Aspens in Assynt in autumn
Late October is the time to spot aspens Populus tremula in the Assynt landscape, since their butter-yellow autumn colours mark out every tree. They are widespread in the parish, in rocky woodlands, in gorges and on cliffs, all places where they are protected from browsing; their sucker shoots are very popular with deer.
One such favoured site is alongside Loch Nedd, where they grow in shore-line scree (photo 1) and on wooded crags above the shore (photo 2). The crofts on the western side of the loch also carry a number of large trees, in situations where they may have been protected from grazing. In passing, we appear to have at least two distinct clones, whose leaves unfold and fall about a fortnight apart.
My neighbour, John Ross, has a magnificent stand of old aspens on his croft (NC1331), which tower over the end of my vegetable patch (photo 3). I admire their fallen leaves every autumn, most yellow, but some deep red (photo 4). Leaves I picked up recently (photo 5) had two other organisms associated with them. Many of them have blackening patches caused by an ascomycete fungus Venturia macularis (confirmed by mycologist Bruce Ing), which merge to turn the whole leaf black.
Rather less common are swellings of the leaf stalks, galls caused by the midge Contarinia petioli, which in Assynt I have only come across once outside Nedd, north of Loch Veyatie (NC1913). In this case two galls have formed (photo 6) and coalesced just below the blade of the leaf, each now with the emergence hole of the adult midge.
Words and photos Ian M. Evans