White-tailed Deer and Invasive Plants

Most don't understand the relationship between deer and invasive plants or even know a relationship exists. I came across the below article on the Quality Deer Management Association's (QDMA) web site and thought I would share it with my readers. It hits the nail on the head.......high deer impact and invasive plant overabundance go hand in hand. As overabundant deer eliminate preferred native plant species voids are created and native plant competition, that would normally keep invasive plants out, is eliminated. As timber stands are disturbed through harvesting or natural tree mortality, few native plants are able to grow out of the reach of deer. Eventually, the understory gets overtaken by invasive plants, which deer prefer not to eat. 

This is just one more reason the keep deer in balance with their habitat. I have always taught that deer management is a two-pronged approach: Population Management along with Habitat Management. You can't have deer without good habitat to support them. Too often we want to try and carry more deer without providing quality habitat. Please read the article below by Celia Vuocolo as she relates her experience in how deer and invasive plants go hand in hand. Celia and her parents own a 172 acre farm in Hunterdon County, New Jersey.

Whitetails & Invasive Plants: A Dangerous Combination

“I can’t even tell you when we can do the next timber harvest,” our consulting forester, Doug Tavella, said to me in the summer of 2010. “Browsing by deer is so bad that you have almost no hardwood regeneration. That, combined with all of the non-native invasive plants, has stunted the development of your woodlot. You need to do something about the deer.”

These were the last words I wanted to hear. The 172- acre farm that my family and I own and manage in Hunterdon County, New Jersey, has never faced a threat quite like this before. Since 1974, our farm has been under a forest management plan. Like many of the traditional farms in New Jersey, agriculture was abandoned on our land in the early part of the 20th Century. This allowed for the regeneration of the woodland, creating a solid upland hardwood forest that comprises about 95 percent of our property. But forestry doesn’t just make sense for our property, it’s also our means of survival. Maintaining a large piece of property (172 acres is large for New Jersey!) in the most densely populated state in the country can be financially difficult. And it was starting to look like the combination of overpopulated whitetails, an increase in non-native invasive plants, and timber harvesting was threatening our livelihood and our woodland’s sustainability.

I knew I had to come up with a game plan. To understand how things got so bad, I had to go back to the beginning and look at how we managed our woodlot and our deer. Our woodlot is composed of four different even-aged timber stands, classed by age and timber type. The first timber harvest occurred in the fall of 1974. It was modest, and was done on a parcel of about 4 acres. Upland hardwoods like oaks, ash, and yellow poplar with 16-inch diameters were harvested. However, our big timber-harvest projects occurred consecutively in 1994, 1995, 1999, and 2000. In 1994 and 1995, we used the shelterwood technique as a way to increase the production of our white oaks, and harvested about 18,700 board feet.

The goal in our 1999 and 2000 timber projects was timber stand improvement (TSI), so undesirable trees were thinned from two different stands in those seasons. All of our timber management projects and goals were carefully planned and carried out with our consulting forester. We followed every best management practice (BMP) and guideline. Although timber production was a goal, forest stewardship and sustainability always trumped it. We had managed our forest properly, with hardwood regeneration and wildlife biodiversity in mind. So, what happened?

I like to call it the “perfect storm.” In the mid to late1990s, right when we were doing our most intensive timber harvests, the whitetail population in New Jersey, particularly in Hunterdon County, exploded. By opening up the forest canopy to allow for hardwood regeneration and plant growth, we basically set a dinner table for the whitetails. All of the native forbs, grasses, and hardwood saplings were wiped out. Since nothing else was able to grow, non-native and invasive plant species moved right in and established themselves.

Most of the non-native and invasive plants found on our property showed up on the scene the same way many alien plants have in the United States: they were intentionally or accidentally planted at some point in our country’s history. Our main offender at the farm, multiflora rose, was actually distributed and encouraged by the U.S. Soil Conservation Service in the 1930s through the 1960s as a type of natural livestock fencing. Non-native invasives haven’t evolved with the rest of the native ecosystem, so wildlife, like deer, won’t usually eat them. This is great for the invasives, and since they have no natural enemies, they’re free to multiply unchecked. Wherever there is environmental disturbance and available sunlight, invasives will appear. Invasive plants thrive on disturbed ground, whether it is from forestry practices or road construction. Now our woodland is chock full of multiflora rose, Japanese stiltgrass, garlic mustard, Japanese barberry, and a multitude of other non-natives that are completely useless to our wildlife.

