Tree pollen

• Birch: Particularly aggressive allergens. Most common tree pollen sensitization in Germany. The pollen flies from April to May. Size: 16-31 µm. The most important birch allergen is Bet v 1. Cross allergies: to pollen from alder, hazel, oak, copper beech, hornbeam and sweet chestnut but also to apples, aniseed, apricots, avocados, bananas, basil, pears, chili peppers, cashew nuts, dill, fennel, hazelnuts, carrots, potatoes, cherries, kiwis, coriander, caraway, lovage, lychees, almonds, marjoram, mangoes, oregano, peaches, peppermint, plums, pistachios, celery, tomatoes and thyme.
• Beech (Carpinus betulus = hornbeam) Allergies are rare. The pollen flies from April to May and is 45-50 µm in size. The marker laying is Car p 1. Cross allergies: to pollen from birch, oak, alder and hazel.
• Oak: Allergies are rare. The pollen flies from April to May. The pollen grains are 16-37 µm in size. The main allergen of oak pollen is the protein Que a 1. Cross allergies: to pollen from birch, beech, alder and hazel.
• Alder: Frequent sensitization. The pollen is considered to be very aggressive. They fly from February to April. Size: 14-35 µm. The main allergen of alder pollen is the protein Aln g 1. Cross-allergies: to pollen from birch, beech, oak, hazel.
• Ash, common: Rarely allergies; if sensitization exists, then usually as severe allergic reactions. The pollen flies in March and April. Size: 18-26 µm. The main allergen is Fra e 1. Cross allergies: to pollen from olive tree, lilac, privet and forsythia.
• Hornbeam: Rare allergies; the pollen flies in April and May. Size: 22-36 µm. The main allergen of hornbeam pollen is the protein Car b 1. Cross-allergies: to pollen from birch, hazel and alder.
• Hazelnut: second most common allergen among tree pollen. Hazelnut pollen allergy is sometimes already noticeable in January. The pollen flies from January to March. Size: 8-32 µm. The main allergen of hazel pollen is the protein Cor a 1. Cross-allergies: to pollen from birch, alder, copper beech.
• Chestnut (horse chestnut): Insect-pollinated plants; pollen is not wind-borne. Allergies to chestnut blossoms are rare. Chestnut blossom between April and June. Pollen size: 15-35 µm. Cross-allergies are not known.
• Pine: Most common allergen among all conifer pollen. Sensitization is rather rare. Pollen season: May and June. Allergies to pine pollen only occur in combination with other sensitizations.
• Lime: Insect and wind-pollinated plants. The pollen is only present in low concentrations. Rare allergies. Flowering time: June and July. Pollen size: 18-37 µm. Cross-allergies are not known.
• Olive: Pollen sensitization not present in Germany. Allergy widespread in the Mediterranean region. The pollen flies between April and June. Size: 17-24 µm. Main allergens: Ole e 1 to e 6. Cross allergies: to pollen of ash, privet, lilac, pineapple and horseradish.
• Black poplar: Pollen sensitization is rare. Flowering time: March and April. Size: 25-32 µm. Cross-allergies are not known.
• Elm: Allergies are very rare; usually only as a concomitant symptom with other sensitizations. The pollen flies in March and April. Size: 28-38 µm.
• Willow: Insect-pollinated plants. Rarely causes allergies. Flowering time: March to April. Pollen size: 16-28 µm. Cross-allergies are not known.

In contrast to grass pollen, allergenic tree pollen comes from different plant families distributed in very different geographical regions.