Early spring in the Derwent Walk Country Park, Gateshead

 Some pictures from a walk last week in the Derwent Walk Country Park, Winlaton Mill, Gateshead.

Silver birches and willows, seen from the top of the Nine Arches railway viaduct over the river Derwent. The buds of the birches take on a purplish hue at this time of year, as they begin to swell, while the willows have an orange tint.

Carrion crow. Handsome birds, with a hint of blue iridescence in their plumage.

A fine display of colt'sfoot

Dutch rush Equisetum hyemale spore cones beginning to disperse spores. An uncommon plant, but there are some fine patches of it beside the footpath.

Golden saxifrage in full flower in a ditch beside the old railway line.

A heron with some fine chest plumes, feeding in the river Derwent.

Beard lichen Usnea sp. Remarkable that this pollution-sensitive species is now established here, when you consider that this was formerly a location for coal mines, an ironworks and the Derwenthaugh coking plant that only closed down in 1986.

A magpie in one of the meadows

Primroses in flower

A soaring red kite

Toads coming out of hibernation in the woodland, heading for Clockburn lake, on the site of the old coking plant

Wood anemones in flower in woodland beside the river Derwent

Silver birch seeds

 Silver birch seed catkins are ripening now and fall apart at the slightest touch. Their seeds are an important food resource for several small finches, including siskins, goldfinches and redpolls.

When the catkins disintegrate they separate into woody, arrow-shaped bracts, releasing the much smaller seeds that are surrounded by a broad translucent wing. They can be carried long distances on a windy day - one of the factors that make this tree such a prolific coloniser of open habitats.

 

Wind pollinated trees and hay fever

 As winter draws to a close I always look forward to the first hazel catkins, that signal a change in the seasons ......... but then, when spring finally does arrive, I remember that I suffer from hay fever. The early-flowering trees are wind-pollinated, producing vast clouds of sneeze-inducing pollen. 

Wind pollination is a chancy business and once the pollen is released it's rapidly diluted in the air, so the chances of an individual pollen grain landing on a female flower stigma, leading to the formation of a seed, decreases exponentially with the distance between then. So the only way to improve the odds is for trees to release great quantities of pollen

Male catkins of hazel.

Tiny, female stigmas of hazel

Male flowers of ash, about to open

Ash flowers, fully expanded

Silver birch male catkins, a major contributor to hay fever

Silver bird male catkins

Elm flowers. Before Dutch elm disease arrived, the bare crowns of mature elm trees were covered in a purple haze of flowers, a magnificent sight, now just a memory.

Most wind-pollinated trees produce their flowers on bare twigs, unencumbered by foliage that might hinder pollen release, but beech is an exception. It may be that beech bud burst is delayed because its foliage is very sensitive to late frosts. 

Evergreen coniferous trees like Scots pine tend to produce their male, pollen producing cones on the tips of their branches, well clear of the foliage, where pollen is easily carried away by the wind.

More tree silhouettes in winter

Graceful silver birches Betula pendula

Sweet chestnut Castanea sativa

Hawthorn Crataegus monogyna. A tough, impenetrable tangle of branches, often with a twisted, fluted trunk when it is given time and space to grow into a tree.

Common lime Tilia europaea. Often has burrs at the roots with a mass of twigs, which have been trimmed in this specimen.

The mass of twigs growing from the burrs at the base of an untrimmed common lime

Beech Fagus sylvatica. Slender twigs with pointed buds.

Elder Sambucus nigra usually grows as a large hedgerow shrub that'sseverely cut back annually and only has a short life span but if it's left alone and given space it will grow into a small, densely-branched tree like this. Old elders have deeply fissured corky bark and twigs covered in yellow Xanthoria parietina lichen.

For more on winter tree silhouettes click here

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