I don’t know if this will help you anyhow.

With trees, especially during winter it can be harder, you can approach the topic in many different ways, it all depends on what effect you are mostly interested in.

Seek the tree that stands out in its surroundings to build on that contrast or find some trees that can be composed nicely in a frame to focus on a harmony? Those basic things can be very helpful, if you want, you can show balance or lack of it.

Good practice can be focusing on your feelings and searching for a picture that will go well with what you feel, because only you will see it there, in that moment. You feel sad or tired — search for a sad and tired tree and capture it… or maybe you feel calm and focused on continuing that book or episode of great series? Then find a tree that could be in that book or be a frame from that series…

Or maybe you want to get lost in the woods and search for some great patterns and shapes — light can be really amazing there, or… maybe wait for a foggy day?

Can you imagine at least a vague version of what you would like to create and then follow that vision?

Lastly, if it’s a subject that you don’t feel at all and you just want to force yourself out of the comfort zone as a practice — just go, batteries fully charged and take as many photos as your camera will let you. This is actually scientifically proven method, when doing anything creative / expressive go for quantity first and later search for quality. It is so much easier to select at least one fine / good picture from over two hundred than from zero.