel model for young stand management (crop trees). Parameters, estimates and variance components of the equations for the number of coniferous trees, number of birches, height of trees, and diameter of trees. The most common values of the class variables were used as a reference class.
Predictor Number of coniferous trees Number of birches Average height of trees Average diameter of trees
Estimate SE χ2-value Estimate SE χ2-value Estimate SE χ2-value Estimate SE χ2-value
Intercept 7.66 0.49 245.0 *** 3.00 0.35 71.5 *** 4.97 0.27 334.2 *** 5.05 0.27 338.1 ***
Discrepancy –0.24 0.23 1.1 ns –0.22 0.16 1.9 ns –0.57 0.14 16.7 *** –0.09 0.15 0.4 ns
Random part
 SD (uj)
  IA 3.33 2.3722 - 2.38 1.2422 - 1.87 0.7329 - 1.87 0.7455 -
  SC 3.19 2.2295 - 2.23 1.1465 - 1.39 0.4267 - 1.68 0.6365 -
 SD (uji)
  IA 2.35 0.3152 - 2.35 0.3152 - 1.18 0.0802 - 1.42 0.1158 -
  SC 2.13 0.423 - 1.94 0.3515 - 0.99 0.0913 - 1.27 0.1512 -
Discrepancy = difference between self-control (SC) and independent-assessment (IA). SE = Standard error, SD = Standard deviation.
* significant at 0.05, ** significant at 0.01 and *** significant at 0.001 level. “ns” = non-significant at 0.1 level.
Subscripts i and j refer to sample plot and stand.
Table 16. Multivariate multilevel model for young stand management (crop trees). Variances explained at different hierarchical levels for number of coniferous trees, number of birches, height of trees, and diameter of trees. The fixed effects are the same as in Table 15.
Variable and hierarchy level Variance Proportion % Error variance of self-control Correlation
r 		Error
proportion %
Without fixed effects With
fixed effects 		Difference
% 		Without fixed effects With
fixed effects 		Without fixed effects With
fixed effects 		Difference
%
Number of coniferus trees
Stand 11.115 - - 66.9 - 1.04 - - –0.30 9
Sample plot 5.507 - - 33.1 - - - - - -
Number of birches
Stand 5.676 - - 50.8 - 0.20 - - –0.43 3
Sample plot 5.507 - - 49.2 - - - - - -
Height of stand (m)
Stand 3.513 - - 63.5 - 0.69 - - –0.44 20
Sample plot 2.023 - - 36.5 - - - - - -
Average diameter of stand (cm)
Stand 3.500 - - 71.4 - 0.63 - - –0.74 18
Sample plot 1.400 - - 28.6 - - - - - -
Table 17. Multivariate multilevel model for young stand management (removed trees). Parameter estimates and variance components of the equations for number of stumps and average diameter of stumps. The most common values of the class variables were used as a reference class.
Predictor   Number of stumps Average diameter of stumps (cm)
Estimate SE χ2 -value Estimate SE χ2 -value
Intercept 13.73 1.30 112.3 *** 2.4045 0.11 477.8 ***
Discrepancy 7.606 1.78 18.4 *** 0.5604 0.15 14.9 ***
Dominant tree
 Spruce
  IA 3.41 1.57 4.7 * 0.00 0.13 0.0 ns
  SC 1.86 2.38 0.6 ns 0.18 0.18 1.0 ns
 Birch
  IA 3.81 1.48 6.6 * 0.17 0.13 1.9 ns
  SC 3.59 2.40 2.2 ns –0.12 0.19 0.4 ns
 Mixed
  IA 3.61 1.88 3.7 * 0.25 0.16 2.3 ns
  SC 5.12 4.16 1.5 ns –0.37 0.36 1.1 ns
Random part
 SD (uj)
  IA 6.62 10.885 - 0.57 0.0811 -
  SC 9.08 20.0964 - 0.71 0.1347 -
 SD (uji)
  IA 10.56 6.4266 - 0.94 0.0517 -
  SC 9.18 7.8922 - 0.75 0.0589 -
Discrepancy = difference between self-control (SC) and independent-assessment (IA). SE = Standard error, SD = Standard deviation.
* significant at 0.05, ** significant at 0.01 and *** significant at 0.001 level. “ns” = non-significant at 0.1 level.
Subscripts i and j refer to sample plot and stand.
Table 18. Multivariate multilevel model for young stand management (removed trees). Variances explained at different hierarchical levels for number of stumps and average diameter of stumps. The fixed effects are the same as in Table 17.
Variable and
hierarchy level 		Variance Proportion % Error variance of self-control Correlation r Error
proportion %
Without fixed effects With
fixed effects 		Difference % Without fixed effects With
fixed effects 		Without fixed effects With
fixed effects 		Difference %
No. of stumps
Stand 44.68 43.76 2.1 28.5 28.2 55.55 56.27 –1 –0.18 129
Sample plot 112.13 111.48 0.6 71.5 71.8 - - - - -
Average stump diameter (cm)
Stand 0.33 0.32 2.9 27.3 26.7 0.22 0.24 –9 –0.10 76
Sample plot 0.89 0.89 –0.1 72.7 73.3 - - - - -