Altitudinal zonation: Difference between revisions

The humidity of certain zones, including precipitation levels, atmospheric humidity, and potential for [[evapotranspiration]], varies with elevation and is a significant factor in determining altitudinal zonation.<ref name=frahm1991 >{{harvnb|Frahm|Gradstein|1991}}</ref> The most important variable is precipitation at various elevations.<ref>{{harvnb|Daubenmire|1943|pp=349–352}}</ref> As warm, moist air rises up the windward side of a mountain, the air temperature cools and loses its capacity to hold moisture. Thus, the greatest amount of rainfall is expected at mid-latitudesaltitudes and can support [[deciduous forest]] development. Above a certain elevation the rising air becomes too dry and cold, and thus discourages tree growth.<ref name=autogenerated1 /> Even though rainfall may not be a significant factor for some mountains, atmospheric humidity or [[aridity]] can be more important climatic stresses that affect altitudinal zones.<ref name=stadel1990 >{{harvnb|Stadel|1990}}</ref> Both overall levels of precipitation and humidity influence soil moisture as well. One of the most important factors that control the lower boundary of the Encinal or forest level is the ratio of [[evaporation]] to soil moisture.<ref name=shreve1922>{{harvnb|Shreve|1922}}</ref>