Stephen1 wrote:
Twybill wrote;
"That is why the excessive self seeding of Sycamore within woods is bad for bluebells as these trees come into leaf far too early and shade out and suppress the bluebell."
That's an interesting hypothesis - I would guess based on anecdote? If not and you know whether it has been tested empirically, or have a reference for it from a peer reviewed journal I would be very grateful. I've been working on the ecology of bluebells for the last six years and haven't come across this idea before. I have to admit that I feel it unlikely to be demonstrably correct."
My Reply to this:
Sorry, no reference or peer review, just observation, which may only be valid for the woods in the Pennines of West Yorkshire. I am not sure why you think it unlikely to be demonstrably correct.
Sycamore is a very invasive element of our local tree flora and dominates the damper areas. It grows where Ash would normally be and displaces it. Sycamore comes into leaf a good month to 6 weeks before Ash, so where bluebells would have time to flower before canopy closure, with the dense shade of Sycamore it doesn't flower and dies off.
In these high rainfall woods, Sycamore will also dominate Oak woods and besides shading the bluebells, they also slowly kill the Oak trees.