Green Options

The number of large-diameter trees in Yosemite National Park have declined 24-percent between the 1930s and 1990s.

The findings are based on a study done by the U.S. Geological Survey and the University of Washington. Scientists compared tree densities from 1932-1936 to those from 1988-1999 where large-diameter trees are those with a diameter greater than three feet.

Along with large-diameter tree loss, they also found a shift to fire-intolerant trees. Amazingly, this shift was experienced in areas that hadn’t seen a wildfire in nearly a century. Trees changed from fire-tolerant ponderosa pines to fire-intolerant white fir and incense cedar. In burned areas, however, the pines remained dominant.

We’ve all heard the legend of Johnny Appleseed, the legendary apple tree planter of the United States. He walked across the country with his walking stick, and a bucket of seeds, just walking and planting as he went. Everywhere he went, apple trees sprouted up. And he was a hero. It is such a hero that Yosemite is looking for now.

The number of large trees is falling in Yosemite National Park, but no Johnny can be found. And the decrease is bad news for many species, including spotted owls, mosses, orchids and fishers (a carnivore related to weasels). These species, as well as others, are losing their habitat with the loss of the trees.