Tree form is the description of a trees natural shape, when left to grow naturally the tree can be beautiful and awe inspiring . In the growing season deciduous trees can look huge and full of life, and you usually can see how the tree has grown and shaped itself for it's environment, how a solitary tree presents a unified smooth outline to allow the wind to move around the tree rather then through it, or how it shares the space with other trees so they can all catch sunlight, and how they cooperate/compete in presenting a uniformed smooth guiding face to prevailing winds. The mix and splash of colour and texture of a mixed woodland or forest can be a very pretty sight, and this mix comes to its best in autumn as each individual tree in the woodland, prepares itself for the onset of winter. This is the time when in turn each tree stands out from the crowd and displays it's autumn colours like debutants at a ball.
Trees growing in Britain, not all are Natives trees
But it's winter time with the branches bare that the beautiful can turn to inspiring when the skeleton is laid bare and the true complexity and symmetry of the trees structure can be seen. When you can study how the lower branches grow in a way to shade it's trunk from the scorching heat of the sun, and how the tree tries to shade the ground to keep it's roots cool, and how the upper branches grow in a way to allow rain to be caught and directed so the rain water is channeled down the trunk towards it's roots, or other trees that sluices the rain off like a raincoat so it's trunk does not get wet.
All trees have a method and purpose in life and that's to survive and procreate.