Paramount among the objectives of forestry in general and of silviculture in particular is the maintenance of the productivity of the living forest. The site is the total combination of factors, living and inanimate, of a place that determines this productivity. The site factors that are most subject to long-lasting harm are those of the soil, which is the most nearly nonrenewable of the resources in silviculture. The basic supply of solar energy, the most vital site factor, is beyond silvicultural control. Silviculture rests heavily on manipulation of the microclimate of a site, but its effects on the macroclimate are limited to those caused by photosynthetic removal of carbon dioxide from the atmosphere.
Forests are the result rather than the cause of geographical precipitation patterns.
Silviculture is not conducted in a pure state of nature, and this state ceased to be pure when society advanced beyond the food-gathering stage. To the extent that civilization is partly artificial, it can be argued that forestry must also be partly artificial in ways calculated to keep the world ecosystem in healthy dynamic equilibrium. However, the farther that any artificially induced process departs from nature, the more perilous it is if only because it becomes harder to predict the results. The web of life is so intricate that it is easy to argue that one should do nothing to the forest for fear of doing something wrong. This is the indictment pure science continually brings against the technology of applied science.