The Douglas fir is a tall iconic pine tree in Western North America forming a forest that winds unbroken from the Western spine of British Columbia all the way to the Mexican cordillera. The environmental conditions of Canada and Mexico are obviously very different, but even on much smaller scales—say, the top of a mountain compared with a valley below it—the rainfall, temperature, soil nutrients and dozens of other factors can vary quite a bit. The Douglas fir grows well in so many of these places that it turns a dramatically varied landscape into one smooth, continuous forest complete with all the species it supports.
Click here for original story, Evolution on the smallest of scales smooths out the patchwork patterns of where plants and animals live
Source: Phys.org