On average 1487 l are saved per dollar invested in forest restoration at five sites on Hawai‘i Island.

$0.67 in present value terms is required to protect 1000 l of freshwater over a 50-year time horizon.

Water yield benefits of restoration increase over time, while management costs tend to be front-loaded.

Forest restoration may be cheaper than other groundwater alternatives such as desalination.

It is important to consider the long run when comparing the benefits and costs of conservation activities.