Alder (Alnus) is as a rule the first species whose pollen reaches the air in Serbia. It flowers in late winter, often before anything else has come into leaf, so the trouble it causes is regularly mistaken for a cold — a "winter cold that will not clear" in February is very often a reaction to alder pollen.
What alder is and where it grows
Alder is a deciduous tree of the birch family (Betulaceae), tied closely to wet ground. The two common species in Serbia are black alder (Alnus glutinosa), which grows along rivers and in floodplain forests, and gray alder (Alnus incana), more frequent in the hills and mountains of western and south-western Serbia.
It is recognizable by its dark, fissured bark, rounded leaves with a slightly notched tip, and the small woody cones that stay on the branches through winter. In spring it carries elongated hanging catkins that release the pollen.
Season and distribution in Serbia
The alder season runs from February to April, usually peaking in March. In mild winters flowering starts as early as late January. As with the other early spring species, the weather drives the course of the season: a few warm days in a row open the catkins, and a cold spell halts flowering for a while.
Its distribution follows the watercourses. Alder is most abundant in the floodplain forests and riverside belts of the Sava, Danube, Drina, Tisa, Tamiš, and Velika Morava, in the wetlands of Srem and Bačka, along the Kolubara near Valjevo, and along the Ibar and Zapadna Morava. People living in the riverside districts of Belgrade, Novi Sad, Pančevo, Šabac, and Valjevo are more exposed than those in city centers away from the water.
Modeled data for Serbian cities
For cities in Serbia, pelud.net does not show measured values but an estimate derived from the European CAMS model (via the Open-Meteo service). The model describes the start and course of the season and the differences between regions well, but it does not capture the alder stand two hundred meters from your building. Pollen measurement in Serbia is carried out by the Serbian Environmental Protection Agency through its network of aeropalynological stations.
Symptoms
- sneezing and a runny nose in late winter
- blocked nose
- itching and watering eyes
- itching of the palate and throat
- in people with asthma, worsening symptoms, especially in cold, dry air
The key difference from a cold: the trouble lasts for weeks, there is no fever, and symptoms are worse outdoors in dry, windy weather than indoors.
Cross-reactivity with birch, hazel, and food
Alder, hazel, and birch belong to the same order, Fagales, and their main allergens are related. Someone who reacts to one of them as a rule reacts to the others, so the seasons run into one another: alder and hazel in February and March, birch in April, hornbeam and oak in May.
Because of the similarity to birch's main allergen (Bet v 1), alder allergy also brings oral allergy syndrome with apple, hazelnut, peach, carrot, and celeriac. Cooked or baked foods as a rule cause no trouble.
Treatment
- Second-generation antihistamines relieve sneezing, itching, and discharge.
- A nasal corticosteroid spray should be started as early as late January if you have had symptoms in February in previous years — starting preventively works better than responding to symptoms already under way.
- Eye drops for pronounced conjunctivitis.
- Immunotherapy for birch and related species also covers alder, since it targets the shared allergens of the Fagales order.
Practical tips
- Do not write February symptoms off as a cold — if they recur every year at the same time, talk to your doctor about allergy testing.
- Plan riverside walks and time in floodplain forests during February and March for the days after rain.
- Keep windows closed in dry, windy weather and ventilate in the evening.
- Sunglasses and a scarf reduce contact between pollen and your eyes and face.
- If you work in riverside forests or do any felling, wear a mask — cutting trees during the season releases large amounts of pollen.
Note
This is not medical advice. For an assessment of symptoms, treatment, or immunotherapy, consult your doctor or an allergist.