GIS-Based Watershed Unit Forest Landscape Visual Quality Assessment in Yangshuo Section of Lijiang River Basin, China

Abstract

The Yangshuo Section of the Lijiang River Basin (YS of LRB) is the essence of the Guilin landscape in China. The typical karst landforms and changing topography form a unique forest landscape in YS of LRB. In order to reveal the visual quality of itse forest landscape, this research used GIS spatial analysis technology combined with Analytic Hierarchy Process (AHP), the assessment factors were leveled and assigned, and some abstract assessment indicators in the visual quality assessment were quantified. Three primary indicators of forest landscape visual quality (FLVQ) assessment in YS of LRB, including Scenic Quality (SQ), Visual Sensitivity (VS), and Visual Absorption Capability (VAC), are proposed. Visual assessment units are divided based on the watershed, and a process and framework for the comprehensive assessment of FLVQ was established at the watershed scale. The results show that the FLVQ in YS of LRB is generally at a low level. The area percentage of FLVQ at high (13′&11′), medium (9′) and low (7′&5′) levels are 10.95%, 29.67% and 59.38%, respectively. The comprehensive score of FLVQ in the karst area is slightly lower than that in the non-karst area, but the karst area of the units with the highest FLVQ accounts for 99.58% of the FLVQ of karst areas along the Lijiang River distributed in the Lijiang River Scenic Area, greater than that of any other areas. The FLVQ in regions with high vegetation coverage and large topographic changes is relatively higher. Slope, relief amplitude, and vegetation richness directly affect the visual quality of forest landscape. Under the influence of local scenic area protection policies and relatively stable natural climate, the FLVQ in YS of LRB has maintained a stable level in the past 20 years. The areas with low FLVQ are mainly cultivated land and construction land, which have low vegetation coverage and no obvious change in terrain. Based on the comprehensive assessment results of FLVQ in YS of LRB, the management goals and future development suitability of forest landscape is discussed. This research proposes appropriate construction and management strategies for forest landscape structures. The results are helpful for providing a scientific research basis for forest landscape resource conservation, landscape site selection, and forest ecotourism development in the Karst landscape area. The impact of human disturbance on the forest landscape fragmentation and the growth characteristics of forests under different landforms are the focus of future FLVQ research on similar areas.