Friends of the Earth has organised a lobby of councillors across the country asking them to support doubling of tree cover. I support that objective. We must plant trees to create a carbon reservoir to slow climate change, boost wildlife and improve public health. But should it be a wave of small woodland schemes or a huge project like a Marches National Forest? We must get this right. That means selecting the right species of trees, ensuring we have enough skilled arboriculturists to manage woodland, planning for public access and ensuring a market for the harvested timber. Timber is a long term crop, so we must ensure that tenants and landowners have the right incentives and support. Trees must be planted in biodiversity poor areas, not those rich in wildlife or already storing carbon.