This study estimated the value of a forest in Spain at more than five times what is estimated using standard national accounting methods (GDP, I assume). If this is the case, it suggests to me that the idea of just tweaking GDP to include ecosystem services isn’t going to work. The article is open access.

National accounting either ignores or fails to give due values to the ecosystem services, products, incomes and environmental assetsof a country. To overcome these shortcomings, we apply spatially-explicit extended accounts that incorporate a novel environmental income indicator, which we test in the forests of Andalusia (Spain). Extended accounts incorporate nine farmer activities (timber, cork, firewood, nuts, livestock grazing, conservation forestry, hunting, residential services and private amenity) and seven government activities (fire services, free access recreation, free access mushroom, carbon, landscape conservation, threatened biodiversity and water yield). To make sure the valuation remains consistent with standard accounts, we simulate exchange values for non-market final forest product consumption in order to measure individual ecosystem services and environmental income indicators. Manufactured capital and environmental assets are also integrated. When comparing extended to standard accounts, our results are 3.6 times higher for gross value added. These differences are explained primarily by the omission in the standard accounts of carbon activities and undervaluation of private amenity, free access recreation, landscape and threatened biodiversity ecosystem services. Extended accounts measure a value of Andalusian forest ecosystem services 5.4 times higher than that measured using the valuation criteria of standard accounts.