Why did Native Americans in northern California build houses with Tule?

In the marshes of northern California, Native Americans found the ideal material for house-building, a bulrush known as tule.

They wove the stalks of this wild plant into large, flexible mats that, placed over a frame of saplings, created the walls of their houses. Airy and light, tule mats kept the Indians’ houses cool and comfortable by blocking out harsh sun while letting air flow through.