Did you get a permit or other permission from the appropriate park authority to collect this tree? It harms public perception of the hobby when people collect trees without going through the proper channels and can make it harder for others to collect in the future because the officials in charge of managing these natural resources may get a negative impression of bonsai people as lacking respect for their conservation authority. Later on, when someone comes along, follows protocol, and asks nicely they get told, “No, we don’t allow that,” because the park ranger remembers the time when someone took a tree in the middle of the night and left a big open hole in the ground that the city had to send a crew out to fill in, etc. Basically, don’t be that guy. There can also be legal issues if you’re caught collecting without permission.