Scenarios based on NFI13

In MELA summary reports, the regional results of the industrial roundwood and energy wood removals are presented for three scenarios:
- NT maximum economic removal
- SY maximum sustained yield
- TH realized cutting removals

The results are based on a new method to generate calculation data from the NFI data. Furthermore, the definitions of calculation periods and energy wood loggings have been changed compared to the results based on earlier NFI data. The calculation time is 130 years including five 10-years periods and four 20-years periods. At the calculation unit level, the amount of energy wood removal must be at least 40 m³ per/ hectare for logging to be carried out. And only spruce stumps with the stump diameter thicker than 35 cm are lifted for energy use from spruce dominated stands.

In addition to these scenarios, there is one comparison maximum sustained yield scenario SYB based on the old method to generate calculation data used in the earlier rounds of calculations. In this scenario, also the earlier used definitions of calculation periods and energy wood loggings are utilized. The calculation time 50 years divided in five 10-years periods. The minimum amount of energy wood removal is 25 m³/ per hectare and the minimum stump diameter for lifted spruce stumps is 25 cm.

The scenarios were calculated separately for 19 regions using the administrative boundaries with the situation at the beginning of 2023 using the JLP optimization package (Lappi 1992) included in the MELA2016 software (Hirvelä et al. 2017). The results for the Southern and Northern Finland as well as for the whole country were compiled as sums of the regional results. The Northern Finland includes the regions of North Ostrobothnia, Kainuu and Lapland. Other regions belong to the Southern Finland.

All the net present value calculations have been made using the roadside prices for industrial roundwood (saw logs and pulpwood) and the prices of forest chips at the mill yard for the energy wood subtracted with the costs of logging and silvicultural operations. All three scenarios were based on the current Finnish silvicultural guidelines and the restrictions on wood production according to the NFI data were taken into account. The ownership structure of the forests and the forest owners’ timber sales behaviour were not taken into account in the scenarios.

NT : Maximum economic removal

Maximum economic removal scenario defines the industrial roundwood and energy wood harvest levels that maximize the net present value without taking into account any sustainability constraints or the demand of wood products. This scenario will harvest all the cutting possibilities as soon as they are feasible for harvesting according to the silvicultural recommendations and which do not fulfill the economic prerequisite (5 % discount rate) for further growing. This scenario defines the maximum short-term economical timber supply.

SY : Maximum sustained yield

The maximum sustained removal is defined by maximizing the net present value with five discount rates (1 %, 2%, 3 %, 4 % and 5 %) subject to non-declining periodic removals of industrial roundwood, energy wood and saw logs as well as non-declining periodic net income. There are no sustainability constraints concerning tree species, cutting methods, age classes or the growth/drain -ratio in order to efficiently utilize the dynamics of forest structure. Energy wood removal can consist of stems, cutting residues, stumps and roots.

TH : Realized cutting removals

Realized cutting removal scenario outlines the development of forest resources if the current (2021–2023) industrial roundwood (Luke 2024c) and energy wood (Luke 2024f) harvesting levels are carried out in the future. The current consumption level of fuelwood in small-scale housing is also taken into account (Luke 2024e). In this scenario, the net present value is maximized with the 4 % discount rate subject to realized cutting removals by timber assortments. The primary target is to fulfill the realized removal levels of total roundwood and total energy wood and after that to reach the removal levels of saw logs and industrial wood by tree species and energy wood by assortments. The realized removals are used as constraints in the optimization and by default they are allowed to vary ± 0.5 % which can be increased for each constraint separately if needed. There are no restrictions concerning the removals e.g. by cutting methods, diameter classes or forest site types.

SYB : Maximum sustained yield based on the old initial data generation method

The maximum sustained removal is defined by maximizing the net present value with discount rate of 4 % subject to non-declining periodic removals of industrial roundwood, energy wood and saw logs as well as non-declining periodic net income. The definitions are the same as in the SY scenario except the method to generate the calculation data from NFI data, the definitions of calculation periods and the details of the energy wood loggings. For more details on the differences, see the text above.