Table 1. Summary statistics of the datasets (min; mean; max).
Dataset Number of plots Tree height [m] Stem diameter [cm] Stem volume [m3/ha] Age [yr]
Micro stand and LPM approach 856* 3.5;19.2;34 4;27.1;67.9 1;284;2058 10;50;168
Systematic design 216** 4.9;18.2;31.6 5.2;24.1;51.9 2;229;655 14;51;160
Evaluation plots 30*** 15.8;24;32.4 20;30.6;42.3 157;360;685 33;60;112
* 5 m radius
** 10 m radius
*** 40 m radius
LPM = local pivotal method
Table 2. Summary statistics of the different alternatives (min; mean; max).
Dataset Number of plots Tree height [m] Stem diameter [cm] Stem volume [m3/ha] Age [yr]
S500 500* 3.5;19.2;33.7 4;27.1;62.3 2;287;2058 12;50;131
S250 250* 3.5;19.1;32.3 4;26.9;59.7 2;276;930 13;49;131
S91 91* 3.5;19.3;32.4 4;27.7;59.4 2;301;1510 12;50;131
subS91 91* 3.5;19.6;33.7 4;27.7;62.3 2;303;2058 13;50;100
syst5m 216** 4.4;18;37.1 4.6;23;51.4 3;226;748 14;51;160
syst10m 216*** 4.9;18.2;31.6 5.2;24.1;51.9 2;229;655 14;51;160
* 5 m radius
** 5 m radius extracted from the 10 m radius plots
*** 10 m radius
Table 3. Summary of the relative root mean square error (RelRMSE) and relative bias (within parenthesis) values, for the forest variables basal area weighted mean tree height (BWH), basal area weighted mean tree diameter (BWD), mean stem volume per hectare (MSV), basal area (BA) and stand mean age (MA), indicating the accuracy of the airborne laser scanning based imputation of the reference plot data to the 40 m radius evaluation plots for the six different estimated alternatives.
Alternative RelRMSE (%)
BWH BWD MSV BA MA
S500 9.6(–6.8) 8.7(5.7) 24.7(9.9) 26.8(17.1) 21.6(–7.7)
S250 10.8(–7.8) 9.0(4.7) 18.6(–2.1) 16.2(8.1) 20.4(–9.6)
S91 13.6(–9.5) 10.7(3.4) 23.3(–3.1) 20.5(8.5) 28.7(–13.2)
subS91 10.6(–7.0) 11.9(5.8) 38.8(11.9) 38.2(19) 25.0(–7.9)
Syst10m 8.4(–5.6) 8.0(0.0) 23.8(–10.6) 18.3(–8.0) 20.0(–4.0)
Syst5m 10.1(–8.0) 8.7(–4.2) 27.3(–14.9) 18.3(–8.0) 23.1(–6.2)
Table 4. Summary of error indices of the estimated diameter distributions indicating the accuracy of the estimated diameter distributions using the two different sampling methods, local pivotal method and systematic, with different reference plot intensity. The index value 0 indicates a perfect match of the compared distributions.
Alternative Error indices of the estimated diameter distributions - total variation distance index
Mean Minimum Maximum sd*
S500 0.27 0.12 0.64 0.11
S250 0.29 0.15 0.62 0.1
S91 0.35 0.13 0.69 0.12
subS91 0.35 0.2 0.54 0.1
Syst10m 0.24 0.12 0.48 0.08
Syst5m 0.28 0.15 0.53 0.09
* sd: standard deviation