Forest Management and Climate Change

FOREST MANAGEMENT AND CLIMATE CHANGE A NEW APPROACH TO THE FRENCH MITIGATION STRATEGY Gaëtan du Bus de Warnaffe January 2020 Sylvain Angerand Forest Management and Climate Change A new approach to the French mitigation strategy Gaëtan du Bus de Warnaffe Janvier 2020 Sylvain Angerand This report was produced in partnership with Fern, Canopée and Friends of the Earth France. The project has received funding from the European Climate Foundation, the David and Lucile Packard Foundation, the Foundation ‘Nature et Découvertes’, and the LIFE Programme of the European Union. Cover photo credit: Bernard Débarque 2 TABLE OF CONTENTS SUMMARY . .5 1. CONTEXT AND OBJECTIVES �� 7 2. LITERATURE REVIEW �� 8 Introduction ��8 2.1. Carbon cycle and storage in forest ecosystems ��8 2.2. Carbon storage in wood products . .10 2.3. Substitution effects ��10 2.4. Impact of forest management decisions on the contribution of the forestry sector to combating climate change ��12 2.4.1. Share of forests and trees left to develop naturally . .12 2.4.2. Cutting, standing volume and harvesting limits ��13 1) Type of cutting (selective cutting or clear-cutting): � � � � � � � � � � � � � � � � � � � � � � � � � �13 2) Intensity and frequency in the case of selective cutting: � � � � � � � � � � � � � � � � � � � � �14 3) Selected harvesting limit: � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �14 4) Destiny of branches and stumps: � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �15 2.4.3. Preferred or planted species ��15 2.4.4. Regeneration methods, tillage and soil improvers ��16 2.4.5. Health aspects ��16 2.4.6. Wildfires and storms . .17 2.4.7. Biophysical factors ��17 2.4.8. Products created and emissions generated through wood extraction ��17 2.5. Current mitigation strategies . .17 3. STRATEGIC PROPOSAL . 21 3.1. Introduction ��21 3.2. An essential prerequisite: Analysing the limits to increased harvesting ��22 3.2.1. Area managed, productivity and current harvesting ��22 3.2.2. Obstacles to wood extraction . .23 1) Exploitability � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �23 2) Land tenure barriers � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �24 3.2.3. Manageable areas and limits to increasing harvesting ��25 3.3. Pillar 1: Preserving and increasing carbon stocks in the ecosystem . .25 3.3.1. Expanding and safeguarding natural forests . .26 3.3.2. Renewing stands in deadlocked areas . .26 3.3.3. Practising continuous cover forestry ��28 3 GESTION FORESTIÈRE ET CHANGEMENT CLIMATIQUE 3.4. Pillar 2: Preserving and increasing carbon stocks in wood products . .30 3.5. Pillar 3: Substituting with wood and reducing emissions from the sector ��30 3.6. Analysis of 2020-2050 scenarios . .31 3.6.1. Common basis ��31 Natural forest (NF) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �32 Continuous cover forestry (CCF) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �32 Deadlocks (DEA) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �35 3.6.2. Harvesting levels. .35 3.6.3. Mortality rate ��37 3.6.4. Evolution of areas by management context ��39 4. CALCULATION METHODOLOGY . 40 4.1. Context, scope and baseline data ��40 4.2. Calculating changes in stocks between 2020 and 2050 . .41 4.2.1. Basic principles . .41 4.2.2. Living biomass ��42 4.2.3. Dead biomass and operating losses . .43 4.2.4. Soil carbon . .44 4.2.5. Harvesting ��45 4.2.6. Storage of wood products ��46 4.2.7. Displacement and emissions in the sector . .46 4.2.8. Conversion factors ��47 4.2.9. Summary of the selected parameters ��47 5. RESULTS AND DISCUSSION . 49 5.1. Evolution of the harvesting rate of stemwood ��49 5.2. Changes in carbon stocks ��51 Assessing storage changes and gains made through substitution between 2020 and 2050 ��55 5.3. Quantity and quality of dead wood ��56 5.4. Evolution of the sink ��57 5.5. Detailed analysis of the R60-M1 scenario (compromise) . .60 5.5.1. Evolution of storage by management situation . .60 5.5.2. Spatial distribution of harvesting ��63 5.5.3. Harvesting and stocks of generated products ��64 5.5.4. Arbitration in the use of wood harvested for industry or for energy generation ��64 5.6. Outlook 2050–2100 ��65 5.7. Summary of determining factors for the sink ��68 5.8. Comparison with other scenarios ��69 6. STUDY CONCLUSION �� 71 7. BIBLIOGRAPHY �� 73 4 SUMMARY Through this study, we have attempted to provide a deeper understanding of the evolution of the carbon sink represented by forests and the wood sector, in order to propose and analyse a strategy to optimise the role of forest management in mitigating climate change by 2050. The climate role of forests and their management involves wide and complex areas of science. Although not exhaustive, the literature review demonstrates a rich and interesting breadth of work. The strategies currently proposed are sometimes contradictory and there are lively debates, in particular about harvesting rates and the emphasis placed on substituting non-renewable energy and materials by wood. This analysis shows that in order to store carbon, we will need to: (1) preserve and if possible increase above-ground and below-ground stocks through adapted forestry, (2) preserve and increase stocks in wood products, and (3) substitute wood for competing materials while limiting emissions generated by the wood sector. We then study the maximum scope for increasing harvesting. Total net production of wood in French forests is estimated at 120 cubic megametres per year (Mm3/yr) and the total harvesting rate at 50%. Taking into account physical limits, and land tenure and social barriers, the maximum area that can be harvested is estimated at

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