Winter Botany: Marcescent Leaf Mysteries

BlackOakMarcescentLeaves,KAOIf you happen to be wandering through Squam Swamp or Squam Farm as autumn gives way to winter, you may notice that while most of the trees have already shed their foliage, oaks (Quercus spp.) and American beech (Fagus grandifolia) may still retain old dried leaves rattling spookily in the wind. Some individuals seem to remain almost fully dressed, while others have only tattered remnants. This penchant for retaining leaves into the winter is called “marcescence,” and there are a few theories that have been proposed to explain why some trees display this trait and others don’t.

In pondering the “how and why” of this situation, it’s helpful to consider the reasons why our northern deciduous hardwoods drop their leaves in autumn in the first place. As day length shortens and temperatures drop, photosynthesis becomes less and less productive. Shorter days, and low sun angle mean that less light reaches the trees, and a certain temperature range is best for leaves to transform light into food efficiently (50-68°F). In the summer, trees have other adaptations to help cool their leaves to maximize their time spent in the optimum temperature range, but that’s a blog article for another season!


Dried beech leaves turn a fawn color and many remain on the branch until spring when new leaves emerge.

To make matters worse, freezing temperatures rupture the cell walls of leaves as the water inside them expands, unless they are equipped with special protective mechanisms — also a blog article for another day.

Meanwhile, cold and drying winds make desiccation a real problem. Leaves become a losing proposition in a New England winter. Broadleaf trees would need to make a slew of adaptations to retain their leaves into the winter and make it worth their while. American holly (Ilex opaca) is one of the few trees that does this, with glossy leathery evergreen leaves

Retaining leaves is even more of a liability in areas prone to heavy snow and ice storms, because leaves keep snow from shedding effectively, and ice builds up on the larger surface area of leaves far more than on slender twigs or needles. Deciduous trees have evolved a dramatic solution to deal with this problem. Unlike evergreens such as pine and spruce, they create a “shutoff valve” in the stem of each leaf called an abscission layer when the days begin to shorten and temperatures drop. Oaks and beech do not have this shutoff valve, so the leaves may remain on the twigs until spring, unless they are torn off by wind and general wear-and-tear.

Something has to make it worthwhile for oaks and beech to keep their no-longer-photosynthesizing leaves long after other hardwood species cut their losses. One of the theories is that the leftover leaves—crunchy, dried out, and not very tasty — persuade browsers to browse elsewhere. Research has shown that the tough leaves are nutritionally poor compared with the young twigs and the buds, and deer and moose prefer leaf-free twigs when given a choice.


What’s for lunch in winter? Fresh beech sprout twigs!

Considering the heavy browsing you will find on beech sprouts in Squam Swamp, maybe the trees will take any edge they can get! Perhaps it’s no big deal to occasionally lose some branches in your canopy from extra snow and ice loading, but being gnawed to the ground repeatedly means you will never get to rise above the forest floor to produce a seed crop of your own. That would be a pretty strong evolutionary pressure.

Whatever the benefits or drawbacks to marcescence, it becomes a handy shortcut to recognize groves of oak and beech as you move through the fall and winter forest. Long after the branches of tupelo and sassafras are stripped bare, oaks and beech are easy to spot from a distance. Since these species also provide valuable “mast” for wildlife (bumper crops of thousands of seeds or nuts every few seasons), hunters take notice of these hotspots. On the mainland, acorn and beech mast crops are a major food source for bears, turkeys, deer, squirrels, and other hungry animals. On Nantucket, deer and squirrels would be happy to take care of the abundance of nuts and seeds all by themselves, but get some help from birds such as blue jays and crows.

BeechCanopy Marcescence,KAO

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Will It Be A Snowy Winter?

Our favorite winter residents are back, the Snowy Owls (Bubo scandiacus)! The first sighting for Nantucket was at Smith’s Point this week. If you consider yourself a birder, or just an admirer, it is always thrilling to see these stunning birds of prey with their intense yellow eyes.


