- A Winter Walk in the Bookham Commons
The starkness of the winter woods draws the eye to features perhaps not readily noticed when the deciduous foliage distracts the attention. This weekend I found my ‘eye’ drawn to the distinctive patterns on the bark of the oak, silver birch, beech and yew trees. Why are trees clad so differently? The function of ‘bark’ is protection keeping out pests and keeping in moisture and nutrients, adding strength and rigidity but allowing for a certain flexibility of movement among other attributes.
Close examination of the aged oak with its crisscrosses of rough, lumpy bark revealed deep fissures, secluded hidey holes for insects and small creatures to shelter from the cold. Towards the foot of the massive trunk the bark is often moss-clad, buckled and bulging in girth under the pressure from tons of lumber up above.
In contrast, the smooth-suited beech seems to give nothing away. The bark appears to shed little, displays a uniform colour and texture and stands straight. The feature that caught my eye was the way some beeches spread out their roots over ground for extra stability before disappearing beneath.
The welts and scores rent in the bark of the silver birch tear up its bright coat as the tree ages. Cracks appear and the bark puckers into a gnarled mosaic complete with furrows and more hidey holes for insect life. Here and there sprinkle of algae and lichen add a green hue. The younger slimmer silver birches appear altogether lighter and smoother with a papery feel. Around the strange arrangement of horizontal slits, fine paper curls lift at the edges. These lines look as if they have been applied using a ruler. Only one or two inches long, aligned in parallel, circling the trunk; what is their purpose? Stretch slits perhaps.
Finally the yew, strikes me as an arid tree, the bark is ‘dry brown’, flaking and sloughing off in fine scales with a mottled appearance. Even though there is a dry cast to the bark the wood of the tree was used for bows and arrows, which tells me it can’t be brittle.
The ‘biodiversity’ we see in the primary producers, the trees of the commons, opens up the possibilities for biodiversity on the next trophic level. The more diversity, the more resilience, the better the chances of nature putting up a fight against disease and invasion, threats from pollution, climate change and habitat destruction.
Not only is the biodiversity of the commons fascinating to explore but the stories under the surface are endless.
- A Short Walk Around Bookham Commons and the First Signs of Spring.
The recent uplift in temperatures has begun to transform life in the commons, even though the signs are often so very small, the effect is a seasonal shift, the stirrings of spring.
Entering the commons by way of the tunnel car park, the first signs only became apparent when gazing toward the setting sun. Illuminated in the watery winter rays were insects, tiny and fragile winged insects, possibly mayflies, bobbing up and down on invisible threads about a meter and a half above ground. These dancing flies seemed suspended along the line of the sunlight and when approached become still, disappearing from view, onto the nearest leaf.
Lichen and moss covering branches on the avenue of oak trees were responding to the extra light adding a faint green tinge to the lattice of budding branches overhead. A tour around the muddy edges of the pond and investigation into the submerged clumps of grasses, revealed no signs of frog spawn, however a little distance apart were stands of hazel flushed with catkins.
On the approach to the tunnel car park in the fading light, a flying creature, not a bird but a bat, a very small bat dipped and swooped across a natural amphitheater, the aerial space between the crowns of three towering oaks.
Its height and rapid flight movements made identification difficult but recognising and noting particular features helps to guide later identification in reference books. The reference guide, RSPB’s Wildlife of Britain, lists 5 species of bats: the brown long-eared bat, the common pipistrelle, Daubenton’s bat, the noctule bat and the serotine bat.
According to the information on geographic distribution, all 5 bats can be found in the area of Bookham Commons. By process of elimination the description of the noctule and serotine bats are too large in body and wing span to qualify, and judging by the silhouette the absence of long ears eliminates the brown long-eared bat. The common pipistrelle is described as having a somewhat jerky flight pattern which again, does not fit, leaving the possibility of Daubenton’s bat.
Interestingly, Daubenton’s bat favours open wooded areas, so that’s a tick for habitat type and, the clincher, ‘roosts in cracks in trees, and buildings and under bridges.’ Nearby, less than 30 meters from the site where the bat was spotted lay a potential roosting site in the railway tunnel, underneath the tunnel car park. There is the possibility that the sighting could have been Daubenton’s bat, but as every good naturalist knows, a positive identification of a species requires rigor and scientific investigation technique.
Even though positive identification is not always successful, there is a pleasant satisfaction in bearing witness to the ecological system at work through the changing seasons, the rise in temperatures allowing the insects to hatch, the insectivores responding to the food source and the cycle of life continues.
- Autumn in Bookham Commons
There are few sights as glorious as a woodland in autumn. The autumnal palate is a delight in this temperate climate of the British Isles. From burning copper to glowing amber, the result of each tree’s efforts to draw out from its leaves the last vestiges of nutrition, is a wonder of nature we watch every year and never grow tired of. Continue reading ‘Autumn in Bookham Commons’