Appendix 4: Correspondence between NWM and HAP types
Table 6 overleaf shows the correlation between NWM types and woodland HAP types. There are several issues of which it is important to be aware when using this table. These are:
- As the NWM does not predict woodland type down to NVC sub-community, there are a few types for which is not possible to determine the equivalent HAP type. E.g. W7b is a wet woodland type, whereas W7a and W7c would be classified as upland mixed ash. In these cases the answer exists within the NVC, but we cannot use the NWM to predict it.
- Some NVC types cannot be converted to single HAP types without further information being available. E.g. W11 and W17 could be classified either as upland oakwood, where oak is (or has been) present, or upland birchwood, where oak is absent. In such cases the answer does not exist within the NVC.
In practice, any uncertainties are unlikely to cause problems. Targeted site survey will identify which HAP type is more likely to develop.
Mosaic and interchangeable types have been classified as follows:
- Type 1 – the NWM type is matched to a single woodland HAP type. E.g. both components of the mosaic W11+W17 fall within Upland oakwood.
- Type 2 – the NWM type could be classified as one of two HAP types. E.g. woodland developing on a site predicted as W11/W9 may be classified as either oakwood or ashwood.
- Type 3 – the NWM type represents a mixture of HAP types. E.g. woodland developing on a site predicted as W18+W4 is likely to be a mosaic of native pine woodland and upland birchwood.
Basin bog woodland/scrub has been classified as wet woodland, but it should be noted that potential tree cover is likely to be very low. Likewise, NWM types for which W4 with open ground is the chief component have been classified as wet woodland or upland birchwood as appropriate, and are also likely to develop very low tree cover.
Table 6. allocation of NWM types to HAP types
| NWM type | BAP |
| W7 Alder-ash with yellow pimpernel | Ash |
| W7+W9 Mosaic | Ash |
| W9 Upland mixed broadleaf with dog’s mercury | Ash |
| W9+W7 Mosaic | Ash |
| W11/W7 | Ash, Oak or mosaic |
| W11/W9 | Ash, Oak or mosaic |
| W11+W7 Mosaic | Ash, Oak or mosaic |
| W7/W11 | Ash, Oak or mosaic |
| W7+W11 Mosaic | Ash, Oak or mosaic |
| W7+W17 Mosaic | Ash, Oak or mosaic |
| W9/W11 | Ash, Oak or mosaic |
| W17/W18 | Birch, Pine or mosaic |
| W17/W18 + W4 Birch (with open ground) Mosaic | Birch, Pine or mosaic |
| W18 + W4 + Peatland with scattered trees/scrub Mosaic | Birch, Pine or mosaic |
| W18/W17 | Birch, Pine or mosaic |
| W18+W4 Mosaic | Birch, Pine or mosaic |
| W4 + W18 Mosaic | Birch, Pine or mosaic |
| W4 Birch (with open ground) + Peatland with scattered trees/scrub + W17/W18 Mosaic | Birch, Wet or mosaic |
| W4 Birch (with open ground)+ Peatland with scattered trees/scrub | Birch, Wet or mosaic |
| W10 Lowland mixed broadleaved with bluebell/wild hyacinth | Mixed broadleaved |
| W10/W8 | Mixed broadleaved |
| W8 Lowland mixed broadleaved with dog’s mercury | Mixed broadleaved |
| W10 + W7 Mosaic | Mixed broadleaved, Ash or mosaic |
| W10/W7 | Mixed broadleaved, Ash or mosaic |
| W7/W10 | Mixed broadleaved, Ash or mosaic |
| W11+W4 Mosaic | Oak, Birch or mosaic |
| W17 Upland Oak-Birch with bilberry/blaeberry | Oak, Birch or mosaic |
| W18 + W11 Mosaic | Pine |
| W18 Scots pine with heather | Pine |
| W18+Peatland with scattered trees/scrub Mosaic | Pine |
| W17+W4 Mosaic | Upland Birchwood |
| W4 + W17 Mosaic | Upland Birchwood |
| W4 Birch (with open ground) + W17/W18 Mosaic | Upland Birchwood |
| W4 Birch with purple moor grass | Upland Birchwood |
| W4 Birch with purple moor grass and open ground | Upland Birchwood |
| W11 + basin bog woodland/scrub | Upland Oak |
| W11 Upland Oak-Birch with bluebell/wild hyacinth | Upland Oak |
| W11/W17 | Upland Oak |
| W17/W11 | Upland Oak |
| Basin Bog woodland/scrub | Wet |
| Basin Bog woodland/scrub + W11 | Wet |
| W6 + W11 Mosaic | Wet |
| W6 Alder with stinging nettle | Wet |
| W7 + Peatland with scattered trees/scrub | Wet |
| W7+W4 Mosaic | Wet |
| Birch/Willow | Other land |
| Built-up land | Other land |
| Developed rural land | Other land |
| Inland Water | Other land |
| Juniper | Other land |
| Other land | Other land |
| Mixed montane scrub | Other land |
| Peatland with scattered trees/scrub | Other land |
| Peatland with scattered trees/scrub + W18 Mosaic | Other land |
| Peatland with scattered trees/scrub + W4 Birch + W17/W18 Mosaic | Other land |
| Peatland with scattered trees/scrub + W4 Birch with Purple Moor Grass and open ground mosaic | Other land |
| Scattered Birch/Willow | Other land |
| Scattered Juniper | Other land |
| Scattered mixed montane scrub | Other land |
| Unsuitable for tree/scrub growth | Other land |
| W19 Juniper woodland with wood sorrel | Other land |