By Nellie and Anna
Welcome to the third, self-guided tour of habitats in winter, brought to you in collaboration with the Columbia Land Conservancy! Today’s Wonder Wander post introduces the newly installed tour of Oak-Maple Forest habitat at Borden’s Pond Conservation Area in Chatham.
Follow along with this blog post to explore some wonders of the Oak-Maple Forest and/or check out these wonders in-person at Borden’s Pond Conservation Area from now until March 15th.
For those of you who have received our year-end appeal gift of the Wonder Wander Journal, this also reflects the February “Oak-Maple Forest” habitat. Find out more about our self-guided Wonder Wander walks and how to get a digital or hard copy of our Wonder Wander Journal at: hvfarmscape.org/wonder.
This map (below) of Borden’s Pond Conservation Area highlights where the Oak-Maple Forest Wonder Wander is located! It’s on a section of the red trail that is north of the blue trail. You can access that part of the trail from the green, blue and red trails. Do note that the quickest way to get there is by following the green trail, taking a right up the blue trail, and a left up the red trail. Please keep in mind that the trail is on a steep slope; use caution when traversing this trail, and you may want to consider weather conditions before your visit (it was very icy this morning!).
Oak-Maple Forest might be the most abundant of our mature forest habitats. It often strikes folks as a “typical” deciduous forest, with good sized trees and a relatively open understory. The largest trees are usually oaks (including Red, White, Chestnut and/or Black Oak). The rest of the forest canopy includes Sugar Maple, Red Maple, and other deciduous species.
The following image illustrates the bark and buds of many of these common trees in this Oak-Maple Forest. If you’ve also been staying up to speed on the Winter Botany course Conrad has been installing at Crellin Park and PS21, some of these might look familiar?! Either way, it might be helpful to check these out in order to recognize some friends in the Oak-Maple Forest. Thank you to the Northern Forest Atlas Foundation for supplementing our collection of images!
Alright! Now let’s get walking..
Our first stop is a beautiful example of a hanging (“pensile”) cup nest. Such nests are often constructed between the fork of small branches, with material such as adhesive spider webs or sticky plant fiber used to affix the rim of the nest to the branches, leaving the cup suspended. While this nest is a little worse for wear, one can still get a sense of the two layers that comprise such nests—an outer layer with strips of bark, wasp nest paper, and other plant material encasing an inner lining, such as the pine needles seen in the one here.
Vireos are one type of bird that make pensile cup nests, and also prefer deciduous habitats, sometimes near a forest edge or opening (such as a path).
Farther up the trail we point out a pair of Sugar Maples: a young Sugar Maple next to a mature Sugar Maple. Note how the bark differs with age.
One of the main reasons we decided to highlight this habitat in February was because of maple sugaring! Late winter through early spring is sugaring season, when the combination of below freezing nights and above freezing days causes the sap to flow. The processes involved in sap flow are surprisingly complicated. Unlike most trees, some of the cells of maples are largely filled with gas, not water, and scientists believe the interaction of these gas-filled cells with the freeze-thaw cycle creates negative and positive pressure that ultimately pushes and pulls the sap around the tree. The sugaring season lasts as long as these conditions persist and the buds have not yet developed.
Mature Sugar Maples often have patches of whitish bark caused by the aptly named “Whitewash Lichen” (likely a species of Phlyctis) which tends to be most common (but not only) on Sugar Maple bark. Whitewash Lichen is a crustose lichen—a type of lichen that adheres so closely to a substrate as to become inseparable, almost as if it was painted on.
As you’ll likely notice, this Oak-Maple Forest is located on a steep slope and has a relatively open understory. These two observations, along with the lack of early successional trees (ie Black Cherry, White Ash, White Birch), suggest that this Oak-Maple Forest was likely not cleared for agricultural purposes, aside from selective logging.
