Forest migration northward. Though "Fagus" and "Picea" populations did not expand directionally, they have grown in the Scandinavian range. The movement of "Picea" species in the past 1000 years has shown a strong connection to climate change through a model comparison. In the more recent past, there has been documentation of elevation shifts in distribution of many core forest tree species of Catalonia. The populations of two tree species (European Beech, "Fagus sylvatica"; and Holm Oak, "Quercus ilex") were evaluated in their dynamics over elevations through time. Generally, Holm Oak reside lower on mountain slopes than does European Beech. In the past
Dioscorea sylvatica variable species, with several extremely distinct varieties. It is threatened from illegal collecting for traditional medicine, as well as for the horticultural trade. As a consequence it is listed as Vulnerable. Dioscorea sylvatica Dioscorea sylvatica ("forest elephants foot") is a species of a twining tuberous vine that is native to Africa. It is common and widespread in forest and thicket, throughout the summer rainfall areas of East and Southern Africa. It produces a distinctively flattened caudex, often with lobes that spread out. The creeping shoots grow throughout most of the year, though each will periodically die back and be replaced