Betula pubescens

Downy Birch

Physical Traits & Growth

Typical max. heightiMaximum height in typical conditions, in metres. Full data also shows maximum achievable height in exceptional conditions.:
20m 1
25m 5
Usually up to 20m, rarely 25-30m 6
28m 7

Max. canopy widthiLikely maximum horizontal width of the canopy, in metres:
Irregular, ovoid to conical, 6-8m wide 1
4-8m wide 2
Irregular 3

Size of shadowiSize of shadow based on a fully grown tree, categorised as low, medium or high: Low (144 sqm)

Canopy densityiShading intensity of the canopy when in full leaf. Categorised from open to dense.:
Open 1
Light 2

Leaf emergenceiTime of leaf emergence, categorised as very early, early, late, or evergreen: Early (Apr to Nov 1)

Growth rateiHow quickly the tree grows during establishment. Categorised as low, moderate or high, with very high used in exceptional cases.: Moderate to high 12

LongevityiExpected lifespan of the tree: Longevity of 100-200 years 2 or up to 100 years 8

Management & Systems

Typical systemsiCommon agroforestry or silvicultural systems where this species is used:
Well suited to upland conditions 12, even more so than Betula pendula 2
Pasture 5

Approach to silvicultureiCoppicing and pollarding ability:
Weak at coppicing 3
Can be coppiced on long rotation 1

Establishment requirementsiCommon requirements to establish the tree:
Fast growing 1
Regular mulching required because sensitive to weed competition 5
Susceptible to browsing 6
Risk of poor growth in tubes 9

Management requirementsiCommon long-term management needs such as pruning. Categorised as low, moderate or high.: Minimal or no pruning 1

Pruning timeiOptimal season for pruning: Summer or winter (mid) 1

Downy Birch, Reading, UK / Tom Staton / https://creativecommons.org/licenses/by-sa/4.0/deed.en

Products & Economy

Food productsiCommon food products such as fruits and nuts: –

Wood productsiCommon wood products, including timber, turnery, and pulp:
Timber 1, pulp 5
Max YC 8 4 or 7 2

BiomassiCommon biomass products such as fuelwood: Fuelwood 5

Speciality productsiOther speciality and niche products: Tree sap 5

Time until market (food)iNumber of years until the tree produces food products: –

Time until market (timber)iNumber of years until the tree produces wood products: 30-40 year timber rotation 6

Ecology & Utility

Nutrient and organic matter accumulationiRough estimate of soil-improving properties, with larger and deeper-rooting trees predicted to have higher value. Categorised as low, moderate or high.:
Low – shallow to moderate root depth, small canopy area
Useful for reforestation of acid soils 68

Nitrogen fixationiNitrogen-fixing properties, categorised as yes or no: No

High carbon sequestrationiAll trees sequester carbon, but faster-growing, larger trees generally have higher sequestration potential.:
Short-term (20 years): Moderate
Medium-term (40 years): Moderate
Long-term (60 years): Relatively low

Native status in the UKiCategorised as native, long-established, or recent introduction.: Native 1

High wildlife valueiMost trees are likely to be of some value to wildlife, but some trees are of generally higher value to various wildlife groups:
High 5
Highest value for mycorrhizal fungi and foliage invertebrates 5

Pollinators

Flowering period (pollinator benefit)iTypical flowering months: Apr-May 1

High pollen and nectar value for pollinatorsiValue of flowers to pollinators: Low 1

Susceptibility & Risks

Risk of toxicity to livestockiReported potential toxicity to livestock, categorised as yes or no. Toxicity is complex and often context-specific.: None known

Risks to farming operationsiOther risks such as suckering roots, very large tree size, secondary host for aphids, and flammability: None known

Disease susceptibilityiSusceptibility of the tree (not tree products) to diseases, e.g. fungal and bacterial disease:
High
Host to a very high number of pathogens, especially fungi 9
Susceptible to birch dieback 3
Highly susceptible to honey fungus 5
May be susceptible to honey fungus, a tree rust and powdery mildews 6

Invertebrate pest susceptibilityiSusceptibility of the tree (not tree products) to invertebrate pests, e.g. aphids and other insects:
Low (high future risk)
Few pests 5
May be susceptible to birch borers, leaf-mining sawflies, and aphids 6

Vertebrate damage susceptibilityiSusceptibility of the tree (not tree products) to vertebrate pests, e.g. squirrels and deer:
Low to moderate
Low sensitivity to browsing 7, moderate palatability 8
‘Sometimes’ browsed by deer, and preferred over B. pendula 5