Downy Birch
Betula pubescens
The downy birch is a pioneer tree species primarily distributed in raised bogs, carr forests, and on wet, nutrient-poor soils. It is characterized by its white bark and velvety, pubescent young twigs, which distinguish it from the silver birch. The tree typically reaches heights of up to 20 meters and is extremely frost-hardy and tolerant of high water tables.
Details
Oxygen production
Photosynthetic oxygen production during the growing season.
Habitat function
Important nesting site for birds; food plant for butterfly larvae; host for mycorrhizal fungi.
Nutrient uptake
Efficient nutrient uptake from extremely acidic and nutrient-poor substrates.
Food source for
Redpoll (seeds), Black Grouse (buds), over 100 specialized insect species.
Human use
Use of wood for furniture and plywood; birch sap as a tonic; leaves for teas (diuretic).
Ecology
Ecological role
Pioneer tree species in bog succession; provides habitat for specialized insects and birds; contributes to humus formation.
Natural predators
Phytophagous insects such as the birch sawfly; fungi such as the birch polypore (Piptoporus betulinus).
Competitor species
Scots pine (Pinus sylvestris) on drier bog sites; Alder (Alnus glutinosa) in carr forests.
Ecosystem service
Carbon sequestration in peat soils, water retention in the landscape, erosion control on banks.
Threats
Drainage of bogs, peat extraction, eutrophication of sites, climate change (drying out).
Scientific profile
Profile
Protection & threats
Main threats
Drainage of bogs and wetlands, eutrophication (nitrogen deposition), falling groundwater levels due to climate change.