The wood itself would be a soft wood. It is the glue and the preservative that makes it marine grade. Also it is not supposed to have any voids in the inside of the sheet.
There are both softwood plywoods (made from either Southern yellow pine or Douglas fir) and hardwood plywoods. Hardwood plywood comes in four types: poplar plywood, which is poplar all the way through; MDF core, which has veneers of hardwood glued to the faces of MDF; veneer core, which is poplar plywood with veneers of higher-cost hardwoods glued to the faces; and marine hardwood, which is high-strength hardwood all the way through. The last one is very expensive, and hard to find.
Almost all plywood is made from softwood however some plywood it made from hardwood.
Any strong wood. In the US, softwood plywood is generally made from Douglas fir or southern yellow pine. Most hardwood plywood is "veneer core." This means they make sheets of plywood from poplar--an inexpensive hardwood but plenty good for plywood--then put veneers of a more expensive hardwood on both sides of the finished sheet. If you run into oak "marine plywood" all the plies are made from oak. Oak is extremely hard to make into good plywood cores because it is so hard, so oak marine plywood is really expensive.
Any strong wood. In the US, softwood plywood is generally made from Douglas fir or southern yellow pine. Most hardwood plywood is "veneer core." This means they make sheets of plywood from poplar--an inexpensive hardwood but plenty good for plywood--then put veneers of a more expensive hardwood on both sides of the finished sheet. If you run into oak "marine plywood" all the plies are made from oak. Oak is extremely hard to make into good plywood cores because it is so hard, so oak marine plywood is really expensive.
Softwoods, Hardwoods and Mixed woods
i think they are hardwood, softwood and plywood although I am not positive. I will check it and get back to you though.
hardwood softwood and plywood
Pulp is neither hardwood nor softwood. Hardwood and softwood are classification of wood types. Both hardwood and softwood can be pulped. There are various types of hardwood pulps and softwood pulps.
Its a Softwood
Hardwood Timber, Softwood Timber and Plywood
softwood
Hardwood