| Table 1. Summary of the data from the 314 field plot (250 m2). | |||
| Characteristic | Minimum | Maximum | Mean |
| hL (m) | 7.03 | 32.51 | 16.41 |
| hdom (m) | 8.96 | 33.60 | 19.39 |
| dg (cm) | 8.3 | 44.2 | 17.8 |
| N (ha–1) | 160 | 3120 | 1246 |
| G (m2 ha–1) | 3.32 | 78.42 | 28.52 |
| V (m3 ha–1) | 14.91 | 992.12 | 242.93 |
| Tree species distribution | |||
| Spruce (%) | 0 | 100 | 69 |
| Pine (%) | 0 | 100 | 22 |
| Broadleaved species (%) | 0 | 83 | 9 |
| hL = Lorey’s mean height, hdom = dominant height, dg = mean basal area diameter, N = stem number, G = basal area, V = volume. | |||
| Table 2. The accuracy of the resulting data in the three strata and overall, for Lorey’s mean height, stem number and volume in leave-one-plot-out cross validation. | |||||||||
| Lorey’s mean height | |||||||||
| ALS | DAP | ||||||||
| Stratum | N | R2 | Mean dif. (%) | RMSE (%) | R2 | Mean dif. (%) | RMSE (%) | ||
| 1 | 78 | 0.88 | –0.1 | 6.9 | 0.80 | 0.0 | 6.7 | ||
| 2 | 106 | 0.86 | 0.0 | 7.7 | 0.85 | 0.0 | 8.0 | ||
| 3 | 130 | 0.90 | 0.0 | 7.4 | 0.85 | 0.0 | 9.0 | ||
| Total | 314 | 0.91 | –0.04 | 7.42 | 0.90 | 0.0 | 7.95 | ||
| Stem number | |||||||||
| ALS | DAP | ||||||||
| Stratum | N | R2 | Mean dif. (%) | RMSE (%) | R2 | Mean dif. (%) | RMSE (%) | ||
| 1 | 78 | 0.69 | 0.1 | 28.1 | * | 0.51 | –0.1 | 35.6 | * |
| 2 | 106 | 0.56 | 0.0 | 35.4 | 0.43 | 0.0 | 39.9 | ||
| 3 | 130 | 0.65 | 0.0 | 24.2 | * | 0.57 | 0.0 | 26.8 | * |
| Total | 314 | 0.64 | 0.05 | 28.34 | 0.52 | –0.02 | 32.72 | ||
| Volume | |||||||||
| ALS | DAP | ||||||||
| Stratum | N | R2 | Mean dif. (%) | RMSE (%) | R2 | Mean dif. (%) | RMSE (%) | ||
| 1 | 78 | 0.82 | 0.3 | 20.8 | 0.71 | 0.0 | 25.7 | ||
| 2 | 106 | 0.89 | 0.0 | 19.2 | 0.79 | –0.1 | 26.6 | ||
| 3 | 130 | 0.92 | 0.0 | 18.3 | 0.84 | –0.1 | 25.6 | ||
| Total | 314 | 0.91 | 0.08 | 20.78 | 0.81 | –0.05 | 27.14 | ||
| * Dummy variables representing airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) acquisitions significant at 5%-level. | |||||||||
| Table 3. The results of five cost-plus-loss analysis, and the mean volume, relative standard error of volume, and stem number in these studies. | ||||||||
| S | A | Method | R | M | Loss (€ ha–1) | Mean Vol | RMSE (%) Vol | RMSE (%) N |
| 1 | a | ALS | 3 | 0 | 13.4 | 219 | 12.0 | 20.6 |
| 1 | a | MPI | 3 | 0 | 50.9 | 219 | NA | 30.4 |
| 1 | b | ALS | 3 | 0 | 13.3 | 224 | 12.1 | 15.7 |
| 1 | b | MPI | 3 | 0 | 46.3 | 224 | NA | 36 |
| 2 | c | ALS_MV | 3 | 1 | 327.7 | 209 | 9.9 | 37.1 |
| 2 | c | ALS_DD | 3 | 1 | 60.7 | 209 | 14.1 | 33.2 |
| 2 | c | ITC | 3 | 1 | 78.9 | 209 | 33.4 | 62.8 |
| 2 | c | SITC | 3 | 1 | 109.2 | 209 | 28 | 26.7 |
| 3 | d | Plot10 | 2 | 1 | 9.02 | 272 | 9 | 8 |
| 3 | d | Plot5 | 2 | 1 | 13.95 | 272 | 10 | 12 |
| 3 | d | ImpLS | 2 | 1 | 80.65 | 272 | 18 | 19 |
