Because I recently needed to research my family history, in order to take part in a DNA study into mental illness, I became interested for the first time in starting to compile my family tree in a more detailed and organised way. I haven’t started doing it yet, but I have been thinking about the whole idea, and in particular the image of a ‘tree’.

The usual picture of a family tree has ‘me’ (or the person compiling their own tree) at the base, as the trunk of the tree. The trunk then splits into two main branches, which are the parents, and then further subdivides into smaller branches and eventually twigs as you progress through the generations. And this picture is so well-accepted that I’ve never questioned it before, but something seemed to niggle at me, and I’ve been turning the idea over in my head, and I’ve figured out what it is.

The tree shouldn’t start with me at all. It ends with me. I am the product of all those generations, not their source – and all those ancestors are my roots, not my branches. To find out their histories I have to dig down, delving into the murk of the past to clear the earth off those roots. Some will be strong healthy roots, which have spread out and started new saplings of their own. Others may be withered and brittle, soft and delicate with damp rot, gnawed by rodents, infested with weevils, or cut off abruptly with a sharp spade. Some will stretch into the distance, eventually narrowing to the tiniest tendrils and tangled threads in the thick clay of deep history.

So the trunk of this tree is still me, the present generation – but in this case the spreading branches and twigs will be the future, all the generations and descendants yet to come. In the case of my own family, however, this presents a picture of a rather spindly little tree, with three sibling branches and only one twig. (As opposed to my husband’s, for example, which is a huge sprawling forest, consisting of dozens of cousins, littered with ex-partners, step-children and half-siblings, and with a next generation of hundreds of green and leafy little twiglets.) Our one twig could go on to spread further, of course, but I’m still unsatisfied with this image. It seems to be a picture of a bush with multiple stems, not a tree at all – as my generation consists of three people, not just me. And it is inexorably entwined with other family bushes, through marriage – after all, our sole twig has two parents, not just the one related to me, and through the other branch it has cousins and uncles and grandparents and other roots and branches not connected with ours, but spreading out and down in the same patch of soil, and up into the same sky.

So for each person to imagine their own personal tree is really a false image, although it might say something about how we view our own place in the world – naturally, we are each the centre of our own universe, and it couldn’t be otherwise. We are actually all part of one forest, though – the entire human race is related to each other if you dig deep enough into prehistory, and even recent generations have roots so tangled and criss-crossed together that separating them into individual ‘families’ seems almost futile. For genetic research, obviously we need to be able to identify bloodlines, and at its most simple level, each individual of course has only two parents, so the traditional ‘tree’ picture has a practical use.

But it shows nothing about how families and relatives really are. We are not all individual trees with our own set of roots and branches – how could we be? We are more like stems of one enormous bramble bush, with roots spreading in all directions, branches crossing and re-crossing, new stems shooting out at odd angles or running underground to burst out of the undergrowth in a new place. There are tough old grandmother branches surrounded by bright young twigs, and solitary thorny stems which unexpectedly burst into fruit high up out of reach; pushy adventurous stalks which climb buildings, colonise clearings and peer over fences; sneaky vine-like ones which cling to neighboring trees; and occasionally a hopeless tangled mass with an unsuspected empty centre, providing a fortified hideout for an enterprising squirrel or a shy fox.

I think in my case I will be less interested in exactly how each rootlet is connected to the others than I am in their individual stories – I would like to know more about their lives, not just births, deaths and marriages. I will, though, be fascinated by traits which appear to crop up repeatedly through generations, especially those that I feel I may share. This was the original purpose of my existing research, after all – to see if I could identify a recurring history of mental illness in my own family. It does seem to be there, although there has been no previous diagnosis that I know of yet. Further and more detailed research may dig up more definite results though – time to get out the spade.