The Caspian Hyrcanian mixed forests form an 800-kilometer belt nestled between the Caspian Sea and the Elburz Mountains, lying mostly in northern Iran with portions reaching the Lenkoran lowlands and Talysh Mountains of southeastern Azerbaijan. These are temperate broadleaf and mixed deciduous forests, with Oriental beech the dominant species and characteristic trees including chestnut-leaved oak, European hornbeam, Persian ironwood, the Persian silk tree, and relict genera such as Caucasian zelkova and wingnut. The climate is humid and semi-subtropical at lower elevations, grading to oceanic and humid continental conditions in the mountains, and the high humidity drives exceptional forest productivity. The forests are an ancient Pleistocene refuge often called the "mother of European forests" because many plants dispersed across the continent from here after the glaciations; they were designated a UNESCO World Heritage Site in 2019 (expanded into Azerbaijan in 2023) and shelter wildlife such as the flagship Persian leopard, brown bear, and wolf. Several of their native trees, including the Persian silk tree and Persian ironwood, are familiar to gardeners as ornamentals.

At a glance

About the temperate broadleaf & mixed forests biome

Four-season forests of deciduous hardwoods — oak, maple, beech — often mixed with conifers, shaped by warm summers and cold winters. Trees leaf out in spring and color in autumn; the generally fertile soils have made these forests heavily settled and farmed.

Catalog plants suited to this ecoregion

Computed from each plant's stated USDA zone range against this ecoregion's CHELSA-derived current zone range, with the CHELSA mid-century warming delta applied for the projection. Plants whose stated range falls outside both the current and projected zone end up dropped; the rest land in one of the three buckets below.

Collections for this ecoregion

Curated multi-plant collections whose members all fit this ecoregion's zone range — no won't-grow members smuggled in. Overall fit class shown per collection is the weakest link across its members.

Related ecoregions