Urban wilderness anyone?

From a comment on an earlier post about some bright spark suggesting Birmingham should be a national park:

I naturally don't agree with creating a new national park there (?) but a rethinking of the value of "brownfield" sites would be welcome, as such sites are often much more ecologically valuable than "greenfield" sites which have been ploughed for decades or centuries; is such a (heavily subsidised) place really worth more than a stand of self-seeding trees along the canal?

I think this is a cracking idea, not only is my commenter (Asquith) spot on about the ecological desert that is agricultural monoculture but a lot of former industrial sites in the urban north (Mr A lives in Stoke, not so very different than Bradford) have no intrinsic value as development land - indeed, in many cases, the cost of remidiation and decontamination vastly exceeds any assumed land value.

Near where I was brought up is the South Norwood Country Park. When I was a kid it was called "the sewage farm". It seems to me that rewilding inner urban areas is not only ecologically valuable but also creates new leisure spaces helping raise the value possibilities of those urban places.

Urban wilderness?
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