A Novel Method for Calculating Stand Structural Diversity Based on the Relationship of Adjacent Trees

Yanbo Hu,Gangying Hui,Gongqiao Zhang,Wenzhen Liu,Zhonghua Zhao

doi:10.3390/f13020343

Yanbo Hu, Gangying Hui + Show 3 more

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https://doi.org/10.3390/f13020343

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Abstract

Understanding the diversity and complexity of stand structure is important for managing the biodiversity of forest ecosystem, and stand structural diversity is essential for evaluating forest management activities. Based on the relationship of adjacent trees, a quantitative method of stand structure diversity is proposed to express the heterogeneity of stand structure in tree species, distribution pattern, species separation and size differentiation. In this study, we defined the diversity of structural unit types and derived a new index of forest structural diversity (SD′) employing the additivity principle of the Shannon–Weiner index. The efficiency of the index was verified by applying the new measure to sixteen field survey samples at different locations. The mountain rainforest in Hainan had the highest forest structural diversity, followed by broad-leaved Korean pine forests in Jiaohe (2), Jiaohe (1) and an oak-broadleaved mixed natural forest at Xiaolongshan (2). The SD′ values of plantations and pure natural forest were lower. The simulated data of different thinning methods and the intensity of broad-leaved Korean pine forests show that the new measure can reflect forest management changes on stand structure diversity. The value of SD′ compared with no treatments and the differences were greater as thinning intensity increased. The SD′ index provides minimum and maximum values for different structural unit types in forests to achieve a unified comparative basis for calculating forest structure diversity. It has the characteristics of the general diversity index and can well express the diversity of tree species, distribution pattern and size differentiation simultaneously. The SD′ index can not only calculate the structural diversity of mixed species forests but can also be used to calculate the structural diversity of pure forests. It can also be used to evaluate the change in stand structure diversity after management interventions.

Highlights

Forest structure is the driver for forest growth and ecological processes and the result of forest dynamics and biophysical processes, and at the same time, forest structure is directly linked to forest ecosystem goods and services [1]
The plots we analyzed in this study covered different forest types from cold temperate natural pure forest to tropical species-rich montane rainforest, including several plantations (Table 3)
The number of tree species in the plots decreased with increasing latitude from tropical montane rainforest (Jianfengling, plot 1) to cold temperate natural pure forest (Honghuaerji, plot 9 and plot 10), and the number of tree species ranged from 1 to 84 in the plots

Summary

Introduction

Forest structure is the driver for forest growth and ecological processes and the result of forest dynamics and biophysical processes, and at the same time, forest structure is directly linked to forest ecosystem goods and services [1]. As the basic study unit of forest structure, stand structure comprehensively reflects forest development processes, such as regeneration patterns, plant interaction, self-thinning and disturbances [2]. The larger the variation of size or age structure, the more complex the stand structure, the greater the diversity of niche or food that can maintain various animals and plants and microorganisms, and the higher the overall biodiversity of the stand [3,4]. Stand structure plays an important role in, and is affected by, management activities such as harvesting, thinning, controlling competing ground vegetation and planting [5]. Increasing the diversity and complexity of stand structure is the foundation of, and an effective approach for, maintaining and increasing forest ecosystem biodiversity [6,7,8]. Some forest management methods have begun to focus on improving the diversity of forest structure such as near-natural forest management (NNFM) [9,10] and structure-based forest management (SBFM) [11]

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