Monday, 22 October 2018

Autumn or Fall?

In the USA autumn is 'the fall'. This is an appropriate term for the northern states such as Maine or Oregon but in Florida, where leaf-fall is much less of a phenomenon, the term is surely less suitable.

In Britain it is autumn, and John Clare's poem of that name would sound odd had he called it 'The Fall': it would sound like an account of someone's tumble down the stairs.

                     I love the fitfull (sic) gusts that shakes
                    The casement all the day
                    And from the mossy elm tree takes
                    The faded leaf away
                    Twirling it by the window-pane
                    With thousand others down the lane...

Clare speaks of the leaves, shed in their billions, whose next role will be to enrich the soil via decay. Most of us also think of these spent organs and in so doing tend to overlook he other component of the litter - falling twigs.
Leaves cover a track near our house on Stefen Hill, Daventry.
21 October, 2018

The phenomenon of twig fall is known as cladoptosis and, unlike the autumnal shedding of leaves, it can happen at any time of the year, most frequently of course during gales. Twigs (and don't ask for a definition, we all have a pretty good idea of what a twig is) may get diseased or may simply be rendered redundant and die as a result of being cast in the shade by more vigorous branches. Twigs will of course, like leaf litter, decay, but the process just takes a little longer. These twigs may form a sort of scaffolding on the woodland floor and a myriad of spiders such as Neriene peltata and Linyphia triangularis makes use of this situation to construct their snares. Also, to a far greater extent than leaves, twigs may carry an encrustation of lichens.

Larger twigs, torn off in a gale, may still be formed of living tissue so willow or alder twigs, if falling on to wet ground, may take root.

Last month at the meeting of the Boddington and District Garden Club Chris won a raffle prize consisting of a specially designed rake and container for collecting fallen leaves. No doubt a few twigs will be garnered with the leaves. They will be allowed to decay beside our allotment when they will be spread as a soil conditioner. Fallen leaves/twigs contain few nutrients as these have be largely withdrawn by the tree. Nevertheless the decomposed material will help to form humus and improve the general state of the soil, helping to create a nice, crumbly tilth.

Today I went a-gathering and in so doing couldn't resist examining the leaves still clinging on. A beech leaf had been galled by the fly Hartigiola annulipes. It is not rare but in this area seems uncommon, with the U.K. distribution map not showing any apparent records for Northants.  The upright galls are slightly hairy and quite distinctive.

Beech leaf showing the galls of Hartigiola annulipes. Stefen Hill,
Daventry. 21 October, 2018

I gathered a substantial quantity of leaf/twiggy litter and will check it out, if time permits, for the various invertebrates potentially present. It will then be allotment bound.

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