Kashyyyk is an Class M Planet has four continents, which were mostly covered in lush, tree-filled forests, although the planet does have a small amount of desert region in the rain-shadow of its small mountain ranges. In addition, a few sandy beaches can be found along the shores of its oceans. Kashyyyk's prevalent ecology can be politely described as a "layered deathtrap," as the planet's surface is covered with wroshyr trees several kilometers high, and the dangers presented by local wildlife increased as one descended toward the forest floor.

According to Wookiee culture, this vertical environment consists of seven levels. The bulk of Wookiee civilization is located on the uppermost seventh level, and even the bravest Wookiees rarely venture below the fourth level. The ground level is known as the Shadowlands and, sometimes, the "netherworld."

Besides the primary sentient Wookiees, Kashyyyk is home to a host of other animal species including can-cells, flame beetles, gorryl slugs, katarns, kinraths, kkekkrrg rros, kroyies, mykals, netcasters, sureggi, tach, webweavers, various species of banthas, and even a small population of terentateks.