Chemical-free Invasive Species Removal
Certain types of plants, known as "alien invasive species," are harmful to our local ecosystems because they can outcompete beneficial native plants. Invasives directly threaten native species by outcompeting them for space and resources, and indirectly threaten them via changes to vegetation community, soil chemistry, and nutrient cycling. In the broader context of changing climate and anthropogenic action, invasive plant species have often overwhelmed local landscapes, at the detriment of habitat functioning and aesthetic value. As a result, there is often a need to assess large areas of land and put in place control methods to remove, or reduce, the impacts of such species. Below are some examples of invasive species recommendations and actions we have taken over the years:
Common Ground Farm, Wappinger’s Falls, NY
One Nature completed an invasive species management plan for an organic farm and surrounding lands. The plan calls for no herbicides or otherwise harmful chemical products. Instead, it relies on hand and machine removal, site access changes, and an intensive agricultural cover crop seeding schedule. Under supervision of the Sullivan County Soil and Water Conservation District, our team of botanists and ecologists performed extensive walking transects and analysis of aerial photographs. Some of the alien species identified on the site include:
Euonymus alatus (Burning Bush)
Vicia cracca (Cow Vetch)
Microstegium vimineum (Japanese Stilt Grass)
Artmesia vulgaris (Mugwort)
Celastrus orbiculatus (Oriental Bittersweet)
Phragmites australis (Common Reed)
Ampelopsis brevipedunculata (Porcelainberry)
Fallopia baldschuanica (Silver Lace Vine)
Implementation of the plan requires an adaptive management approach that reacts appropriately to bi-weekly, seasonal, and annual reporting procedures. All control methods meet USDA organic farming requirements.
Capozzi Park, Bridgeport, CT
In the winter of 2018 we conducted a vegetation survey which revealed that the park is heavily dominated by non-native invasive species such as Artemisia vulgaris (Mugwort), Lonicera japonica (Japanese Honeysuckle), Rosa multiflora (Multiflora Rose), and Ailanthus altissima (Tree-of-Heaven). Artemisia vulgaris and Lonicera japonica in particular dominate large areas of understory. Ailanthus altissima occupies a quarter to a third of the canopy layer. During our field work we marked A. altissima at breast height with spray paint blaze. Over 50 A. altissima individuals of varying diameter were found on site.
Our recommended management plan was as followed:
Remove all non-native trees and large shrubs (except those within a 40’ buffer of the eastern property line), stump grind, and chip in place.
Remove the entire forest floor understory with a flail mower. Cutting is a simple and effective way of stymying invasive species growth in a short period of time. Removal of the root system of aggressive invasive species such as Lonicera japonica and Rosa multiflora via digging or hand-pulling would be extremely labor intensive and time consuming in current conditions. Instead, we recommend using a flail mower to cut down aboveground growth of understory species, creating a clear and manageable forest floor. Dense and mature shrubs such as Lonicera sp can be cut manually with loppers or handsaws.
Once the ground has been cleared, rolls of biodegradable corrugated cardboard must be spread over the entire forest floor of the site. Covering and mulching the ground is crucial to the prevention of weed regrowth throughout disturbed soils. The corrugated cardboard will serve as a temporary mechanical barrier to weed growth that will degrade naturally over time.
Next, 6” of wood chips shall be placed on the ground to cover the cardboard. This approach will deter most plant regrowth in the first year. The wood chips will also serve as mulch for planted trees in the future. Combined with Step 3, the mulching will ultimately create a nutrient-rich soil layer with significantly fewer weedy species.
Seasonal maintenance such as weeding will be required in the long term to stunt any invasive re-colonization. Under no conditions would any herbicides, chemical fertilizers, or other plant control substances that would not be allowed on a USDA Organic farm be utilized at any time in the Park. Removed plant material will be disposed of appropriately off-site.