It’s the main accurate way, at least for living trees. By the way, I’m including cross-dating here since even though it’s slightly different from ring counting, it uses the same basic idea just extended to a wider group of trees.

There are other methods but none really have a proven track record of accuracy the way tree-ring based methods do.

For well documented trees that coexisted with literate cultures, historical records can be used, though these records can sometimes be wrong. Some trees have ages from oral tradition too but these are difficult to verify.

Overall, I view non-ring-based methods with skepticism and some are outright preposterous, especially the common claims you see online which have no methodology listed. But even some published estimates using alternative techniques seem dubious. Perhaps they will be replicated and proven in the future but the evidence is tenuous today.