Downy Birch Betula pubescens
Downy Birch is a perennial tree native to Greenland. It grows to 41 ft and blooms May. A keystone plant for native insects and the food web.
More about this plant
Betula pubescens, commonly known as downy birch and also as moor birch, white birch, European white birch or hairy birch, is a species of deciduous tree, native and abundant throughout northern Europe and northern Asia, growing further north than any other broadleaf tree. It is closely related to, and often confused with, the silver birch, but grows in wetter places with heavier soils and poorer drainage; smaller trees can also be confused with the dwarf birch. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 5 derived from its U.S. range
- Drought tolerance
- Low
- Shade tolerance
- Low
- Wet-soil tolerance
- Moderate waterlogging
- Height
- 41 ft
- Mature width
- ≈ 19 ft wide wild/forest-grown — open-grown specimens spread wider
- Lifespan
- Perennial
- Foliage
- Deciduous broadleaf
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~411 caterpillar species · keystone genus
Betula supports ~411 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a powerhouse genus.
Recorded feeding on Betula in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees 3 bee visitors
3 native & managed bee species are documented visiting Downy Birch :
Wildlife & visitors 2 birds · 1 nectaring
Open records of who else uses Downy Birch — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 2 birds species (fruit, seed, browse):
1 adult butterfly & moth species is recorded nectaring at its flowers:
How we know this (3) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
Sources for this entry (29) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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