A number of land-cover products, both global and regional, have been produced and more are forthcoming. Assessing their accuracy would be greatly facilitated by a global validation database of reference sites that allows for comparative assessments of uncertainty for multiple land-cover data sets. We propose a stratified random sampling design for collecting reference data. Because the global validation database is intended to be applicable to a variety of land-cover products, the stratification should be implemented independently of any specific map to facilitate general utility of the data. The stratification implemented is based on the Köppen climate/vegetation classification and population density. A map of the Köppen classification was manually edited and intersected by two layers of population density and a land water mask. A total of 21 strata were defined and an initial global sample of 500 reference sites was selected, with each site being a 5 × 5 km block. The decision of how to allocate the sample size to strata was informed by examining the distribution of the sample area of land cover for two global products resulting from different sample size allocations to the 21 strata. The initial global sample of 500 sites selected from the Köppen-based stratification indicates that these strata can be used effectively to distribute sample sites among rarer land-cover classes of the two global maps examined, although the strata were not constructed using these maps. This is the first article of two, with the second paper presenting details of how the sampling design can be readily augmented to increase the sample size in targeted strata for the purpose of increasing the sample sizes for rare classes of a particular map being evaluated.

New England has been a prime example of the idea of forest transition. Deforestation commenced in the early seventeenth century and intensified up until the late 1800s. Following abandonment of farmland, forest cover increased until recent years. In this article, we examine recent trends of forest change in New England. What does the continuation of forest transition look like? What are the drivers and characteristics of land change beyond the initial transition? Land use change, not including areas of forest harvest, was mapped across New England (Maine excluded) between 1990 and 2005 using satellite data. A total of 133,000 ha were deforested for use as residential or commercial development. The net forest loss was 129,000 ha (2.8% of the forest present in 1990). If the observed pattern is present elsewhere, we could be witnessing a secondary phase of forest transition that involves a loss of forest driven by urban growth rather than agricultural expansion. The accuracy of the forest change map was assessed and the area estimates of forest change are based on both the map and the accuracy assessment results.