Hyrcanian Forests

The Hyrcanian forests (جنگل‌های هیرکانی) are the broadleaf forests that cover the northern slopes of the Alborz mountains along the Caspian Sea, from Golestan in the east to Gilan and into Azerbaijan in the west. Their history goes back 25 to 50 million years, they survived the ice ages that wiped out similar forests elsewhere, and UNESCO inscribed them as a World Heritage Site in 2019.

Why a rainforest grows next to a desert country

Most visitors expect Iran to be dry, and most of it is. The north is the exception. Moist air from the Caspian is pushed up against the Alborz, a wall of mountains rising to more than 4,000 metres within a few dozen kilometres of the shore. As the air rises it cools and drops its water as rain and mist, so the seaward slopes are green and dripping while the far side, towards Tehran and Semnan, is semi-desert. Annual rainfall on the western Caspian coast, around Gilan, is among the highest in Iran.

The name comes from Hyrcania, the ancient province south-east of the Caspian, centred on the Gorgan plain. Old Persian Varkâna, “land of wolves”, survives in the name of the city of Gorgan.

A forest from before the ice ages

Tens of millions of years ago, warm-temperate broadleaf forest of this kind covered much of the northern hemisphere. Ice-age cold destroyed most of it in Europe and western Asia. The southern Caspian, sheltered by mountains and moderated by the sea, stayed mild and wet enough for the forest to survive. That is why UNESCO describes the Hyrcanian forests as a relict: they keep species and whole plant communities whose relatives elsewhere are known only as fossils.

The best-known example is the Persian ironwood, Parrotia persica (انجیلی, anjili), a tree found almost only here. Its wood is very hard, its trunks fuse where branches touch, and in autumn its leaves turn yellow, red and purple, giving the lower forest its famous autumn colours.

Forest zones from shore to treeline

Lowlands, below about 700 m

The coastal plain was once covered by chestnut-leaved oak, box, alder and ironwood, with figs, date-plum, Persian silk trees and climbers. Most of it has been cleared for rice paddies, tea gardens, citrus orchards and towns, so lowland forest now survives mainly in patches and parks.

Middle slopes, about 700 to 1,500 m

This is the cloud belt and the heart of the forest. Oriental beech (راش, râsh) dominates, alone or with hornbeam, maple, oak and elm, and accounts for about a third of the forest’s timber volume. Mist hangs here for days at a time.

Upper slopes and the treeline

Higher up the trees shrink to Caucasian oak, hornbeam and shrubland, and then open into mountain meadows and steppe. Relict conifers are rare: yew, juniper and a little cypress are almost the only ones.

Animals

The forest still holds a full set of large predators, which is rare in the Middle East: the Persian leopard, wolf, brown bear and lynx, alongside wild boar, jungle cat, badger and otter. Red deer and roe deer live in the eastern forests around Golestan National Park, Iran’s oldest national park. You are unlikely to see the big mammals, but birds are easy to hear: woodpeckers, owls and birds of prey.

Pressures on the forest

The Hyrcanian belt has shrunk greatly over the last century. Clearance for farming and villas, roads cut through the hills, overgrazing, wildfires and decades of logging have all taken a share. Box trees, a key understorey species, have been badly hit by blight and the box tree moth in the 2010s. The UNESCO listing covers selected protected areas rather than the whole belt, and its value depends on the land between them being kept too.

Where to see the forest

• Golestan National Park in the east, on the road between Gorgan and Mashhad, for the most intact forest and wildlife.
• Abr forest (جنگل ابر, “cloud forest”) near Shahrud, where mist pours over the ridge from the Caspian side.
• The Chalus road and Kandovan pass from Tehran to the coast, for a cross-section from bare mountains to dense forest.
• Sisangan and Noor on the Mazandaran coast, lowland forest parks near the sea.
• Masuleh and Gilan’s hills in the west, for forest, rain and tea gardens. See Masuleh and Rasht.

Practical notes

Spring and autumn are the best seasons: April to June for fresh green and wildflowers, October and November for autumn colour. Summer is humid and the coast is crowded with holidaymakers from Tehran. Trails are often unmarked and mist can come down fast, so walk with a local guide or stay on known paths, and carry rain gear in any season. Never light fires in the forest. Check current conditions locally and follow your own government’s travel advice for Iran.

For the region as a whole, its towns, food and roads, read our guide to Shomal, the north of Iran. The mountain that towers over these forests is Mount Damavand, and the nearby travertine springs of Badab-e Surt sit on the forest’s dry southern edge.