Part 1
Original environment rehabilitation manual refers to the rehabilitation of the environment to its previous state (the state in which it was in 1900; before any major human interference to the environment was done).
Definition specifics
Rehabilitation of the environment to its previous state thus means that some human interference (eg some manipulation in rivers, some degree of human buildings and infrastructure, ...) would be tolerated, but only to a degree that interference to the ecosystem is kept to a minimum. Also, the manual would focus on a rehabilitation rather than a restoration, meaning that it would not envision to make the environment an exact copy of how the environment was in the 1900's (apart from the urban areas which would'nt be altered), but rather an environment which still produces products that are essential to humans (eg food, clothing, ...) but thus so with the least possible influence to the outside environment. This could be done by growing herbs at a location (far) away from the consumer's location, but also near the user. The latter option would decrease costs and increase self-sufficiency, and the interaction between humans and the natural environment could still be kept low (eg by modifying the plants to make the seeds infertile). The first option could reduce the interaction between humans and the natural environment even more (as no asexual propogation can occur neither) and might be more cost-efficient to grow certain crops (grains for example thrive best in colder climates, ...), and an additional advantage of colder climates is that most natural vegetation is already eradicated and replaced by herbs, making it more cost-effective of growing herbs here than in subtropical and tropical areas. If the second option is nevertheless required given the local circumstances, zoning may be best implemented.