The History of the Tree in the Wood.

The history of the tree is in each piece of wood but it can not always be easily read. One of the easiest stories to read is when a tree has been cut across the grain. Because the wood has to shrink as it dries (a living tree is about 60% water and this will come down to 10% or below for a centrally heated house) when it is cut like this it inevitably cracks. When it is planked along the grain it can move in different ways so does not necessarily crack.

This circle of wood is 31″ diameter at the narrowest point and over 3′ at the widest which makes it an ideal size as a coffee or a side table. The history of the tree shows clearly. Having counted the rings and making it 151 excluding the bark even if my eyes went a bit funny trying to count all those lines we are still talking about a tree over 150 years old.

Ash is a light coloured wood when it is young with no visable difference between heartwood and sapwood. However, as it grows older it the inner wood becomes dark and it is known as olive ash as it looks similar to olive wood. The figuring at the middle of this tree however is more complicated than that. The lighter marking in the middle is where the tree is just starting to rot. If this tree hadn’t been felled it would have become hollow in the centre.

The history of the tree also shows clearly in this wood. This photo, also ash, shows how much difference there can be in the growth rate from one year to another. This tree grew under a cliff by the edge of a river where there was no soil. It therefore grew very slowly. Most years the growth is so slow it is difficult to count the years without having magnified it as in this photo. Yet one year stands out with significantly more growth. Which year? How was it so different?

The way the growth rate varies from year to year has been used by scientists in a discipline called dentrochronology or tree-ring dating. I have come across it due to an interest in prehistory, especially megalithic cultures. The dating of these cultures was by radiocarbon dating but this is not totally reliable and dentrochronology has now calibrated these dates, actually finding that the cultures were older than previously thought. It has also been used to look at past ecologies and dating ancient buildings due to the wood used.There are living trees that are over 5,000 years old (bristlecone pines in America) which has been a great help in dating as these are then matched with dead trees to go back further in time. There has also been lots of work in Germany which has definately dated back over 12,000 years using oak and pine.