Carbon dating is a method used to determine the age of organic materials by measuring the remaining amount of carbon-14, a radioactive isotope. Living organisms absorb carbon-14 from the atmosphere. When they die, absorption stops, and the carbon-14 decays with a known half-life of about 5730 years. The age $t$ is calculated using the decay formula: $t=\frac{\ln \left(\frac{N_0}{N}\right)}{\lambda }$, where $N_0$ is the initial amount, $N$ is the current amount, and $\lambda$ is the decay constant. It is specifically used for dating once-living things like wood or bone.

Final Answer: age of deadwood.