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

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.

Species and structural diversity of trees at the structural type level

“…Although the concept and characterisation of biodiversity have been widely discussed [ 12 , 13 , 16 , 43 ], surprisingly little is known about the spatial characteristics of biodiversity at forest stand scales [ 31 , 44 ]. In many montane tropical and subtropical forests, even small forest patches may exhibit high structural complexity and a range of growing conditions [ 45 ], and biodiversity at each scale is very high [ 15 , 25 , 36 , 38 ].…”

“…The relationship between species diversity and mixture can be modelled using exponential or linear functions. [ 63 ] integrated the number of tree species per structural unit into simple mingling formula (Table 2 ), and [ 31 ] integrated the stand spatial structure parameters into diversity indices to evaluate tree spatial diversity. Together with our results, these studies demonstrate that species diversity is closely related to the structure of neighbouring trees.…”

Selection of the Optimal Timber Harvest Based on Optimizing Stand Spatial Structure of Broadleaf Mixed Forests

“…Zhao et al [23] show that the uniform angle index showed a small trend of increasing and decreasing over time because the long-term natural regeneration of the stand resulted in the distribution of trees in some plots tending towards an aggregated distribution. Peet et al [37] show that the competitive pressure between trees increased, and the trees growing in a more competitive environment had a higher mortality with the tree growth.…”

“…The diameter class diversity dominance index mainly reflects the dominance of the richest diameter class distribution. The evenness index is mainly used to describe the evenness of the range distribution of different diameter classes [23,24]. In this study, the Margalef, Shannon and Simpson indices, and Pielou and Simpson evenness indices were selected to describe the diameter class diversity change rule to reflect stand structure diversity [25,26] (Table 4).…”

Gestión forestal para la adaptación al cambio global. Evaluación de tratamientos selvícolas para la diversificación y regeneración de masas de repoblación

“…Las claras son tratamientos que, según su tipo, pueden promover la diversificación estructural de forma rápida. Las claras por lo bajo, al eliminar el estrato dominado, tienden a disminuir la diversidad estructural de la masa justo después de la intervención (Zhao et al, 2022), sin embargo, otros trabajos, como el de Gauthier et al (2015), muestran que con el paso del tiempo también pueden suponer un estímulo a la diversidad estructural del rodal. El peso de la clara por lo bajo también tiene un efecto, que para Montes et al (2004) fue específico para cada una de las especies estudiadas, pues las claras fuertes promovieron una mayor diversidad estructural en montes bajos de Quercus pyrenaica Willd., mientras que fueron las débiles las que lo consiguieron en los de Quercus faginea Lam.…”