Understanding 3D structural complexity of individual Scots pine trees with different management history.

Ninni Saarinen,Samuli Junttila,Tuomas Yrttimaa,Saija Huuskonen,Jari Hynynen,Kim Calders,Ville Luoma,Ville Kankare,Hans Verbeeck

doi:10.1002/ece3.7216

Abstract

Tree functional traits together with processes such as forest regeneration, growth, and mortality affect forest and tree structure. Forest management inherently impacts these processes. Moreover, forest structure, biodiversity, resilience, and carbon uptake can be sustained and enhanced with forest management activities. To assess structural complexity of individual trees, comprehensive and quantitative measures are needed, and they are often lacking for current forest management practices. Here, we utilized 3D information from individual Scots pine (Pinus sylvestris L.) trees obtained with terrestrial laser scanning to, first, assess effects of forest management on structural complexity of individual trees and, second, understand relationship between several tree attributes and structural complexity. We studied structural complexity of individual trees represented by a single scale‐independent metric called “box dimension.” This study aimed at identifying drivers affecting structural complexity of individual Scots pine trees in boreal forest conditions. The results showed that thinning increased structural complexity of individual Scots pine trees. Furthermore, we found a relationship between structural complexity and stem and crown size and shape as well as tree growth. Thus, it can be concluded that forest management affected structural complexity of individual Scots pine trees in managed boreal forests, and stem, crown, and growth attributes were identified as drivers of it.

Highlights

Forests are the largest terrestrial ecosystem covering one third of the earth's surface area (Roxburgh and Noble, 2013), and they provide a range of services such as carbon uptake (Hardiman et al, 2011), productivity (Puettmann et al, 2015), biodiversity (Fedrowitz et al, 2014), and resilience (Messier et al, 2013)
Possibilities for forest management in considering these more varied objectives are acknowledged, but objective measures of structural diversity have been lacking as 3D information on structure of forests and trees has practically been unavailable before various laser scanning sensors
This study provides an example how structural complexity of individual trees can be quantitatively assessed and how it is affected by forest management

Summary

Introduction

Forests are the largest terrestrial ecosystem covering one third of the earth's surface area (Roxburgh and Noble, 2013), and they provide a range of services such as carbon uptake (Hardiman et al, 2011), productivity (Puettmann et al, 2015), biodiversity (Fedrowitz et al, 2014), and resilience (Messier et al, 2013). Objective and quantitative measures for structural complexity of individual trees are needed to better understand relationship between forest structural diversity and ecosystem services such as biodiversity, productivity, and carbon uptake (Hardiman et al, 2011; Messier et al, 2013; Puettmann et al, 2015; Zenner, 2015)

Objectives

Findings

Discussion

Conclusion