1. I'm surprised you were able to find it at all
2. look for more
3. Advise Merchant of your find and ask him why there are ticks on tree and where they came from, what region, Certain ticks carry disease.
If you are sure the tick didnt come from your household, pet clothing or a friends house, then notify your states Health Dept. Your Merchant could be bringing in something even he doesnt know. Last question, did the Merchant have an animal?