Alder (Tree)
Description
Alder trees (Alnus species) are deciduous trees or large shrubs belonging to the birch family (Betulaceae). They are commonly found near rivers, wetlands, and damp woodlands where they play an important ecological role in nitrogen fixation. Alders are recognizable by their drooping male catkins and small, persistent woody female cones. They release abundant pollen in late winter and early spring before their leaves fully emerge. Common species include black alder (Alnus glutinosa) in Europe and red alder (Alnus rubra) in North America.
Allergy Symptoms
Alder pollen triggers early spring allergies and commonly causes:
- Sneezing and runny or congested nose
- Itchy, watery, and red eyes
- Coughing and throat irritation
- Wheezing and exacerbation of asthma symptoms
People allergic to alder pollen may experience Oral Allergy Syndrome (OAS), causing itching or tingling of the mouth and throat when consuming certain raw foods. Due to cross-reactivity with birch pollen allergens, common trigger foods include apples, pears, cherries, peaches, hazelnuts, and almonds. Cooking these foods typically reduces or eliminates the allergic reaction.
Typical Pollination Period
Alder pollen season typically begins in late winter, from January to March, with peak pollen release occurring around February to March in temperate regions of the Northern Hemisphere. As one of the earliest pollinating trees, alder often marks the beginning of tree pollen season. The exact timing varies with climate conditions, occurring earlier in milder coastal regions and later in colder inland areas.
Geographic Distribution
Alder trees are widely distributed across the Northern Hemisphere:
- Europe: Common throughout, particularly in wet lowland areas and along watercourses
- North America: Prevalent in the Pacific Northwest, extending from Alaska to California, and in eastern regions
- Asia: Found in parts of Russia, Japan, and other temperate Asian regions
Tips for Reducing Exposure and Managing Allergies
- Monitor local pollen forecasts and limit outdoor activities during high pollen days
- Keep windows closed and use air purifiers with HEPA filters indoors
- Shower and change clothes after spending time outdoors
- Use antihistamines or nasal corticosteroids as recommended by a healthcare professional
- Be aware of cross-reactive foods if you experience Oral Allergy Syndrome
- Consider allergy testing and immunotherapy for persistent or severe symptoms