I fail to see how you can propose the use of timber as a sustainable material (“How green is your brand?”, 12 April, building.co.uk). It takes many years for a tree to grow, unless it is of a pine variety

The decimation of the rainforests owing to human expansion is bad enough for the environment without encouraging the wider use of timber in building. Before you know it the only trees we will have will be pines, the ground will turn acidic and few things will grow. Where will the world be then?

Sustainability isn’t about saving the planet, it’s about coal and oil running out and finding something to replace them.

Trevor Bettell, via www.building.co.uk