[7] The lower hills are mostly barren and treeless, but pine grows on the main mountains that form the East Afghan montane conifer forests.

From here it passes to Tari Mangal, Pewar, Alizai, Khewas, Shilawzan, Luqman Khel, Maikay, Chappri Rest House, Zeran, and Upper Khyber Agency.

The base of the mountains consists of Proterozoic gneisses and granites with admixtures of gabbros, mafic metavolcanic rocks, marble and migmatites.

[12] On the southern flank of the Sikaram Sar follow from 2500 m from bottom to top: alluvial soils in valleys, limestone and dolomite up to 4000 m, an intermediate zone of slate at 4000 m, above crystalline rock.

[14] Above the nearly barren lower slopes, forests of pine and deodar cedar thrived on the main range, but devastation during the Afghan civil wars reduced timber resources.

According to US military intelligence, many al-Qaeda fighters, including Osama bin Laden, crossed the Spīn Ghar to escape to Pakistan during the Tora Bora offensive in 2001.