Snowy Owl at Eel Point (Photo: Libby Buck)

Have you ever wondered why we typically see them on our beaches in the winter? During the summer months, Snowy Owls breed up in the tundra of the Arctic and some of the population will migrate south for the winter. The tundra is a wide-open, treeless terrain, similar to how a beach looks in the winter. They like to stay close to the ground to hunt so having a wide-open terrain allows them to see from all directions. The main diet for a Snowy Owl consists of small rodents such as lemmings or voles and birds sitting on the water offshore. When they are spotted on the island, they are usually seen resting on a dune or perched on a low structure. The best locations to find these birds around Nantucket are at Coskata-Coatue Wildlife Refuge, Great Point, Smith’s Point, & Eel Point.


Snowy Owl at Coskata-Coatue Wildlife Refuge (Photo: Neil Foley)

The winter of 2013-2014 was an “irruption” year for these owls. There were so many young owls that during their winter migration, they were flying as far south as Florida. There was speculation as to why this happened and many people believed it was because their food supply was low. Lemmings and other rodents were scarce, so they were on the search for food. However, as it turned out, it was quite the opposite. It was actually a boom year for lemming reproduction, creating an abundance of food for Snowys, which in turn, allowed them to successfully rear more offspring as well. Researchers saw this as an opportunity to learn more about this species and decided to put GPS transmitters on as many owls as they could to find out where they go. If you want to learn more about this project please visit:


Snowy Owl at Coskata-Coatue Wildlife Refuge (Photo: Neil Foley)

If you are worried about trying to get a glimpse of one, there is no need to rush. This is just the first sighting and more will soon arrive. Snowy owls tend to stay around all winter long, leaving at the end of April to early May. But you just never know, this past season a young male stayed out at Great Point until July 12th.  Please keep in mind while viewing these birds to be respectful and keep your distance.


Snowy Owl at Coskata-Coatue Wildlife Refuge (Photo: Libby Buck)



The Nantucket Conservation Foundation is a private, non-profit land trust that depends contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us!

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Pest House Pond Water Quality Management is Underway

Pest House Pond NPC photo

An aerial view of Pest House Pond (photo: Nantucket Pond Coalition)

Pest House Pond is small, brackish wetland approximately ¾ acre in size located along the shoreline of Nantucket Harbor between Monomoy and Shimmo. The pond and surrounding property totaling 3.6 acres was donated to the Foundation in 1973 by the Shimmo Association, with an additional 1-acre abutting parcel donated by Mrs. I. H. Burnside in 1979.

You may wonder – how Pest House Pond get its peculiar name? It was named for the “Pest House” that once existed in this vicinity in the 1760’s when there was a smallpox epidemic taking place on the island. Anyone exhibiting symptoms or suspected of being exposed was sent to this facility for treatment and to prevent the rest of the population from becoming infected with this serious, highly contagious disease.

Pest House Pond Location cropped.jpg

For the past several years, our Science and Stewardship Department has been investigating the cause of consistent algal blooms in this small wetland, which is surrounded by seasonal residential development. We worked with researchers from UMass Boston in 2004 – 2008, who collected multiple years of water quality monitoring data. Results indicated that leachates from lawn fertilizer use and septic systems on surrounding properties were the most likely sources of the excess nutrients responsible for the algal growth.

Public outreach and education efforts were initiated to encourage the neighbors to alter their landscaping practices and regularly service their septic systems. With their cooperation, the situation improved somewhat in that the algal blooms no longer covered the entire surface of the pond during the late summer, as was once the case. Nonetheless, in recent years there has still been substantial algae populations present in the pond during the late spring, summer and fall months.

Pest House Pond from Greenberg Path June 15 2017

Algae on the pond surface during the summer of 2017

For over 70 years, Pest House Pond has been connected to Nantucket Harbor via an underground pipe that drains onto the beach between the high and low tide lines just north of the Cathcart Road access. Although the reasons for installing the pipe are unknown, it was likely a historic public works project aimed at draining the pond for mosquito control. Both the Foundation and the Town of Nantucket have had ongoing concerns about water quality impacts to Nantucket Harbor from this pond discharge.

