Beautiful Bark

Auckland Park, in Bishop Auckland in County Durham, has a fine collection of venerable trees with beautiful bark patterns. 

Hawthorn Crataegus monogyna

Fluted trunk on an old hawthorn ....

.... with an elegant twist

Grey poplar Populus alba. The flat surfaces, between the fissures, are covered with diamond-shaped scars that look as though the bark has been hit with a pick, which is most evident on young trees like the one you can see by clicking here.

The old grey poplars have the most deeply fissured bark of any trees in the park ....

.... with splits so deep that they resemble crevasses 

Young silver birch bark peels away in thin layers (click here for a picture) but as it ages the bark splits and forms flaky plates ...... 

...... like this

Sweet chestnut Castanea sativa, with a bark pattern that resembles raised branching fibres ...

... with deep crevices where all manner of small invertebrates can spend the winter

Chumbawumba tree

Trees are admirably resilient organisms and it usually takes a lot to kill one outright. They can be broken by gales, struck by lightning, flooded, droughted or cut down to ground level and they'll still sprout new growth when spring arrives. Even when they're infected with a fatal fungal disease it can take years for them to die, while all the while they continue to produce seeds. It takes something pretty cataclysmic to kill most trees stone dead.

This rowan, in Backstone bank wood in Weardale, reminds me of the Chumbawumba tune Tubthumping, with its chorus I get knocked down/I get up again/you're never gonna keep me down. If you are not familiar with this particular earworm you can listen to it here. Don't listen for too long - you might never get it out of your head.

It's a mature rowan that was blown over in a gale over fifteen years ago. The windward roots snapped but the leeward roots remained intact and embedded in the soil, so it continued to grow and produce new vertical shoots from the fallen trunk which is slowly subsiding into the woodland floor and is now covered by a carpet of moss. Those new shoots have grown into half a dozen tall, straight trees in their own right.

Where once there was one rowan, now there is a whole row of them. Resilience.

(Double-click on the pictures for a larger, clearer image)

Inner beauty of a successful weed

Hedgerows are full of young goosegrass Galium aparine plants at the moment, whose rapid growth has been encouraged by mild winter temperatures. 

This is one of our most successful and ubiquitous weeds, beautifully adapted to fast growth, prolific seed production and efficient seed dispersal.

The seeds, which are covered in tiny hooks and are dispersed in the fur and feathers of animals, germinate in late autumn and early winter so that by spring the young plants have a head start on surrounding vegetation and begin to flower quickly.


The stems elongate very quickly too and the plant is finely adapted to using surrounding plants for support, thanks to ....



... a covering of tiny, backward-facing hooks on the stems and leaves, seen here under the microscope. In fertile agricultural soils the plant can thread its way through a hedge by early summer, sometimes reaching a length of six feet or more and smothering the hedge by the end of summer, all the while producing thousands of hooked seeds from tiny white flowers that are visited by small insects but probably self-pollinate too.

One reason why goosegrass is such a prolific seed producer is that its habit of scrambling over other plants, using those hooks, means that it doesn't need to invest much energy to producing a strong stem. It takes a hawthorn several years to reach a height of six feet, building stem strength through woody tissue production, but goosegrass can reach the same height in about three months.



 This image shows a one cell-thick section through a stem and those yellow stained cells, in a ring in the centre, are the only ones that have any woody strengthening in their cell walls - all the blue-stained cells are pure cellulose. 

The narrow line of yellow staining on the outside of the stem is the waxy cuticle, that protects the plant from water loss.