Tree Spiking Mitigation Act of 2021 This bill directs the Forest Service and the Bureau of Land Management (BLM) to coordinate to take necessary actions to ensure the detection, identification, and, as determined to be appropriate, mitigation of tree spiking devices located on federal lands. A tree spiking device includes spikes, nails, or other objects hammered, driven, fastened, or otherwise placed into or on any timber to impede logging. To carry out such activities, the Forest Service and the BLM shall prioritize areas in which (1) incidences of tree spiking devices have occurred, or (2) the Forest Service and the BLM suspect that there are tree spiking devices. No later than 90 days after the enactment of this bill, the Forest Service and the BLM shall, where appropriate, update safety guidelines and training protocols to include the awareness, detection, identification, and mitigation of tree spiking devices.