It was gut-wrenching when I realized that many people alive today have never seen a truly mature tree up close.
In the Eastern USA, only tiny remnants of old-growth forest remain; all the rest, over 99%, was clear-cut within the last 100-150 years.
Most tree species here have a lifespan of 300-500 years—likely longer, since extant examples of truly old trees are so rare, there is limited ability to study them. In a suburban environment, almost all of the trees you see around you are mere saplings. A 50 year old oak tree is a youth only beginning its life.
The forest where I work is 100 years old; it was clear cut around 1920. It is still so young.
When I dig into the ground there, there is a layer about an inch thick of rich, plush, moist, fragrant topsoil, packed with mycelium and light and soft as a foam mattress. Underneath that the ground becomes hard and chalky in color, with a mineral odor.
It takes 100 years to build an inch of topsoil.
That topsoil, that marvelous, rich, living substance, took 100 years to build.
I am sorry your textbooks lied to you. Do you remember pictures in diagrams of soil layers, with a six-inch topsoil layer and a few feet of subsoil above bedrock?
That's not true anymore. If you are not an "outdoorsy" person that hikes off trail in forests regularly, it is likely that you have never touched true topsoil. The soil underlying lawns is depleted, compacted garbage with hardly any life in it. It seems more similar to rocks than soil to me now.
You see, tilling the soil and repeatedly disturbing it for agriculture destroys the topsoil layer, and there is no healthy plant community to regenerate it.
The North American prairies used to hold layers of topsoil more than eight or nine feet deep. That was a huge carbon sink, taking carbon out of the atmosphere and storing it underground.
Then European colonists settled the prairie and tried to drive the bison to extinction as part of the plan to drive Native Americans to extinction, and plowed up that topsoil...and the results were devastating. You might recall being taught about the Dust Bowl. Disrupting that incredible topsoil layer held in place by 12-foot-tall prairie grasses and over 100 different wildflower species caused the nation to be engulfed in horrific dirt storms that turned the sky black and had people hundreds of miles away coughing up clods of mud and sweeping thick drifts of dirt out of their homes.
But plowing is fundamental to agricultural civilizations at their very origins! you might say.
Where did those early civilizations live? River valleys.
Why river valleys? They're fertile because of seasonal flooding that deposits rich silt that can then be planted in.
And where does that silt come from?
Well, a huge river is created by smaller rivers coming together, which is created by smaller creeks coming together, which have their origins in the mountains and uplands, which are no good for farming but often covered in rich, dense forests.
The forests create the rich soil that makes agriculture possible. An ancient forest is so powerful, it brings life to civilizations and communities hundreds of miles away.
You may have heard that cattle farming is a significant source of greenhouse gas emissions. A huge chunk of that is just the conversion of an existing forest or grassland to pasture land. Robust plant communities like forests, wetlands, and grasslands are carbon sinks, storing carbon and removing it from the atmosphere. The destruction of these environments is a direct source of carbon emissions.
All is not lost. Nature knows how to regenerate herself after devastating events; she's done so countless times before, and forests are not static places anyway. They are in a constant state of regrowth and change. Human caretakers have been able to manage ancient forests for thousands of years. It is colonialism and the ideology of profit and greed that is so destructive, not human presence.
Preserve the old growth forests of the present, yes, but it is even more vital to protect the old growth forests of the future.
