Downloads the Global Age Mapping Integration (GAMI) v2.1 forest-age dataset
(Besnard et al. 2024, GFZ Data Services, doi:10.5880/GFZ.1.4.2023.006), the 0.5-degree
`class_fraction` product read by readGAMI. GAMI provides the within-forest
age distribution (12 age classes, 20-member ensemble) for 2010 and 2020.
See also
[downloadSource()], readGAMI