White Magic

Snow + winter-flowering shrubs = magic

Rhododendron dauricum

Mahonia x media 'Charity'

In Durham University Botanic Gardens at lunchtime today. Double-click for a larger image.

The Afterlife of Trees

I think it might have been Oliver Rackham, botanist and noted expert on woodlands, who once commented that the only object in woodlands more valuable than a live tree was a dead one, since they host so many species of wood-boring beetles and other insects that breed in dead wood. This ancient beech stump, in Durham University Botanic Garden’s new woodland nature trail, is riddled with emergence holes from insects that have bred in it, but its most conspicuous features are the magnificent specimens of the bracket fungus (Ganoderma sp.) that was almost certainly the cause of its death. This parasitic fungus weakens the tree and infected trunks typically snap somewhere above head height during gales. The fungus is perennial, so each year the bracket develops a new zone of spore-producing tissue around its periphery and generates so many spores that they cover the vegetation below with what looks like a layer of cocoa powder. You can estimate the age of the bracket by counting the number of ‘steps’ on its upper surface; each marks the end of a year’s growth. During their ten years of existence, these brackets must have produced billions of spores. You can read more about the woodland nature trail at http://www.dur.ac.uk/botanic.garden/?itemno=7173

Return of the native

Catching sight of a speckled wood butterfly isn’t a big deal in many parts of the country, but up here in County Durham it was, until about three years ago, something to get excited about. Until the 1840s this butterfly was quite common in the region, then it went into steep decline. When Tom Dunn and Jim Parrack published ‘The Moths and Butterflies of Northumberland and Durham’ in 1986 they considered it to be extinct in both counties but wistfully noted that “since it still survives in Yorkshire it is theoretically possible for it to return”. How heartening, then, to find that over the last few years it has recolonised both counties, moving rapidly northwards. It seems that climate change is the reason. I photographed this one in Durham University Botanic Garden yesterday.