Trading Natural Riparian Forests for Urban Shelterbelt Plantations—A Sustainability Assessment of the Kökyar Protection Forest in NW China

Abstract

Cities at the fringe of the Taklimakan desert in NW China are prone to dust and sand storms with serious consequences for human well-being. The Kökyar Protection Forest was established in the 1980s as an ecological engineering project with the intent of protecting the city of Aksu, NW China, from these impacts. It is designed as a combination of poplar shelterbelts and orchards, irrigated by river water from the Aksu River, the main tributary of the Tarim River. Prevalent literature describes it as an afforestation project for combatting desertification with manifold positive effects for the economic, social, and environmental dimension of sustainable development. This paper sets out to challenge these claims by a sustainability assessment in which the plantation is examined from a broader perspective, embedding it to the wider context of social and environmental problems in South Xinjiang. Methods comprise evapotranspiration calculations, interviews, a socioeconomic household survey, stakeholder dialogues, and literature research. Results affirm its economic sustainability, but see a mixed record for the social sphere. From the nature conservation point of view, it has to be classified as unsustainable because its high irrigation water consumption results in the downstream desiccation and desertification of natural riparian forests along the Tarim River, causing a forest loss in the downstream area twice the size of the forest gain in the upstream area. There is a trade-off between artificial shelterbelt plantations for urban ecosystem services on the one hand side, and natural riparian forests and their biodiversity on the other hand side. The paper recommends restricting agricultural extension, and using locally adapted less water consuming agroforestry schemes to protect urban dwellers from dust stress.

Getting the message right on nature‐based solutions to climate change

“…This may arise in situations where there are benefits to project participants but costs to non‐participants or where a project benefits all members of a community locally but imposes costs to communities elsewhere (Chausson et al, 2020). For example, an urban shelterbelt in China protects city‐dwellers from dust storms, but Uighur communities downstream suffer because the heavy irrigation demand of the shelterbelt is drying out the native riparian forests on which they depend (Missall et al, 2018).…”

“…Conversely, if non‐native tree plantations replace intact native ecosystems such as ancient grasslands, peatlands or woodlands, the outcomes for biodiversity will be poor (Balthazar et al, 2015; Barlow et al, 2007; Bond, 2016; Bremer & Farley, 2010; Stephens & Wagner, 2007). Native biodiversity can also suffer if exotic species used in plantations become invasive (García‐Palacios et al, 2010), over‐dominant (Yu et al, 2012) or reduce water supplies (Missall et al, 2018).…”

Biodiversity outcomes of nature-based solutions for climate change adaptation: Characterising the evidence base

“…Of these three, there were six negative climate impact outcomes overall with two being for timber production and two being for water availability. For example, plantations of non-native tree species in China established to protect towns from dust storms resulted in loss of native shrubland and over-abstraction of water for irrigation, leading to the loss of 8,000 ha of native forest downstream (Missall et al, 2018). Supplementary Table S4 provides further specific examples of associations between ecosystem health and adaptation outcomes; Supplementary Table S5 gives more details on the types and directions of adaptation outcomes for interventions in this study.…”

The Future of Water Management in Central Asia

“…Two articles [18,19] look at the use of tree shelterbelts vs. natural riparian forests in urban areas and tree shelterbelts to improve water management. Missall et al [18] perform a sustainability assessment of the Kökyar Protection Forest in NW China (Tarim River Basin). This area is prone to dust and sand storms with detrimental effects on human health.…”