Dr Corbett raises some excellent points in his letter to the editor last Friday, with regard to Forest and Bird's involvement in mangrove removal in the Tauranga harbour.
In 2009 Forest and Bird opposed the Regional Council's application to remove mangroves in the harbour using a mulching machine. Amongst other matters we believed that money spent on mangrove removal would be better spent on addressing the causes of increased mangrove distribution, i.e. sedimentation and nutrification of the harbour.
In December 2010 we raised concerns that the mulched mangrove left behind was not dissipating and was smothering seabed fauna. In addition the mulched areas were not recovering as anticipated and nutrients trapped in the substrate below the mangroves may be escaping to the harbour.
We suggested that the council take a precautionary approach and trial alternative removal methods on a small scale combined with comprehensive monitoring. The council chose to trial some alternative methods of mangrove removal while concurrently removing more mangroves using the mulching machine.
The alternative removal methods were not adopted by the council.
We continue to monitor the effects of mangrove removal in Tauranga harbour including the recent monitoring results undertaken by the council and proposals to spend significant amounts of money on mangrove stump areas and seedling removal within the mulched areas and other areas of the harbour.
We also maintain our dialogue with the National Institute of Water and Atmosphere who are undertaking a comprehensive research study of mangrove removal within the Tauranga harbour as part of a 6 year Foundation for Research, Science and Technology funded research project.
Forest and Bird are focusing on solutions to sedimentation and nutrification of the harbour as part of its Kaimai Mamaku Campaign and are positively engaging with the Manaaki Taha Moana research project and the Bay of Plenty Regional Council, Waikato Regional Council and DOC Kaimai Catchments Project.
Forest and Bird successfully opposed a proposal to remove all mangroves within the Mangawhai harbour in Northland recently and have submitted a submission in opposition to the proposed removal of mangroves in Whangamata harbour.

Al Fleming, Forest & Bird
Central North Island Field Officer.