Summer in the Sugarbush

Sam Blair, UVM Intern, Reflects on the Bird-Friendly Maple Project

Inspiring the next generation of conservation leaders is a core principle of Audubon's work in Vermont. Sam Blair, the 2018 UVM Rubenstein Conservation Education Fellow, returned to work with us this year as an intern with the Bird-Friendly Maple Project. Here is an account of his summer in the sugarbush.

It’s 9:30 am and the mist is starting to lift as Steve Hagenbuch, Tim Duclos, and I wend our way up through the mountain fields of the Merck Forest and Farmland Center. We are following the “mainline,” strung between wooden posts, which in spring carries sap from the Center’s sugarbush to a wood-fired evaporator in the sugarhouse. Our destination is that sugarbush and today’s Bird-Friendly Maple Project assessment. The air is clean and smells lightly of hay and wet ferns – the smell of roughly 3,000 acres of forest and farmland breathing. Bobolinks rise up from the meadows around us, hovering overhead and singing their strange “R2-D2” song. Tim’s dog Rodeo keeps us company, stopping frequently to roll enthusiastically in the wet grass.

All told, we represent at least two conservation organizations (Rodeo might count himself a member of a third – the Organization for the Preservation of Squirrels and Good Smells), and today we have come together to think about forest birds and the role maple sugarbushes can play in their conservation. Tim is the Conservation Manager at Merck Forest, and Steve is a Conservation Biologist for Audubon Vermont’s Healthy Forests and Working Lands programs. I am Audubon Vermont’s Bird-Friendly Maple Project Intern, and this summer I’m getting a look into the very special work underway in Vermont’s maple-producing forests.

The Bird-Friendly Maple Project is a market-based conservation program that seeks to support maple syrup producers who make management decisions with birds in mind. These decisions really have to do with making forests that are tapped for maple sap as ecologically “whole” as they can be. This may seem like a no-brainer – they’re woods, after all; aren’t they “whole” already? But in fact the maple sugarbush, also known as the sugar woods, the sugar lot, the sugar “orchard”, and probably many other names besides, is a uniquely human creation – the product of a long history of management decisions that have altered what we might conceive of as the “natural state” of the forest.

What’s so interesting about Audubon Vermont’s Bird-Friendly Maple Project is the way it challenges us to consider, in the sugarbush, a landscape fundamentally shaped by human priorities. Bird-Friendly Maple seeks to re-order those priorities, not through goodwill alone, but by creating an economic incentive for change. In a crowded marketplace, Audubon Vermont offers producers who manage their sugarbushes to the Project’s standards the opportunity to label their syrup as “Bird-Friendly.” Hopefully, this recognition process can help producers who are committed to responsible sap production stand out; this, in turn, can make management decisions that consider more than just maximizing sap production more economically viable.

The Bird-Friendly Maple Project’s guidelines focus on two fundamental aspects of forest ecology – tree species diversity and forest structure – in an effort to create whole and healthy forests. A diverse, structure-rich woods has many types of trees of many ages, rather than “even-aged” stands of a single crop tree such as sugar maple. Forests with high tree species diversity are appealing to a wide range of birds and insects, and are also healthy and robust ecosystems, less prone to devastating, unregulated infestations of insect species like the forest tent caterpillar. Forest structure, on the other hand, means lots of stuff – big and little trees that appeal to a wide range of living things; “standing dead wood” where insects are at work breaking down lignin and cellulose, and birds are in turn at work eating the insects; and logs and branches slowly decomposing on the ground, returning their nutrients to the forest floor. There are kinds of mosses that grow only on the tops of logs, their spores carried in the fur of chipmunks racing along the natural pathways formed by the fallen trees. This is the kind of specificity and fine-tuned adaptation we find in a forest; orienting management practices towards creating diverse, structure-rich forests means enabling these complicated and beautiful systems to function.

As we enter the woods, we start to hear the “pleased, pleased, pleased to meet-cha” song of the Chestnut-Sided Warbler, a denizen of this scrubby transitional “ecotone” between field and forest. We make our way up through ever-branching logging roads overgrown with Rubus (raspberry and blackberry) bushes and tall grasses. They brush our legs, leaving them soaked with dew. The transition to mature forest is starting to take hold when we hear the distant “tea-cher, tea-cher” of the Ovenbird calling from the forest understory.

