Ecosystem services face two substantial questions:  a) how do human actions lead to changes in the structure and function of ecosystems, and in turn how does this change the production of ecosystem services, b) what are the relative values of ecosystem services, especially in cases where there are tradeoffs between producing services.  I address these two questions using landscape level models and data from the Willamette Basin, Oregon, USA, and other regions.  These studies highlight aspects where enough is known to be confident of mapping and valuing ecosystem services and aspects where more knowledge is needed before the science of ecosystem services is sufficiently developed to provide useful advice to decision-makers.