Kindly tell me whether I can use which in place of that, in the sentences below. If the answer is No, please explain why. I know that it has something to do with defining and non-defining clauses. Unfortunately, I'm unable to identify them in the sentences below.
Although I love taking my bike out on long rides, there are cycling trails that I tend to avoid. Those are the ones that lack lush green surroundings.
Thank you very much for your help.