Editing IPCC:AR6/WGIII/Chapter-7 (section)

==== 7.4.2.3 Improved Forest Management ====

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'''Activities, co-benefits, risks and implementation opportunities and barriers.''' Improved sustainable forest management of already managed forests can lead to higher forest carbon stocks, better quality of produced wood, continuously produced wood, while maintaining and enhancing the forest carbon stock, and can also partially prevent and counteract the impacts of disturbances ( [[#Kurz--2008|Kurz et al. 2008]] ; [[#Marlon--2012|Marlon et al. 2012]] ; [[#Abatzoglou--2016|Abatzoglou and Williams 2016]] ; [[#Seidl--2017|Seidl et al. 2017]] ; [[#Nabuurs--2017|Nabuurs et al. 2017]] ; [[#Tian--2018|Tian et al. 2018]] ; [[#Ekholm--2020|Ekholm 2020]] ). Furthermore, it can provide benefits for climate change adaptation, biodiversity conservation, microclimatic regulation, soil erosion protection and water and flood regulation with reduced lateral carbon fluxes ( [[#Ashton--2012|Ashton et al. 2012]] ; [[#Martínez-Mena--2019|Martínez-Mena et al. 2019]] ; [[#Verkerk--2020|Verkerk et al. 2020]] ). Often, in existing (managed) forests with existing carbon stocks, large changes per hectare cannot be expected, although many forest owners may respond to carbon price incentives ( [[#Favero--2020|Favero et al. 2020]] ; [[#Ekholm--2020|Ekholm 2020]] ). The full mitigation effects can be assessed in conjunction with the overall forest and wood use system i.e., carbon stock changes in standing trees, soil, harvested wood products (HWPs) and its bioenergy component with the avoided emissions through substitution. Forest management strategies aimed at increasing the biomass stock may have adverse side effects, such as decreasing the stand-level structural complexity, large emphasis on pure fast-growing stands, risks for biodiversity and resilience to natural disasters.

Generally, measures can consist of one or combination of longer rotations, less intensive harvests, continuous-cover forestry, mixed stands, more adapted species, selected provenances, high quality wood assortments, and so on. Further, there is a trade-off between management in various parts of the forest product value chain, resulting in a wide range of results on the role of managed forests in mitigation (Agostini et al. 2013; [[#Braun--2016|Braun et al. 2016]] ; [[#Soimakallio--2016|Soimakallio et al. 2016]] ; [[#Gustavsson--2017|Gustavsson et al. 2017]] ; [[#Erb--2017|Erb et al. 2017]] ; [[#Favero--2020|Favero et al. 2020]] ; [[#Hurmekoski--2020|Hurmekoski et al. 2020]] ). Some studies conclude that reduction in forest carbon stocks due to harvest exceeds for decades the joint sequestration of carbon in harvested wood product stocks and emissions avoided through wood use ( [[#Soimakallio--2016|Soimakallio et al. 2016]] ; [[#Seppälä--2019|Seppälä et al. 2019]] ), whereas others emphasise country level examples where investments in forest management have led to higher growing stocks while producing more wood ( [[#Schulze--2020|Schulze et al. 2020]] ; [[#Ouden--2020|Ouden et al. 2020]] ; [[#Cowie--2021|Cowie et al. 2021]] ).

'''Conclusions from AR5 and IPCC Special Reports (SR1.5, SROCC and SRCCL); mitigation potential, costs, and pathways.''' In the SRCCL, forest management activities have the potential to mitigate 0.4–2.1 GtCO 2 -eq yr –1 by 2050 ( ''medium confidence'' ) (SRCCL: [[#Griscom--2017|Griscom et al. 2017]] ; [[#Roe--2019|Roe et al. 2019]] ). The higher estimate stems from assumptions of applications on roughly 1.9 billion ha of already managed forest which can be seen as very optimistic. It combines both natural forest management as well as improved plantations, on average with a small net additional effect per hectare, not including substitution effects in the energy sector nor the buildings sector.

