Carbon in Mature Native Forests in Australia: The Role of Direct Weighing in the Derivation of Allometric Equations

Abstract

Accurate estimates of forest biomass are essential to understand the contribution of forests to climate change mitigation efforts. In this manuscript, we report on biomass determinations for 586 directly weighed trees located in three important native forest areas in Australia. The sites were paired according to management strategy; i.e., managed for periodic cycles of harvest or conservation only. The key aim of the work was to test whether non-site specific available biomass relationships are reliable, especially in the estimation of the biomass of trees with a large diameter at breast height (DBH). The above-ground carbon (AGC) estimates for largely undisturbed forests ranged from approximately 200-400 t C ha −1 . Existing allometric equations were generally poor at estimating biomass for mature trees, especially those of large DBH. Direct weighing of biomass ensured a degree of certainty in the results that cannot be associated with previous studies that relied on sub-sampling, or with studies that relied on existing allometric equations. Thus, caution should be exercised when interpreting the results of previous studies that did not rely on direct weighing of the biomass in the context of decisions around optimum forest management regimens, and the contribution of mature forest stands to the global carbon balance.

A Permian nurse log and evidence for facilitation in high-latitudeGlossopterisforests

“…2A), estimated the living, above‐ground biomass at 146–400 Mg/ha (depending on the method used) and the basal area 65–80 m 2 /ha (Miller et al 2016). These values fall within the range of estimates for some mature temperate rainforests of Australia, Europe and North America (Balian & Naiman 2005; Keith et al 2009; Jacob et al 2013; Ximenes et al 2018). Combined with previous data on growth ring anatomy (Creber 1990; Francis 1994; Taylor & Ryberg 2007), these results show that the productivity of late Permian high‐latitude glossopterid forests was similar to modern forests in temperate regions.…”

Towards a Carbon Accounting Framework for Assessing the Benefits of Biogenic Wood Carbon to Net Zero Carbon Targets

“…Approaches are spatial accounting boundaries delineated for HWP C estimation, i.e., they constitute the different ways of delineating HWP carbon stocks and flows, either at national or subnational unit levels [5,19]. Approaches delineate the different components of carbon stocks or flows included in or excluded from HWP C estimation [7,30]. Examples of components included or excluded from different approaches may include in-region or out-region production and consumption of HWPs, emissions associated with HWP production and consumption, and substitution effects of in-region or out-region production or consumption of HWPs, etc.…”

“…Despite having HWP carbon reported over the years nationally and globally under the Kyoto Protocol (KP) and the United Nations Framework Convention on Climate Change (UNFCCC), carbon stored in HWPs is still either poorly accounted for and/or under-reported [3,[30][31][32]. While carbon stored in harvested wood products was previously assumed to be oxidized in the biomass harvest year [3,32], others do not have sufficient data to appropriately quantify the carbon stored during HWP use phase and in HWPs discarded in SWDS [10,19].…”

Allometric Equations to Estimate Aboveground Biomass in Spotted Gum (Corymbia citriodora Subspecies variegata) Plantations in Queensland

“…Several allometric models for estimating forest biomass have been established worldwide, and there are over 400 models for biomass estimation in natural forests and plantations in Australia [3,15]. The majority of these estimates were developed for natural forests such as those dominated by Eucalyptus species [3,[16][17][18][19][20][21]. Biomass datasets derived through destructive sampling for spotted gum (CCV) are relatively rare and have not been published in Queensland.…”