A Novel Comprehensive Evaluation Method of Forest State Based on Unit Circle

Abstract

Comprehensive evaluation of forest state is the precondition and critical step for forest management. To solve the problem that the radar plot and unit circle only focus on the value of each the evaluation index, this paper proposes a novel method for comprehensively and simultaneously evaluating the functionality and inhomogeneity of forest state based on the modified unit circle method. We evaluated the forest state of the Quercus aliena BL. var. acuteserrata Maxim. ex Wenz. broad-leaved mixed forest in the Xiaolong Mountains Forest Area of Gansu Province and the Pinus koraiensis Sieb. et Zucc. broad-leaved mixed forest in Jilin Province in China. According to the principle of comprehensive, scientific and operability, 10 evaluation indices on forest structure and vitality were selected to construct the evaluation indicator system. Each index was normalized based on the assignment method and ensured to be strictly positive based on reciprocal transformation method. The areas and arc length of the closed graph, formed by connecting every two adjacent indicators, in the radar plot and unit circle were extracted. Based on the isoperimetric theorem (isoperimetric inequality), a comprehensive evaluation model was constructed. Compared with radar chart and unit circle method, each index in the newly proposed unit circle method is represented by an independent sector region, reflecting the contribution of the index to the overall evaluation result. Each index has the same relative importance weight, contributing to the estimation the relative sizes of each aspect of forest state. The unique area and arc length of the closed graph help summarize the overall performance with a global score. The expression effect of improved unit circle has been enhanced, and as an English proverb put it, “A picture is worth a thousand words.” The new proposed method simultaneously evaluates the functionality and inhomogeneity of the forest state and it is a powerful tool for the diagnosis of forest state problems and the decision-making of forest management.

Stand spatial structure and productivity based on random structural unit in Larix principis‐rupprechtii forests

“…The equal central angle of each sector ensures that all indicators have the same relative importance, eliminating the uncertainties associated with methods like radar charts, which depend on the number of indicators (Frank et al, 2015). Additionally, it resolves the inconsistencies linked to indicator order found in the unit circle approach (Zhang et al, 2018), thus providing a more judicious assessment of the actual stand state. Moreover, the combination of FSSI and the enhanced unit circle method can intuitively reflect and evaluate the strengths and weaknesses of the stand spatial structure, providing valuable guidance for optimizing stand spatial structure.…”

“…This approach advances our comprehensive evaluation of stand spatial structures. For complex forestry resource data, visualization tools like radar charts and unit circles augment our comprehension and receptivity of the evaluation insights (Zhang et al, 2018).…”

Stability and Spatial Structure of Chinese Pine (Pinus tabuliformis Carr.) Plantations in Loess Hilly Region: A Case Study from Huanglong Mountain

“…The unit circle method maps the stability value of an indicator to the square of its standardized value [21]. If the standardized value is 0.5, its mapped stability value is 0.25, while values corresponding to standardized values of 0 and 1 remain 0 and 1, respectively [22]. This non-linear mapping approach underscores the significance of attaining optimal performance in each indicator aspect rather than relying on their interchangeability.…”

“…This non-linear mapping approach underscores the significance of attaining optimal performance in each indicator aspect rather than relying on their interchangeability. Given the method's underlying mechanics and its advantages in visualization, it has become a widely employed tool in comprehensive evaluation [22]. Similarly, it holds promise for infusing fresh vigor into the stability assessment of plantations.…”

Performance Evaluation Metrics and Approaches for Target Tracking: A Survey

“…This paper focuses on the performance evaluation (PE) of target-tracking algorithms, which plays a key role in the comparison of existing algorithms and in putting forward a new algorithm. PE is referred to the assessment and the evaluation of various performance metrics of a system [ 13 , 14 ], whose significance lies in providing evaluation results of the system performance [ 15 ], as well as the reference basis for the optimization of the system performance.…”