Аннотация:Tree populations change in distribution, abundance and association in response to long-term changes in climate. Isopoll maps for selected taxa in western Eurasia and eastern North America illustrate features of these 'migrations' which can be seen on both continents despite their major geographical contrasts and the different taxa involved. These maps show differential rates and directions of migration among taxa and illustrate different behaviour among taxa that today share similar distributions and/or grow together in communities. Communities are thus shown to be merely temporary assemblages of species brought together by the environmental conditions prevailing at any particular time. Migration of plant taxa is considered as a response to orbitally-forced climate changes at timescales of 105 years, and is compared to bird migration as
