Naturalist’s Notebook: The Missing Sponge

By Andrew Kirkpatrick, Manager of Land Stewardship

If you take a walk along Smith Run, coming up Ravine Loop below Penn’s Native Acres, the hillsides where the beeches, oaks and maples grow show signs of distress.  The structural roots of the trees are visible at the soil line when they should be tucked away cozily wrapped in the warm blanket of leaf litter and organic rich soil.  Instead, because of exotic invasive earthworms, which can be observed by scraping away the thin layer of leaves on the ground, the roots are exposed and left to fend for themselves in all of the elements; freezing winter winds, driving rains, and blazing sun.  If you look up, the impact on the trees is apparent.  Bare branches and diminished canopy reveal their stresses.  The trees are dying.  

In healthy, undisturbed forest soil, we would discover a universe of fungus, microorganisms, bacteria, and insects thriving. All of these elements facilitate the healthy growth and development of plant roots. The vast root mat matrix of the organic horizon (the top layer of healthy soil) in the forest acts like a gigantic sponge that collects water when it rains and holds it in storage for trees to use in the drier months of the year.  

However, in highly disturbed areas like the Schuylkill Center, the organic horizon of the soil is absent. Soil horizon is a technical term for the classification of the cake-like layers of soil.  The organic horizon is missing here because hundreds of years of agricultural use have long since removed the original rich soil and left mostly thin, mineral soil at the top of the profile.  In fact, parts of our property were in farmland almost until the Center’s founding in 1965. The forest has not been able to redevelop the O horizon as it might have otherwise, largely due to the activity of invasive earthworms.

photo by Julia Aguilar

photo by Julia Aguilar

Invasive earthworm and castings

Invasive earthworm and castings

The invasive earthworms are much larger than our native ones, tunnel deeper into the earth and voraciously devour the leaf litter that would accumulate annually in the fall, break down over time to replenish the soil, and rebuild the O horizon.  So what is left is a loose accumulation of worm castings on a destabilized base that washes away into our streams every time it rains, carrying many nutrients with them.  And when the dry times of the year arrive, the trees have no reserve of nutrients to draw upon.  Instead our forest is stressed and vulnerable to attack from pests and diseases that it would otherwise be able to fend off.  

Planting Fox Glen_5-20-17 (10)20170516_115508We can address these problems by improving the soil and providing the roots of trees with a healthy environment to grow and develop.  In our Fox Glen restoration site, as we planted new trees we covered the ground around them with wood chips to help the roots retain moisture.  The wood chips will break down over time and add to the organic content of the soil.  

If we want our forest at the Schuylkill Center to survive climate change and the increasing stresses that come from an urban environment, we must help it to be as resilient as possible by replacing the missing sponge.

About the author

photo by Heather FowlerAndrew has a master’s degree in landscape architecture and ecological restoration from Temple University.  He hiked the Appalachian Trail from Georgia to Maine in 2005-2006.

Photo by Heather Fowler, WHYY

An excerpt from this piece was published in our summer newsletter in June 2017.

Seedlings

Of Soil and Seeds

By Melissa Nase, Manager of Land Stewardship

With ice on the ground and some remnants of snow lingering in the shadows, it is hard to believe the growing season at Schuylkill Center will begin in just a handful of weeks.  For gardeners like me, these cold days are the perfect opportunity to leisurely browse the glossy, colorful seed catalogs and dream about what to add to the garden this year, the bounty of the harvest, and warm summer days spent among blooms.  I hope to add some more shade-loving native plants to my back yard, and stave off the continual encroachment of my neighbor’s English ivy.  Rarely, does the thought of soil enter into our daydreams – although, as any gardener will tell you, it is one of the most important components to any healthy, productive garden.  Besides the minerals and nutrients that soil offers plants, it is teeming with the microscopic life of the food soil web.  Bacteria, fungi, nematodes, and arthropods, along with the ubiquitous earthworm, break down organic matter, making nutrients available to plants and participating in a food chain that includes birds and even larger mammals.  Besides protecting your crops from pests and diseases, these soil creatures create pockets of air in the soil, affecting soil structure and drainage.

So, how can you ensure the health of your soil?  One step to consider, especially if you plan to grow food crops, is to get your garden soil tested.  There are many resources for soil testing, including a low-cost option from the PSU Extension program.  Analyzing the soil for nutrient levels, pH, and contaminants is a good initial step to deciding what action to take to get the best results from your garden.  Often, fixing nutrient deficiencies is as easy as mixing some more organic matter like compost or decomposed manure into your garden soil.

If you start your plants from seeds, the potting mix you use is also an important decision.  Most potting soils contain just a few ingredients: organic matter, a fertilizer, peat moss to hold moisture, and a component to help drainage and create air pockets, such as perlite.

SeedlingsAt the Schuylkill Center, we’re always seeking sustainability, and that includes our nursery practices.  Since the establishment of the Native Plant Nursery in 2006, it has been the goal of land stewardship staff to reduce and eliminate potential negative impacts on the environment due to the nursery.  So at the outset, this framework provided guidance as to the types of materials used in the nursery like fertilizer, soils, and seeds, and led to the decision to seek out a peat-free soil.  Although peat is used in almost all potting soils, it should be considered a finite natural resource because it is harvested at an unsustainable, rapid pace, yet only grows millimeters per year.  As a result, it takes the peat bogs hundreds of years to return to their original state, if they are not wiped out completely.  Just like trees, peat bogs store significant amounts of carbon.  In fact, they are one of the largest storers of carbon and greenhouse gases on the plant, which is a further reason to preserve them.

Organic MechanicsAll of this led us to Organic Mechanics, a local soil company which does not use peat in any of their mixes.  Instead, they use compost and coconut coir, both recycled materials with the added benefits of greater moisture retention and increased nutrient content.

This year, in preparation for spring planting, you can buy organic, sustainable soil through the Schuylkill Center.  Our first annual Soil Sale is underway now – you can pre-order a range of peat-free soil products at a discounted price, and pick up them at the Center on February 21st – just in time to start your vegetables.  More about that here.

Cattail Pond

Restoring Cattail Pond


By Melissa Nase, Manager of Land Stewardship

Toad in Cattail PondCattail Pond sits in a serene, sunlit woodland opening at the edge of our forest, just a few quick steps outside our back door.  It is a special place, nestled into one of the few areas on the property that is free from undulating topography, naturally protected by a steep slope uphill from it and surrounding trees.  Taking all of this into consideration, it’s not surprising that there are also ruins of a barn near the pond, part of a former homestead and a reminder of the rich history of this land. Continue reading