Non-use values

Attended a meeting on "Road Map for Indonesian Forestry" -- or something like that. I was bothered by the way some people calculate non-use values of forestry. Well, in fact, they did not calculate or estimate them. They took them from studies published some years ago, and simply normalized them with 2000 dollar prices. They did not consider growth rate of the forest. Not to mention damage rate. I was worried because the values are pooled in one table along with the use-values -- also combination of previous studies' figures. Forest grows (or dies). You can't simply normalize its value.