(according to/nach: Fischer & al., Exkursionsflora 2008/3rd Ed.)
Altitudinal zones vary with climate - they're not measured in 'absolute' metres but are defined by the plants growing there. The tree line for example may vary according to exposition (southerly, northerly, etc.) and landform/profile, but also according to climate (lower in 'Pannonian' Eastern Austria, significantly higher in more 'Atlantic' Western Austria).
NIVAL ------------ above snow line - Gletscherstufe: Kryptoplankton, Nunatakkerfluren
~~~~~~~~~~~~~~~~~~ 2800-3100 msm ~~~~~~~~~~~~~~~~~~
SUBNIVAL ------ just below snow line - Gletscherzungenzone: Polsterpflanzen, Moose, Flechten~~~~~~~~~~~~~~~~~~ 2500-2800 msm ~~~~~~~~~~~~~~~~~~
ALPIN ------------ Alpine zone, no trees - gehölzfreie Zone (ausser Zwergsträucher)
~~~~~~~~~~~~~~~ 1900-2300 (2500) msm ~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~ 1800-2100 (2300) msm ~~~~~~~~~~~~~~~
SUBALPIN ------ 'twisted wood' zone - Krummholzzone
TIEF-SUBA. ----- (Randalpen) aufgelockerte Fichtenwälder; (Innenalpen) Lärchen-Fichten-Wälder
~~~~~~~~~~~~~~~~~~ 1500-2000 msm ~~~~~~~~~~~~~~~~~~
OBER-MONT. --- (Zwischenalpen) Fichten-Tannen-Wälder; (Innenalpen) Fichten-(Lärchen)-Wälder
MONTAN -------- mountain zone (woodlands) - bewaldete Bergstufe (geschlossener Wald)
~~~~~~~~~~~~~~~~ 700-900 (1000) msm ~~~~~~~~~~~~~~~~
UNTER-MONT. - (Randalpen) Buchenwälder; (Innenalpen) Fichtenwälder~~~~~~~~~~~~~~~~~ 350-450 (600) msm ~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~ 250-400 (500) msm ~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~ 0 msm ~~~~~~~~~~~~~~~~~~~~~