Editing IPCC:AR6/SRCCL/Chapter-4 (section)

=== 4.9.3 Reversing land degradation through reforestation ===

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==== 4.9.3.1 South Korea case study on reforestation success ====

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In the first half of the 20th century, forests in the Republic of Korea (South Korea) were severely degraded and deforested during foreign occupations and the Korean War. Unsustainable harvest for timber and fuelwood resulted in severely degraded landscapes, heavy soil erosion and large areas denuded of vegetation cover. Recognising that South Korea’s economic health would depend on a healthy environment, South Korea established a national forest service (1967) and embarked on the first phase of a 10-year reforestation programme in 1973 (Forest Development Program), which was followed by subsequent reforestation programmes that ended in 1987, after 2.4 Mha of forests were restored (Figure 4.9).

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'''Figure 4.9'''

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'''Example of severely degraded hills in South Korea and stages of forest restoration. The top two photos are taken in the early 1970s, before and after restoration, the third photo about five years after restoration, and the bottom photo was taken about 20 years after restoration. Many examples of such restoration success exist throughout South […]'''
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[[File:fdb023a3ba1655c460f57efa8a7abd4e Figure-4.9-1024x576.jpg]]

Example of severely degraded hills in South Korea and stages of forest restoration. The top two photos are taken in the early 1970s, before and after restoration, the third photo about five years after restoration, and the bottom photo was taken about 20 years after restoration. Many examples of such restoration success exist throughout South Korea. (Photos: Copyright © Korea Forest Service)

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As a consequence of reforestation, forest volume increased from 11.3 m <sup>3</sup> ha–1 in 1973 to 125.6 m <sup>3</sup> ha–1 in 2010 and 150.2 m <sup>3</sup> ha–1 in 2016 (Korea Forest Service 2017 <sup>[[#fn:r1313|1313]]</sup> ). Increases in forest volume had significant co-benefits such as increasing water yield by 43% and reducing soil losses by 87% from 1971 to 2010 (Kim et al. 2017 <sup>[[#fn:r1314|1314]]</sup> ).

The forest carbon density in South Korea has increased from 5–7 MgC ha–1 in the period 1955–1973 to more than 30 MgC ha <sup>–1</sup> in the late 1990s (Choi et al. 2002 <sup>[[#fn:r1315|1315]]</sup> ). Estimates of carbon uptake rates in the late 1990s were 12 TgC yr <sup>–1</sup> (Choi et al. 2002 <sup>[[#fn:r1316|1316]]</sup> ). For the period 1954 to 2012, carbon uptake was 8.3 TgC yr <sup>–1</sup> (Lee et al. 2014 <sup>[[#fn:r1317|1317]]</sup> ), lower than other estimates because reforestation programmes did not start until 1973. Net ecosystem production in South Korea was 10.55 ± 1.09 TgC yr <sup>−1</sup> in the 1980s, 10.47 ± 7.28 Tg C yr <sup>−1</sup> in the 1990s, and 6.32 ± 5.02 Tg C yr <sup>−1</sup> in the 2000s, showing a gradual decline as average forest age increased (Cui et al. 2014 <sup>[[#fn:r1318|1318]]</sup> ). The estimated past and projected future increase in the carbon content of South Korea’s forest area during 1992–2034 was 11.8 TgC yr <sup>–1</sup> (Kim et al. 2016 <sup>[[#fn:r1319|1319]]</sup> ).

During the period of forest restoration, South Korea also promoted inter-agency cooperation and coordination, especially between the energy and forest sectors, to replace firewood with fossil fuels, and to reduce demand for firewood to help forest recovery (Bae et al. 2012 <sup>[[#fn:r1320|1320]]</sup> ). As experience with forest restoration programmes has increased, emphasis has shifted from fuelwood plantations, often with exotic species and hybrid varieties to planting more native species and encouraging natural regeneration (Kim and Zsuffa 1994 <sup>[[#fn:r1321|1321]]</sup> ; Lee et al. 2015 <sup>[[#fn:r1322|1322]]</sup> ). Avoiding monocultures in reforestation programmes can reduce susceptibility to pests (Kim and Zsuffa 1994 <sup>[[#fn:r1323|1323]]</sup> ). Other important factors in the success of the reforestation programme were that private landowners were heavily involved in initial efforts (both corporate entities and smallholders) and that the reforestation programme was made part of the national economic development programme (Lamb 2014 <sup>[[#fn:r1324|1324]]</sup> ).

