In this picture, you can see evidence of three distinct time periods. First the white oak tree, a relic from a pre-pioneer period, luckily still remains after over a century of intensive management. My guess is that tree is 150-200 years old. Prior to the white invasion, native humans where well adapted to the fire climate of the west and even encouraged it when they could. An open forest with frequent fires produces more food. Its that simple.
Next the grass, no not that kind of grass! In 1850ish, these areas where settled by European homesteaders. As they found small patches of prairie or oak savannah, they expanded these openings by removing the scattered Douglas-fir up to the edges of the denser woods. They too would use fire as a tool to keep these areas open, primarily to graze sheep.
Over time, sheep would become harder to raise and they would shift to cows. As fire policy in the west evolved, it soon became unpopular to burn large tracks of ground, and soon preventing fire was a national mandate. I also heard that changes in public attitudes towards trapping and killing predators also influenced the shift to cows.
This brings us to the Douglas-fir. The taller ones are about 60 years old and getting close to 120 feet tall. These trees represent that point in time where the fire exclusion policy became actual practice. I also believe that there was less pressure to maintain large prairies for food as the decedents of the settlers became more dependent on revenue from other sources (like a job at the mill, etc.). Go out into any of your open areas on your land and find the small fir trees growing in the understory. Sixty years from now they will look like the ones in the picture! (If you let them…)
You can also see the younger fir in the right of the picture. These trees continue to fill in around the edges of the openings, and soon will re-take this area completely. And to think that just 100 years ago, one would have never thought these areas could be a forest! Yet they are. Consider this next time you see a forest clearing, clear-cut, agricultural opening, etc… If the soil layer has not been removed, or paved, most changes to vegetation are temporary. Extremely temporary – when you consider the time scale of the western forests – which spans millions of years. Even the mighty human being is a blink of this history.