| 3 | d | ImpLa | 2 | 1 | 107.82 | 272 | 18 | 21 |
| 3 | d | ImpSp | 2 | 1 | 194.03 | 272 | 33 | 33 |
| 3 | d | Plot10 | 4 | 1 | 1.89 | 272 | 9 | 8 |
| 3 | d | Plot5 | 4 | 1 | 3.46 | 272 | 10 | 12 |
| 3 | d | ImpLS | 4 | 1 | 36.29 | 272 | 18 | 19 |
| 3 | d | ImpLa | 4 | 1 | 79.29 | 272 | 18 | 21 |
| 3 | d | ImpSp | 4 | 1 | 201.90 | 272 | 33 | 33 |
| 4 | e | visual | 3 | 1 | 469.95 | 57.5 | 60.4 | 105.2 |
| 4 | e | ALS1 | 3 | 1 | 412.11 | 42.2 | 44.6 | 73.3 |
| 4 | e | ALS2 | 3 | 1 | 448.26 | 48.7 | 59.9 | 84.6 |
| 5 | f | ALS | 3 | 0 | 76.26 | 242.9 | 20.8 | 28.4 |
| 5 | f | DAP | 3 | 0 | 82.79 | 242.9 | 27.2 | 32.8 |
| Study (S) is 1: Eid et al. 2004; 2: Bergseng et al. 2015; 3: Duvemo et al. 2007; 4: Mäkinen et al. 2010; 5: the current study. Area (A) is a: Våler; b: Krødsherad; c: Aurskog; d: Remningstorp; e: simulated data; f: the current study area. Method is ALS: area-based laser scanning; MPI: manual photo interpretation; ALS_MV: area-based laser scanning with mean values; ALS_DD: area-based laser scanning with diameter distribution; ITC: individual tree crowns; SITC: semi-individual tree crowns; Plot5: 5 field plots; Plot10: 10 field plots; ImpLS: imputation using laser scanning and satellites; ImpLa: imputations using laser scanning; ImpSp: using satellite, visual assessment in field; ALS1 and ALS2: denote two different data sets for which the errors are simulated. R = interest rate (%). M is 0: stand-level growth model; 1: single-tree growth model. | ||||||||
| Table 4. The main features of observed losses with airborne laser scanning (ALS) and digital aerial photogrammetry (DAP). | ||
| Loss (€ ha–1) | ||
| DAP | ALS | |
| Min. | 0.00 | 0.00 |
| Median | 0.00 | 0.00 |
| Mean | 82.79 | 76.26 |
| Max. | 1841.62 | 1841.62 |
| Table 5. The mean and maximum loss and the standard deviation of losses in the three volume groups for the first period and the whole planning horizon in € ha–1 with airborne laser scanning (ALS) and digital aerial photogrammetry (DAP). | |||||||
| Method | Group m3 ha–1 | First period | Planning horizon | ||||
| Mean | Max | Sd | Mean | Max | Sd | ||
| ALS | V < 392 | 9.62 | 451.88 | 47.75 | 52.71 | 914.43 | 132.02 |
| 392 < V < 597 | 223.16 | 1841.62 | 522.27 | 262.56 | 1841.62 | 530.56 | |
| V > 597 | 0.0 | 0 | 0 | 0.0 | 0 | 0 | |
| DAP | V < 392 | 6.02 | 508.09 | 37.90 | 57.11 | 1183.05 | 145.80 |
| 392 < V < 597 | 238.79 | 1841.62 | 526.19 | 285.92 | 1841.62 | 542.46 | |
| V > 597 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Table 6. The performance of the model predicting the mean loss in the case studies. | ||||
| Estimate | Std. Error | t value | Pr(>|t|) | |
| Intercept | 238.7186 | 119.2609 | 2.002 | 0.0606 |
| Mean Volume | –0.9457 | 0.3686 | –2.565 | 0.0195 |
| Relative RMSE, volume | 4.3930 | 1.7947 | 2.448 | 0.0249 |