2020 has been a difficult, disease-filled year, and it turns out humans aren’t the only ones who feel that way. Our local beech trees in Hillside Woods have been infected with beech leaf disease. This disease will kill a mature beech tree in about 6-10 years, and a younger one even more quickly. First discovered in Ohio (you don’t hear that often), the disease is believed to be associated with the presence of nematodes, a kind of worm. It’s unclear whether the disease is caused by the worms themselves or by pathogens carried by the worms. Beech leaf disease is especially concerning because beech trees constitute a large part of our local tree population: about 11% of Hillside Woods is American beech, and they are the fifth most common species of trees in all of NYS. Beeches are a valued nesting site for birds and provide food for a variety of wildlife, including squirrels, birds and deer. Losing our beech trees will be devastating.
You can recognize beeches by their smooth, grey bark, which often make them a target of graffiti. In fact, the word “beech” is thought to have contributed to the origin of the word “book,” as people used to carve runes into beech bark. Beech trees have dark green, oval leaves that have a pointed tip. Additionally, the side-veins coming off the mid-rib (the line down the middle of the leaf) are slanted and parallel to one another.
To determine whether a beech has been infected, you can look for striping - or banding - and shriveled-up curling of beech leaves. Beech leaf disease also manifests itself in decreased leaf and bud production, and a tree can have both infected and uninfected branches. Eventually, the leaves affected by disease will wither, yellow and die. Beech leaf disease can be confused for other things, including mildew, erineum patches, and anthracnose. To avoid confusion, look for distinct banding—yellow or brown stripes—in the leaves, which is pretty much unique to beech leaf disease. You can also test for the nematode. Leaves from Hillside Woods beech trees have been analyzed by a DEC lab and tested positive.
If you notice beech leaf disease on your property, avoid moving fire wood or other lumber from that area, so that other beeches aren’t infected. If you see a beech tree that you believe has been infected, you can assist the DEC (Department of Environmental Conservation) in stopping the spread by photographing and emailing photos and location info to foresthealth@dec.ny.gov.
For more information, visit the DEC beech leaf disease info page or this article from the American Association for the Advancement of Science.
Recently you may have noticed some white lines across certain trees in the Hillside Woods. Maybe you assumed it was some poorly delivered trail markings or a minimalist Banksy project. It is neither. These white lines are part of the Hillside Woods Restoration Project’s effort to combat invasive species in our woods. Trained volunteers have marked two invasive tree species: Norway maple and tree of heaven (aka ailanthus). These trees are being surveyed so that they can be removed. Invasive species like these trees compete with native plants, offer little to nothing to native animals, and decrease the biodiversity of an area. But these aren’t the only invasives present in Hastings, so why these trees specifically?
The Norway maple has a particularly large presence in our woods, which is problematic for a number of reasons. It leafs-out early, casts dark shade and has a shallow root system, all of which disrupt the growth of native plant species that need ample sunlight to grow, especially wildflowers and the sugar maple. In a domino effect, this also affects native birds and insects, who depend on these native plants for food. The Norway maple may also serve as a host for aphids, small insects which in large numbers will damage other plants.
The second tree you need to know about is the alianthius, more commonly known as the tree of heaven, a rather misleading name. The tree of heaven produces allelopathic chemicals, which are chemicals that leach into the soil and inhibit the growth of other plants. Quite rude, really. The tree of heaven also attracts the spotted lanternfly, an agricultural pest that attacks native trees and produces a sugary fluid that encourages mold and disease. The tree of heaven’s impressive root system can buckle pavement, and it’s partly this root system which makes it very hard to get rid of. In fact, you may recognize the tree of heaven from A Tree Grows in Brooklyn by Betty Smith, in which it symbolized perseverance, especially in challenging or dangerous environments. But with the time and dedication of many, both the tree of heaven and the Norway maple can be removed and our woods can become a happier, healthier place.
How to Identify these Two Invasive Trees
Norway Maple
The leaves of Norway maples are wider than they are long.
They have five distinct lobes, or sections, on each leaf.
During the spring, it has clusters of yellow-greenish flowers, which mature to seed pockets with helicopter-like blades during summer.
In the fall, the Norway maple turns yellow.
The Norway maple looks very similar to it’s non-invasive native cousin, the sugar maple. Here are a few key characteristics that differentiate the Norway maple from the sugar maple:
The Norway maples have white sap. If you break the stem off a leaf and see white sap then you know it’s a Norway maple. Good way to remember: white sap, snow is white, and there’s lots of snow in Norway.
Norway maples have longer stems.
They tend to have less bug-bitten leaves, due to the fact Norway maples are invasive and aren’t consumed by most native insects.
Tree of Heaven (Ailanthus)
The tree of heaven has long-stemmed leaves with anywhere from 10 to 40 leaflets.
Its individual leaflets are a few inches long, with bumps at the base.
Its bark is described as looking like cantaloupe skin.
It has yellow flowers in early summer to late spring, which become clusters of orange-yellowish seed pods during late summer.
The tree of heaven has a pungent odor. Its distinct smell has been described as burnt peanut butter, “that new gym smell,” or burning rubber. Next time you spot one in the woods, crack a stem or leaf, take a whiff, and you can decide for yourself the odor.
The tree of heaven may look similar to wisteria, another invasive plant. However, you can easily pluck tree of heaven seedlings in your garden in early spring through summer. Sprouting wisteria tends to be connected to a longer root and is harder to remove.
Additional Info
Norway maple: http://nyis.info/invasive_species/norway-maple/
Tree of heaven: https://www.wnyprism.org/invasive_species/tree-of-heaven/
Spotted lanternfly: http://nyis.info/invasive_species/spotted-lanternfly/