 The cool nutrient-rich waters of the north Pacific are able to provide kelp forests with millions of plankton – the base of the aquatic food chain – due to an upwelling of water from the deep sea in the stormy, winter months.Trees of San Diego–Tijuana included chamise, scrub oak, manzanita, live oak, lodgepole pine, black oak and closed-cone pine forests.Lowland shrubs included California sagebrush, black sage, white sage, California buckwheat, as well as cacti and succulents.