Calculations were made for five ten years periods (though each management schedule was continued to the final felling or at the maximum up to the 150 years). The results are reported only for the first 30-year period and the years beyond that era are for sustainability reasons.
In MELA2016 - program (Hirvelä ym. 2017) treewise basal-area growth models are calibrated using growth measurement data from 8th NFI. For calibration, growth measurements were adjusted with growth indices to the average level of diameter increment for years 1965–1994 (Henttonen 2000, Hynynen et al. 2002). For calculations presented here, tree basal-area growth models for forest land were calibrated using growth measurement data from 11th NFI. For calibration, growth measurements were adjusted with growth indices to the average level of diameter increment for years 1984–2013 (Korhonen et al. 2007). The calibration was done with sample trees from NFI measured in years 2009–2013. Sample trees in a sample plot were accepted to calibration data if the sample plot was at forest land, the whole sample plot was in a single stand and no cuttings were recorded for the 10-year period before the measurement year. The estimate of volume growth obtained using calibrated basal area growth was still adjusted up to the NFI12 measured growth level.
The estimate of volume growth obtained using calibrated basal area growth was still adjusted using the realized average 30 year weather data for 1970–1999 (1999 is the middle year of the calibration period of 1984–2013) and 1988–2017 and transformation functions of Matala et al (2005). Those functions were used in order to predict the change in the growth as a function of the increases in mean air temperature and CO2 concentration between the long term averages of 1999 and 2017 which were in the Southern Finland 0.89 °C and 41.2 ppm and in the Northern Finland 0.996 °C and 41.2 ppm. By this way, the estimate of volume growth for 2019–2028 with during the years 2019–2021 realized removals was 103.1 mill. m3/year while the growth estimate using NFI12–NFI13 data measured 2017–2021 growth (middle year 2013) was 103.2 mill. m3/year (Luke2023b).
Average basal area growth of sample trees
| Tree species | Sample trees n |
Basal area growth of sample trees, cm2/5 years |
|||
| NFI11, corrected with indices | MELA2016 | ||||
| No calibration | Calibrated | ||||
| Mineral soils | |||||
| Pine | 17 592 | 42.1 | 41.6 | 43.9 | |
| Spruce | 11 958 | 50.7 | 57.2 | 52.4 | |
| Hardwoods | 8 049 | 35.9 | 30.1 | 34.0 | |
| Total | 37 599 | 43.5 | 44.1 | 44.5 | |
| Unditched organic soils | |||||
| Pine | 785 | 24.8 | 8.5 | 18.1 | |
| Spruce | 557 | 28.0 | 17.2 | 23.3 | |
| Hardwoods | 586 | 19.3 | 9.4 | 13.3 | |
| Total | 1 928 | 24.1 | 11.3 | 18.1 | |
| Ditched organic soils | |||||
| Pine | 5 497 | 34.3 | 25.5 | 35.3 | |
| Spruce | 2 213 | 45.9 | 38.1 | 41.7 | |
| Hardwoods | 2 933 | 26.4 | 22.1 | 23.8 | |
| Total | 10 643 | 34.5 | 27.2 | 33.4 | |
Logging residue (waste wood) is part of cutting drain that is felled but not hauled from the forest and it is defined as non-commercial fraction of felled stems i.e. part of a stem that does not fulfill the minimum Finnish timber assortment standards by size and quality of the industrial roundwood.
In MELA, stem volume (incl. bark) of an individual tree and the volumes of saw logs, pulpwood, energy stemwood and waste wood (non-commercial fraction of a stem) as solid cubic meter are obtained applying taper curve models and volume functions of Laasasenaho (1982). The saw log volume obtained by the models of Laasasenaho is still reduced by the built-in log-volume reduction model of Mehtätalo (2002). This reduction is added to the pulpwood.
However, in practice the amount of waste wood in loggings can differ from the model estimated due to the stump height, used minimum measures, defected stems or due to the commercial timber not hauled. To reduce this gap the model estimations of waste wood of MELA in each logging was calibrated with NFI12 measurements (table below), such that the percentage in each pure industrial roundwood felling MELA event matched up with NFI12 figures. The reduction, when necessary, was made from pulpwood.
