In this paper we discuss the (Pareto) optimal provision of a public good (desirable or undesirable) in an intergenerational model of an economy, where regeneration is an endogenous decision variable of the households in the economy. We show that in addition to providing desirable public goods and/or levying the well known Pigouvian taxes on polluting industries, a government must subsidize households who are consuming a desirable public good and tax consumers who are consuming an undesirable public good (pollution). In addition, we show that there is public rate of return, distinct from the market rate of return, that should be used by the government for the evaluation of investments in public goods. This public rate of return is smaller than the market rate of return in a growing economy and larger than the market rate of return in a declining economy. We investigate biases in both the public and market rates of return, as well as in other parameters which characterize the economy, as a result of nonoptimal governmental behavior. We discuss the question of how to aggregate biases due to different public goods.