Japanese Cedar (Tree)
Description
The Japanese cedar (Cryptomeria japonica), known as “Sugi” in Japan, is a large evergreen conifer in the family Cupressaceae. It has distinctive needle-like leaves arranged in spirals and reddish-brown, fibrous bark. Japanese cedar is one of Japan’s most important commercial timber species, prized for its rapid growth, straight trunk, and durable wood used in construction, furniture, and traditional architecture. Extensive post-war reforestation created vast plantations that now release massive amounts of seasonal pollen.
Allergy Symptoms
Japanese cedar pollen causes “sugi pollinosis” — the most common seasonal allergic disease in Japan, affecting more than one-third of the population. Symptoms include:
- Sneezing and runny or congested nose
- Itchy, watery, red eyes
- Coughing and throat irritation
- Asthma flare-ups and wheezing
- Skin irritation in some people
Some people experience Oral Allergy Syndrome (OAS), particularly with tomatoes. There’s also strong cross-reactivity with Japanese cypress (hinoki) pollen, so many sufferers have extended symptoms through both pollen seasons.
Typical Pollination Period
Japanese cedar releases pollen from February to April, peaking in March. Timing and intensity vary by region and weather — in southern Japan, pollination may start as early as January; in northern regions, it extends later into spring.
Geographic Distribution
Japanese cedar trees are found mainly in:
- Japan: Native and extensively planted, making up a significant portion of Japan’s forests
- Other regions: Cultivated in parts of China, Korea, and occasionally in other temperate regions for timber; found in some gardens and arboreta in Europe and North America as an ornamental
Tips for Allergy Sufferers
- Check pollen forecasts and limit time outdoors when counts are high
- Keep windows closed and use HEPA air purifiers
- Shower and change clothes after being outside
- Antihistamines or nasal corticosteroids can help — ask your doctor
- Wear masks and glasses outdoors during peak pollen periods
- Watch for cross-reactivity with Japanese cypress, which follows the cedar season
- For severe symptoms, consider allergy testing or immunotherapy