Relative fractions of waste wood in NFI12 by tree species, felling types and by regions, % of cutting drain:
| Region | Tree species | Final fellings | Other fellings |
| South Finland | Pine | 1.6 | 5.1 |
| Spruce | 2.1 | 7.6 | |
| Deciduous | 8.8 | 16.5 | |
| North Finland | Pine | 3.1 | 6.8 |
| Spruce | 5.3 | 13.9 | |
| Deciduous | 15.7 | 20.2 |
The effects of the calibration of logging residue have been discussed in Luke (2023a) and Hirvelä et al. (2023).
A finite number of alternative management schedules were automatically simulated for NFI plots with MELA2016 (Hirvelä ym. 2017). Simulations were based on tree level natural process models for ingrowth, growth and mortality (e.g. Hynynen et al., 2002) and feasible (sound and acceptable) stand level management actions. Possible management actions were thinnings based either on number of trees or on basal area, final fellings (clear cutting and seed tree cutting), preparation of regeneration areas, natural and artificial regeneration, and tending of young stands. Energy wood (forest chips) were harvested as logging residues (branches and tops, or branches, tops and stumps) from final fellings or as whole trees or trunks from thinnings (integrated with roundwood logging or as separate energy wood logging). Management actions were simulated when the criterias of current Finnish silvicultural guidelines (Äijälä et al. 2019) or the guidelines for energy wood logging (Koistinen et al. 2019) were satisfied. Regeneration was simulated when growing stock achieved either the minimum regeneration diameter based on 2-3 % revenue requirement or the minimum regeneration age. For each management activity there was also always a no-treatment alternative. Management actions were simulated only on the forest land available for wood production. For forest land with restricted availability for wood production only intermediate fellings were possible – final fellings were not allowed. No management actions were allowed on protected forests and no cuttings were made on poorly productive forest land even if the wood production was allowed. Prescribed burning, drainage of new areas, fertilization or pruning were not included in the management alternatives.
The calculations for forest greenhouse gas calculations includes the overall balance of greenhouse gases from the forest stand and soil, while excluding stored emissions from harvested wood products. In the regional assessments, a positive balance indicates a net emission, while a negative balance indicates a net removal. Kärkkäinen et al. (2023)
The net carbon sequestration of growing forest biomass (stem wood, branches, leaves, needles, stumps, and roots) was calculated using the stock change method. This is calculated as the difference in carbon content between two time periods (in this case at the beginning and end of a ten-year period). The amount of carbon in the forest biomass was estimated using Repola's (2008, 2009) stand- level biomass models incorporated in the MELA2016 software, using the assumption that 50% of the dry weight of the biomass is carbon. The calculations were conducted using a ten-year time period, with the annual net sequestration evaluated as the average of that period. For a more descriptive explanation of the simulation and calculation method refer to Hirvelä et al. (2023). These estimates were made for the entire forest and peatland, using NFI12–13 data and assuming no changes in land areas during scenario calculations. In this way, the potential for deforestation or afforestation were not considered. Kärkkäinen et al. (2023)
We conducted soil greenhouse gas calculations separately for mineral soils and drained peatlands. The calculations for mineral soils were carried out using the Yasso07 model (Tuomi et al. 2011). Input data at the regional level included estimates of harvest residues and natural mortality from the MELA calculations, as well as estimates of litter produced by living trees. To evaluate the initial state of regional soil carbon stocks we conducted a spin-up utilizing average litter inputs from VMI10, VMI11, and VMI12 datasets for different components, such as leaves, branches, stems, and roots, and with meteorological data from the Finnish Meteorological Institute (Venäläinen et al. 2005). Historical weather data from the nearest weather stations were used for each region. The Yasso07 soil model was used for the initial state modeling from 1980 onwards, using 30-year average weather data (such as mean temperature, temperature range, and precipitation) separately for each region. Future predictions of soil carbon stock changes utilized weather data from 2019 onwards for each region. Kärkkäinen et al. (2023)
