Reply to Comment on: 'Burning management and carbon sequestration of upland heather moorland in the UK'

Abstract

In a recent paper (Farage et al. 2009) we reported on the use of rotational burning of heather (Calluna vulgaris) to improve the grazing and habitat, especially for grouse (Lapogus lapogus scoticus), using data collected from a grouse moor in the Yorkshire Dales, UK. The results from this study implied that careful burning management at this site did not have a major detrimental effect on the carbon budget, which for this moor lay within the range of an annual net loss of 34 gC/m per year to a net uptake of 146 gC/m per year. In their comment on this paper, Legg et al. (2010, this issue) responded critically to the findings on the potential effect that heather burning has on the carbon balance. As clearly stated in our paper, the aim of this investigation was to provide some initial data on the impact that rotational burning of upland heather has on the local carbon budget. Many issues surround moorland management, several of which have been fervently debated, including the practice of burning. However, little attention has been given to the effects this has on carbon storage. Our paper set out to address this issue by providing some preliminary analysis. As we emphasised, the research was a small-scale investigation using data from two burns undertaken at just one site. We were focusing exclusively on interpretation in an attempt to provide an initial understanding of the magnitude of the effect that rotational heather burning has on the carbon balance, since at present there is a paucity of information available on this important topic. We acknowledged on several occasions that much more investigation is required both here and at other sites across the region and country. Undoubtedly the quantities of heather lost to burning are potentially subject to variation according to a variety of management practices and the environmental circumstances specific to the locality. Conditions affecting burning of these upland sites can also vary markedly with time, even within a few hours. We illustrated this point with example from the work of Kayll (1966), who, more than 4 decades ago in north-east Scotland, measured above-ground losses of >93% for an autumn burn and <30% for a spring fire. In order to put the potential losses of carbon from burning in context, fluxes from other processes required consideration. This necessitated sourcing calculations from a variety of other studies chosen as carefully as possible to match conditions of our own site. A summary of all these references was provided in the Appendix to the original paper. In order to obtain a complete account, this necessitated using data collected from some locations that were not ideal but nevertheless still provided a useful indication of the likely magnitude involved. Consequently, as we re-emphasised, this highlighted the need for much more additional research to provide more detailed, and in many cases, more appropriate data. We thank Legg et al. for their comments and for presenting the data from their own studies. We concur that this issue deserves highlighting and stimulates the need for further research.