December 2024

It is early November. As I look out from my study window, an oak tree in front of me is showing hues of brown and yellow among the disappearing green if its leaves. I have mentioned before that deciduous trees are the exception globally. Most planetary trees are evergreen and live in the tropics. The rest live in the boreal ecosystem between latitude 50 and 70. Between these latitudes temperatures often drop to minus 20° C and below. But hey, that is us is it not? Ah yes, but Britain is exceptionally mild for our latitude. We (e.g. London) are roughly on the latitude (55° N) shared by Saskatoon (52° N) in Canada, and Moscow (55° N) in Russia. Most (but not all) of the natural trees in the latter 2 locations are evergreen and conifers. However, most of our native trees are deciduous. We only have 3 native conifers, and 2 of them do not have cones (but berries) as we know them, these are Juniper and Yew. The third native conifer is Scots Pine. All other conifers are alien to Britain. Some conifers are also deciduous, such as the Florida Swamp Cypress and the Larches.

So why are we special? Well, firstly we have the Atlantic conveyer, also known as the Gulf Stream and North Atlantic drift/current. This is warm water brought to our shores in Britain that influences our climate, making us warmer than we should be at our Latitude. Our prevailing wind is also a south westerly, doing the same thing. However, if the wind direction changes to an easterly or northerly, we get correspondingly cooler. Even very cold down to about minus 16° C occasionally. That is when we lose our exotic plants if they are outside.

The flowers of our native plants tend to be rather small such as birds foot trefoil and vervain. If they are abundant such as bluebell and primrose, they make a fantastic show, but to make an impression in our gardens, we like to import large showy flowers like dahlias, tulips and hollyhocks. These may be the first to suffer when we get a sharp frost. However, there is a trend now to plant wildflower seeds in our gardens, and this is good, because many of our insects are best adapted to native plants. Plants did not have flowers until insects appeared. They act as visual attractants to insects. There is now a fantastic dependence by flowers on insects to pollinate them, to produce viable seeds, and also a dependence of insects upon the nectar and pollen that they collect from the plants. However, many insects have also discovered (like we have) that the leaves of many plants taste good and are also nutritious. The insects that eat the leaves also become nutritious and are essential to insectivorous birds such as swifts, swallows and blue tits. Who in turn are essential food for sparrowhawks, hobbies and merlins. All birds of prey eventually die, and are then consumed by microorganisms, insects such as sexton beetles or carnivores such as foxes. So the cycle of life goes on.