There are lots of things that weren't fully implemented in the Alpha, from running water to plants that can be harvested. In order to make up for the lack of plants to harvest, however, they added random plant drops into the trees, to allow players to have access to those materials. Also missing from the Alpha was any way to get hurt. With no threats to worry about, players were free to focus on mining and building. In the Closed Beta, the plant drops appear to be gone, so I'm assuming the ability to harvest plants is either coming soon or is available now, if you have the ability to create the appropriate tools to harvest them...
...which is totally possible, since everything can be (and has to be) created with mined resources, first. In the Closed Beta, you even have to use the appropriate workstation to create a Claim Flag, before you can create your own structures. Mind you, it doesn't take a lot of materials to create a Claim Flag; I had collected everything I needed before I happened upon someone's workstation and was able to make one from what I had on me.
Now, I need to craft a Selection Tool, which allows much more in-depth manipulation of objects. To do that, I'll need to get my hands on 30 Elemental Iron, 30 Iron Ingot and 10 Topaz and I'll need to find a Stone Forge...