The Environment

Tree planting is not really a solution, it is slow, time consuming, expensive an prone to failure.
I reckon through my work over 25 years I've planted a few thousand, but where I have had far more success is letting trees grow.
All the major forests woodlands and jungles and mangroves are naturally occurring.
The best thing we can do is get our councils to identify bits of their land (unless we own some space ourselves) and ask them to leave it to nature. (i.e. stop mowing the grass)
Trees quickly grow, but the councils are worried about public perception. So if we all just keep asking we could make a huge difference. At the moment most councillors get letters about the grass not being cut.
By way of illustration heres a photo and a story. The massive tree was diseased and over a few years it died. The council planted a replacement in the shadow of the old one, and it immediately succumbed to the same disease. But 22 seedlings of 6 different species sprung up where the tree had shaded the ground before. They have needed no watering, no intervention, are disease resistant and completely free.