We are in the final throes of autumn as I sit down to write this. December, and winter is about to begin. Before we know it, we will be entering a new
year. Although the darker days are upon us, at least the autumnal foliage on the trees has once again given us a magnificent display.
Just to explain the process that leads us to this annual phenomenon, a green leaf is green because of the presence of a pigment know as
chlorophyll, which is inside a special part of a cell in the leaf structure. When it is abundant in the leaf’s cells, as it is during the growing season, the
chlorophyll’s green colour dominates and masks out the colours of any other pigments that may be present in the leaf. Thus, the leaves of summer are
characteristically green. Chlorophyll has a vital function: it captures solar rays and uses the resulting energy in the manufacture of the plant’s food –
simple sugars which are produced from water and carbon dioxide. These sugars are the basis of the plant’s nourishment – the sole source of the carbohydrates needed for growth and development. In their food-manufacturing process, the chlorophylls break down, and are being continually used
up. During the growing season, however, the plant replenishes the chlorophyll so that the supply remains high and the leaves stay green.
In late summer, as daylight hours shorten and temperatures cool, the veins that carry fluids into and out of the leaf are gradually closed off as a layer of special cork cells forms at the base of each leaf. As this cork layer develops, water and mineral intake into the leaf is reduced, slowly at first, and then more rapidly. During this time, the chlorophyll begins to decrease. Often, the veins are still green after the tissues between them have almost completely changed colour.
While all this has been going on and the trees appear to be in their death throes, hazel trees are starting their life again by producing catkins. The male
flowers are long yellow catkins, known as ‘lamb’s tails’. They first appear around late October to early November, and are short and green. Between
February and April they open up to release their pollen. The female flowers, which grow on the same tree, are small, red and bud-like in appearance. It is the female flowers which later develop into the hazel or cob nuts. Bees find it difficult to collect hazel pollen and can only gather it in small loads. This is because the wind-pollinated hazel has pollen that is not sticky and actually repels one grain against another. Also hazel is monoecious, meaning that both male and female flowers are found on the same tree, although hazel flowers must be pollinated by pollen from other hazel trees.
During the long December nights, tawny owls may be heard staking out territory, with both the male and the female birds creating the classic owl ‘tu-wit tu-who’. Tawny owls pair off from the age of one year, and stay together in a usually monogamous relationship for life. An established pair’s territory is defended year-round and maintained with little, if any, boundarychange from year to year. The pair sit in cover on a branch close to a tree trunk during the day, and usually roost separately from July to October. Roosting owls may be discovered and mobbed by small birds during the day, but they normally
ignore the disturbance.
During the daytime, robins are one of the few birds that can be heard singing during winter, as both the males and females maintain territories for feeding during this period, which may be their breeding territories later. Around Christmas time, robins begin exploring other robins’ territories looking for a mate. They then pair up by mid-January and females stop singing. It’s also mating time for the fox, so listen out for their blood-curdling screams at night. If you don’t hear them, you are almost certain to smell them! At this time of year they advertise their presence to each other by scent marking their paths with their urine.
All of our amphibian and reptile species (i.e. common and natterjack toads, slow-worm, common and sand lizards, common, smooth and great crested newts, adder, smooth and grass snakes) are hidden away underground until spring, and sometimes together in mixed groups. Only the common frog chooses a different method by hiding at the bottom of a pond.
So now, as the season of the Holly and the Ivy is upon us, and as we gather mistletoe and scented pine to decorate our houses, it only remains for me to wish you all a peaceful Christmas and a very Happy New Year …
’til next year!
Recent Comments