The fragility of Biodiversity, our wildlife and insects, our pollinators, our trees, on the verge of extinction
Terrestrial Invasives and tree population on Assembly Point
TERRESTRIAL INVASIVES
Trees are essential for a healthy ecosystem. Trees store carbon dioxide, emit oxygen, mitigate soil erosion, and create a canopy to prevent excess water evaporation. They support multiple forms of life including microbes, pollinators, and animals.1 Healthy forests are those in which there are multiple species living together. The diversity of tree species contribute to an ecosystem in which there is efficient use of resources because a variety of trees collectively have different needs from the environment. A variety of trees will not all require the same nutrient and soil fungi, saving resources for all trees to grow. Specific species of trees may be susceptible to predators, whereas other species will not be touched by the same predator.2
The Adirondacks have a wealth of forested land, however these forests are under threat from terrestrial invasive species. Terrestrial invasive species are non-native animals, insects, plants, fungi or other organisms. Terrestrial invasives compete with native species to sustain themselves and have the capacity to eradicate the trees upon which they are feeding or create an adverse environment for tree seedlings to become established. Examples of terrestrial invasives which have been problematic in the Adirondack region include: non-native phragmites (aka: reed grass), yellow iris, bush honeysuckle, beech leaf disease nematode, emerald ash bore, hemlock woody adelgid and spongy moth, to name a few.3 The following information features a few of these invasive species.
KNOTWEED
One of the most pervasive terrestrial invasive on Assembly Point is knotweed.3 It is, however, an invasive that is common throughout the Adirondack region. There are 3 species of knotweed, i.e. Japanese, Giant, and Bohemian. Identifying features include: 1) heart or spade shaped leaves, 2) stems which are green and hollow, with nodes, and resemble bamboo, and 3) clusters of small, white flowers which bloom in August and September. It grows densely and can reach 12’ in height. This plant spreads easily and expansively via rhizomes, an underground root system that can extend 30’ beyond where plants are initially seen above ground. Knotweed is harmful because it overpowers the ability for native plant species to grow, thereby limiting the biodiversity of the plant and animal life of an area in which it is introduced.
Eradicating knotweed requires time, vigilance and careful handling. Mowing these plants is NOT recommended because the rootlets will be spread by the mower and easily take root, creating greater spread of this invasive. Small areas of infestation may be carefully dug out and then remove the plant with the entire root system. Do not throw the plant in the garbage without placing it in a black garbage bag and letting it sit in the sun for 2 weeks. This will prevent the plant from taking root in a place where it is being disposed. Herbicides via injection or spray technique are possible, HOWEVER, this should never be done without considering the danger to water and wetlands, pollinators, and other forms of plant and animal life. Please refer to the following link for information on how to manage knotweed. https://adkinvasives.com/data/files/Documents/A%20Landowners%20Guide%20to%20Knotweed%20Control%20V2.pdf
photos from Lamoile County Vt. Knotweed control along the LCBike Path courtesy of Hyde Park infestation control at bottom of articles
HEMLOCK WOOLLY ADELGID
Eastern hemlocks make up about 10% of the forests in the Adirondacks and they can survive on steep slopes and stream banks. This makes them critical in preventing erosion from water run-off and contributing to maintaining healthy water temperatures and water quality. Woolly adelgid is an invasive species in the form of a tiny insect that is reddish brown or purplish black. The adult insect creates a woolly looking white sac that holds eggs on the underside of the branches of the tree and are present from late fall to early summer. The insects feed on newly developing twigs and on the trees’ starch reserves that are essential for tree growth. The time in which trees decline and die range from 4-10 years.
Injecting pesticides will often help with individual trees, however this is not a feasible solution for managing infestations in the forest nor on the shorelines of the lake where poisons can seep into the drinking water. (3)
Removing bird feeders that are situated close to the hemlocks is one thing that people may do to help prevent the spread of this invasive because birds may actually spread the eggs of the woolly adelgid. (4)
Other Adirondack Trees:
Insects: Currently Emerald Ash Bore and even Woolly Adelgid, need to use chemicals to control these insects. The chemicals are toxic to the lake environment. Scale, another insect, is a bigger issue in our area for Hemlocks than Wooly Adelgid, yet no one talks about this. Most of the Hemlocks on Assembly Pt are being decimated by Scale which weakens the tree allowing other insects and disease to come in. The chemical is the same for Scale as well as Wooly Adelgid. Again toxic to the lake environment. They are working on biological controls but… these are difficult to use.
Climate Change:
A bigger issue, and any work we do on Assembly Pt, the APWQC, will not save the Adirondack trees – this is a global issue. When I graduated from the College of Forestry in 1980, Lake George was considered a plant zone 4 (plants tolerating temperatures down to -30 to -25F), and considered border line 5 (plants can tolerating temperatures down to -20 to -15 F). Now it is a solid 5. Borderline means, a plant would need to be located in a sheltered area where the plant was protected from other environmental conditions like i.e. wind which drops temperature further down.
Planting more Adirondack trees is not necessarily the answer due to deer browsing, temperature ranges of these trees – in some cases it is becoming too warm for them, i.e. Hobblebush and Balsam Fir you generally only see at higher elevations. Not even around the lake basin.
- Trees as Nature-Based Solutions. One Earth. 2020 May 22;2(5):387-389. doi: 10.1016/j.oneear.2020.04.016. PMID: 34171029; PMCID: PMC7243769. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243769/ Accessed on 9/18/23
- eLife. "Forests benefit from tree species variety and genetic diversity: The variety of tree species and the degree of genetic diversity within individual species both affect forest productivity.." ScienceDaily. ScienceDaily, 29 November 2022. www.sciencedaily.com/releases/2022/11/221129112751.htm Accessed on 9/18/23.
- Field Guide to Terrestrial Invasive Species Management of the Adirondacks https://adkinvasives.com/data/files/Documents/Field%20Guide%20to%20TIS.pdf Accessed on 9/18/23
- Adirondack.net. Hemlock Wooly Adelgid. Adirondack.net/invasives-harmful-plants/hemlock-woollyadelgid/#:~:text=How%20Is%20It%20Harmful%3F,years%20following%20the%20initial%20infestation. Accessed on 9/18/23