The primary aim of producing the long-term forecast is to assess the status of the National forest sink and carbon stocks by the second half of the century as specified in the Paris climate change agreement. In particular, the agreement calls for a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, and invites Parties to take action to conserve and enhance, as appropriate, sinks and reservoirs of greenhouse gases, including forests. The EU LULUCF regulation strives to ensure the continuation to decrease its greenhouse gas emissions and enhance removals in line with the Paris Agreement. Ireland has, for some time now, shown that the National forest sink is steadily declining due to numerous factors such as large shifts in age class structure due to afforestation legacy and a large increase in available harvest based on sustainable forest management practices. In addition, the afforested sink is projected to decline due to unsustained level of afforestation going forward due to competing agricultural policies which influence availability of land for afforestation.
Long term projections up to 2050 were developed using the CBM modelling framework, as used for the FRL projections submitted to the EU in December 2018. The 2017 NIR was used as the initiation year to define the state of the forest and the forecast roundwood harvest up to 2050 was used to calibrate harvest events defined in CBM
- All C pools and non-CO2 emissions reported to the UNFCCC are considered.
- Fire emissions are assumed to be the background level (87Gg CO2 eq. per year) based on data for the period 2006-2017. This is the same assumption used for the FRL.
- Afforestation rates from 2017 are assumed to be 8000 ha per year, which is the National target.
- Deforestation assumptions differ slightly to those used in the FRL (993 ha per year) because of new legislation provided in the Forestry act of 2017, which provides disincentives for deforestation. It is assumed that deforestation will decrease by 50% due to the newly introduced Forestry act. This assumption could not be used in the FRL because the act was introduced after the reference period 2000-2010 defined in the EU LULUCF regulation.
- Standards Clearfell and thinning age assumptions are used to simulate management (as used in the 2018-2035 roundwood forecast, Phillips et al., 2016) The level of harvest was based on data derived from the 2016-2050 roundwood forecast.
- The forecast does not consider deforestation, so the effect of a reduction in productive area on the timber supply chain in not considered. But this is considered in the CBM long term forecast by randomly assigning clear fell event for 467ha of deforestation each year form 2017. This means that the available harvest set in the roundwood harvest could not be identical to the CBM simulation (see results below).
- Simulation for the long-term forecast were only carried out using forest categories used in the current GHG inventory (i.e. pre (FM) and post 1990 forest (AR) because there was no spatial attributed data in the roundwood forecast to facilitate assignment of harvest to afforested land transitioning to managed forest land after 30 years.
- The utilisation of harvested wood products is assumed to be consistent with annex to the EU regulation where a constant ratio between solid and energy use of forest biomass for the period from 2000 to 2009 shall be assumed, as done for the FRL. This means that only 30 and 24% of round wood harvest is allocated to sawnwood and woodbased panels, respectively. Therefore, this forecast does not consider impact of the increase demand for forest bioenergy and HWP removals and emissions, should this occur.
long Term GHG Balance
The GHG balance, including HWP, of the total forest area declines from a net removal of 5.5 MtCO2 in 2017 to a net emission of 0.8MtCO2 by 2036 (Figure 1). This trend is reversed over the period 2036 to 2050, where the forest becomes a net removal of CO2eq by the middle of the century. For forest lands afforested before 1990 (AR, Figure 1), the GHG emission/removal trends are driven by an increase in the harvest and harvest to biomass increment ratio. The harvest and harvest to increment ratios for FM land increases slightly and peaks by 2035. However, the GHG trends in FM land appears to be more related to changes in biomass increment, which is associated with age class shifts
Left: GHG balances (including HWP) of FM (orange symbols), AR (grey symbols) and the total forest area (blue symbols and lines) over the period 2017-2050. See detailed fluxes for different pools in annex 1.