Empirical Estimates of Aboveground Carbon in Open Eucalyptus Forests of South-Eastern Australia and Its Potential Implication for National Carbon Accounting

Liubov Volkova,Christopher Weston,Huiquan Bi,Simon Murphy

doi:10.3390/f6103395

Abstract

The aboveground carbon (AGC) storage of open Eucalyptus forests is unknown yet they are estimated to account for almost 25% of all Australian forests and about 60% of forests in Victoria. In this study we provide the best possible estimates of total AGC including tree biomass derived from destructive biomass sampling across 23 study plots established in open Eucalyptus forests in Victoria. The field estimates of AGC were then used for calibration of Australia’s National Carbon Accounting Model, FullCAM. The study aimed to develop a transparent and defendable method to estimate AGC for one of the most common Australian forests. Our calibrations showed that the 8.3 M ha of open Eucalyptus forests of SE Australia sequester at least 139 Mt C more than default FullCAM predictions. Because most of these forests are not subject to human-induced emission such as harvesting, only emissions and stock changes from a small area of these forests is reported in national inventories and international greenhouse emissions agreements. Concern for climate change and emission reduction will inevitably require land managers to come up with defendable methods of estimating forest carbon stocks and changes in all forest types; here we show how FullCAM can be further developed for this purpose.

Highlights

Forests play a crucial role in the global carbon cycle so that maintaining and building forest carbon is central to limiting carbon emissions to the atmosphere from the biosphere.Developing transparent and accurate methods to estimate carbon stocks and changes is challenging because of the variability in forest carbon at a landscape scale, coupled with limited empirical forest biomass and soil carbon observations with which to build and to validate models.In south-eastern (SE) Australia, medium open Eucalyptus forest extends over 8.3 M ha [1] and constitutes a significant and important carbon stock that is subject to change through altered wildland fire regimes, and forest management activities including timber extraction, prescribed fire and afforestation of previously cleared land [2]
To improve estimates of forest carbon stocks the overall objectives of this study were: (1) to estimate total aboveground biomass of medium open Eucalyptus forest including destructively sampled biomass of overstorey and understorey trees and forest floor debris; (2) to develop a generic allometric equation for understorey trees that can be applied across medium open Eucalyptus forests of SE Australia; and (3) to calibrate the default tree yield formula of FullCAM based on our field biomass measurements
We provided one of the most accurate estimates of aboveground biomass (AGB) for medium open Eucalyptus forests currently available in the literature

Summary

Introduction

Forests play a crucial role in the global carbon cycle so that maintaining and building forest carbon is central to limiting carbon emissions to the atmosphere from the biosphere.Developing transparent and accurate methods to estimate carbon stocks and changes is challenging because of the variability in forest carbon at a landscape scale, coupled with limited empirical forest biomass and soil carbon observations with which to build and to validate models.In south-eastern (SE) Australia, medium open Eucalyptus forest (i.e., crown cover >50%–80%and stand height >10–30 meters) extends over 8.3 M ha [1] and constitutes a significant and important carbon stock that is subject to change through altered wildland fire regimes, and forest management activities including timber extraction, prescribed fire and afforestation of previously cleared land [2]. Forests play a crucial role in the global carbon cycle so that maintaining and building forest carbon is central to limiting carbon emissions to the atmosphere from the biosphere. Developing transparent and accurate methods to estimate carbon stocks and changes is challenging because of the variability in forest carbon at a landscape scale, coupled with limited empirical forest biomass and soil carbon observations with which to build and to validate models. Separate estimates of forest carbon stock (e.g., [3,4]). Human-induced changes to carbon stock [5] have been published for the State of Victoria, there is no validation of these predictions with independently derived field observations. A wide range of approaches to estimate forest carbon stocks and changes has been developed within national and state jurisdictions around the world.

Objectives

Methods

Results

Discussion

Conclusion