'''Developments since AR5 and IPCC Special Reports (SR1.5, SROCC and SRCCL).''' The area of forest under management plans has increased in all regions since 2000 by 233 Mha ( [[#FAO--2020e|FAO 2020e]] ). The roughly 1 billion ha of secondary and degraded forests would be ideal to invest in and develop a sustainable sector that pays attention to biodiversity, wood provision and climate mitigation at the same time. This all depends on the effort made, the development of expertise, know-how in the field, nurseries with adapted provenances, etc as was also found for Russian climate-smart forestry options ( [[#Leskinen--2020|Leskinen et al. 2020]] ). Regionally, recently updated economic mitigation potential at USD100 tCO 2 –1 have 179–186 MtCO 2 -eq yr –1 in Africa, 193–313 MtCO 2 -eq yr –1 in Asia and Pacific, 215–220 MtCO 2 -eq yr –1 in Developed Countries , 82–152 MtCO 2 -eq yr –1 in Eastern Europe and West-Central Asia, and 62–204 MtCO 2 -eq yr –1 in Latin America and Caribbean ( [[#Roe--2021|Roe et al. 2021]] ).

Regional studies can take into account the local situation better: Russia [[#Romanovskaya--2020|Romanovskaya et al. (2020)]] estimate the potential of forest fires management at 220–420 MtCO 2 yr –1 , gentle logging technology at 15–59, reduction of wood losses at 61–76 MtCO 2 yr –1 . In North America, ( [[#Austin--2020|Austin et al. 2020]] ) estimate that in the next 30 years, forest management could contribute 154 MtCO 2 yr –1 in the USA and Canada with 81 MtCO 2 yr –1 available at less than USD100 tCO 2 –1 . In one production region (British Columbia) a cost-effective portfolio of scenarios was simulated that directed more of the harvested wood to longer-lived wood products, stopped burning of harvest residues and instead produced bioenergy to displace fossil fuel burning, and reduced harvest levels in regions with low disturbance rates. Net GHG emissions were reduced by an average of –9 MtCO 2 -eq yr –1 ( [[#Smyth--2020|Smyth et al. 2020]] ). In Europe, climate-smart forestry could mitigate an additional 0.19 GtCO 2 yr –1 by 2050 ( [[#Nabuurs--2017|Nabuurs et al. 2017]] ), in line with the regional estimates in ( [[#Roe--2021|Roe et al. 2021]] ).

In the tropics, estimates of the pantropical climate mitigation potential of natural forest management (a light intensity management in secondary forests), across three tropical regions (Latin America, Africa, Asia), is around 0.66 GtCO 2 -eq yr –1 with Asia responding for the largest share followed by Africa and Latin America ( [[#Roe--2021|Roe et al. 2021]] ). Selective logging occurs in at least 20% of the world’s tropical forests and causes at least half of the emissions from tropical forest degradation ( [[#Asner--2005|Asner et al. 2005]] ; [[#Blaser--2011|Blaser and Küchli 2011]] ; [[#Pearson--2017|Pearson et al. 2017]] ). Reduced-impact logging for climate (RIL-C; promotion of reduced wood waste, narrower haul roads, and lower impact skidding equipment) has the potential to reduce logging emissions by 44% ( [[#Ellis--2019|Ellis et al. 2019]] ), while also providing timber production.

'''Critical assessment and conclusion.''' There is ''medium confidence'' that the global technical mitigation potential for improved forest management by 2050 is 1.7 (1–2.1) GtCO 2 yr –1 , and the economic mitigation potential (&lt;USD100 tCO 2 –1 ) is 1.1 (0.6–1.9) GtCO 2 yr –1 . Efforts to change forest management do not only require, for example, a carbon price incentive, but especially require knowledge, institutions, skilled labour, good access and so on. These requirements outline that although the potential is of medium size, we estimate a feasible potential towards the lower end. The net effect is also difficult to assess, as management changes impact not only the forest biomass, but also the wood chain and substitution effects. Further, leakage can arise from efforts to change management for carbon sequestration. Efforts, for example to set aside large areas of forest, may be partly counteracted by higher harvesting pressures elsewhere (Kallio et al. 2018). Studies such as ( [[#Austin--2020|Austin et al. 2020]] ) implicitly account for leakage and thus suggest higher costs than other studies. We therefore judge the mitigation potential at medium potential with medium agreement ''.''

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