Beech Leaf Disease Threatens America’s Forests

The author is a Sophomore at Laurel School in Ohio. Laurel School is YEPT’s first-ever Chapter. To inquire about becoming a YEPT Chapter, contact our adult advisor at Jim@earthcharterindiana.org

Marked by its yellow ribbing and curling leaves, Beech Leaf Disease (BLD) can be spotted almost anywhere in the Eastern United States and Canada if you know what it looks like. Beech Leaf Disease was first discovered in 2012 in Ohio. Since then it has been found in at least 10 states in Northeastern America including New York, Pennsylvania, and Connecticut. It has even made its way into Ontario, Canada.

To understand BLD, you must first be able to identify a beech tree. The bark of a beech tree is unique in its gray color and smooth texture with the only naturally occurring markings shaped like eyes. Beech leaves are dark green with a pointed tip and veins running perpendicular to the midrib. 

Beech Leaf Disease is a chronic disease as opposed to an acute one, meaning that it lasts within a tree for a long time before eventually killing it. A tree infected with BLD has a life expectancy of about 6-10 years though in some places younger trees die earlier.

Photo courtesy of Angela Yeager.

Symptoms 

In spring, symptoms like striping or banding along the veins of the leaves are the first to be seen. This can appear as the veins turning either a yellow color, like they would in fall, or a darker green. Infected trees stand out noticeably from those not infected because this symptom is best viewed from underneath the leaf, the direction from which humans view the canopy. The banding not only affects the way the leaves look but also how they feel. Many trees with these symptoms can feel denser or thicker than those without BLD.

As time progresses the leaves of infected trees will begin to curl in on themselves and shrink. This phase looks very similar to how leaves in the beginning of autumn look except it is all happening while the leaves are still on the branch. Many trees with BLD won’t reach the phase of premature and excessive leaf loss until much later into the disease progression. 

Trees heavily affected by the disease can experience a reduced production of buds and leaves. This is most prevalent in May and June when trees produce a second round of leaves for the rest of the year. Leaves that do get produced by trees that are this affected are often frail and can not do their job properly. A recent study conducted at the Yale School of the Environment found that BLD reduces a tree’s ability to take in carbon, “which can potentially lead to tree mortality by depleting the trees’ stored carbon.” 

Trees with the disease do not always follow the same progression through these symptoms. Some reach stages that others do not.  Even in one tree, BLD can look different from leaf to leaf.

The Impact

BLD is an issue compounded by issues such as climate change and logging. Some consider it a kind of “natural deforestation” because it has all the same effects as man-made deforestation. BLD is important to tackle because of the role that Beech trees play in the environment and in our day-to-day lives. In Northeast Ohio, Beech trees make up almost 25% of the forests. As Dr. Alexa Wagner, a professor at Hiram College in Hiram, Ohio, explains they are “responsible for upholding the health and functioning of many forest systems.” Beech trees serve as habitats for animals like squirrels because they are partially hollow. The acorns that they produce in autumn also provide food for these squirrels and birds in the area. Dr. Wagner furthers that BLD is “threatening the survival of this tree species and its dependents.”

The negative impact of BLD extends to the economy. Beech wood is used to make products such as  chairs, table legs, cabinets, and other pieces of furniture. If a solution for managing this disease is not discovered soon, it could have wide-ranging effects on these critical industries. 

Potential actions

Due to the recency of Beech leaf disease’s discovery, there are almost no treatments for it. Scientists have only just come to a distinct understanding of what causes the disease; small worms called nematodes infect the leaves in Autumn and then do most of their damage as they overwinter in the buds. There are a few proposed fungicides, which are pesticides that kill fungi, as well as nematicides, which are pesticides that kill nematodes, but there is limited research into their effectiveness.. The worst part about this disease is that there is no pause button. So, while we wait on a treatment, BLD will continue to spread as the scientists continue to work. 

This information can seem a bit depressing or disheartening. However there are actions people can take now to further the documentation and understanding of this disease. Many states have websites with surveys where users can document when and where they have notice BLD. For example, Washington DC has an Invasive Species Reporter where concerned citizens can report the date and location of BLD sightings. Documenting the disease helps scientists estimate the rate at which it spreads. If you are interested in studying the disease hands-on, you can check out potential internships or summer programs at colleges near you. At Hiram College in Ohio there are many opportunities to work over the summer with teachers and students researching this disease.