2017-09-13 / From the Forest

Don’t Judge

By Ryan Trapani, Director of Forest Services, CFA

Yesterday found me stranded for a short while near Kerhonkson. I was waiting for some new brakes and decided to go for a walk. Besides, I was kind of hungry anyway. The Route 209 corridor seems like a small pocket of heat and humidity; at least compared to the surrounding hills.

However, this forested jungle offers quite a variety of trees, shrubs, and vines. Apples were beginning to ripen, along with pears, black walnuts, butternuts, acorns, and a variety of hickory nuts. Finally, I found something that was ready for picking – wild grape. Sure, they could use a few more weeks or a good frost to sweeten up, but were good enough. Staining my fingers with each tug, I downed a few clumps before making off.

On my way back, I passed many more apple trees in people’s lawns; I sure wanted to pick some, but didn’t see the owners outside. Then I saw what was once a field, now growing up with small trees and shrubs. I saw walnut saplings, oak, sycamore, black locust and plenty of multi-flora rose, honeysuckle, and autumn olive. There were also many catalpa trees growing too. They must have seeded in from plantings in the hamlet of Kerhonkson. Catalpa is often planted as an ornamental shade tree. Before today, I can’t remember if I saw catalpa regeneration (seedlings) in that quantity before.

Defining “Invasive”

What’s the point? Well, often I’m asked about invasive species while at work for the Catskill Forest Association. The term “invasive” seems highly subjective to me. According to the NYS DEC, “Invasive species are non-native species that can cause harm to the environment or to human health. As a threat to our biodiversity, they have been judged second only to habitat loss. Invasives come from all around the world; the rate of invasion is increasing along with the increase in international trade that accompanies globalization… Invasive species have implications, too, for recreation and for human health.”

It’s true that some invasive plants might fit the bill according to this definition, but some might not depending upon your goals and timeframe. First, let me dare to bring up some of the benefits of “globalization” and their additions to our region’s biodiversity and richness; a concept that is often overlooked. Remember the apples and grapes; both non-native species. Even more significant to our conversation is that both apple and grapes can be considered invasive when the context is right.

Apples and grapevine

Although apple isn’t perceived as invasive today, it can be quite abundant after fields are abandoned, taking over certain areas where birds and mammals have spread their seed. Wild grapevine is known to strangle trees too, especially in the southern portion of the state into New Jersey.

Today, both apple and grapes are relegated to where sunlight is plentiful. Often their skeletons can be found in mature forests that once were younger and their bones left to decay and feed the future forest. Apples and grapes get a pass though; they’ve been grandfathered in since they came before our collective declaration of war on non-native species. Besides, who doesn’t like apple and grapes? Honeybees? Yeah, they’re not from here either.

Other non-natives aren’t so lucky. Autumn olive, white mulberry, honeysuckle, and barberry are instead scoffed at. Autumn olive was once planted by conservation groups for improving wildlife habitat. I guess the birds liked it too much and began spreading it wherever they went. Today, autumn olive, as well as barberry and honeysuckle are targeted for destruction by most environmental groups and the NYS DEC.

White mulberry – on the other hand – is looked down upon by purists touting only the native red mulberry. Here’s the thing. Apparently, white and red get along just fine, and actually hybridize with each other, perhaps making for an all around hardier tree. Still who can argue that as a whole, biodiversity has not actually increased? Remember that field earlier? There were both natives and non-natives growing abundantly, adding more species richness than before.

Invasive? It Depends…

Maybe it’s less important where the plant comes from and more important whether it interferes with your goals or not. If you’re trying to grow certain types of trees, then non-native honeysuckle and barberry might be “invasive.” If I’m trying to foster wild growing apple trees for wildlife, then I know that most of the time, the native white ash or red maple tree is invasive under that context. If improving wildlife habitat is your goal, then even the defamed Japanese barberry can be great bedding cover for white-tailed deer or “rabbitat” for rabbits. Birds love autumn olives and white mulberries, a lot! And turkeys? Forget about it.

Succession & Deer Browse

Many of these invasive species (not all) might be abundant now, but that doesn’t mean they will be going forward. The DEC’s definition does not factor in succession, perhaps the most significant “killer” of some of these most edible “invasive species.” For instance, autumn olive and honeysuckle are shrubs that are intolerant of shade. As the forest matures or succeeds to an older environment, they will eventually die from over-shading.

And lastly, many of these invasive plants (not all) are abundant due to another ecological issue; namely their resistance to deer browsing. Over-browsing deer have helped proliferate some non-native and native plants in recent decades. The recent invasive nature of some native plants has been ignored, while the non-natives have gathered all the attention. Native species growing in abundance include NY fern and hay-scented fern, beech, red maple and black birch for starters.

So, before you cast judgement, eat an autumn olive; they’re almost as good as apples, and decide for yourself. My college professor said deer never ate barberries. I have confirmed the opposite since, many times from my deer stand. www.catskillforest.org

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