The tree species are irreplaceable long-life photosynthesis organisms, they colonized almost everyone vegetation zone. They were able to adapt to conditions of semiterrestrial and terrestrial ecosystems were they create specifi communities. The second phenomenon which tree species in its development submittd is the height gradient – change in altitude. The total amount of precipitation, heat alternatively drought is the most important factors in forest communities creation in forest vegetation gradient. In a changing climate are some forest communities respectively rare tree species (stenoecious species) endangered and is assumed their replacement with euryecious species with higher degree of biodiversity. Therefore is today very important rescue and archiving of endangered tree species but generally all native gene resources as well as in nature also in botanical gardens and arboretums.