What ARE All Those Piles?

What ARE All Those Piles?

    If you walk or even drive through Curtis Arboretum, you’ve probably noticed large piles of sticks, vines and other debris piled near the dog park entrance or at the back gate of Curtis Arboretum.

Those piles are plants—that don’t belong at Curtis. Long ago, this area was filled with native trees, bushes and ground covers.  Gradually, people introduced (both intentionally and accidentally) other kinds of plants that didn’t belong here. These invasive species, as they are known, are aggressive, spread easily, choke out or smother native species and aren’t eaten by our local insects or fauna.  In other words, there are few natural limits on their spread. 

    Over the decades, two woody vines in particular (Oriental bittersweet and porcelain berry) have covered the ground, climbed and entwined around the trees, and buried many shrubs and smaller bushes. Many older trees have died as the leafy vines blocked the sun from the trees’ leaves. The enormous weight of vines have broken mighty branches and weakened tree structure.

    A large group of young trees, planted around 2009, never made it because they were choked out by the vines. Dead and weakened trees diminish the all-important protections that streams, like Rock Creek which runs through Curtis, get from their riparian buffers (the formal name for stream borders of native trees and plants). 

    

    Trees provide many benefits to the stream and environs.  They shade and cool the water, allowing it to hold a greater concentration of dissolved oxygen that stream critters need to breathe.  The roots of trees stabilize the banks so that the soil is not washed away.  The roots also filter runoff from the land---removing pollutants.  The fallen leaves and branches create habitat and nutrient sources for tiny stream critters.  Healthy streams have wide buffers of native trees and shrubs, as well as a ground cover of ferns, grasses and wild perennials.

    Rock Creek needs a lot of help---specifically, the trees and native vegetation.  But before those can be planted to restore the riparian buffer, the invasive tree-killing vines need to be removed and brought under control.

    

    Enter two volunteers: Chrissa Pedersen and myself, Geoffrey Selling (more about us in a future post!). For the past two years, we’ve been cutting, digging and pulling vines and, more recently, hauling the debris out.   Those are the piles you may have seen. 

Geoffrey holding part of a vine cut from a tree

    Somewhere, down the road, we hope to see the Rock Creek buffer restored with an abundance of tall leafy trees and native vegetation.   When the corona virus crisis is over (it WILL happen!!), we will be able to resume regular Friends of Curtis Arboretum (FOCA) workdays and volunteer help will be enthusiastically sought.