Could you provide some additional photos, including one that shows the entire tree? The circled leaf appears to have some kind of disease, but it can't really be diagnosed without some additional images. Is the problem just the leaf curling and the discoloration? How widespread is this on the tree?

Can you provide a close-up photo showing the white, fuzzy-looking objects on the tree branch close to the circled leaf in the photo? Those look like they might be a scale insect, or something similar, but I need a clear, closeup photo to tell. How widespread are those white object on the tree, and are they more prevalent near the damaged leaves?

I only see the two original photos, which don't show much of the tree.  It's hard to tell the species definitively. Is it a magnolia tree? The problem is a type of scale insect, and control will be challenging. Assuming this is a magnolia tree, information is in the following link. Let me know if it is some other species of tree, and I can provide information specific to that tree.

 https://www.canr.msu.edu/news/check_magnolias_for_magnolia_scale_now

Definitely scale. Do you have any old photos of the tree in flower? That would make it easier to identify. Treatment will be very similar to magnolia scale, but exact timing may be a little different. Also, how long have those large rocks been at the base of the tree?  That is stressful to most trees, though some species will tolerate it just fine. A tree that is under stress will have a more difficult time tolerating scale or treatment for scale.

Beautiful photos! And this is a magnolia, so the information I sent you is exactly what you need. Scale insects can unfortunately multiply very rapidly under the right conditions, but careful timing of treatments can get them under control.