The net present value and the cost-benefit ratio of the reforestation programme were 54.3 billion and 5.84 billion USD in 2010, respectively. The breakeven point of the reforestation investment appeared within two decades. Substantial benefits of the reforestation programme included disaster risk reduction and carbon sequestration (Lee et al. 2018a <sup>[[#fn:r1325|1325]]</sup> ).

In summary, the reforestation programme was a comprehensive technical and social initiative that restored forest ecosystems, enhanced the economic performance of rural regions, contributed to disaster risk reduction, and enhanced carbon sequestration (Kim et al. 2017 <sup>[[#fn:r1326|1326]]</sup> ; Lee et al. 2018a <sup>[[#fn:r1327|1327]]</sup> ; UNDP 2017 <sup>[[#fn:r1328|1328]]</sup> ).

The success of the reforestation programme in South Korea and the associated significant carbon sink indicate a high mitigation potential that might be contributed by a potential future reforestation programme in the Democratic People’s Republic of Korea (North Korea) (Lee et al. 2018b <sup>[[#fn:r1329|1329]]</sup> ).

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==== 4.9.3.2 China case study on reforestation success ====

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The dramatic decline in the quantity and quality of natural forests in China resulted in land degradation, such as soil erosion, floods, droughts, carbon emission, and damage to wildlife habitat (Liu and Diamond 2008 <sup>[[#fn:r1330|1330]]</sup> ). In response to failures of previous forestry and land policies, the severe droughts in 1997, and the massive floods in 1998, the central government decided to implement a series of land degradation control policies, including the National Forest Protection Program (NFPP), Grain for Green or the Conversion of Cropland to Forests and Grassland Program (GFGP) (Liu et al. 2008 <sup>[[#fn:r1331|1331]]</sup> ; Yin 2009 <sup>[[#fn:r1332|1332]]</sup> ; Tengberg et al. 2016 <sup>[[#fn:r1333|1333]]</sup> ; Zhang et al. 2000 <sup>[[#fn:r1334|1334]]</sup> ). The NFPP aimed to completely ban logging of natural forests in the upper reaches of the Yangtze and Yellow rivers as well as in Hainan Province by 2000 and to substantially reduce logging in other places (Xu et al. 2006 <sup>[[#fn:r1335|1335]]</sup> ). In 2011, NFPP was renewed for the 10-year second phase, which also added another 11 counties around Danjiangkou Reservoir in Hubei and Henan Provinces, the water source for the middle route of the South-to-North Water Diversion Project (Liu et al. 2013 <sup>[[#fn:r1336|1336]]</sup> ). Furthermore, the NFPP afforested 31 Mha by 2010 through aerial seeding, artificial planting, and mountain closure (i.e., prohibition of human activities such as fuelwood collection and lifestock grazing) (Xu et al. 2006 <sup>[[#fn:r1337|1337]]</sup> ). China banned commercial logging in all natural forests by the end of 2016, which imposed logging bans and harvesting reductions in 68.2 Mha of forest land – including 56.4 Mha of natural forest (approximately 53% of China’s total natural forests).

GFGP became the most ambitious of China’s ecological restoration efforts, with more than 45 billion USD devoted to its implementation since 1990 (Kolinjivadi and Sunderland 2012 <sup>[[#fn:r1338|1338]]</sup> ) The programme involves the conversion of farmland on slopes of 15–25° or greater to forest or grassland (Bennett 2008 <sup>[[#fn:r1339|1339]]</sup> ). The pilot programme started in three provinces – Sichuan, Shaanxi and Gansu – in 1999 (Liu and Diamond 2008 <sup>[[#fn:r1340|1340]]</sup> ). After its initial success, it was extended to 17 provinces by 2000 and finally to all provinces by 2002, including the headwaters of the Yangtze and Yellow rivers (Liu et al. 2008).