Pest House Pond Outfall Pipe Nantucket Harbor June 15 2017 3

The Pest House Pond outflow pipe exits onto the harbor beach near the end of Cathcart Road

In order to gain a better understanding of the condition of the pond and options for managing the persistent algae, we contracted with SWCA Environmental Consultants in Amherst, MA to conduct an environmental assessment. In June 2017, SWCA biologists visited the site and recorded pond water and sediment cross section (bathymetry) data, collected algae samples for laboratory identification, characterized bordering vegetation communities, inspected the outflow pipe and made additional observations. These data were presented in an assessment report that also included an analysis and approximate costs of possible management options to improve the water quality and aesthetics of the pond.

Laboratory analysis documented large infestations of two algae types: Cladophora sp. and Microcystis sp. The former species formed a floating mat that covered approximately 15% of the pond surface. The later species, which is classified as a Cyanophyta-Blue-Green algae, was present in the sub-surface of the entire pond and was recorded within the water column at extremely high levels. Microcystis, which appears to have recently established in the pond, is a potential toxin producer and can be harmful to humans exposed via physical contact or inadvertent ingestion or inhalation. Both types of algae potentially host many types of bacterium, which can include species harmful to humans. Because algae were observed exiting the pond into Nantucket Harbor via the outlet pipe, the Foundation immediately reported this information to the Town of Nantucket’s Natural Resources and Health Departments. An order to remove all sources of the algae from the outflow pipe was subsequently issued by the Nantucket Health Department.

Pest House Pond Algae types

Microcystis sp. (pink) is visible in the water column under the floating Cladophora sp. (green) in Pest House Pond in June 2017 (photo: SWCA Environmental Consultants)

To address this issue, we incorporated the recommendations from SWCA Environmental Consultants into a management plan for Pest House Pond. Removing the outfall pipe was not a feasible option because it is deeply buried under well-established vegetation. Therefore, we applied for and received permitting from the Nantucket Conservation Commission to install a flow control valve in the pond-side end of the pipe, which was put in place in June 2018.

July 2 2018 IMG_1045 pipe valve

The Pest House Pond flow control valve installed in June 2018

In order to monitor water levels in the pond and predict if flooding of nearby adjacent properties may take place during periods of heavy rainfall, we placed a stilling well within the pond and installed a data logger that records water level readings every 4 hours. Data from the logger is transmitted remotely so that it can be downloaded and reviewed anytime without the need for a site visit.

October 12 2018 at 1515 post TS Michael by KCB IMG_1355

The stilling well with water level monitoring data logger (far left) and solar panel with data transmitter (center) installed along the edge of Pest House Pond

Since the valve was installed and closed last June, we have had to open it only three times (for 2-3 days each time) in order to prevent flooding on adjacent property. Otherwise, the valve has remained closed and there has been no pond water input into Nantucket Harbor. This is a huge improvement over the previous situation when the pipe was continuously discharging pond water containing algae and high levels of nutrients into the harbor.

Once we had the ability to isolate the pond from the harbor, we applied for and received permitting to move forward with algae and excess nutrient control within the pond in early August. Also included in this permit was permission to treat a small population of Phragmites (common reed) – a non-native, invasive species – with targeted herbicide. SWCA Environmental Consultants completed one round of treatments in mid-September of this year after the 30-day permit wait period was over, with encouraging results.

October 12 2018 at 1515 post TS Michael by KCB IMG_1357

The pond immediately after treatment in September 2018

Following many years of planning, permitting and working with stakeholders, we are excited to finally be able to move forward with on-site management to address the poor water quality issues in this pond. Now that the permitting component of this project has been completed, we can hit the ground running next year and apply treatments early in the season, as soon as any sign of algae is detected with a goal of preventing future toxic algae blooms in the pond. This project, which is the first of its kind on Nantucket,  will also serve to provide insight into the effectiveness of these management strategies and inform future pond management projects on the island.


