Such stupidity, arrogance and ignorance continues to appall me! F**king trees have been planting themselves for squillions of years without the help of green-tinged do-gooders!!! Cordon off any piece of land in Britain and it will revert to woodland. This process is called 'natural succession' and needs no human intervention (except, these days, the initial cordoning off). Where I live there are plantations from the 1970s and 1980s next to woodland that has re-generated naturally. The natural woodland is strong, vigorous and healthy whereas the spindly trees in the plantations blow down in the slightest breeze, because they have weakened root systems. Nevertheless, the local authorities have chopped down the naturally re-generated trees - and plan to chop down more. They then promise to plant more trees to replace those that they have already, or plan to, chop down! When I mentioned this to one of the culprits he said, "oh, they're just self-seeded" - a very revealing remark!

Plantations are usually very poor in biodiversity terms and very often replace and destroy much more biodiverse (and increasingly rare) native grassland. In addition a plantation is not, in any way, equivalent to the complex eco-system which is an ancient wood. The former bears about as much relation to the latter as a coat of whitewash does to a fresco by Michaelangelo.

In my opinion people who think that planting trees (or, God help us, 'wild flowers') is a 'good thing' are part of the problem. Evil, greedy, f**king developers promise to plant trees to 'mitigate' for their depredations ("We're going to plant some trees" is shorthand for, "we don't give a f**k!").

If you really want to increase biodiversity, venture out of your armchair and go out and really look at the world around you, and learn to identify the other living things that we share it with.
Only if we really know what is in our local environment, and how it is changing over time, can we have any hope of conserving those things which make it unique.