Temperate-boreal forests and woodlands biome include moderate to highly productive tree-dominated systems with a wide range of physiognomic and structural expressions distributed from warm-temperate to boreal latitudes.

Although generally less diverse than Tropical-subtropical forests (T1) in taxa such as flowering plants, primates, and birds, these Temperate-boreal forests exhibit greater temporal and spatial variability in productivity, biomass, phenology, and leaf traits of trees. Temporal variability is expressed primarily through seasonal variation in water balance and/or temperature, which regulate the length and timing of growing and breeding seasons. Inter-annual variation is usually less important than in some other biomes (e.g. T5), but nonetheless may play significant roles in resource availability and disturbance regimes (e.g. fire and storms).

Gradients in minimum temperatures, soil nutrients, and fire regimes differentiate ecosystem functional groups within this biome. These influence traits such as leaf form (broadleaf vs. needleleaf), leaf phenology (evergreen vs. deciduous), ecophysiological and morphological traits promoting nutrient acquisition and conservation, and morphological traits related to flammability, fire resistance, and recovery.

The dominant photoautotrophs (trees) engineer habitats and underpin trophic webs. Resource gradients exert strong bottom-up controls on trophic processes, but in some temperate forests, fires are significant top-down consumers of biomass, as well as influencing flammability feedbacks and timing of life-history processes, such as reproduction and recruitment