Here are some surface types for the following islands:-

Utes -  		"#UTGrass","#UTForest"
Chenerus - 		"#CRGrass1","#CRForest1","#CRForest2"
Proving Grounds - 	"#GZTrava","#GZforest"
Shapur - 		"#DBPolopoust"
Takistan = 		"#TKPolopoust","#TKTrava"
Zargabad - 		"#ZRPolopoust","#ZRTrava","#ZRPole"
Desert_E - 		"#DEPolopoust","#DESkalniSterk"
Tigeria - 		"#tig_trava"
Malden - 		"#hotze_grass","#hotze_wald"
Nogova - 		"#hotze_grass","#hotze_wald"
Yapal - 		"#yap_trava2"
AfghanValley - 		"#AfghanValleyslopeSurface",
			"#AfghanValleysandSurface"

All surface types may not have been checked and are here for 
example only and probably not a complete list.

Best to make your own! Turn on debugging and walk around. The
surface types will constantly be displayed.