The Nantucket Conservation Foundation is a private, non-profit land trust that depends contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us!

Posted in Habitat Management, Invasive Species, Restoration, Water Quality, Wetlands | Leave a comment

Nantucket Leaf Peeping…We DO have Fall color

Seeing the social media posts of family and friends off island in the autumn, it’s easy to think that Nantucket has drawn the short end of the stick when it comes to Fall Color. There was an instagram post earlier this week taken in Town on Nantucket under a pale yellow tree with the sad caption that this was all the fall color Nantucket had to offer.

No, Nantucket doesn’t have dense forests bursting with deciduous tree leaves turning a rainbow of color. Nantucket is more subtle and secretive than that. Here are some of the startling bits of color seen around Nantucket this time of year.

Sometimes the whole landscape is a wash in the colors of fall from the yellow grasses to the burnt red of changing shrubs.


Autumn skies over the straw yellow of little bluestem grass and the bright red of huckleberries


Greens, greys, yellows and reds of the native vegetation around Pest House Pond


Out in the moors, the rolling hillsides shift from green to deep bright red as the huckleberry leaves get ready for winter.

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Misty Middle Moors in fall. Photo Credit: Iris Clearwater


In the forests of Nantucket, the Tupelo trees change color the earliest, shifting to bright red and visible from a distance.


And if all else fails, Nantucket does fall sunsets better than almost anywhere else and this fall has been no exception!


A cotton candy sky while readying to catch bats in a Nantucket pine forest. Photo Credit: Jen Karberg


Sunset from the bluff at the UMASS Field Station. Photo Credit: Jen Karberg



If you know where to look, the beauty of Nantucket in the fall is there to find. Accept this challenge and get out this week to find the hidden fall beauty of this island before the season shifts again – try walking on one of the Nantucket Conservation Foundation’s many properties (there are 9,000 acres to choose from!) and see what kinds of color you might find!




The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us now!







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Eastern Box Turtle Update

A few weeks ago, we reported on a male box turtle that was found on Nantucket. We wanted to give a little history on this turtle as well as an update on his current whereabouts.

In June of 2009, the Nantucket Conservation Foundation received two reports of Eastern box turtles within 2 weeks of each other. The first – a female – was found crossing a dirt road at Head of the Plains and the other – a male – was found in a yard in the Surfside area. What was so unusual about these reports was that box turtles were thought to have been extirpated from the island long ago. To have found two at nearly the same time had us scratching our heads a bit.

Box turtles are common in the pet trade and unfortunately very often released in to the wild when people realize that turtles really don’t make great pets. Our first thought was that perhaps these were either lost pets, or turtles that had intentionally been released. Or, could they be native, wild turtles that just hadn’t been sighted in years and it was just coincidence that they were found within weeks of each other? We certainly didn’t want to confine a wild turtle to a life in a terrarium, but we also didn’t want to set loose a pet turtle unsure whether or not they’d make it through a Nantucket winter (turtles kept in captivity also carry diseases that are easily transmitted to wild turtles – it’s never a good idea to release a turtle that’s been captive its whole life).

We happened to be conducting  work on another species of native Nantucket turtle – the spotted turtle – at the time when these turtles were found. We had a few extra radio transmitters available so we decided to affix them to these two box turtles. This allowed us to hedge our bets and keep an eye on these turtles for a year to make sure they continued to stay healthy, to see where they moved, and make sure they found safe places to hibernate for the winter.

Eastern Box turtle from HofP June 11 2009 008

Placing a radio transmitter on a Female Eastern box turtle on Nantucket.

The person who originally found the male in Surfside felt that the area was so densely populated with houses and roads that it wouldn’t be a safe place to release this turtle. We made the decision to release the male and female together where the female was found at Head of the Plains – perhaps they might even like each other and in the future there would be more box turtles on Nantucket?! But our plans didn’t work out and both turtles made bee lines in opposite directions. Fortunately, both remained healthy, found safe spots to hibernate and emerged in the spring no worse for the wear! We continued to track them until mid-July of 2010 and convinced that they knew how to be wild box turtles, we removed their transmitters and stopped stalking them.