Look at the habitats adjacent to the Oak-Maple Forest: they are flatter, with more vines and shrubs in the understory of younger trees. This begins to tell the story of the former pastures and crop fields that once quilted this area.
Does this map look familiar to you?
This is Chatham! As depicted on a poster from 1886, that can be found on the Library of Congress’ website. As the arrow delineates, the Oak-Maple Forest can be seen on the map surrounded by (what was then) cleared fields! Now, as we know, the Oak-Maple Forest is surrounded by other forest habitats, both planted and spontaneous, that together make up Borden’s Pond Conservation Area.
Knowing that a lot of this Conservation Area used to be used as pasture and crop field, do you see other clues of land use history such as stone walls and old fence lines?
This tree (that you’ll find later on down the trail) “absorbed” an old fence line that once likely surrounded pasture. The process of trees engulfing objects is called edaphoecotropism: as the tree continues to grow taller and wider, the living tissue can grow around an object, and over time, they become one.
Speaking of traces left behind..
White Ash is known for its especially hard and strong wood paired with its ability to be bent (making it ideal for many woodworking applications, such as chairs). In this case, it has bent due to a vine. The triple twist and deep scoring of this White Ash suggests the work of the invasive Oriental Bittersweet. Oriental Bittersweet was introduced to North America in the mid-1800s and can rapidly entwine and girdle trees or choke out native plants. This White Ash seems to have survived, but will forever bear the twisted scar caused by the vine. As you walk, can you spot any other evidence of Oriental Bittersweet in this forest?
Other ash trees in the forest are experiencing an ailment that is more specific to ashes. The exposed areas on these ash trees is due to the “flecking” activity of woodpeckers removing strips of bark in search of insect larvae. For ash, this is a sign of infestation by the invasive Emerald Ash Borer, a bright green beetle whose larvae feed on the inner bark of ash trees.
The Emerald Ash Borer was first discovered in the US in 2002, and has already killed tens of millions of ash trees. After a tree is infested with Emerald Ash Borer it often dies within just a few years. Emerald Ash Borer was first detected in Columbia County in 2019. The years ahead will provide an opportunity for us to observe how forests like this one (though more commonly, Northern and Young Hardwood forests) are impacted by the loss of ash trees.
The Emerald Ash Borer is not the only insect we find traces of in this forest.. The hairy egg masses (below) attached to the tree trunk belong to Gypsy Moth (Lymantria dispar), and will hatch into little caterpillars in the spring. Gyspy Moth caterpillars can defoliate an entire tree before pupating and mating. While they feed on different types of foliage, they seem to prefer oak trees.
Gypsy Moths were brought to Boston from Europe in the late 19th century as a potential silk-worm substitute. They soon escaped and spread wide and far, arriving to this region in the 1930s. Gypsy Moth populations often move in cycles of booms and crashes. While last year had, and this year might have, outbreaks, next year may be different.
This is a Gypsy Moth chrysalis from last season, which likely belonged to the female who laid the nearby eggs. Check out the following blog posts from previous months for more information on Gypsy Moths: 22 June 2020; 20 July 2020.
While winter might not seem to be the time to observe flower buds, there are in fact some buds to keep an eye out for!
Red Maple (Acer rubrum) and Hop Hornbeam (Ostrya virginiana) are two tree species whose flower buds have been set since fall, waiting to break early this spring.
Look up for Red Maple’s clustered flower buds at the end of the twigs, which will open in April.
Hop Hornbeam, abundant in this forest’s understory, has catkins that grow in groups of three, resembling birds’ feet. Each catkin is made up of tiny buds of male flowers, and will elongate as the flowers open to release their pollen in the spring to pollinate female catkins.
We’ll leave you with this beautiful photo of Witch Hazel, in between having flowered in the fall, and waiting patiently to develop into fruits in the spring.. Perhaps you’ll find this shrub along the trail when you visit the Oak-Maple Forest!? We hope you enjoyed this virtual tour, and that you get a chance to observe these wonders in person as well.