New to Forums, with few questions re: game

Yes trees grow, but they take more than a day of real time. Cut trees will regrow but they are supposed to stop if you remove the stump.

Forests are limited to specific voxel types. The ground will show you the border of the forest. Technically, all trees that will ever grow are created when the world is made. Some of them are in a pre-growth (invisible) state, some in a young sapling state, but most are fully grown. Interestingly the entire planet gets covered with trees (in data at least), then the trees in areas that aren't supposed to have them are prevented from being placed in the world.

If the game is not running then nothing is growing. We don't calculate growth based on clock time. The game world has its own clock that runs at real-world speed. This clock stops when you unload the world. Conversely, dedicated servers that run all the time are always growing things. This can make growing crops tricky if you are unable to log on during their ripe phase.

Things spawn on the ground all the time. The more time you spend in an area, the more stuff will pop up for you to find.

Yes and no. There are some ores that are centered around 16m depth. They are almost always placed next to surface deposits. Sometimes digging at the last bits of surface ore will reveal much more than you expect. There are a few isolated deep deposits. I'm not sure if our designers put them there by accident or to see if anyone ever finds them. I certainly wouldn't count on finding them without digging into the material maps. Looking with a shovel or pickaxe would be pointless.