Below is a map of the Head of the Plains area southeast of Madaket and the relocation points of each turtle over 2009 and 2010, including where they hibernated.

Box Turtle Locations

2009-2010 Locations of two box turtles on Nantucket

After we removed their transmitters, we filed a small notch in to a scute on the edge of their carapace (shell) so that if they were every re-found, we would know their identity. We also took a toe nail clipping for genetic analysis to hopefully get some answers as to whether these were wild or captive turtles. Every year we wondered how they fared but never saw them again….

Until now!

On October 11th, a little boy name Guy and his mom Dana, reported the first known sighting of the male box turtle near a stand of pitch pine trees on Hummock Pond Rd!

guy and turtle

We were so thrilled to know that at least one of the box turtles is still out there, alive and well! He looks almost exactly the same as he did when we released him, except for a small scar on his carapace. As the crow flies, he is 1.8 miles from his last known location having crossed Hummock Pond and Hummock Pond Rd! And, once again, we affixed him with a radio transmitter and so resume our stalking of the male Eastern box turtle for another year in the hopes that we find out more about where he goes, how he uses habitat and, fingers crossed, perhaps he will lead us to other box turtles on Island! Very soon after he was found, he chose a protected spot in the pine woods and began burrowing down to hibernate now that it has gotten colder. We will check on him periodically throughout the winter and will update once again when he emerges in the spring!


Male Eastern box turtle with radio transmitter

We always encourage people to report wildlife sightings to us! Please call the Nantucket Conservation Foundation office at (508) 228-2884.


The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us now!

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Fun Fall Sightings!

Today was an exciting day for us here at the Nantucket Conservation Foundation! We were reunited with an old friend.


In the summer of 2009, we received two separate reports of Eastern box turtles (Terrapene carolina) – a male found in Surfside, and a female found at the Head of the Plains. At the time, these were unusual sightings as Edith Andrews recalled that box turtles had not been seen regularly on Nantucket since the 1960’s. Box turtles have turned up in archaeological digs on Island and are known from the fossil record, but it was believed their populations had been extirpated from the island. We were unsure if perhaps these two turtles were pets that had been set free, and had coincidentally turned up at the same time? Or were they last hold outs of this species on Nantucket? Both appeared healthy so we decided not to keep them in captivity, but instead we placed radio transmitters on them and followed their fate for a year.

Eastern Box turtle from HofP June 11 2009 008

Placing a radio transmitter on a Female Eastern box turtle on Nantucket

Thankfully, both hibernated through the winter and emerged in the spring healthy. They wandered the Head of the Plains and Ram Pasture area, feeding throughout the summer. Satisfied that these two knew just what turtles should do, we removed their transmitters, filed a tiny notch in to their shell so we would always have a way to recognize them, wished them well and set them free. Every summer we are on the look out for these turtles and always wonder about them – but never see them.

Today, we received a call at the NCF office from a woman and her young son reporting that they had found a box turtle at a home along Hummock Pond Road. A quick google search brought them to our turtle blog where they learned what species they had found and that we wanted people to report turtle sightings! Low and behold, they’d found our long lost male box turtle 9 years later.

We were so happy to know that this turtle is still alive and seems very healthy. As the crow flies, he’s about 2.5 miles from where he was last seen which includes a few major road crossings. We hope that we’ll see him again in the future and are always optimistic that we’ll find the female again too someday! As always, we encourage everyone to call us with sightings of these rare and beautiful creatures. If you see them as you wander our properties, we would love to know! Please take pics, collect a GPS point and call us at (508) 228-2884!



The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us!


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In Bloom Now: American Cow-Parsnip

Milestone & Turner Rd Cow parsnip, J Lentowski

American cow-parsnip (Heracleum maximum) growing in disturbed soil around a paper birch near the intersection of Milestone and Turner Roads.