Fast-forward to the summer of 2010, where I am having a conversation with our forester that I never wanted to have. After researching our timber management history (I was a kid during most of it), I came to the same conclusion he did: we have to do something about the deer. Our timber management practices were solid, and we did everything we were supposed to do. However, our deer management practices have always been severely lacking. I am not a hunter, nor was my mother or father. Throughout the 1970s and 1980s, a few relatives and some family friends hunted the land, with no regulations other than what the state required. In the mid 1990s, my father allowed a local hunt club on the property, and they had been hunting ever since. It became obvious to me that traditional hunting was just not cutting it, and that we needed a different kind of hunting program on the property. I had known about the QDMA for a little over a year, and I came to realize that by using the methods and ideals of QDM, I could manage our deer herd and therefore manage our woodlot.

Finding a local group of hunters interested in QDM wasn’t too hard. I also found it easy to strike up a healthy and mutually beneficial relationship with our new club. Although I am a land manager and they are hunters, we share the same goals and ideals about how to manage our habitat and deer herd. Our first order of business is to assess the herd with a trail-camera survey this year. Like our hunt club, our goal as landowners is to reduce deer density to a healthy level so that hardwood regeneration can start to occur once more and the quality of the deer herd is re-established. I feel confident that using QDM is the first step in the solution to re-establishing biodiversity on our farm.

However, the problem with forest regeneration on our property is two sided, and although one aspect is on the right track, the other one is not as simple to fix. In the years since our timber harvests, my family and I have concentrated our efforts on controlling the non-native and invasive plants in our woodlot. Our struggle with these foreign invaders has yielded some victories in certain areas of the farm, but there have been many losses. Removing a thick understory of non-native invasive plants that spans acres is not an easy or inexpensive task. 

First of all, we can’t successfully remove the invasives without getting the initial instigator under control: the deer population. If the deer are still too plentiful, they will wipe out any new native plant growth that comes up after the invasives are removed. Secondly, removing all of the invasives can be incredibly time consuming and expensive. The amount of manpower, time, and equipment needed is overwhelming. Some areas of the property are so thick with multiflora rose that they create up to a half-acre of impenetrable vegetation. One area in particular, at the site of our first timber harvest in 1974, has been nick-named ’Nam by one of our new hunters. The only way to tackle these areas is with heavy machinery that can clear a couple of acres in a day, and start from scratch.

Resolving our issue of re-establishing a healthy forest is a long way off. However, I have faith that with some resourceful thinking and QDM, we will be able to conquer this problem. By enlisting a QDM oriented hunt club on our property, we may actually kill two birds with one stone. Our club recognizes the need to restore and enhance our property’s natural habitat in conjunction with managing the deer herd. My hope is that by combining my family’s continued efforts with our club’s habitat management goals, that we may be able to curb the tide and get a handle on our invasive plant problem.

I’ve learned that managing habitat is not always black and white; there are actually a lot of shades of gray. My family was unaware of the fluctuations of New Jersey’s deer herd in the 1990s and its devastating effect on our future livelihood. We didn’t realize the dangers of opening up the tree canopy and disturbing the forest floor. Once the composition of our woodlot changed, it created a ripple effect that impacted all wildlife.

We all know that habitat management is one of the Four Cornerstones of QDM, but it goes beyond simply managing for the best quality forage. Non-native and invasive plants are in every state, and it’s important to know what they look like, and whether you have any, before you disturb the soil and increase sunlight to the ground. By removing invasive plants and ensuring valuable native plants become established, you’re that much closer to guaranteeing the highest quality habitat for deer, enhancing the biodiversity of your land, and sustaining forest management practices for years to come.

I have learned a valuable lesson about land management, and I will carry this knowledge with me as my family and I continue to restore our property.

About the Author: Celia Vuocolo is the Sustainable Habitat Program Assistant with the Piedmont Environmental Council of Virgina. She earned a degree in conservation and wildlife management from Delaware Valley College in Pennsylvania. She is a Level 1 QDMA Deer Steward. You can follow Celia on Twitter @CeliaVuocolo. This article was first published in QDMA's Quality Whitetails magazine.