The Environment From the fifth to the tenth centuries, most of Europe was covered with vast forests. Thus the land available for agriculture was limited. Also, peasants dissatisfied with their conditions could flee from oppression and take refuge in the forest. Europe was undergoing an intensely cold climatic spell in this period.
This led to severe and prolonged winters, a shortened growing season for crops, and reduced yields from agriculture. From the eleventh century, Europe entered a warm phase. Average temperatures increased, which had a profound effect on agriculture. Peasants now had a longer growing season and the soil, now less subjected to frost, could be more easily ploughed.
Environmental historians have noted that there was a significant receding of the forest line in many parts of Europe. This made expansion of the area under cultivation possible.