Monitoring standing dead wood for carbon accounting in tropical savanna

Abstract

Changes in the biomass of dead wood can be substantial in tropical woodland and should be included in complete carbon budgets. A recent estimate of biomass changes from long-term, permanent monitoring sites within the eucalypt woodlands of Queensland suggests that carbon accumulated in dead standing wood is similar to the amount of carbon accumulated within live woody biomass. However, this assessment did not include trees that were dead at the commencement of monitoring but have since been burnt or fallen over. Original data are presented from a permanent monitoring site, suggesting that on average 27% of dead standing biomass is consumed per low-intensity fire. The consumption of standing dead wood by fire, together with likely ‘fall-down rates’, could offset a substantial proportion of recently estimated dead standing wood carbon sink. The potential for using existing allometric equations to ascribe biomass to the components of dead standing wood (trunks, branches, bark) on permanent monitoring plots is reviewed. Some valid generalisations can be recognised but a lack of standardisation in allometric studies presents problems. It is suggested that data from survey, monitoring and experiments could drive worthwhile models of dead standing wood biomass. This pool will probably vary substantially through time and space, depending on climatic conditions, fire and termite activity.