Estimating Large Area Forest Carbon Stocks—A Pragmatic Design Based Strategy

Andrew Haywood,Christine Stone

doi:10.3390/f8040099

Abstract

Reducing uncertainty in forest carbon estimates at local and regional scales has become increasingly important due to the centrality of the terrestrial carbon cycle in issues of climate change. In Victoria, Australia, public natural forests extend over 7.2 M ha and constitute a significant and important carbon stock. Recently, a wide range of approaches to estimate carbon stocks within these forests have been developed and applied. However, there are a number of data and estimation limitations associated with these studies. In response, over the last five years, the State of Victoria has implemented a pragmatic plot-based design consisting of pre-stratified permanent observational units located on a state-wide grid. Using the ground sampling grid, we estimated aboveground and belowground carbon stocks (including soil to 0.3 m depth) in both National Parks and State Forests, across a wide range of bioregions. Estimates of carbon stocks and associated uncertainty were conducted using simple design based estimators. We detected significantly more carbon in total aboveground and belowground components in State Forests (408.9 t ha−1, 95% confidence interval 388.8–428.9 t ha−1) than National Parks (267.6 t ha−1, 251.9–283.3 t ha−1). We were also able to estimate forest carbon stocks (and associated uncertainty) for 21 strata that represent all of Victoria’s bioregions and public tenures. It is anticipated that the lessons learnt from this study may support the discussion on planning and implementing low cost large area forest carbon stock sampling in other jurisdictions.

Highlights

Natural forests play a crucial role in the global carbon cycle; as such, maintaining and building natural forest carbon is central to mitigating carbon emissions to the atmosphere from the biosphere.Developing and implementing transparent and accurate methods to estimate natural forests’ carbon stocks and changes is challenging because of the variability at a regional scale, coupled with limited empirical forest biomass and soil carbon observations.In Victoria, Australia, public natural forests extend over 7.2 M ha [1] and constitute a significant and important carbon stock that is subject to change through altered wildland fire regimes, and forest management activities including timber extraction, ecological thinning, and prescribed fire [2]
This paper describes the field protocols, the carbon models, and the methods of obtaining forest carbon stocks using the Victorian Forest Monitoring Program (VFMP)
It is anticipated that the lessons learnt from this study may support the discussion on planning and implementing low cost large area forest carbon stock sampling in other jurisdictions

Summary

Introduction

Natural forests play a crucial role in the global carbon cycle; as such, maintaining and building natural forest carbon is central to mitigating carbon emissions to the atmosphere from the biosphere.Developing and implementing transparent and accurate methods to estimate natural forests’ carbon stocks and changes is challenging because of the variability at a regional scale, coupled with limited empirical forest biomass and soil carbon observations.In Victoria, Australia, public natural forests extend over 7.2 M ha [1] and constitute a significant and important carbon stock that is subject to change through altered wildland fire regimes, and forest management activities including timber extraction, ecological thinning, and prescribed fire [2]. (c) bias assessment for the model-based estimation is missing and/or modelled predictions without independent ground plot observations [4,5,8,11,13]; (d) data and/or models have limited coverage of population [3,8,10,11,12,15]; (e) data excludes some carbon pools such as coarse woody debris and litter [3,6,13]; (f) data excludes some or all of understorey life forms [3,6,13]; (g) ground plot data have inconsistent standards between measurements [8,11,13] In response to this situation, the Victorian Department of Environment, Land, Water and Planning has implemented the Victorian Forest Monitoring Program (VFMP) [16].

Methods

Results

Conclusion