Estimates of carbon dioxide emissions from peatlands utilized a method developed by Alm et al. (2023), specifically designed for determining CO2 emissions from drained peatlands. This method calculates CO2 emissions according to the following formula: CO2Net = RNet - 44/12 * (IAGL+ IBGL+IAGR+IBGR), where RHet represents heterotrophic soil respiration, IAGL and IBGL are annual carbon inputs from above- and below-ground litter produced by trees and ground vegetation, and IAGR and IBGR represent annual carbon inputs from above- and below-ground litter originating from harvest residues and natural mortality. Key variables in the modeling include the species-specific basal area of drained peatland forest types and regional temperature data. The models and approaches are developed by Alm et al. (2023), which provides comprehensive description of the calculation approach. Kärkkäinen et al. (2023)
Emissions of CH4 and N2O from drained peatlands were calculated according to site-specific area data, applying emission factors for organic soils from Ojanen et al. (2010, 2018) and Statistics Finland ( 2022). Kärkkäinen et al. (2023)
In economic calculations concerning industrial roundwood (saw logs and pulpwood) were made using roadside prices, which were induced by adding harvesting costs on stumpage prices. Used stumpage prices for each region are based on the average realized unit prices in 2012-2021 (€/m3) by timber assortments deflated to the year 2021 (Luke 2022b). Average harvesting costs of saw logs and pulpwood are uniformly defined for whole country according to the realized unit prices in 2012–2021 (€/m3) deflated to the year 2021 (Luke 2022c).
Applied stumpage prices (€/m3) and harvesting costs (€/m3) used in defining road-side prices of industrial roundwood for different regions. Birch pulpwood prices were used for saw logs and pulpwood of aspen. For other broadleaved species, the prices were based on the stumpage prices of birch pulpwood in first thinnings which were on the average 4.15 €/m3 lower than the average price of birch pulpwood in all thinnings.
| Stumpage price, €/m3 | ||||||
| Region | Saw log | Pulpwood | ||||
| Pine | Spruce | Birch | Pine | Spruce | Birch | |
| Uusimaa | 59.35 | 61.80 | 44.15 | 16.50 | 19.55 | 16.55 |
| Varsinais-Suomi | 59.60 | 60.95 | 40.45 | 17.55 | 19.65 | 16.80 |
| Satakunta | 60.10 | 61.80 | 39.25 | 17.60 | 20.25 | 17.25 |
| Kanta-Häme | 60.00 | 62.15 | 44.15 | 16.95 | 19.85 | 17.00 |
| Pirkanmaa | 60.05 | 61.95 | 42.15 | 17.00 | 19.65 | 16.90 |
| Päijät-Häme | 60.75 | 62.20 | 45.85 | 17.35 | 19.65 | 17.05 |
| Kymenlaakso | 60.55 | 62.20 | 44.40 | 17.90 | 20.05 | 16.95 |
| South Karelia | 61.05 | 61.70 | 45.75 | 17.85 | 19.65 | 16.80 |
| Etelä-Savo | 60.40 | 61.20 | 47.90 | 17.75 | 19.20 | 16.95 |
| Pohjois-Savo | 57.45 | 59.75 | 44.15 | 16.90 | 18.10 | 16.75 |
| North Karelia | 57.55 | 58.25 | 45.00 | 16.55 | 17.45 | 15.95 |
| Central Finland | 59.50 | 61.50 | 44.60 | 17.60 | 19.80 | 17.00 |
| South Ostrobothnia | 59.05 | 60.20 | 38.50 | 17.90 | 19.15 | 17.50 |
| Ostrobothnia | 59.00 | 59.55 | 36.60 | 17.70 | 19.05 | 17.45 |
| Central Ostrobothnia | 59.15 | 59.40 | 38.50 | 18.05 | 19.45 | 17.75 |
| North Ostrobothnia | 56.20 | 57.15 | 38.65 | 17.50 | 19.10 | 17.20 |
| Kainuu | 54.60 | 55.40 | 39.80 | 16.40 | 17.70 | 15.65 |
| Lapland | 51.15 | 49.90 | 15.65 | 16.80 | 17.75 | 15.65 |
| Region | Harvesting costs,€/m3 | |||||
| Saw log | Pulpwood | |||||
| Whole country | 7.90 | 14.30 | ||||
Economic calculations with energy wood were based on the unit prices (€/Mwh) for forest chips at the mill yard according to the average realized average pricess in 2012–2021 deflated to the year 2021 in the whole country (Statistics: Energy prices 2022). The unit prices for Mwh were transformed to the units prices of cubic meters by multiplying them with 2.
