If you walk through the dense canopies of the Amazon or Borneo, or even the Appalachians and other forests in the US, you notice that nature has a way of “self-managing” to reduce the kinds of risks we face in highly converted neighborhoods in the United States.
In natural forests, trees grow together to form ecosystems that are self-supporting. Closely-spaced trees protect one another from wind. Old and sick trees are often overtaken by vines and insects; they eventually fall and/or die, and decompose. Younger trees in the understory take advantage of the canopy opening to access more sunlight and fill in the gaps. The diversity of shapes, sizes, and ages in the forest makes for fabulous habit for all kinds of other flora and fauna.
When left to their natural devices, drier forests, like those found out west, have historically experienced ground fires that would clear underbrush and thin out smaller trees, reducing the chance of dangerously hot blazes. Without these occasional burns, dense trees and thick underbrush serve as potent fuel for the massive burns we’re seeing this summer.
As I look out at my own backyard, I see where things have gone wrong. A well-meaning former owner planted “low maintenance” English Ivy. The invasive non-native plant, left untended, raced up several trees, creating wounds in their trunks into which marched colonies of termites and carpenter ants. As these trees died, their neighboring trees were robbed of the safety in numbers against wind and heavy rains, and the standing dead or wounded trees became liabilities when storms come through. Just last year, Hurricane Irene downed a termite-eaten hickory that nearly took out our shed.
Making matters worse, these decades-old icons of our neighborhood aren’t being replaced with new growth, due at least in part to gardeners routinely cleaning up “weeds” (which many people define as anything that grows where we don’t want it), thereby preventing young saplings from getting a strong foothold.
In the West, development interventions have caused even more dramatic problems. Last century’s policy of extinguishing all natural fires in American forests—for fear they would threaten people and property—has left us with a tinderbox of choking brush and densely packed trees that, in the face of a warming planet, takes little to ignite.
Unfortunately, we can no longer simply let nature do its thing. We’ve altered the landscape so much over time that the trees need a little help.