Birch, Bees, and Biology: Does Science Suggest We Should Site Hives Near Birch Trees?

Based on: Biedermann et al., 2019 – Phase III trial of birch-pollen SLIT-tablet

birch-pollen-allergen

Birch Pollen Allergen Bet V1 (from Wikipedia)

Why a Clinical Allergy Trial Matters to Beekeepers

Although the attached paper is a medical study—testing a birch-pollen immunotherapy tablet—it contains valuable ecological and botanical information about birch pollen, related tree species, and pollen abundance. These findings help us understand:

  • How birch trees behave as pollen sources
  • The timing and scale of birch pollen production
  • Cross-reactivity within birch-related trees (alder, hazel, hornbeam, oak)
  • Whether birch pollen has attributes that could influence bees, forage, or apiary siting

The paper is not about bees, but its detailed pollen data (timing, intensity, season length) and species relationships provide useful context for assessing whether birch trees are beneficial companions for apiaries.

by the Scientific & Technical Working Group: Karl Colyer and Paul Verrier

What the Paper Shows About Birch and Its Relatives

The study revolves around the birch-homologous group of trees which all include the highly allergenic Bet V1 protein in their pollen.

The paper states clearly on page 2:

  • The birch group includes birch, alder, hazel, hornbeam, and oak.
  • These trees have similar Bet V1 allergens, with highly related protein sequences and strong biological cross-reactivity.

While this is framed in the context of human allergy, it also tells us that these trees share evolutionary, biochemical and seasonal characteristics—relevant when considering their value as early forage for bees.

Birch pollen season characteristics
The trial provides unusually precise pollen data (page 4):

  • Birch pollen season length averaged 24 days, ranging from 10–42.
  • Daily birch pollen counts averaged 284 grains/m³, with peaks up to nearly 800.
  • Alder and hazel seasons precede birch but do not fully overlap.

This confirms birch is a high-volume pollen source in early spring—something important for brood development.

Is Birch a Valuable Forage Tree for Honey Bees?

Pollen value

Birch is wind-pollinated, not insect-pollinated. This means:

  • It produces large quantities of pollen
  • The pollen is readily accessible to bees
  • Birch provides pollen very early in the season, when colonies need protein for brood rearing

Bees are known to forage on birch pollen opportunistically. It is not their absolute favourite compared with willow, hazel or early herbaceous species, but they will use it when available—especially during pollen scarcity.

Nutritional considerations

Birch pollen is moderate to good in terms of protein, and, critically, available in abundance when few other trees are producing. In areas lacking willow, or in cold springs, birch may play a supporting role in sustaining brood build-up.

Seasonal stagger with other species

Because hazel and alder typically release pollen before birch, and oaks follow later, planting or working near these species creates a progressive tree pollen sequence:

 Hazel → Alder → Birch → Oak

This can give colonies several weeks of continuous pollen flow—a major advantage in early spring.

Does Birch Pose Any Drawbacks for Apiaries?

1. Human allergy concerns

The paper demonstrates that birch pollen is one of the most potent aeroallergens in Europe. (page 2: sensitisation in Europe ~24%; alder 21%, hazel 23%).

However, keeping hives near birch does not increase pollen exposure to nearby people, because bees do not spread birch pollen; birch is wind-pollinated.

The clinical trial confirms birch is allergenic to humans—not that it is problematic for bees.

2. Nectar value

Birch provides little to no nectar, so it will not support honey production. Its usefulness is mainly as an early pollen source and for ecological diversity.

Would BIBBA Members Benefit from Placing Hives Near Birch Trees?

Benefits

  1. Reliable early-season pollen source
    Birch produces abundant pollen during a critical period for colony expansion. High pollen counts documented in the paper (page 4) confirm its productivity.
  2. Complements other native tree species
    Birch fits neatly within the early forage calendar alongside hazel, alder and willow.
  3. Supports native bee ecotypes
    The Amm-type colonies traditionally handled by BIBBA members tend to build up early and steadily. Access to a sustained pollen flow is valuable for these genetics.
  4. Landscape-scale benefits
    Birch is a pioneer species, supports biodiversity, and thrives in marginal soils—making it well-suited to environmental improvement work alongside beekeeping.

Limitations

  • Birch alone will not sustain colonies; its pollen is helpful nutritionally but not exceptional.
  • It lacks nectar, so it cannot replace willow or early-flowering shrubs.

Final Conclusion

Yes—it is beneficial to keep hives near birch trees, particularly when integrated into a diverse spring forage landscape.

The attached paper provides strong evidence that:

  • Birch is a prolific source of early-season pollen
  • It forms part of a cluster of trees with staggered but overlapping pollen seasons
  • Its pollen production levels are high and seasonally reliable
  • There are noadverse implications for bees or apiary management

Therefore, BIBBA members can confidently treat birch as a useful complementary forage tree, especially where willow or hazel are limited. While birch is not the best spring tree in isolation, its combination of abundance, timing, and ecological resilience makes it a valuable asset in landscapes that support sustainable, locally-adapted beekeeping

Notes from the BIBBA Scientific & Technical Team

  1. It is a pity they did not publish the pollen counts of the other related species. Yes, the species overlap in production and if you are in an area that is good and damp, then you may well get all these growing and delivering pollen in sequence. Yes, it is good to locate colonies near these.
  2. Similar wet areas also frequently give rise to the pendulous sedge (Carex spp) which provides huge pollen loads in early spring and is another opportunistic source for honeybees.
  3. Oak is now being frequently planted around the edges when woodlands are cleared out and is also a good source of pollen.
  4. In terms of it being safe to put bees by all these trees - yes as long as the beekeeper does not suffer from the allergens in the pollens.