Their wide spreading roots loosen hard-packed soil, aerate the earth and help reduce erosion.

它们宽阔的根系松动了坚硬的土壤，使土壤通气并有助于减少侵蚀。

After the conifers, the most important of the Yosemite trees are the oaks, two species; the California live-oak (Quercus agrifolia), with black trunks, reaching a thickness of from four to nearly seven feet, wide spreading branches and bright deeply-scalloped leaves.

在针叶树之后，优胜美地最重要的树木是橡树，有两种；加州活橡树 (Quercus agrifolia)，树干黑色，粗达 4 到近 7 英尺，宽阔的树枝和明亮的深扇形叶子。