You will note that by world standards, all of these numbers are low. But almost all vegitation zones in Eritrea are semi-arid with either annual plants or deciduous perennials which produce during a short rainy season of just a few months. So productivity throughout Eritrea is low. The rough biomass estimates are produced by taking a set of mean monthly NDVI images, and comparing the average and the minimum of this set. They are compared with the minimum image in order to factor out geographic variations due to elevation, humidity, soil type, and rock type effects.
Some few areas have some green vegetation all year.
I enjoy both visting and working in Eritrea and am available for short-term consultations and technical training seminars. Robert Van Buskirk 3217 College Ave. Last update by rvb August 9, 1998.