1

Fig. 1. The location of the study area.

Table 1. Main features of the two data types.
  NFI FC
Plot type Relascope Variable radius circular
Radius/relascope factor Central Finland factor 2 (max. radius 12.52 m), Southern North Finland factor 1.5 (max. radius 12.45 m). Radius 5.64–9 m
Selection of plots Systematic clustered sampling Subjective stratified selection
Positioning GPS (appr. 5 m accuracy) GPS (appr. 1 m accuracy)
Average number of tally trees 11.5 37.7
Range of the number of tally trees per plot 1–29 8–109
Area represented by one plot a) Central Finland 338 ha, Southern North Finland 417 ha 318 ha (varies per inventory area)
Measurement years 2006–2010 2010
a) Expansion factor according to NFI11 design and 5 year data.
2

Fig. 2. The field sample layout in the study area defined by the laser scanning coverage (forestry land is shown in green, © MML, 2011). NFI plots = blue circles and FC plots = black rectangles.

Table 2. The statistics of the used sample plot combinations: mean, standard deviation (SD), maximum (Max).
Statistic Dataset H, m D, cm Vol, m3/ha Pine, m3/ha Spruce, m3/ha Broadl., m3/ha
Mean FC 12.07 14.29 116.97 62.22 32.54 22.22
Mean Replaced 12.18 14.68 116.87 64.25 31.32 21.3
Mean NFIa 12.93 16.08 117.42 64.79 24.35 28.28
Mean NFIb 13.54 17.12 117.72 68.99 22.88 25.86
Mean FC+NFIa 12.32 14.8 117.1 62.95 30.21 23.94
Mean FC+NFIb 12.34 14.81 117.11 63.46 30.77 22.88
SD FC 4.94 6.4 82.61 58.78 54.65 33.48
SD Replaced 4.94 6.51 81.86 60.28 53.6 33.55
SD NFIa 3.27 4.36 70.54 55 45.23 46.92
SD NFIb 3.18 4.42 67.08 56.7 37.23 42.88
SD FC+NFIa 4.54 5.94 79.31 57.7 52.24 37.85
SD FC+NFIb 4.7 6.18 79.93 58.41 52 35.38
Max FC 22 33.6 428.6 329.1 321.3 233.4
Max Replaced 22 33.6 428.6 329.1 321.3 265.8
Max NFIa 20.4 27.6 347.6 255.3 333 265.8
Max NFIb 20.4 27.6 282.7 255.3 161.6 265.8
Max FC+NFIa 22 33.6 428.6 329.1 333 265.8
Max FC+NFIb 22 33.6 428.6 329.1 321.3 265.8
H = mean height, D = mean diameter, Vol. = total volume of growing stock, Pine/Spruce/Broadl. = volume of pine/spruce/broadleaved trees
3

Fig. 3. The distribution of volume on the FC and NFI plots.

Table 3. The attributes covered by the ALS data for lidar pulses.
Column Attribute description
1 x co-ordinate (X, EUREF-FIN Easting)
2 y co-ordinate (Y, EUREF-FIN Northing)
3 z co-ordinate (Z, height above sea level)
4 Intensity (I)
5 Classification (ground pulse / other)
6 Number of the return
Table 4a. Accuracy of the mean-height estimates.
Reference Target RMSE (m) RMSE (%) Bias (m)
FC FC 1.05 8.67 0.01
Replaced FC 1.11 9.20 0.05
FC+NFIb FC 1.08 8.93 0.02
Replaced Replaced 1.17 9.56 0.00
FC+NFIb NFIb 1.42 10.49 –0.12
FC FC+NFIb 1.12 9.10 –0.01
FC+NFIb FC+NFIb 1.15 9.31 –0.01
FC+NFIa FC+NFIa 1.18 9.57 0.00
Table 4b. Accuracy of the mean-diameter estimates.
Reference Target RMSE (cm) RMSE (%) Bias (cm)
FC FC 2.23 15.64 –0.01
Replaced FC 2.33 16.29 0.29
FC+NFIb FC 2.26 15.83 0.14
Replaced Replaced 2.39 16.27 –0.01
FC+NFIb NFIb 2.93 17.12 –0.87
FC FC+NFIb 2.38 16.10 –0.18
FC+NFIb FC+NFIb 2.40 16.20 –0.05
FC+NFIa FC+NFIa 2.35 15.88 0.00
Table 4c. Accuracy of the total-volume estimates.
Reference Target RMSE (m3/ha) RMSE (%) Bias (m3/ha)
FC FC 25.43 21.74 0.02
Replaced FC 27.70 23.68 –0.18
FC+NFIb FC 26.75 22.87 –0.97
Replaced Replaced 26.72 23.64 0.05
FC+NFIb NFIb 32.69 27.77 4.82
FC FC+NFIb 27.33 23.34 0.94
FC+NFIb FC+NFIb 27.93 23.85 0.09
FC+NFIa FC+NFIa 29.41 25.12 0.01
Table 4d. Accuracy of the pine volume estimates.
Reference Target RMSE (m3/ha) RMSE (%) Bias (m3/ha)
FC FC 30.41 48.87 1.56
Replaced FC 30.84 49.56 1.75
FC+NFIb FC 29.85 47.98 0.55
Replaced Replaced 30.90 48.09 0.92
FC+NFIb NFIb 33.08 47.96 4.95
FC FC+NFIb 32.02 50.46 2.27
FC+NFIb FC+NFIb 30.47 48.01 1.36
FC+NFIa FC+NFIa 32.58 51.76 1.54
Table 4e. Accuracy of the spruce volume estimates.
Reference Target RMSE (m3/ha) RMSE (%) Bias (m3/ha)
FC FC 23.73 72.92 –0.33
Replaced FC 24.01 73.8 –0.86
FC+NFIb FC 23.16 71.16 –1.00
Replaced Replaced 23.53 75.12 0.06
FC+NFIb NFIb 20.41 89.22 3.75
FC FC+NFIb 23.95 77.84 0.57
FC+NFIb FC+NFIb 22.68 73.7 –0.13
FC+NFIa FC+NFIa 24.12 79.85 –0.12
Table 4f. Accuracy of the broadleaf volume estimates.
Reference Target RMSE (m3/ha) RMSE (%) Bias (m3/ha)
FC FC 19.72 88.75 –1.21
Replaced FC 21.01 94.56 –1.06
FC+NFIb FC 19.21 86.45 –0.52
Replaced Replaced 20.29 95.29 –0.94
FC+NFIb NFIb 28.27 109.35 –3.89
FC FC+NFIb 21.6 94.37 –1.90
FC+NFIb FC+NFIb 21.16 92.47 –1.14
FC+NFIa FC+NFIa 22.12 92.40 –1.40