Yes, but the species must be taken into account. It's generally safe to harvest firewood from a fallen tree. However, some trees offer better firewood than others, so you should consider the species of tree that has fallen on your lawn. Overall, hardwood species offer better firewood than softwood species.
It's generally safe to harvest firewood from fallen trees and branches, but depending on the species, some of the firewood is better than others. Hardwood species offer better firewood than softwood, such as fir, hemlock and cedar. Cedars are excellent for lighting firewood, since they break very easily, weaving those small chips ideal for starting fires. Cedar is considered a soft wood, as are fir, pine and sequoia, so the longer, warmer Douglas fir and hemlock trees are excellent firewood for long-burning fires.
You can report city trees and branches that have fallen to the ground on public property to the Parks and Recreation Department (DPR). Public property includes streets, sidewalks, parks, and other public places. Please wait a moment and try again. You can check the status of your damaged or fallen tree report, or other tree service request, by calling 311 or visiting 311 online.
You can use dead trees as firewood, but you should consider the type of tree, as some produce better firewood than others. Specifically, hardwood trees are often better than softwood species such as firewood. Also consider the condition of the wood, the size of the tree and whether it houses animals or insects.