Beneath our feet elderberry (Sambucus spp.), blue cohosh (Caulophyllum thalictroides) and Jack-in-the-pulpit (Arisaema triphyllum) hint that the soils are becoming rich and alkaline – perfect habitat for the sugar maple (Acer saccharum) we’ve come seeking. Soon we can see plastic tubing in the distance, indicating the edge of the sugarbush. These “lateral lines” run from tree to maple tree and carry sap in the spring. They are left up throughout the year because it’s such a chore to install and maintain them. One can imagine the days of horse-drawn sleighs and metal sap buckets in these woods – but those days are in the past now, and on this expansive and historically significant property that past is perhaps more legible than in many other places.

These woods were not always so shaded, moist, and welcoming as they are today. Around the end of 1800’s almost 75% of the arable land that now constitutes the Merck Forest and Farmland Center was cleared for pasture or agricultural fields. Even the woods we are entering now were likely cleared, although other patches of sugar maple must have been present on the property, managed to produce annually, at the time of the 1880 US Agricultural Census, 2,450 pounds of maple sugar. In the 1940’s, after the hill farms that quilted this landscape had fallen into decline, George W. Merck of Merck Pharmaceuticals began buying up land and established one of the first land management experiments in the United States. Eighty years later, the Merck Forest is a testament to the power of long-term, progressive forest management, and to the capacity of education to inspire “curiosity, love and responsibility toward our natural and working lands.”

As we reach the sugarbush, we enter assessment mode. Steve’s head is on a swivel as he takes in his surroundings and begins to build an understanding of these woods. We start by estimating in quartiles the percent cover of the overstory, midstory, and understory. For our first plot, these layers of the forest are at 76-100%, 51-75%, and 1-25% cover, respectively. These estimates may sound meaningless, but in fact they give us a sense of the forest’s structure that goes beyond numbers and towards a feeling of geist or spirit. In this case, imagine a full, green, leafy canopy, beneath which a sizeable and healthy population of young “pole-sized” trees works up towards the sun. You can see quite far through the understory because the ground is almost bare of leafy vegetation. The light is diffuse and soft. Mosquitoes buzz and bite.

We note the dominant tree species in each layer, and check for the presence of any invasive species (here, a light infestation of honeysuckle pulled by Tim as Steve and I work). We then count the number of downed logs and fine woody brush piles within our plot, habitat features which offer food, shelter, and display sites for priority bird species like the Hermit Thrush and Ruffed Grouse. Finally, we “swing the prism,” one of the many wonderfully impressionistic (read: vague) forestry terms I’ve learned to love. In fact, this enigmatic process comes down to a device about as simple as you could imagine – a small piece of glass ground at an angle, the “prism,” which allows us to determine which trees count as “in” or “out” depending on the tree’s diameter and its distance from the observer. I won’t go further than that because, frankly, I can’t explain how it works.

In our first plot, we observe that the forest is “well-stocked” with timber at 80 square feet of basal area/acre. This means that, if we put all the tree trunks within this one-acre plot together, they would make up an 80 square foot block of wood. Of that large and strange-looking wood cube, three quarters would be sugar maple and one quarter would be white ash. All of this from a tiny prism of glass: elegant. Navigating by GPS, we move on to the next plot center. On the map, this is a much simpler proposition than it turns out to be in practice, as the GPS leads us up and down cliffs and through thick piles of brush and tangled vegetation.

Having repeated the whole process eight times, we end the day back where we started, this time headed down-hill towards the sugarhouse. We’re hungry, but not much worse for wear. The sugarbush, I have learned, is a great place for conversation, and today’s walk was no exception. Today, we found ourselves asking what it is that makes this work meaningful. In the end, we agreed, it is the application of scientific knowledge to the real-world challenges of conservation that makes us feel like our work matters. And ultimately, it is the effort to educate and inspire, to instill a sense of care for the world in which we are entangled, that motivates all of the work Audubon Vermont and our partners do. That, I feel as I bite into my sandwich, is something worth working for.

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