The Sunken Forest Tour: Holly Grove

The Sunken Forest is one of just two American Holly Maritime Forests in the world.

NPS/Sucena

Near the beginning of this tour we mentioned that the Sunken Forest is one of two maritime holly forests on the planet. You are probably familiar with holly. It’s pointed leaves, and the bright red berries of the female plants are often associated with the holiday season. Look closely at the bark and you may also notice its slight greenish hue, and the odd eye-like knots that adorn its surface. Those eyes are, or course, not eyes at all, but the remnants of old branches shed from the tree in a process called “self-pruning.”  

 

Ilex Opaca, or American Holly is a broadleaved evergreen native to the Northeastern United States. Though it is hardy, it is not a particularly salt-tolerant plant and so, rarely occurs in this density as close to the ocean as we are now. Protected from the salt spray by the tall set of primary and secondary dunes, these trees have beaten the odds and grown in a most unlikely spot.

 

There are, unfortunately, signs of trouble in regard to this rare stand of holly trees. Look out to the ground and you may notice almost no young saplings or adolescent holly. Over the last sixty or so years the Sunken Forest has undergone a dramatic transformation. What was once a thick understory is now relatively barren, a worrying sign for future generations. But, what happened to all of the young holly?

 

You may be surprised to hear this, but holly saplings are popular food items for herbivores such as deer on Fire Island. Though it’s leaves are sharp and painful in mature holly, young saplings feature soft and juicy leaves. As a result of overgrazing, due in no small part to the exceedingly large population of deer on Fire Island, an entire generation of holly trees is missing from the forest. This means that if and when an adult holly tree dies or is knocked over, its children are no longer there to replace it.

 

But how can the deer be having this impact on the Sunken Forest only now? The unfortunate answer lies in our hands. There are estimated to be as many as three to four times as many deer on Fire Island then can survive here on their own based on the island's acreage. This unusually dense population appears to be the result of illegal or accidental feeding. Whether they are rummaging through garbage pails, or taking food from the hands of visitors, deer often become sickly or unhealthy from this process. Even still, many survive and reproduce at much higher rates than you would expect in a wild space. As a result of their proliferation, the Sunken Forest and many other habitats on Fire Island have been placed in jeopardy.

 

What can you do to help both the deer and the Sunken Forest? Above all it our goal to ensure that we keep wildlife wild. This means that under no circumstances should we feed or interact with wild animals such as deer. We must also take care to secure our food and garbage away from deer. With this in mind we can all do our part to take care of this environment holistically, ensuring the health and safety of the deer, the holly, and all of the other plants and animals which make this place unique.