Classification and distribution of forest by geography

The development of the main systems of vegetation classification based mainly on climatic factors is described and physiognomic, floristic and ecosystemic approaches are highlighted. The excursus ranges from the former idea of classification defined by a historical perspective to the recent synthetic expressions that represent and predict real and potential vegetation. Next, the classification of vegetation is described by means of climograms, which are synthetic expressions of the effect of climate on forests. New techniques of classification based on remote sensing are briefly discussed. Detection of vegetation with optical and radar sensors and the subsequent supervised or unsupervised human classification is analyzed. Main forest ecosystems classification is reported finally and forests' distribution on the Earth regions (Africa, Asia, Europe, North and South America, Oceania) is illustrated.