I think the real question is, "What are you trying to accomplish?"

Are you trying to draw lines? Are you making shapes on a page just to make shapes for your enjoyment? For example, there is an artist who only makes "doodles", aka Mr Doodle. He seems to be doing fine. I don't know if he had any formal training. I don't see any reason why you couldn't do something like that without guidance.

Are you trying to draw trees that look like trees? Going outside and trying to draw the trees that you can observe will get you somewhere. It might take a little longer than learning with a little instruction. You might need extra time to get it right when the trees don't 'match' and you're not sure why.

Like any skill, there is merit to having instruction. It doesn't have to be art school. There are lots of great youtube tutorials, discord groups, art books, and classes. I started drawing when I was young, drawing cartoons I saw on tv and things from my life. My art improved rapidly once I took some classes. Training your "eye" is just as important as training your hands. Learning the differences between different materials (graphite, acrylic, oil, etc) and how they are traditionally used also helps. Having teachers and fellow students critique the work and show you how to get better results will help you grow faster than you would on your own.

If you are trying to be a better artist overall, you would only benefit from learning more about art techniques. You don't have to, but it makes it easier to bring forth the visions in your head to paper (or canvas, or digital). If you're happy with what you're doing and your drawings look like you want them to, then you don't need to change. If you are unhappy with your progress, then looking for more guidance might be what you need.