Yes but the reflected light is a set of events in your brain.
Events as defined here
https://en.wikipedia.org/wiki/Spacetime

[No, the reflected light triggers a set of events in your brain after it meets your eyes.]

Yes the reflected light triggers a set of events in the brain via eyes etc.

Now these events at any given instant are responsible for the experience of seeing the tree.

This experience of seeing consist of 2 components at every instant
1. "U" The Tree
2. "I" the thing looking at it.

If "I" does not exist then there can be no experience.

For anything to exist it must exist at every instant.

Thus for "I" to exist at all it must exist at every instant.

If "I" exist in an instant then it will essentially be making a connection with the multitude of events making "U" at that instant.

Alternatively if you think its seeing the tree one event at a time, it will never see a whole tree as it can never know more than a single event.