Is the rainforest is more valuable when left intact than when destroyed?

Unfortunately, humans find a need to destroy nature for our own benefit. It's a sad truth. Instead of finding reasonably priced alternatives to trees (for paper, etc), we continue to destroy rainforests. By destroying rainforests, we are destroying species of animals and plants. So in the end, SHOULD they be destroyed? Ethically, the answer is no. Economically, someone may argue otherwise.