>>508632637
most of what you call "forest, jungles and scrubland" is actually farmed and maintained, full of little houses and dirt roads. the plots are not squares but irregular patterns so they dont show from space but look closer, in reality approx 40% of sub saharian africa is agricultural land. That (10.5 million km2) is is roughly the combined size of the USA and Mexico. Not all is intesively cropped but still, a lot. Also rivers, and good climate allows for many crops every year