I am struggling to find defined guidance anywhere on when woodland becomes ‘Lowland Mixed Deciduous’ Priority habitat (HPI) and when it is just non-priority habitat woodland. I get that if woodland has just been planted and is clearly plantation it is not semi-natural and would be unlikely to qualify as HPI but where is the transition to HPI?
For example, if I am looking at an area of woodland with a fairly developed understory and a diverse mixture of broadleaf trees, however the canopy trees are all of similar age and height and planting lines can still be seen (although maybe not immediately obvious), does this still classify as Lowland Mixed Deciduous woodland priority habitat?
Presumably you have seen this https://data.jncc.gov.uk/data/2829ce47-1ca5-41e7-bc1a-871c1cc0b3ae/UKBAP-BAPHabitats-30-LowlandMixedDecWood.pdf
But that does not really answer your question.
It may be a mixture of age, species composition and history i.e. the trees may not be very old but the site might have been deciduous for a long time. Hopefully there is some account taken of the whole ecosystem not just the trees as the soil ecosystem may take a lot longer to replace than the trees.
Yea that all sounds sensible, from what I can gather it all seem down to a bit of intuition if something looks ‘semi-natural’ or like a plantation. A lot easier to decide if you start finding ancient woodland indicators and there is a complex ground layer but I’m finding it harder to make the call when the ground layer is dominated by bramble/bracken which could be an example of W10 woodland or equally could have spring up in a relatively short amount of time
