Eucalyptus were introduced in California before Jack London's time. Pioneer families needed wood, which was in short supply, for many items such as furniture and utility poles. Planting eucalyptus, a fast-growing import from Australia, was believed by many to be a solution.
Before you stand the original crop rows occupied by offspring of trees London had planted. He hoped harvesting eucalyptus would pay of other experiments. In 1910, 15,000 seedlings cost him only $150. Eventually, he planted 80,000, of three species: E. viminalis, E. tereticornis, and E. globulus. Unfortunately, London's experiment failed. The trees were only useful as firewood.
To justify asking publishers for money in advance, London sometimes exaggerated ranch expenses:
"You see, I am running an expensive ranch - said ranch being expensive because of the fact that I am heavily investing in it. I am planting eucalyptus trees, and at present moment have a hundred thousand trees in. Each year I plant from 20,000 to 40,000 trees. This makes rather a tidy wage-list when, for months at a time, there are fifty men on the pay-roll." — Jack London.