Can I take Tasmanian Huon pine wooden gifts into China, coasters, place mats?

If it is not made of rare or valuable materials like sanders, it would be ok for you to bring. And you'd better declare it at the customs. Besides, you can bring the introduction or other certificates to prove the materials when declaration.

Coasters and place mats are allowed to enter China. Don't worry. Just put them in your checked luggage.