Bitchett Common and One Tree Hill Beech Trees

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:

Dene Park starts to look a little autumnal

Its a little while since I've visited Dene Park, and the leaves of the trees and some of the bracken are now starting to turn just a little, reminding us of the rapidly shortening days and the onset of autumn.

As I arrived in the car park several dragonflies were circling the gravelled area, possibly male brown hawkers, Aeshna grandis. Too fast to take photos I'm afraid.

As I got into the wood, there was some bird song, including magpies and the fine hooting of a Brown Owl
The number of plants in flower is gradually decreasing, but to compensate a late burst of Eyebright, Euphrasia, flowers have appeared in the verges and open patches, I didn't even know it grew here at Dene Park! Its official flowering season is July to September, so this should be the last flush of flowering.

The leaves are a glossy oval in overall shape, hairless above, but they are so very deeply cut- toothed, so that you almost lose the oval in the pattern of dentations. The stems and sometimes the leaves are purplish.

The flowers are really wonderfully coloured, with their pure white backgrounds, splashed with clear purple lines and yellow flushes seen here on the lower lips. The stamens or inner floral tube can only just be seen, a counterpointed very dark violet against the pale throats of the flowers.

The flower form is pretty fantastic as well, with the upper lip twice bi-lobed and upturned, and the lower lip projecting much further out and widely tri-lobed, each lobe of the lower lip also clearly divided into two, giving an overall appearance rather like an orchid!

Here is a flower from Polhill Bank yesterday to compare, in particular to note the obvious projection of the inner floral tube:

There are about 21 currently recognised species in the genus in the UK, with 60+ hybrids, and they are almost impossible to separate, so Francis Rose describes only Euphrasia nemorosa, as a typical species. It could well have been a different species that I was looking at today on the wet clay of the woodland in the Low Weald and perhaps yet another that I was looking at yesterday on the shallow and skeletal chalk soils at Polhill Bank.

Euphrasia is used by herbalists in poultices and teas to treat eye complaints, and is reputed to have a range of other medicinal properties as well. Its therefore definitely "a sight for sore eyes"!

The other new plant I saw today was Goldenrod, Solidago virgaurea, I usually only see Canadian Goldenrod, Solidago canadensis, a much bigger and overall very different plant. Francis Rose has Goldenrod as growing in dry woods, so it is therefore a bit confusing to find it in Dene Park, but there was no doubt that this is what it was. I'll try to remember to get a photo next time!

The first fungi of the autumn season have started to appear, and here is one I found just on the side of the path,

while this is a whitish bracket, porose on the underside, on a dead branch just off the path in the scrambles area

As I completed the circuit more patrolling hawker dragonflies, probably either Southern or Migrant Hawkers but including a low-flying one along the last uphill section of the path that looked completely black at first (and also second!) glance. I've absolutely no idea what it could have been - but what a great walk it turned out to be, in what seemed at first to be not very promising conditions!

Polhill Bank

After doing a bit of College work, some shopping, calling in at the Parish Office and painting some external windows, I took Monty for his afternoon walk up to a bit of the North Kent Downs I have never been to before, Polhill Bank.

The M25 cuts through the Downs here, but Polhill Bank also faces the Darenth Valley as well as the Gault Vale looking South towards Sevenoaks, so you get the contrast of peaceful rural views delighting the eye with the roar of traffic in your ears. The easiest way to access the reserve is to park in the A224 layby on the other side of the M25 cutting and cross the footbridge over the motorway towards the reserve, looking down on the rushing traffic of London's orbital motorway 70 - 80 feet below your feet.

A quick path through the beech-woods on the skeletal soils of the crest leads you through the reserve gate and out onto the steep Bank itself, with the view opening out in front of you:

Just as I arrived a brownish raptor with a white rump and a long tail flew over. It looked like a female or immature Hen Harrier, Circus cyaneus, but of course it couldn't have been - wrong place, wrong season!
There was still a good variety of plants in flower, including the Devil's-bit Scabious, Succisa pratensis with its undivided leaves, although I usually associate this plant with wetter soils. Here is the one large patch I saw with one female Common Blue nectaring on one plant:

It is interesting to compare the Devil's-bit with a true Scabious, the Small Scabious, Scabiosa columbaria, a characteristic flower of the chalk downs in Kent. The outer flowers are much larger than the central ones, and the stamens that you can see are clearly balanced on their central filaments. Note the greyish spider surprisingly well camouflaged against the blue background,

