Strictly grammatically speaking, Your sentences look right to me. Yet, the construction doesn't sound English to my ears... Why don't you try: 1. Only when/if forests are protected from logging can photosynthesis operate. 2. When mountainous lands are damaged for business, (then) people's lives are ...
You can make an it-cleft sentence form of 'It is *** that ...' if and only if '***' behaves as a syntactic unit in the original sentence. The it-cleft is usually applied to a word or a phrase in a single-clause sentence, and rarely applied to a subordinate clause of a complex sentence. However somehow the structures "It is only when ... that ..." and "It is only where...