Well, spring has well and truly sprung now and even the oak trees now have leaves changing the tree-scape from the greys and browns of winter to the greens of summer. April, May and June are an intensive period of regeneration in nature, a time when lawns have to be mown regularly, because if they are not, they would turn into a hay field. Hay-making traditionally starts in June when the grasses are ripe and full of energy for feeding to live-stock during the rest of the year when required. If the hay is not cut, succession starts as seeds from other larger species of plants such as acorns from oak trees germinate among the grass-roots and attempt to create an oak woodland.
Every grassland hides a forest trying to get out. If it does, this is called succession. Succession id helped by the animals that visit the grassland, especially the birds. Oak jays are especially adapted to recreate oak woodlands. In the autumn, oak jays obsessively collect acorns from under the oak trees and carry them in a pouch below their beak to an open area (field) and plant them in the soil, ostensibly as a potential cache for the future, but in reality, many are not re-found and germinate. These will get mown down by the next hay-cut, but if the hay is not cut, will develop a new forest. Black-berries will also be eaten from the brambles in the hedgerows by field-mice which will also roam the fields looking for other food. In the process, the tiny seeds will pass through the mice and be expelled, still viable, in the mouse droppings and will germinate among the grasses. Thus, the brambles will also spread into the fields to protect the young oak trees. The many thrush species such as song thrushes, mistle thrushes, blackbirds, redwings and fieldfares will eat the hawthorn berries (haws) in the winter and likewise disperse the seeds in their droppings as they also fly over or forage in the fields. So, young oaks, brambles and hawthorn trees are common successors to grassland and will rapidly grow to create a new woodland. However, it takes centuries to create an ancient woodland in which dozens or scores of other plant species will develop as the cycle of life continues with old trees dying or being blown over to create new clearings into which new species will be introduced by woodland animals and wind such the seed of willows and poplars. Not so much wind in the willows as willows in the wind.