A commoner flower across the small reserve as a whole is the Eyebright, Euphrasia species, the tiny whitish flowers of which are everywhere you look, and a fantastic flower when you look at them close up:

and here is the ubiquitous Wild Basil, Clinopodium vulgare, with its dense whorls of flowers which however only open several at a time,

and another Labiate, the beautiful and very common Marjoram, Origanum vulgare, with its much lighter flowers in tighter packed terminal panicles, each with their beautiful projecting stamens, and the aromatic leaves with much less impressed veins (seen in the original photos). If you click on the photo and expand it up, you can just see a thrips or thunderfly on one of the flowers at the top right of the panicle:

This is the Dwarf Thistle, Cirsium acaule, a plant nearly completely specific to calcareous grassland,

and this is the odd-looking Carline Thistle, Carlina vulgaris, which may look strange but with its purple sheen, still very attractive to bees:

while this is Common Soapwort, Saponaria officinalis, a common plant on different soils in the region,

Here is the low growing Lesser Trefoil, Trifolium dubium, creeping along the ground,

and the even lower growing Hoary Plantain, Plantago media, with its attractive pinkish flowers the only plantain pollinated by insects as opposed to wind-pollinated

This is the Common Knapweed, Centaurea nigra, but here on these poor soils it grows to a fraction of the size I normally see it in the woods, The composite flower-head however remains unmistakeable:

and here is the Perforate St Johns Wort, Hypericum perforatum, with the characteristic black dots on the petal edges just visible if you click and expand the picture,

and finally I couldn't resist putting in a last flower, the Rock-rose, Helianthemum nummularium, although its a rather blurry picture, it is still so fundamentally characteristic of these poor chalky soils.

However on several of the Kent Wildlife Trust chalkland reserves all this diversity is uncder threat from this one yellowish invasive grass, Tor-grass, which threatens to out-compete and overwhelm the floristic diversity of the chalk downland, unless the grazing is very carefully and flexibly managed:

Although its nearly the end of the butterfly season, and the day was very breezy, the open ground was packed with Meadow Browns, Maniola jurtina,

some generally rather small Gatekeepers, Pyronia tithonus. This one is slightly unusual in that it appears to have only one white spot on the dark eye.

and the occasional Common Blue, Polyommatus icarus, like this female, (postscript - it is possible that this is a fairly faded female Chalkhill Blue, Polyommatus coridon, perhaps indicated by the slight indication of lines running across the outer white fringe of the forewing)

Eden Valley walk - The River Medway

After dropping Simon off in Leigh to catch his lift to the airport for his cricket club tour to Portugal, I moved on to the other side of the village to walk Monty upriver along the Eden Valley Path towards Penshurst. Most of the walk was on the Penshurst Estate owned by Viscount de Lisle. The first stage was along the North bank of the River Medway which is quite narrow here, although we are only a few miles upriver from Tonbridge:

The river lies in a valley that is controlled by the Tonbridge flood relief scheme,

and from time to time the whole area is deliberately allowed to flood to prevent the waters rising in the middle of Tonbridge - hence these barriers used to close the road when the flood gates are closed to block the flow of the river a mile lower down, just upriver of Tonbridge

The banks of the river are very steep and the river looks as though it is quite regimented and "canalised" but there is still quite a good mix of vegetation, such as teasel, willowherb, ragwort, the exotic Impatiens and many others,

The Impatiens noli-me-tangere is particularly popular with bumblebees, despite being a non-native:

There is also the occasional clump of hemp-agrimony Eupatorium cannabinum with its pinkish flower-heads each with 4 - 6 tubular pinkish flowers gathered into much larger loose umbels, not very daisy-like in overall appearance. One of the give-aways is the Y-shaped stigma that you can see projecting from some of the flowers, unusually long in Eupatorium

As the flowers develop. more and more Y-shaped stigmas project, until the umbels as a whole look covered in white fluff.

There was also one patch of yellow loosestife with a few flowers left. but most have now been fertilised, producing the odd rather distinctive globular fruit (one celled capsules, each with many seeds) with their clasped sepals and projecting styles. This is indeed a rather strange member of the Primrose family!

On the river itself the banded demoiselles Calopteryx splendens dance along like little helicopters with wings a-blur over the water weed

The river is also lined on one or both sides with poplar and ash trees, with the occasional dead stump left with an inviting woodpecker hole, perhaps useful for bats, or even a little owl,