There is more to add to your piece on nature and mental health (27 March, p 36). First, protected areas worldwide have an economic value in terms of mental health, estimated by research that I was involved in at US$6 trillion per year. Second, national parks and other biodiverse ecosystems improve mental health much more than urban green spaces. Third, health insurers in the US, the national health services in the UK and a mental health charity in Australia already include nature therapies in mainstream mental healthcare. The links between nature and mental health thus go far beyond urban planning and green prescriptions. They provide new political support for protected areas, and an avenue for global mental health rehabilitation after the pandemic.