A is the answer to this question. There are a lot of trees that were available at that time — having a lot of trees used to be very common in the past. Over the past years, the things that people think that they need have caused different areas with trees to be removed.
Life is now considered to be more modern, and people would also need modern facilities and accommodations in order to live comfortably. The number of trees that are available has significantly lowered, but this can still be changed. More people are making an effort to plant more trees so that people can still continue to live comfortably in the future.