They are found across much of Europe, eastern North America and eastern Asia
Climate
Monthly mean temperature ranges between around -10 & 30 °C, with an mean temperature of around 10 °C
Monthly precipitation ranges between 50 & 200 mm, with an annual precipitation of around 500 to 2000 mm
Rainfall is distributed evenly throughout the year
Summers are warm but not too dry; winters are cool but not too cold
Soil
The soil is brown soil, since it is rich & fertile
Active weathering provides plenty of nutrients, and the annual leaf fall provides organic matter to enrich the soil further
Vegetation
The trees are broad-leaved, like oak, beech, birch, and ash
Their broad leaves causes them to lose a lot of water via stomata, so they shed their leaves in autumn to conserve water in reduced heat & light conditions
There is a wide range of habitats and a rich diversity of life, resulting in a stratification of the vegetation:
A canopy of the tops of trees, mainly oak & ash
A sub-canopy of smaller trees and saplings, such as hazel
A herb layer of brambles, bracken, bluebells, wild garlic and ivy
A ground layer close to the soil that is damp & dark so ideal for moss
For much of the year, it is dark, so flowering plants, like bluebells, normally flower early in the spring before the canopy fully develops