A new clash over carbon emissions will decide a crucial Senate vote on the federal government’s climate change bill in an attempt by crossbench senators to strike down rules that offer financial rewards to schemes that claim to help the environment by planting trees. Climate Change Minister Chris Bowen declared on Sunday he was “very, very confident” the government would gain the numbers in the upper house to pass the bill and its 43 per cent emissions reduction target, but he is yet to secure the crossbench support needed for a majority. The latest pressure point is a row over rules in parts of the $4.5 billion Emission Reduction Fund that offer Australian Carbon Credit Units to rural projects that develop new plantations or plant new trees to replace timber cleared from existing plantations. Senators including David Pocock want to halt changes to rules because the projects may not deliver the promised results.