But, 'Emma B', as I noted above, planted trees are NOT (my caps) a replacement for ancient woodland. To repeat what I said before a plantation of trees (yes, even native ones) bears about as much relation to an ancient wood as a coat of whitewash does to a Michaelangelo frescoe. An ancient wood is a complex eco-sysytem - not just a collection of trees - and has evolved over a long period of time. Basically, you can't replace it - once it's gone it's gone - at least for the forseeable future.

Near to my home town there is a site which was clear-felled around 60 or 70 years ago (around the time of the 2nd World War) - but there was enough of the eco-system left (fungi, insects etc.) for the ancient wood to re-establish itself when the trees re-grew from their stumps and through natural succession. Note that in many ancient woods, in the UK, many trees were 'coppiced', i.e. cut down to ground level every 7 to 10 years, whilst a few others were left as clean, straight trunks to provide future building timbers etc. The coppiced trees regrew as a collection of poles, rather than as single trunks. The poles were used for tool handles, fences etc. This appears to have been going on for thousands of years because prehistoric trackways in wetlands, like the Fens or the Somerset Levels, appear to have been made from coppice poles.
Usually ancient woods weren't clear-felled, like the one above, but divided into compartments which were coppiced in rotation.

In spite of all the losses organisations like the National Trust and the Woodland Trust have saved a lot of ancient woods in the last few decades (and some are even being coppiced). Nevertheless, there are habitats which are even more endangered than ancient woodland - and these include wetlands and unimproved grassland. In fact, George Peterken, probably Britain's greatest woodland ecologist, has said that the priority now is grassland - not woodland.

SRS - I hope that you enjoy the Rackham book. Be warned though; although he's a serious academic, once you have read any of his books it is likely that you will never see the world around you in the same way again.