Time travel, sapsucker-style

4 02 2008
oblikk

Carpe diem!

Seize the day!

Live in the now!

These exhortations can be heard from time to time, trying to convince someone to pay more attention to what’s happening in the present. Funny thing is, sometimes it takes a look at the past to put the present in context. I am asked many questions about the history of Sapsucker Woods, and I have been perusing the back catalog of old newsletters to Lab of Ornithology members, trying to piece together some of the manmade influences that had helped to shape its current habitat. In doing so I stumbled upon a rich trove of aerial imagery that goes back over 70 years, and decided to do a retrospective photo history of Sapsucker Woods.

Most people who visit the Lab assume that the pond has always been there, and that this small chunk of woodlands has been protected forever.  The truth, however, is much more interesting.  So, if you’re interested in taking a trip on the wayback machine, or perhaps getting a little help from a cardboard box (a la Calvin & Hobbes), click on the Sapsucker Woods Aerial Photos tab below the header and enjoy.





(winter)berries’ bounty

10 11 2007

The canopy continues to thin here in Sapsucker Woods, leaving the trails adrift in reds and oranges. Oaks and beeches are some of the last holdouts, their leaves providing much of the color in the all-too-soon-to-come winter landscape. However, these leafy slowpokes aren’t the only thing brightening up the grays of late fall; among the most spectacular is an oft-overlooked native shrub that becomes even more beautiful as it drops its leaves. The culprit? Winterberry.

yug

(a thick crop of winterberries)

For most of the year, Common Winterberry (Ilex verticillata) is a nondescript shrub with deep green glossy leaves, but come Fall it sprouts linear clusters of intense red berries that become more prominent as this deciduous holly drops its leaves. It can be found from Nova Scotia to Florida, and west to Missouri, excelling in areas of poor drainage. Around Sapsucker Woods, this is the only native deciduous holly we have, but there is another red-berried plant that it is sometimes confused with: Honeysuckle.

winterbsvhoneysuckvert

(winterberry on left, honeysuckle on right)

Honeysuckle is one of the most invasive shrubs in the area, forming dense thickets of yellowish-gray striated bark along woodland edges. The superficial similarity to winterberry lies in its possession of juicy-looking red berries, and its shrubby nature. You can find honeysuckle just about anywhere you want to look in Sapsucker Woods; much of the understory on the north side of the pond is composed of either honeysuckle or buckthorn (both invasive berry producers), and both were likely brought to Sapsucker Woods by the very creatures we spend so much time studying, namely fruit-eating birds (though each is likely also a favored treat for another woodland nuisance, the white-tailed deer). Honeysuckles also have the ability to spread vegetatively and some research has suggested that they can poison the chances of other plants through allelopathic interactions.

honeysucker

(light-green patch of honeysuckle)

The thing that all three of these berry producers have in common is the production each year of a heavy crop of berries that are characterized by being “low in nutritional content“. Roughly translated, these berries are the equivalent of a can of coke, offering nothing more than a rush of soluble carbohydrates, and this results in them being eaten later in the season as birds (especially migrating birds) target fat-rich foods. While it might not seem intuitive, berries can also be high in fats, and a selection of other berries in the landscape (dogwoods, sassafras, poison ivy) are relatively high in lipids (fats), and offer something closer to a bag of chips to the migrating masses, and most of these berries are gone by the end of Fall.

Given these intrinsic differences in the “value” of a given berry, it’s fun to think about how a fruit eater might choose to exploit these resources, and it is thought that birds try and eat a mix of sugars, proteins, and lipids for nutritional balance. However, by midwinter, all that might be left for a hungry resident is the equivalent of a can of coke…





Snap, crackle, pop…

24 02 2007

treetopAn interesting thing about living in a mixed-deciduous forest is that it can look very different depending on the season. Winter’s loss of leaves can bring more subtle differences like a tree’s bark into focus, and even the most minute variation in bark structure can jump out at you when treebark is the most common thing seen. The shaggy, rough bark of a hickory, the scaled surface of a black cherry, and the smooth surface of beech trees all spark a contrast against a sea of red maple. Yet, there’s something strange lurking in Sapsucker Woods, systematically infecting beech trees and destroying them from within…

A few weeks back I listened to Julie Zickefoose on NPR’s All Things Considered reminisce about an old beech tree on her property. She recounted a bit of wisdom from her father, that “a tree spends its first 50 years growing, the second 50 years living, and its last 50 years dying”. Here in the Sanctuary that lifespan is being shortened — not by unscrupulous name-carvers, or tree-poachers, or even a herd of ravenous beavers. In fact, vertical sliverthe culprit in this infestation is small enough that you probably wouldn’t even notice it if it weren’t for the pockmarks and fractures that blanket adult beech trees. Even its name portends a sinister (yet accurate) demise: Beech Bark Disease (at least it’s one of those disease names that actually tell you something about the disease).

While many of the young trees have yet to become visibly infected, most of the adult trees (many of them easily visible from the trail) show the tracks of this disease, a spiderweb of cracks and crevices in the bark, or a near-uniform pattern of circular pockmarks that indicate an earlier stage in the disease. Public Enemy #1 is an invasive beech scale insect from Europe that made its way to North America sometime in the late 1800s. This insect makes a living by channeling the goodness flowing through a beech tree’s bark into its stomach. These injuries to the tree provide entry to a fungus that has always been present in the environment, but lacked the means to get past the smooth bark. Infection leads to severe weakening of the tree, disfigurement, and possible girdling leading to tree death. After consulting two theses done in Sapsucker Woods (from 1950 and 1980), neither of them mentions this exotic invader, suggesting that the infestations began in the last 20 years.Given the commonness of beech trees in Sapsucker Woods, it would be understandable to wonder about the “future” of this woodlot. Plenty of the larger beech trees have already succumbed, their treetops snapped clean, and their interiors the fertile hunting grounds for a number of woodpeckers. It is likely that the number of beech trees will continue to decline until they are much less common in the environment. This is not the first time that a disease has swept this small woodlot: 15% of the trees surveyed in parts of the forest in 1950 were Elm trees, and there is nary an elm today, victims of Dutch Elm Disease outbreaks of the 1950s. You won’t find an american chestnut tree either, thanks to the chestnut blight of the 1920s. And yet the woodland perseveres. All of that standing deadwood is good for something, and it probably explains the persistent presence and species diversity of the 10-15 woodpeckers that visit my backyard.fractures closeupThere is hope, too, for the afflicted beech. Natural resistance to the disease has been noted in other populations, and we can keep our fingers crossed that over time these stately old trees remain prolific and seed the woodlands with resistant youngsters.So — on your next walk, keep your eyes out for BBD and say hello to the disappearing beeches…