What Invasive Species are Harming Hudson Valley Trees?

Although old age, environmental factors, weather patterns and accidents can cause trees to require our services as a tree removal, trimming feeding & cabling company, a little-understood factor is invasive species. 

Invasive species, as the name suggests, are plants and insects that aren’t from our region originally, and have a parasitic relationship with the native trees and plants that are here. If an invasive species finds its way to your property’s trees, it’s possible that your tree won’t have the long, healthy life that it could have had.

In this blog post, we take a look at the four most common invasive species that have invaded our area of Ulster County, Dutchess County, Columbia County, and Greene County, and counted up the number of reports of them on the iMapInvasives reporting system.

1. Oriental Bittersweet (601 Reports)

Coming in first is Oriental Bittersweet. This invasive vine can have a major impact on trees in our area of Dutchess County, Ulster County and Columbia County, but not Greene County, if the data is to be believed.. It has the ability to quickly wrap itself around trees and strangle them, growing thicker and tighter as it restricts the flow of water and nutrients within a tree. It can also shade out the tree’s leaves, add extra weight that leads to branches breaking, and makes trees more vulnerable to other stressors.

Oriental bittersweet, in effect, is a major reason why local trees are having to be taken down. If you see a vine growing up your tree, cutting it at the base and removing it during the dormant season can help prevent it from taking over.

2. Emerald Ash Borer (309 Reports)

Next on the list is the Emerald Ash Borer (Agrilus planipennis), the second most commonly reported invasive species in our region. This tiny but destructive beetle has had a significant impact on our local trees and forests, predominantly in Ulster and Greene County.

It’s a major concern for our region’s ash tree population. It works by disrupting the flow of water and nutrients under the bark of ash trees, leading to a decline in the health of the tree. A telltale sign of an infected tree is a thinning canopy, which shows through in a reduction of leaves and tree vigor. As the infestation continues, the tree’s branches may die off, increasing the risk of falling limbs. 

To detect ash borer, regularly inspect the tree for signs of infestation, particularly “D-Shaped” exit holes and canopy thinning. A certified arborist or pest management expert may be able to remediate the tree.

However, if it’s too late, removal and disposal of the tree is likely necessary.

3. Hemlock Woolly Adelgid (212 Reports)

Next up is the Hemlock Woolly Adelgid (Adelges tsugae), an invasive insect that poses a major threat to the hemlock trees of our region. This aphid-like insect has devastating consequences for our local hemlock trees, especially in Dutchess, Ulster and Greene Counties.

The agelgids feast on trees’ sap, depriving them of essential nutrients, leading to less growth and a weakened tree. Over time, the hemlock may experience needle loss, and twig and branch death. The weakened hemlock then becomes more susceptible to drought, extreme temperatures and other pests.

If you have a hemlock tree, regularly look out for white, wooly masses at the base of needles. An arborist could apply insecticide that would address the hemlock wooly adelgid. 

4. Elongate Hemlock Scale (50 Reports)

Let’s delve into the impact of the Elongate Hemlock Scale (Fiorinia externa), an invasive insect species that poses a significant threat to hemlock trees in Ulster County. Understanding its effects and management is crucial for protecting our hemlock trees. 

The scales feed on the needles of hemlocks, causing needle loss and making the tree weaker and more susceptible to disease and stressors. If left unmanaged, it will lead to the tree dying and becoming a safety hazard, necessitating tree removal.

That’s it for the list! For your reference, here are the top ten invasive species in each region we could map out in the iMapInvasives database:

Northern Dutchess County 

  1. Curly Pondweed (Potamogeton crispus): 182 confirmed
  2. Eurasian Water-milfoil (Myriophyllum spicatum): 180 confirmed
  3. Multiflora Rose (Rosa multiflora): 116 confirmed
  4. Oriental Bittersweet (Celastrus orbiculatus): 94 confirmed
  5. Japanese Barberry (Berberis thunbergii): 61 confirmed
  6. Purple Loosestrife (Lythrum salicaria): 28 confirmed
  7. Hemlock Woolly Adelgid (Adelges tsugae): 26 confirmed
  8. Japanese Stiltgrass (Microstegium vimineum): 23 confirmed
  9. Burning Bush, Winged Euonymus (Euonymus alatus): 22 confirmed
  10. Honeysuckle (species unknown) (Lonicera spp (species unknown)): 17 confirmed

Northern Ulster County

  1. Common Carp (Cyprinus carpio): 464 confirmed
  2. Water Chestnut (Trapa natans): 217 confirmed
  3. Multiflora Rose (Rosa multiflora): 162 confirmed
  4. Oriental Bittersweet (Celastrus orbiculatus): 146 confirmed
  5. Emerald Ash Borer (Agrilus planipennis): 136 confirmed
  6. Purple Loosestrife (Lythrum salicaria): 85 confirmed
  7. Japanese Stiltgrass (Microstegium vimineum): 71 confirmed
  8. Japanese Barberry (Berberis thunbergii): 63 confirmed
  9. Common Buckthorn (Rhamnus cathartica): 61 confirmed
  10. Common reed grass, phragmites (Phragmites australis ssp. australis): 61 confirmed

Western Ulster County

  1. Oriental Bittersweet (Celastrus orbiculatus): 361 confirmed
  2. Japanese Barberry (Berberis thunbergii): 321 confirmed
  3. Emerald Ash Borer (Agrilus planipennis): 154 confirmed
  4. Garlic Mustard (Alliaria petiolata): 150 confirmed
  5. Multiflora Rose (Rosa multiflora): 150 confirmed
  6. Hemlock Woolly Adelgid (Adelges tsugae): 144 confirmed
  7. Japanese Stiltgrass (Microstegium vimineum): 129 confirmed
  8. Japanese Knotweed, Japanese Bamboo (Reynoutria japonica var. japonica): 99 confirmed
  9. Elongate Hemlock Scale (Fiorinia externa): 50 confirmed
  10. Black Locust (Robinia pseudoacacia): 45 confirmed

Columbia County

  1. Common Carp (Cyprinus carpio): 1687 confirmed
  2. Rudd (Scardinius erythrophthalmus): 325 confirmed
  3. Water Chestnut (Trapa natans): 164 confirmed
  4. Tree-of-heaven, Ailanthus (Ailanthus altissima): 113 confirmed
  5. Multiflora Rose (Rosa multiflora): 81 confirmed
  6. Common reed grass, phragmites (Phragmites australis ssp. australis): 78 confirmed
  7. Purple Loosestrife (Lythrum salicaria): 77 confirmed
  8. Japanese Stiltgrass (Microstegium vimineum): 66 confirmed
  9. Oriental Bittersweet (Celastrus orbiculatus): 66 confirmed
  10. Japanese Knotweed, Japanese Bamboo (Reynoutria japonica var. japonica): 66 confirmed

Greene County

  1. Multiflora Rose (Rosa multiflora): 64 confirmed
  2. Japanese Barberry (Berberis thunbergii): 53 confirmed
  3. Purple Loosestrife (Lythrum salicaria): 52 confirmed
  4. Garlic Mustard (Alliaria petiolata): 50 confirmed
  5. Hemlock Woolly Adelgid (Adelges tsugae): 42 confirmed
  6. Japanese Knotweed, Japanese Bamboo (Reynoutria japonica var. japonica): 42 confirmed
  7. Water Chestnut (Trapa natans): 22 confirmed
  8. Emerald Ash Borer (Agrilus planipennis): 19 confirmed
  9. Black Locust (Robinia pseudoacacia): 18 confirmed
  10. Norway Maple (Acer platanoides): 24 confirmed

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