After doing the shopping and being treated to a pub lunch at the Bell in Golden Green by Olive, and after the rain had stopped, I got out to some rather special woodland on the scarp of the Lower Greensand Ridge on the Knole Estate just East of Sevenoaks.
Bitchett and Fawke Commons are both Sites of Special Scientific Interest (SSSIs) because of their sessile oak and beech woodland habitat, which is actually very rare in Kent. The two commons are now woodland, interconnected to the woodland on the National Trust property of One Tree Hill overlooking great views of the Weald to the South. One Tree Hill was mapped as arable and pasture prior to 1911, very different to its tree-covered appearance now. Today I walked mainly in Bitchett Common, finishing off in One Tree Hill. Not many birds about, but at the Northern end of Bitchett Common the peace was broken by three sparrowhawks (I think) "mobbing" and screaming at a buzzard wheeling directly above me - what a fantastic sight (and sound)!
The paths were very slushy after the earlier rain, especially where they had been poached by horses, mainly consisting of composted leaf mulch as much as mud. The slopes were steep and the going a bit tough in places, but at least the rain was holding off now after the earlier downpour. The woods themselves were very dark under the grey cloud of late afternoon, although it did brighten up at about 5:30 to compensate for the sun dropping in the West.
The main tree of interest today was the Beech Tree, Fagus sylvatica, one of the most interesting trees in the UK flora. It requires a lot of warmth in order to produce a good seed crop, and it is said to have arrived late in the colonisation of the UK landmass, and to have only just made it into the UK before the land bridge was cut by the Channel.
Said to be a slow spreader in part due to its large seeds being spread primarily by animals, Beech is thought to be a truly native tree only in the South of England and Wales. It is presumed to be much planted elsewhere, perhaps using continental seed, for example in the famous Beech woods planted to support the furniture trade in the Chilterns - a manufactured landscape if ever there was one.
One of the first things to notice about Beech trees is their smooth thin grey bark, often on very large trunks. Reputed in the arboricultural trade to be a bit fragile and treacherous, losing large branches and falling over far too early, the trees can still be magnificent to look at. There were several examples of both fine upstanding trees and also fallen trees and broken-off main branches to be seen here today. Note the split trunk of the tree on the left, darker than the typically silvery-grey bark of the tree on the right, due to rain-drip or algae I think. However the bark characteristics and the size of the trees alone should normally be diagnostic.
Here is another trunk, again with wet patches and/or lichen I think darkening the bark in patches. Note the slug climbing the trunk about 1.5 m off the ground!
Looking closely at the leaves, which by this time of year look quite tough and dark glossy green, one important ID point to look at is the number of vein pairs - there should be less than 10, or you could be getting confused with hornbeam, Carpinus betulus. If you look at this leaf, you will see 8 leaf vein pairs, so this is well within the Fagus sylvatica specification. Another feature is the relative prominence of the veins at the edge of the leaf. You can also see two infection foci, which might be the start of two fungal infections, or probably more likely, two Eriophyid mite colonies, which should be Eriophyes ?. More of these later.
Although it seemed to be quite widespread here, I haven't seen too much of these mite infestations on our domestic beech hedge or indeed elsewhere, so I don't know whether this is just my inattention, or actually a genuine distribution pattern.
The leaves look very different in spring, when they are a softer much more delicate texture and a much lighter matt green, with long sparse silky hairs, retained through to maturity at the margins. Knowing the leaf vein number will however always keep you on the straight and narrow as far as identification is concerned, and prevent confusion with the otherwise quite similar oval leaves of hornbeam.
Another ID point is the buds, which are red-brown, long and sharp pointed, often called cigar-shaped (again in contrast to hornbeam's shorter stubbier ones in particular). These buds are already well developed now, as with most trees, ready for leaf fall and the long winter. The buds will remain clearly visible through the period of marchaissance or retention of the dead leaves on the juvenile wood at the base of the trees (all the wood in trimmed hedges remains juvenile) over the winter (hornbeam and oak have a similar characteristic) but of course are not available as an ID characteristic over the growing season until next year's buds are laid down again.
Beech is late to burst out of its buds in the spring, one of the latest of the common UK trees, and when it does, the bud scales remnants are often retained, hanging beneath the twigs all season in wind-sheltered areas, as in the lower branches in these dense woods:
A final ID point to look out for from today is the twig appearance with its white raised warts against a notably smooth olive green background:
There are very few other Fagus species around, none in nature in the UK of course, but a few exotic species have been introduced into gardens. A classic example would be the Chinese Beech, Fagus engleri, which can be seen at Sheffield Park, the excellent acid tree and shrub garden in East Sussex. There are however a very large number of cultivars of Fagus sylvatica itself, such as the ubiquitous (over-planted?) "copper" beech cultivars (I like the one that is purple underneath and green on top of the leaves), and the rather rarer cut-leaved form 'Asplenifolia', that I have seen in the arboretum at Westonbirt in Gloucester many years ago, and not since.
