LOOKING down the valley from the house, a few trees are already showing some definite signs of paler leaves, heralding the imminent onset of autumn.

This is much to Geraldine’s disgust, as she picked up on a recent article this week saying this has been the coolest summer for nine years (“I knew it”).

In reality, deciduous trees are about to undergo a significant change that happens every year as we head into the cooler period.

The word deciduous is of Latin origin and means “falling off after use” and although usually applied to trees, it also refers to the annual shedding of antlers in deer and to the shedding of baby teeth in mammals. However, we are about to see the phenomenon that is best known, the autumn leaves.

As is often the case, things are a bit more complicated than they seem. The loss of leaves process actually has three stages and these are all designed to help the trees reduce water loss and prevent freezing in the cold winter.

The first stage is called early rest and actually starts in late summer and is triggered by the shortening daylight hours, rather than the onset of cooler weather.

As the tree enters the winter rest phase, it starts to create ways that will prevent freezing in the coldest months. The trees change the key attributes of the cell structure. They reduce the cell thickness so some water moves out of the cell and also thicken the fluid in the cells, converting starch to sugar (such as maple syrup) creating a natural anti-freeze. They can thicken the fluids further to create a glass-like state which avoids cells crystallising.

Whilst we don’t get the really low temperatures in the UK these days, I was always amazed in Mongolia, at minus 40 degrees, how birch trees could survive - never mind the livestock outside.

I wouldn’t last five minutes without super-efficient warm clothing. It just shows that plants and animals are incredibly suited to all aspects of our climate – it’s amazing where life can survive.