Vast frontiers for even more agricultural improvement remain open. Top producers now grow more than 20 tons of corn per hectare, compared with a world average for all crops of about 2. From one hectare, an American farmer in 1900 could provide calories or protein for a year for 3 people. In 1999 the top farmers can feed 80 people for a year from the same area. So farmland again abounds, disappointing sellers who get cheap prices per hectare almost everywhere.
Forests tell a similar tale.
Forests are cut to clear land for farms and settlements and also for fuel, lumber, and pulp. In the rich countries, nevertheless, forests have re-grown in recent decades. Today an average American consumes about half the timber for all uses as a counterpart in 1900. In the U.S., likely continuing fall in intensity of use of forest products should more than counter the effects of growing population and affluence, leading to an average annual decline in the amount of timber harvested for products. A conservative annual improvement in forest growth would compound the benefits of falling demand.