 Some tribes around Santa Barbara, California and the Channel Islands were using large plank canoes to fish and trade, while tribes in the California delta and San Francisco Bay Area were using tule canoes and some tribes on the Northwest coast carved redwood dugout canoes.The staple foods then used by other Indigenous American tribes, corn and/or potatoes, would not grow without irrigation in the typically short three- to five-month wet season and nine- to seven-month dry seasons of California (see Mediterranean climate).Despite this, the natural abundance of California, and the environmental management techniques developed by California tribes over millennia, allowed for the highest population density in the Americas north of Mexico.