In Anglo-Saxon England substantial parts of the country remained uncultivated and sparsely populated. Forests were extensive in the Weald, in Suffolk, Essex and Middlesex, in a broad belt from the Chilterns in Buckinghamshire through Oxfordshire to Gloucestershire, and in the Welsh Borders. The uplands were already less forested, but similarly uncultivated. Kings hunted in these forests, but no serious restrictions to what the population might want to do there were imposed. This all changed quite dramatically with the conquest of England by the Normans in 1066. William the Conqueror brought with him from the continent a Frankish legal system concerning hunting. The 'beasts of the forest', principally deer and wild boar, became the property of the crown. Forest Law was imposed on large tracts of land that included the Anglo-Saxon forests but also areas like Dartmoor, Exmoor, the Peaks and other uplands with few trees. It even included grazing land, farmland and villages. A Royal Forest became the official hunting ground of the king, where Forest Law, not Common Law, held sway. This law sought to protect the deer and their habitat, i.e. the trees still present after centuries of deforestation. The 'venison and vert' were declared to belong to the king and 'tresspass of the venison and vert' were serious offences. A special court, the Assize of the Forest, traveled through England, divided into two jurisdictions north and south of the River Trent, to hear and adjudicate offences. Under Henry II (r. 1154-1189) the Royal Forests reached their maximum extent, but after his death they went in decline. Even earlier, the kings, strapped for cash as always, had discovered that certain offences such as 'assarting' which amounted to creating farm fields in the forest could be made profitable by imposing fines. Under King John (r. 1199-1216) one of the grievances of his barons was their exclusion from the hunt in the Royal Forests. This led to the granting of more and more 'chases' and deer parks, so that the Royal Forests became more fragmented and smaller. Eventually, whole forests were 'disafforested' which did not primarily mean the cutting of trees, but simply that they were taken out of the jurisdiction of Forest Law. Finally, this law was last brought to bear in 1635 after which growing trees for timber, not hunting, became the primary objective in what remained of the Royal Forests.
With all its injustices and imperfections it is likely that the Royal Forests and Forest Law have slowed down the conversion of land so protected into more intensive uses, be it agriculture or modern forestry. Keeping the land uncultivated and more or less wild has contributed to the preservation of ancient oaks in England. Royal Forests in France and Germany became state forests in which plantation forestry on a large scale was taken up much earlier than in England. As a result, about 7.5% of ancient oaks in England are today growing in the remains of the Royal Forests of England. Perhaps the most famous of all, the Major Oak, stands in a remnant of Sherwood Forest.