If you’re out and about on Nantucket this month and see super-sized umbels of white flowers that resemble Queen Anne’s lace but are the size of dinner plates, topping plants with beefy stems and large coarse leaves, it’s likely you have come across American cow-parsnip (Heracleum maximum). Typically found at the edges of wetlands and salt marshes, this native wildflower can also pop up unexpectedly in clearings where the soil has been disturbed and the soil is fairly rich and damp.

American cow parsnip Leaf, Williams Ln, Ellen Phelan

A compound leaf of American cow-parsnip.

American cow-parsnip flies under the radar its first season, producing only a bunch of leaves, but in the second spring it makes a grand entrance by sending up flower stalks usually 3-6′ tall, and producing umbels that are around 8″ in diameter. While a plant of this size is sure to make a splash no matter what, American cow-parsnip produces an added frisson of fear in a lot of people, because it is a close relative to giant hogweed (Heracleum mantegazzianum), which is a serious invasive weed introduced from Eurasia. Giant hogweed was introduced as an ornamental by Victorian gardeners, who also brought us such delights as Japanese knotweed (Fallopia japonica) and black swallow-wort, also known as dog-strangling vine (Cynanchum louiseae). The Victorians loved novelty in the form of oversized plants, particularly ones with a sinister twist, apparently. Giant hogweed (also called giant cow-parsnip by some) causes a severe blistering skin reaction that leaves permanent scarring, so it has made the blacklist of “Most Dangerous Weeds” in a lot of places.

Amer Cow Parsnip portrait, KAO

American cow-parsnip showing off its compound umbels and compound leaves.

So, if you stumble across an enormous white-umbeled plant that looks like a Queen Anne’s lace from the Little Shop of Horrors, how can you tell whether it’s giant hogweed or American Cow-parsnip? And why should you care?

First off, it’s wise not to handle ANY plants in the Apiaceae (Carrot & Parsley Family) casually, so take a look rather than wading right in. Did you know that even home garden plants like parsley, carrots, and parsnip all produce harmful furanocoumarins in their vegetation? These are chemicals that when rubbed on your skin followed by sun exposure, can cause blistering burns, a condition called phytophotodermatitis. Handling carrots or parsley is not always a problem, but if the plants are wet, or if you get the oils on sensitive skin, or in large quantities, you can wind up with fluid filled blisters like poison ivy, only less itchy. The oils quickly bond to your skin, and spending even a short time in the sun afterwards can cause blisters to form. The giant hogweed reaction is much, much more serious and debilitating.

So, take a look at your Apiaceae carefully, and hands-off. Assuming your plant has the characteristic large coarse-lobed leaves and big white umbels, the next step is to assess the number of branches in the inflorescence. An American cow-parsnip will have up to 45 primary branches in its umbels, while the invasive and much more hazardous giant hogweed will have 50 or more branches. You can figure out the number of primary branches by looking at the top of the flower head, and counting the round bunches or clumps of flowers. Each bunch of flowers in an umbel equals one primary branch.

Cow parsnip branch bundles and umbel

If your plant has umbels with 45 or less branches, you have a native American cow-parsnip, and the only thing you need to do is avoid handling or weed whacking the plants to prevent possible skin reactions, the same sort of precautions you would take with poison ivy or poison sumac. American cow-parsnip is a great pollinator plant feeding many species of native bees, flies, and wasps, and greatly enhances the biodiversity of its surroundings. Biodiversity goes way beyond pollinators, and this plant offers habitat for many other invertebrate species that feed on the leaves, and spiders that lie in wait for prey.

If on the other hand you’ve discovered a plant with 50 or more primary branches on an inflorescence, you may have found giant hogweed. This species has never been recorded as occurring on Nantucket, and we would love to keep it from ever becoming established. Please get in touch with one of the co-chairs of the NBI Invasive Plant Species Committee: either Kelly Omand at Nantucket Conservation Foundation (komand@ nantucketconservation .org) or Sarah Bois of the Linda Loring Nature Foundation (stbois@ llnf. org) to let them know about your find. Pictures and an exact location will help us determine if your plant is a concern.


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