The Spanish anchored in Port San Juan and traded with the Nitinat Natives.

Further inland the valley is characterized by a warm-summer Mediterranean climate (Köppen: Csb).

[4][5][6] The valley lies in a temperate rainforest biome and is home to the coniferous "big trees" associated with British Columbia's coast – western hemlock, western red cedar, Pacific silver fir, yellow cedar, Douglas fir, grand fir, Sitka spruce, and western white pine.

The valley is home to some of the largest and oldest remaining patches of old growth forests on Vancouver Island.

Trees of note include the Red Creek Fir, the largest Douglas fir in the world,[7][8] and San Juan Spruce, the former second largest Sitka spruce in the world.