Dear Readers, as you might remember I was in Coldfall Wood yesterday for our spider walk, and a lot of fun it was too. Well, between midday on Saturday and first thing this morning, one of the dead standing trees alongside the boardwalk has toppled over and smashed part of the bridge.
For once, it’s very unlikely that this was caused by vandalism – it’s too far from the boardwalk for someone to pull, and it’s completely surrounded by stinging nettles so it’s unlikely that someone would have waded through them to give it a push. Standing deadwood is normally pretty stable, so what could have caused the problem? I have a theory, so here goes.
First up, the area here in Coldfall is a habitat known as wet woodland, which is extremely rare, especially in urban areas. Water runs down into the area from a variety of culverted streams, and also seeps in from the higher ground that surrounds it. In the winter the area has, in the past, been flooded to a depth higher than the handrails, and the photos below give an idea of what it’s often like in a normal and exceptionally wet winter.
However. In recent years, there have been some attempts to improve drainage – for one thing, one of the pipes that took excess water away was forever getting blocked, so the water backed up. This was then cleared. But I am now a little concerned that the ‘wetlands’ is getting too dry – where there used to be water mint and water bistort, there’s now a sea of stinging nettles. Clearly, you can have too much of a good thing where drainage is concerned, because the last thing we need is for the wet woodland area to dry up altogether.
Naturally, the amount of water in the wet woodland is to a certain extent weather-dependent (and it has been a pretty dry summer), but I have never seen it this dry in late summer.
Now, of course a dead tree can topple over at any old time. However, I suspect that the the weather (hotter than usual for this time of year) and the dryness (as evidenced by the changing vegetation) are contributing and helping to destabilise the soil. We really do need to sort out the drainage issue here, before we lose this precious and unusual habitat for good.
You can read a bit more about the different kinds of wet woodland, and its value to wildlife, here.