Gu shu (古樹, gǔshù)
Gu shu (古树) means “old trees.” In a tea description, especially for pu-erh, it is a claim about the age of the plants supplying the batch.
The word alone does not tell you the exact age or the proportion of old-tree material in a blend. Ask what age the producer means, where the tea was picked and whether the claim covers the whole batch. An old tea garden can be planted and managed by people; “old” does not mean “wild.”
Plant age is one of many influences on flavour. Cultivar, site, season, cultivation, picking, processing and storage also matter. Tea from younger plants can taste good too.
Body, sweet aftertaste, infusion count and cha qi are not home tests for gu shu. Before an expensive purchase, ask for origin and batch information, the basis of the age estimate, and a sample of that very tea. A high or low price alone proves neither authenticity nor fraud.
Related teas
Chinese tea glossary