As artifacts are uncovered, their locations are mapped with as much precision as possible. They are then labeled with this data, and sent to the lab. Here, several things can be down to it and much additional information obtained. Often, the artifact will just be washed, categorized, counted, and stored. However, if the hypotheses require it, much more can be done.
Trees add one ring per year as they grow.
A master calendar is constructed beginning with very old tree like sequoias or bristle-cone pine and is extended back by matching the patterns on archaeological wood with those on the existing calendar sequence. Once a calendar is complete, other pieces of wood that are found may be matched to it and dated. This C-14 is then absorbed by animals that eat the plants, and humans who eat both the animals and the plants. Because C-14 is radioactive, it decays continuously throughout this process. This means that, since the amount of C-14 is fixed in an organism at the time of death and decreases at a fixed rate, by measuring the amount remaining, you can calculate how long ago it was alive.