Withey Brook on the Trebartha Estate where we are working, has some of the most exciting Atlantic woodland species with the most luxuriant growth of numerous indicator species in Cornwall I have seen.
To go with the abundant bryophyte growth of Bazzania trilobata on boulders in the woods (image 1) & the lichen Lobaria pulmonaria (image 2)….. this is Lobaria virens! (image 3)
What an exciting tree for plant communities! Both the British Bryological Society (BBS) and British Lichen Society (BLS) have had full day events here at the Trebartha Estate.
Whilst on an open grown oak tree in wood pasture, it’s a stone throw from those same conditions of temperate rainforest, in which these species also belong.
When good populations are present, Indicators species and certain plant communities (in this case temperate rainforest) rely on those conditions to continue. Moisture, light levels, ph etc.
Dramatically changing the structure, light and subsequent moisture levels of a woodland risks losing them. Likewise a woodland canopy closing over time can do the same thing.
Rare or desirable species such as indicator plants of this habitat have often been lost to historical management and harvesting practices. Clear felling has lost structural trees within a more open habitat (our veterans of the future are mostly confined to boundaries within a woodland). Some species have dried out for good in those opposite, full exposure conditions and harvesting large areas results in a lack of age diversity. Too often seen in oak coppice woodland, which Cornwall has many.
As with many ancient woodland indicators, lichens and bryophytes of conservation importance are poor colonisers and habitat continuity is a key factor.
Oaks for example have less acid bark as they get older, offering the optimum conditions for these lichens. Management must consider instead, creating mosaics, corridors, and dappled light. Selective felling trees, leaving some to have light surrounding them, those are the ones that become important trees of the future. Allowing light to the tree and trunk also helps those important features of a veteran tree.
Same age structure and subsequent closed canopy caused by past clear felling or coppice management methods, is where we find ourselves most of the time. Attempting to reverse the “same age monoculture” impacts of continuous coppice management. Our main goal in many cases of woodland management is to improve this age diversity once again. Selectively felling trees, gives that natural process a helping hand.
Plant communities, indicator species and understanding the many different woodland habitats is the key requirement to carry out what each woodland needs. This is why Angie has trained since 2018 with Plantlife on temperate rainforest indicators and management of Atlantic woodlands. This has also allowed us to proudly survey Woodland Trust Sites for their potential temperate rain-forest conditions. Subsequently in NVC habitats and plant communities, which will be described in more detail in further posts.
