Guilin’s Forests Reveal Hidden Economics of Nature’s Benefits

Guilin, in southern China, is famous for its limestone peaks and the Li River, but a new study treats the region as something more than a postcard: a laboratory for measuring what nature actually delivers to people. Researchers from Shanxi Agricultural University, Guangxi Minzu University, and Guangxi University have built an integrated framework that quantifies three broad classes of ecosystem services—provisioning, regulating, and cultural—across the 27,800 square kilometers of this forest-rich, karst-dominated landscape, and then measures how well those services work together. The work, published in Frontiers in Forests and Global Change, offers one of the most complete attempts yet to put a price tag on the intangible benefits of forests and to map them in space.

The study area is ideal for such an experiment. Guilin has a forest coverage rate of 75 percent and a population of 4.93 million, and its terrain weaves rivers, forests, grasslands, and karst peaks into a mosaic that is both ecologically fragile and culturally celebrated. The team classified services using the Common International Classification of Ecosystem Services (CICES), selecting indicators that reflect the combined influence of abundant forest and karst conditions: water yield and grain supply for provisioning services; soil conservation, carbon stock, and habitat quality for regulating services; and, for cultural services, aesthetic information, recreation and well-being, natural and cultural heritage, and biodiversity value.

Provisioning and regulating services were quantified with the InVEST model, a widely used tool that simulates ecosystem processes at fine spatial resolution. Water yield was calculated from precipitation, actual evapotranspiration, soil water retention, and karst leakage processes; grain supply was derived from total grain production weighted by the Normalized Difference Vegetation Index. Soil conservation was estimated with the Sediment Delivery Ratio module, carbon stock by summing above-ground, below-ground, soil, and dead organic carbon pools, and habitat quality by modeling habitat suitability against threat factors such as urban expansion and agricultural intensity. All raster datasets were resampled to a consistent 30-meter resolution in Albers Equal Area projection.

Cultural ecosystem services posed the hardest technical challenge, because they are intangible and depend on human perception. The researchers combined two complementary methods. First, they ran a discrete choice experiment (DCE), a stated-preference technique grounded in random utility theory, in which 600 valid respondents—297 urban and 303 county-town and rural residents, with a 97.09 percent valid response rate—chose among hypothetical improvement scenarios. Attributes included vegetation cover and water transparency for aesthetics, ecological trails and parks for recreation, protected heritage sites, IUCN Red List species counts, and payment tiers of 50 to 200 yuan. An orthogonal design in SAS 9.4 reduced the theoretical 243 alternatives to 18 choice scenarios organized into 6 choice sets, with a D-efficiency of 92.53 percent. Second, participatory geographic information systems (PPGIS) asked respondents to mark on a map the places they associated with specific cultural benefits, allowing the monetary values to be spatially visualized through kernel density estimation.

The results show that aesthetic information commands the highest willingness to pay, reaching a maximum of 978 yuan, and is perceived across most of the landscape. Recreation and well-being has the lowest monetary value but the most widespread distribution, reflecting abundant substitutes. Biodiversity value and natural and cultural heritage concentrate in nature reserves and heritage sites, limiting their spatial extent but attracting relatively high payments per location. When synthesized, cultural services form high-value clusters in the urban districts and Yangshuo County, with persistent value gradients across other counties.

Provisioning services in Guilin are generally at a medium level, higher in the southern and central regions and lower in the north. High-value areas include the urban districts, Lingui, Yangshuo, Lipu, and Pingle, where river valley plains support contiguous cultivated land and strong water yield. Low-value areas cluster in Ziyuan and Longsheng counties, where mountains, karst landforms, and fragmented farmland constrain agriculture. Regulating services are relatively high overall, with a pattern of higher values in the east and west and lower values in the center: mountainous counties excel at soil conservation, carbon storage, and habitat maintenance, while the urban core, with concentrated construction land and population, performs weakest.

To capture how the three service classes interact, the team introduced a spatial analytic geometry model. Each service is represented as a vector force in a three-dimensional space, and the combined effect yields three indices: the total coupling degree (TCD), the coordination deviation degree (CDD), which measures how far actual relationships deviate from perfect synergy, and the coordination transformation degree (CTD), which reflects the comprehensive development level after subtracting trade-offs. At the municipal scale, Guilin records a CDD of 0.236 and a CTD of 0.279—relatively good coordination but suboptimal integrated development. Low CDD values concentrate in the urban districts, Yangshuo, and Quanzhou County, while high CDD areas include Guanyang, Ziyuan, Gongcheng, and Longsheng, where strong regulating services coexist with weak provisioning and cultural services.

Pearson correlation analysis of pairwise interactions revealed a weak positive relationship between provisioning and cultural services (approximately 0.15) and a weak negative relationship between regulating and cultural services (about −0.13). The authors explain that areas with high cultural service values typically experience significant human influence, and such intensive activity often degrades regulating functions. The mismatch between where services are produced and where they are valued also raises questions of equity: northern mountainous areas shoulder heavy ecological conservation burdens but capture limited development benefits, while the urban core and Li River corridor profit from tourism yet pressure ecosystems.

A spatial econometric analysis identified the drivers behind the CTD. A Moran’s I index of 0.2178 confirmed spatial correlation, and the LM-lag test supported a spatial lag model. Temperature (coefficient −6.239, p < 0.001), terrain ruggedness (−1.816, p = 0.002), population density (−0.814, p = 0.042), and industrial structure (−0.210, p = 0.073) exert significant negative effects, while forest coverage (0.123, p = 0.081) and GDP (0.710, p = 0.055) show positive effects. High temperatures intensify evapotranspiration, reduce crop yields and water supply, accelerate organic matter decomposition, and suppress outdoor recreation. Karst terrain fragments habitats and shallow soils limit agriculture. Tourism-dominated economies occupy farmland, harden surfaces, and commercialize landscapes, eroding cultural authenticity.

The study proposes a transferable framework for other forest-rich regions, structured as a core classification plus local modules that adapt cultural service attributes to regional landscapes and traditions. Policy recommendations include strengthening grain production in Pingle and Quanzhou, protecting farmland during urban expansion through transfer of development rights, building sponge city infrastructure and ecological shelterbelts to improve soil conservation, restoring degraded forests within ecological red lines, and establishing cross-regional ecological compensation. For cultural services, the authors suggest digital heritage maps, refined management of tourism hotspots like Yangshuo and the Longji Rice Terraces, permeable trail materials, and community co-management. The ultimate goal is to raise the comprehensive development level of ecosystem services while preserving the delicate balance between Guilin’s celebrated scenery and the ecological processes that sustain it.

Subject of Research: Ecosystem services

Article Title: Assessment of multiple ecosystem services and interrelation-ships in Forest-rich regions: a case study of Guilin, China

Article References: Kang, Q., Chen, Z., & Huang, C. (2026). Assessment of multiple ecosystem services and interrelation-ships in Forest-rich regions: a case study of Guilin, China. Frontiers in Forests and Global Change, 9, Article 1815737. https://doi.org/10.3389/ffgc.2026.1815737

Image Credits: AI Generated

DOI: 10.3389/ffgc.2026.1815737

Keywords: ecosystem services, cultural ecosystem services, forests, Guilin, InVEST, discrete choice experiment, PPGIS, spatial econometrics, karst landscape, China, Assessment, multiple