Beech (Fagus sylvatica)
Flowering: April - May
The tree may reach up 30 to 40 meters height. The alternate leaves are oval, with a slightly crenate margin and silky hairs. The straight trunk is smooth and grey. The male catkins are globulous, pendulous and with long peduncles. Female catkins are less visible and are grouped by two in terminal cupules. The beech fruits, called nuts, are grouped by 2, 3 or 4 in soft-spined cupules.
In Belgium, the beech is frequently found in forests. It is often planted in parks and along paths too. The beech prefers some shade and grows on any soil types as long as precipitations are abundant and as the atmospheric humidity is high.
Pollen amounts in the air may highly fluctuate from year to year. High total annual counts are observed only every 5 to 7 year. These years correlate with a high production of nuts. Beech pollen-related allergy is relatively occasional.
Cross-reactive allergy: individuals sensitized to birch pollen may experience allergy symptoms after exposure to beech pollen. Indeed, there is cross-reactivity between the Fagaceae (sweet chestnut, beech and oak) and the Betulaceae (alder, birch, hornbeam and hazel) pollens.