phil
check out this short video clip i put together on what bothers me about using the transaction prices you and ann have obtained: what can we learn from these transaction prices about relative valuations ? Well not a lot. The reason is becasue  (1) it's marginal not average valuations that transaction prices reveal and (2) theory could be very indeterminate here on what to expect given you have a wealth maximizer trading with a govt agency like DOC.

My general equilib version of the theory has DOC (and LINZ) totally unconcerned with development potential of land..but that very fact leaves open a huge potential for (a) efficnet exchnages (efficient between these two trading parties, not efficien in the sense of chanig the objectives of the govt bargaining agent) and an extremely wide variation in the range of avergae rates of exchange betweeen mountain top graing land and lakeside development land - which is precisley what you observe. This isn't to say some other bargaining theory won't narrow down the range of permissible (in the theory) exchanges, but it does create room for explaining the trades that do occur in terms  fo a simple GE model via variation in endowment point relative to aggregate acres of the tow types of land.

Anyhow
check it out
apologies for the rapid fire commentary but i was in a rush to get away....