Temperate forests are resilient survivors of a 65-million-year climate cooling trend

Nature · Published 3 October 2026 Swipe more like this →

In short: Spanning 10 million square kilometers, temperate forests are not just collections of trees but dynamic ecosystems shaped by deep history. From the Cenozoic Era to the modern day, these forests have navigated ice ages, migration, and human expansion, evolving unique strategies to endure the planet's most fluctuating seasonal climates.

Temperate forests emerged roughly 65.5 million years ago at the dawn of the Cenozoic Era as global climates cooled and became increasingly seasonal. As tropical environments retreated toward the equator, plant lineages either went extinct or adapted to the new, cooler conditions. This evolutionary pressure birthed the three primary forest types: deciduous trees, which evolved from rainforest ancestors to survive winter dormancy; evergreen broad-leaved forests, which thrived in consistently moist regions; and sclerophyllous forests, which developed thick, hard leaves to withstand erratic rainfall.

The survival of these forests has been a constant battle against climatic instability. During the last two million years, rapid cycles of glacial ice ages and warmer interglacial periods forced tree species to migrate to remain within suitable temperature ranges. This migration was limited by geography; mountains and seas acted as barriers, leading to local extinctions. In Europe, for example, species like the buckeye and sweet gum were pushed out of their natural ranges, leaving behind a floristically impoverished landscape compared to the diversity found in other regions.

Human impact has further reshaped these biomes over millennia. By 8,000 years ago, Mediterranean sclerophyllous forests were already being cleared for timber and agriculture. Similar patterns followed in China 4,000 years ago, and by 500 years ago, Europe’s original deciduous forests had largely vanished, surviving primarily in folklore. In the Southern Hemisphere, the influence was equally profound; Aboriginal burning practices over 38,000 years expanded Australian sclerophyllous forests, while Polynesian settlers in New Zealand destroyed roughly half of the country's native forest cover within a millennium of their arrival.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• Temperate forests stack four living layers beneath canopies up to 61 metres tall
• Pacific temperate rainforests are the last global stronghold where ancient conifers still dominate landscapes
• The tallest and oldest living trees on Earth are both conifers
• Why old-growth forests are more than just a collection of very ancient trees
• The invisible boundary in our oceans that can hide submarines and trap heat
• Sulfur is the silent engine driving life, decay, and the chemistry of our planet.
• Why these forests shed their leaves to survive months of intense seasonal drought
• Why some tropical forests shed their leaves while others remain lush and green
• Why do some of the world's most iconic landscapes struggle to grow trees?
• Hidden underwater prairies are essential to our planet's climate and marine health
• Why the world's most productive ecosystems are vanishing at an alarming, unsustainable rate
• The ocean's skin is a massive, living chemical reactor covering most of our planet.

More in Earth science basics · More in Nature · Latest · A–Z · All topics