Initial forest age distribution may generate computational sinks or sources of carbon: A generic approach to test assumptions underlying the EU LULUCF forest reference levels

Jari Vauhkonen,Tuula Packalen,Antti Asikainen,Antti Mutanen

doi:10.1186/s13021-021-00177-4

Abstract

BackgroundThe current EU LULUCF regulation calls for member state-specific Forest Reference Levels (FRLs) for benchmark in the accounting of greenhouse gas emissions and removals of managed forest land during the compliance period (2021–2030). According to the technical guidance on developing and reporting the FRLs, it could be actualized by projecting a ratio of harvested to total available biomass. We tested how the initial age distribution may affect the aforementioned ratio by simulating the continuation of forest management based on several descriptive shapes of forest age class distribution.ResultsOur simulations suggest that when the FRLs are prepared by employing the harvest ratio and forest management is assumed strictly age dynamics driven, the shape of the initial forest age class distribution gives rise to computational sinks or sources of carbon in managed forest land. Harvests projected according to the ratio corresponded those resulting from the age dynamics only in the case of uniform age distribution.ConclusionsThe result calls for a better consideration of variation in initial states between countries when determining the future LULUCF regulation. Our exercise demonstrates how generic simulations in a standardized modeling framework could help in ex-ante impact assessment of proposed changes to the LULUCF regulation.

Highlights

The current EU LULUCF regulation calls for member state-specific Forest Reference Levels (FRLs) for benchmark in the accounting of greenhouse gas emissions and removals of managed forest land during the compliance period (2021–2030)
In our simulations, forest management contributes to a FRL as a computational source of carbon, when the harvests realized in the Compliance Period (CP) exceed those obtained by projecting the ratio of harvested to total available biomass of the Reference Period (RP), and a computational sink otherwise
The simulation can be claimed simplistic; it involves the key aspects of the FRL, i.e., continuation of forest management in the RP based on a regime that is strictly determined by the age distribution during the entire simulation

Summary

Introduction

The current EU LULUCF regulation calls for member state-specific Forest Reference Levels (FRLs) for benchmark in the accounting of greenhouse gas emissions and removals of managed forest land during the compliance period (2021–2030). In accounting the emissions and removals of managed forest land, member state-specific Forest Reference Levels (FRLs) are used. The FRL “shall be based on the continuation of sustainable forest management practice, as documented in the period from 2000 to 2009 with regard to dynamic age-related forest characteristics in national forests, using the best available data”. The regulation states that the FRL “shall take account of the future impact of dynamic age-related forest characteristics in order not to unduly constrain forest management intensity as a core element of sustainable forest management practice, with the aim of maintaining or strengthening long-term carbon sinks”

Objectives

Methods

Results

Discussion

Conclusion