Does the Type of Plywood Affect Its Strength?

The difference in strength may be minimal, but it does exist. In general, better plywood quality is determined more by the face veneer, the number of layers, and the core material rather than just the outer species. Just a heads up, the sanded plywood from most big box stores is often low quality.

Generally, the plywood species doesn't make a huge difference in strength since it's usually just the outer layer that varies. Most of the strength comes from the inner layers which are made the same way across different types.

It really depends on the core material. For example, softwood plywood can sometimes feel damp and less sturdy, whereas Baltic birch tends to feel solid and is stronger. Also, you can often tell the quality by the price—higher-priced plywood tends to be better quality!

Definitely, hardwoods are generally stronger than softwoods, both in plywood and solid lumber.