But flooding is also so high that only the crowns of trees are visible. When floodwaters recede, there are few roads, so visiting plots in dry season is near impossible. In Nicaragua, there is also the problem of military guerilla warfare. FIA s inaccessible plots don t hold a candle to those in developing countries. FIA traditionally assumes that imagery is not very valuable unless there is ground truth.
Remote imagery is the norm for developing countries.
In some situations, FIA is justified in estimating resources remotely. Uses and trends of resources in Brazil s Amazon are limited to unwritten language or experience by locals. In many areas such as these, assembling indigenous knowledge about forest resources is a logical starting point, as precise observations are rare. As with many nontree species throught the world, annual wood ring counts to estimate growth and yield of trees are virtually nonexistent in the tropics, so the rare long-term observations may be the only other way to reliably estimate rates of growth and mortality. In Puerto Rico, long-term tree measurement studies, e.g., Weaver 1979, Parresol 1995 provide otherwise unavailable information to predict growth and yield of individual tree species.