Moving onto the invertebrates that can be found on beech, the first to note is the presumed Eriophyid mite colonies noted earlier. Here they are, rather better developed, with the raised brick-red pimples clearly visible over the yellow patches of infested leaf tissue, on a leaf growing out over a track. There is nothing in the literature about these, so I may be mis-identifying the cause of these distortions - and they could be atypical (degraded?) Hartigiola annulipes galls instead:
This may be a different species, with a single isolated colony, yellower and hairier. Or this one at least should be being caused by the common gall midge, Hartigiola annulipes.
This distortion to the leaf is caused by a leafminer, a Lepidopteran I think, that causes this raised pucker gall along the veins, concealing a larva hidden in the leaf tissue beneath. I think this was most likely to be caused by Phyllonorycter maestingella, described on this website and this site as well. When I opened a couple, in each case I only found some slightly sticky frass concentrated in a mass at one end, exactly as predicted, so presumably the pupa had already emerged and the micro-moth departed. I'll need to keep looking, there's maybe a couple of weeks left this year for me to find a late larva or pupa!
This is another leaf blotch leafminer, I think, or possibly a fungal infection!
There were also signs of leafhopper damage, the fine white speckling feeding marks of the nymphs and adults sucking away at groups of leaf mesophyll cells from the lower leaf surface,
This particular leaf looks like it has got a fungal infection, with acervuli dotting each infected area,
With so much to see here I was quite jealous of people who can own houses in the very middle of the woodland - here is the wonderfully named Starvecrow House, entirely isolated in this haven, only reached by a track through the trees:
Bitchett and Fawke Commons are both Sites of Special Scientific Interest (SSSIs) because of their sessile oak and beech woodland habitat, which is actually very rare in Kent. The two commons are now woodland, interconnected to the woodland on the National Trust property of One Tree Hill overlooking great views of the Weald to the South. One Tree Hill was mapped as arable and pasture prior to 1911, very different to its tree-covered appearance now. Today I walked mainly in Bitchett Common, finishing off in One Tree Hill. Not many birds about, but at the Northern end of Bitchett Common the peace was broken by three sparrowhawks (I think) "mobbing" and screaming at a buzzard wheeling directly above me - what a fantastic sight (and sound)!
The paths were very slushy after the earlier rain, especially where they had been poached by horses, mainly consisting of composted leaf mulch as much as mud. The slopes were steep and the going a bit tough in places, but at least the rain was holding off now after the earlier downpour. The woods themselves were very dark under the grey cloud of late afternoon, although it did brighten up at about 5:30 to compensate for the sun dropping in the West.
Said to be a slow spreader in part due to its large seeds being spread primarily by animals, Beech is thought to be a truly native tree only in the South of England and Wales. It is presumed to be much planted elsewhere, perhaps using continental seed, for example in the famous Beech woods planted to support the furniture trade in the Chilterns - a manufactured landscape if ever there was one.
One of the first things to notice about Beech trees is their smooth thin grey bark, often on very large trunks. Reputed in the arboricultural trade to be a bit fragile and treacherous, losing large branches and falling over far too early, the trees can still be magnificent to look at. There were several examples of both fine upstanding trees and also fallen trees and broken-off main branches to be seen here today. Note the split trunk of the tree on the left, darker than the typically silvery-grey bark of the tree on the right, due to rain-drip or algae I think. However the bark characteristics and the size of the trees alone should normally be diagnostic.
Although it seemed to be quite widespread here, I haven't seen too much of these mite infestations on our domestic beech hedge or indeed elsewhere, so I don't know whether this is just my inattention, or actually a genuine distribution pattern.
Another ID point is the buds, which are red-brown, long and sharp pointed, often called cigar-shaped (again in contrast to hornbeam's shorter stubbier ones in particular). These buds are already well developed now, as with most trees, ready for leaf fall and the long winter. The buds will remain clearly visible through the period of marchaissance or retention of the dead leaves on the juvenile wood at the base of the trees (all the wood in trimmed hedges remains juvenile) over the winter (hornbeam and oak have a similar characteristic) but of course are not available as an ID characteristic over the growing season until next year's buds are laid down again.
Moving onto the invertebrates that can be found on beech, the first to note is the presumed Eriophyid mite colonies noted earlier. Here they are, rather better developed, with the raised brick-red pimples clearly visible over the yellow patches of infested leaf tissue, on a leaf growing out over a track. There is nothing in the literature about these, so I may be mis-identifying the cause of these distortions - and they could be atypical (degraded?) Hartigiola annulipes galls instead:
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