| Particle | Price at the mill yard, €/m3 |
| Trunk | 46.80 |
| Branches | 46.80 |
| Stumps and roots | 46.80 |
The applied unit prices (€/h) used in estimating the logging costs of industrial roundwood (saw logs and pulpwood). Prices include wages, social costs, compensations for tools, profits of entrepreneurship.
| Task | Unit price, €/h |
| Forest haulage | 81.50 |
| Harvest | 103.20 |
| Manual logging | 29.80 |
The applied unit prices (€/h or €/m3) used on esimating the costs of energy wood procurement. Prices include wages, social costs and compensations for tools. No subsidies for energy wood logging and chipping in young stand improvement thinnings were taken into account.
| Task | Unit price |
| Forest haulage, €/h | 81.50 |
| Felling with harvester, €/h | 100.00 |
| Manual felling, €/h | 29.80 |
| Compensation of felling logging residues in to the piles, €/m3 | 0.48 |
| Stump lifting with excavator, €/h | 90.20 |
| Mobile chipper at the road side, €/h | 220.00 |
| Long-distance transport with trucks, €/h | 81.00 |
| Costs of loading and unloading of trucks, €/h | 55.00 |
| Fixed stationary crusher, €/m3 | 2.90 |
Unit prices for silvicultural tasks are calculated as the average realized prices in 2012-2021 by tasks (Luke 2023d) deflated to the year 2021.
Applied unit prices of silvicultural work (€/ha, €/h or €/plant).
| Task | Southern-Finland | Middle Finland | Ostrobothnia region | Northern Finland |
| Harrowing and scarification , €/ha | 347.00 | 308.00 | 272.0 | 214.00 |
| Ploughing and mounding, €/ha | 448.00 | 434.00 | 420.00 | 344.00 |
| Cost on pine seeds, €/ha | 230.00 | 240.00 | 250.00 | 230.00 |
| Pine seedling, €/plant | 0.16 | 0.16 | 0.16 | 0.16 |
| Spruce seedling, €/plant | 0.18 | 0.18 | 0.18 | 0.18 |
| Birch seedling, €/plant | 0.32 | 0.32 | 0.32 | 0.32 |
| Supplementary pine seedling, €/plant | 0.19 | 0.19 | 0.19 | 0.19 |
| Supplementary spruce seedling, €/plant | 0,28 | 0,28 | 0,28 | 0,28 |
| Supplementary birch seedling, €/plant | 0.43 | 0.43 | 0.43 | 0.43 |
| Silvicultural work, €/h | 22.40 | 22.40 | 22.40 | 22.40 |
| Prevention of grass, €/ha | 388.00 | 355.00 | 413.00 | 357.00 |
| Clearing and tending, €/h | 29.80 | 29.80 | 29.80 | 29.80 |
| Supplementary drainage, €/ha | 237.00 | 201.00 | 249.00 | 196.00 |
| Planning and supervision, €/h | 22.40 | 22.40 | 22.40 | 22.40 |
Districts used here:
Southern Finland: regions 1–10 (Uusimaa, Varsinais-Suomi, Satakunta, Kanta-Häme, Pirkanmaa,
Päijät-Häme, Kymenlaakso, South Carelia and Etelä-Savo)
Middle Finland: regions 11–13 (Etelä-Savo, Pohjois-Savo and North Carelia)
Ostrobothnia region: regions 14-16 (South Ostrobothnia, Ostrobothnia and Central Ostrobothnia)
Norhern Finland: regions 17–19 (North Ostrobothnia, Kainuu and Lapland)