Yes, you can fix the rope between two trees without affecting the anchor. The Slackline always applies a high pressure on the anchor point (trees or other fixed points used); we recommend, therefore, to always check on them before using the Slackline. If you have doubts about their strength, it is always better to fix the Slackline at their base (of a tree or pole) and lift the line with one of our frame stands: in this way, with a simple lever, you will reduce much of the force of the Slackline.
If you see a minimum risk in installing a webbing between two trees (or other support), it is always better to avoid that set up. In that case, you can anchor to the ground through our Outdoor Kit No-Trees, rather than risk incurring in damages or injuries.