Very admirable in welcoming the new principal/administrator(?)m but the picture show no regard for hearing health . A petrol trimmer makes 100+ decibel of noises. [Safe level is under 80 decibel.] That can cause permanent damage to your hearing in 10 minutes. To use a trimmer on a government or public site may be a breach of work safety laws or directives.

For your sake, please use ear muffs – at least in-ear speakers.