 In the above, \(k\) is the equilibrium occupancy of the territory. Given this model, the northern spotted owl can persist if, and only if, \(h &gt; 1- k\). Lande determined that in 1987, 38% of forest in western Washington and Oregon was older than two hundred years. So, \(h = 0.38\). Fieldwork suggests that 44% of sites were occupied. Thus, \(p = 0.44\). We can determine \(k\) from this equation, \(k=1-h(1-p)\). Hence, \(k = 0.79\). The forest plans suggested leaving between \(7 - 16\%\) of 200 or more year old forest. But given that \(1 - k = 0.21\), Lande argued \(7 - 16\%\) was insufficient and the forest plans should be revised. Lande and others’ work led to the US Forest Service withdrawing six old growth forest timber sales in Oregon and Washington and became a component of the 1994 adoption of the Northwest Forest Plan that protected 8 million acres of old-growth forests. This was an increase to protecting 80% of the owl’s remaining habitat in comparison to 5% protected by the Forest Service’s original owl plan.