NFPP and GFGP have dramatically improved China’s land conditions and ecosystem services, and thus have mitigated the unprecedented land degradation in China (Liu et al. 2013 <sup>[[#fn:r1341|1341]]</sup> ; Liu et al. 2002 <sup>[[#fn:r1342|1342]]</sup> ; Long et al. 2006 <sup>[[#fn:r1343|1343]]</sup> ; Xu et al. 2006 <sup>[[#fn:r1344|1344]]</sup> ). NFPP protected 107 Mha forest area and increased forest area by 10 Mha between 2000 and 2010. For the second phase (2011–2020), the NFPP plans to increase forest cover by a further 5.2 Mha, capture 416 million tons of carbon, provide 648,500 forestry jobs, further reduce land degradation, and enhance biodiversity (Liu et al. 2013 <sup>[[#fn:r1345|1345]]</sup> ). During 2000–2007, sediment concentration in the Yellow River had declined by 38%. In the Yellow River basin, it was estimated that surface runoff would be reduced by 450 million m3 from 2000 to 2020, which is equivalent to 0.76% of the total surface water resources (Jia et al. 2006). GFGP had cumulatively increased vegetative cover by 25 Mha, with 8.8 Mha of cropland being converted to forest and grassland, 14.3 Mha barren land being afforested, and 2.0 Mha of forest regeneration from mountain closure. Forest cover within the GFGP region has increased 2% during the first eight years (Liu et al. 2008 <sup>[[#fn:r1346|1346]]</sup> ). In Guizhou Province, GFGP plots had 35–53% less loss of phosphorus than non-GFGP plots (Liu et al. 2002 <sup>[[#fn:r1347|1347]]</sup> ). In Wuqi County of Shaanxi Province, the Chaigou Watershed had 48% and 55% higher soil moisture and moisture-holding capacity in GFGP plots than in non-GFGP plots, respectively (Liu et al. 2002 <sup>[[#fn:r1348|1348]]</sup> ). According to reports on China’s first national ecosystem assessment (2000–2010), for carbon sequestration and soil retention, coefficients for the GFGP targeting forest restoration and NFPP are positive and statistically significant. For sand fixation, GFGP targeting grassland restoration is positive and statistically significant. Remote sensing observations confirm that vegetation cover increased and bare soil declined in China over the period 2001 to 2015 (Qiu et al. 2017 <sup>[[#fn:r1349|1349]]</sup> ). But, where afforestation is sustained by drip irrigation from groundwater, questions about plantation sustainability arise (Chen et al. 2018a <sup>[[#fn:r1350|1350]]</sup> ). Moreover, greater gains in biodiversity could be achieved by promoting mixed forests over monocultures (Hua et al. 2016 <sup>[[#fn:r1351|1351]]</sup> ).

NFPP-related activities received a total commitment of 93.7 billion yuan (about 14 billion USD at 2018 exchange rate) between 1998 and 2009. Most of the money was used to offset economic losses of forest enterprises caused by the transformation from logging to tree plantations and forest management (Liu et al. 2008 <sup>[[#fn:r1352|1352]]</sup> ). By 2009, the cumulative total investment through the NFPP and GFGP exceeded 50 billion USD2009 and directly involved more than 120 million farmers in 32 million households in the GFGP alone (Liu et al. 2013 <sup>[[#fn:r1353|1353]]</sup> ). All programmes reduce or reverse land degradation and improve human well-being. Thus, a coupled human and natural systems perspective (Liu et al. 2008 <sup>[[#fn:r1354|1354]]</sup> ) would be helpful to understand the complexity of policies and their impacts, and to establish long-term management mechanisms to improve the livelihood of participants in these programmes and other land management policies in China and many other parts of the world.

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