1

Fig. 1. Cumulative precipitation in Finland from 1 April to 31 August 2015–2017.

2

Fig. 2. Location of the validation data sampling points (1 = Hämeenkyrö, 2 = Kaipola, 3 = Kotka and 4 = Oulu).

Table 1. Harvesting areas in each location classified by the harvesting and forwarding time.
Class Hämeenkyrö Kaipola Kotka Oulu Total
1 6 4 5 3 18
2 5 4 5 0 14
3 6 6 4 1 17
Total 17 14 14 4 49
3

Fig. 3. Relation between the potential evaporation alteration and material weight alteration (Class B and C) (orange, continuous line = LOESS model; blue, dashed line = non-linear model).

4

Fig. 4. Relation between the potential evaporation alteration and material weight alteration after rainfall periods (Class B) (orange, continuous line = LOESS model; blue, dashed line = non-linear model).

5

Fig. 5. Relation between the potential evaporation alteration and material weight alteration before rain periods (Class C) (orange, continuous line = LOESS model; blue, dashed line = non-linear model).

6

Fig. 6. Relation between the precipitation amount and material weight alteration (Class A) (orange, continuous line = LOESS model; blue, dashed line = non-linear model).

Table 2. Parameters a11…a22 and b11 …b22 in Eqs. 2–5, Model 1.
Eq. b11 b12 b21 b22
2 0.01 1.90
3 4.10 –7.40
Eq. a11 a12 a21 a22
4 –0.04 –0.20
5 0.30 –0.70
Table 3. Moisture content of fresh logging residues depending on the harvesting month in Finland.
Moisture content of fresh harvesting residues, monthly, %
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Pine 55 55 55 54 54 54 54 53 54 54 55 54
Spruce 52 52 51 51 50 50 50 50 51 51 51 52
Table 4. Green density factors for logging residues in Southern Finland and Ostrobothnia (Luonnonvarakeskuksen määräys 1/2017).
Weight
class 		Moisture
content 		Time period Green density
factor
% 1/4–30/4 1/5–15/8 16/8–30/9 1/10–31/3 kg m–3
1 > 50 Non-seasoned or wet residues, with snow and ice 950
2 45–50 fresh, 20 days ↓ fresh, 10 days ↓ fresh, 20 days ↓ fresh 840
3 40–44 ≥ 20 days → 15 days ↓ ≥ 20 days ≥ 20 days 770
4 35–39 - 20 days ↓ 20 days ↑ 20 days ↑ 700
5 30–34 - 35 days ↓ 20 days ↑ - 650
6 < 30 - ≥ 80 days 20 days ↑ - 600
Table 5. Green density factors for logging residues in Kainuu, Lapland and Northern Lapland (Luonnonvarakeskuksen määräys 1/2017).
Weight
class 		Moisture content Time period Green density factor
% 16/4–15/5 16/5–31/7 1/8–15/9 16/9–15/4 kg m–3
1 > 50 Non-seasoned or wet residues, with snow and ice 950
2 45–50 fresh, 20 days ↓ fresh, 15 days ↓ fresh, 20 days ↓ fresh 840
3 40–44 ≥ 20 days → 20 days ↓ ≥ 20 days ≥ 20 days 770
4 35–39 - 30 days ↓ 20 days ↑ 20 days ↑ 700
5 < 35 - ≥ 65 days 20 days ↑ - 650
7

Fig. 7. Geographical region allocation of green density factors (Luonnonvarakeskuksen määräys 1/2017).

8

Fig. 8. Difference between observed and modelled moisture content for Models 1–3.

9

Fig. 9. Difference between the observed and modelled moisture for individual harvesting sites in relation to the storage time.

Table 6. Accuracy of the models by harvesting sites class. Number and percentage of the sites where the estimated moisture content was within the targeted ±5% accuracy range.
Harvesting Class Number of Sites Model 1 Model 2 Model 3
1 18 11 (61%)  9 (50%) 12 (67%)
2 14 8 (57%) 7 (50%) 4 (29%)
3 17 4 (24%) 5 (29%) 4 (24%)
Total 49 23 (47%) 21 (43%) 20 (41%)