Ephemerals are busting out all over – Sweet spring flowers in the Sourlands

After a long and frightful winter, I was more than ready to start looking for signs of spring. Honestly, I started looking very early in March because I just wanted winter to be behind me, but unfortunately the forest was not ready to wake up just because I wanted it to. Impatiently I waited, always searching the forest for little micro climates that might be a week or two ahead of the rest of the forest. Early April gave me the first sigh of relief as the Spring Beauties bloomed, then the Blood Root and then Spicebush burst into its brilliant chartreuse flowers. Slowly as the month moved forward, the forest awoke with brilliant colors and the chorus of birds returning North. Spring is always full of hope and promise of the things yet to come, and this year, the Sourland Forest gave me the relief that I have desperately been searching for.

Spring Beauties, Claytonia virginica, is always the first spring ephemeral that tells me that spring is on her way.

Blood root, Sanguinaria canadensis, is one of my personal favorites (but lets be honest, I have many MANY favorites) is accompanied by the much sought after Ramps, Allium tricoccum. Now, let us talk just a minute about something very important. DO NOT DIG UP THE RAMPS. I will repeat myself in case someone didn’t understand what I said. DO NOT DIG UP THE RAMPS. The Ramps in this photo are at least 7 years old. AT LEAST! This slow growing plant can have its populations wiped out by irresponsible foragers. The leaves of Ramps have wonderful flavor and if you wish to responsibly harvest, take 1 leaf for every 10 plants you see. Why not take one plant? Well, you are probably not the only person that will come across that particular patch of Ramps, and if everyone took one plant, you again will wipe out the population. Be responsible, love this land and forest and leave the ramp bulbs in the ground so that they can continue to grow, produce seed and spread.

Spicebush, Lindera benzoin, the unbelievably valuable and completely underrated Sourland shrub. This shrub is important for migrating neotropical birds to nest in, as well as provide nectar for early pollinators and food for migratory birds and other forest critters. I am on a personal quest to convince everyone to plant some in their yard to replace their Forsythia. Spicebush, the OG yellow-flowered shrub.

A natural bouquet of Blood root, Sanguinaria canadensis.

My Littlest dude came out to hunt for spring flowers with me too!

The Rue Anenome, Thalictrum thalictroides, was his favorite!

Skunk cabbage, Symplocarpus foetidus, looking other worldly.

Cutleaf Toothwort, Cardamine concatenata, reminds me of a ballerina dancing across a stage.

Trout Lily, Erythronium americanum, dramatic in this morning’s light.

Christmas Fern, Polystichum acrostichoides, reaching out newly unfurling fronds like a land octopus!

Virginia Pennywort, Obolaria virginica, diminutive and in danger. This precious flower is one of the threatened species that takes refuge in the Sourlands.

A Mayapple, Podophyllum peltatum, being held back by the memories of last year. Soon, she will break free and rise above what was left behind.

This was taken during one of my many spring ephemeral walks this year. I am fortunate enough to be surrounded by smart, enthusiastic and adventurous women who share my love of plants and are more than happy to spend a wet April morning searching for flowers.

A little Potentilla with a perimeter of dew.

Wood Anemone, Anemone quinquefolia, a master of being both shy and flirtatious.

This Columbine, Aquilegia canadensis, was the absolute highlight of my spring flowers! I squealed and ran to it like a child runs to an ice cream truck. I have never seen this stunning native flower in the wild. I purchased a few from Wild Ridge Plants last year because I think they are just absolutely beautiful, but to see it in the wild… the best cherry on top I could dream of.

Spring in the Sourlands: The great amphibian migration!

Why did the frog cross the road? To find love in vernal pools!

Ever since I began working for the Sourland Conservancy four years ago, I have been waiting for this moment. I think that even though I have a mask on, you can clearly see my utter and complete delight in what is happening. What is happening? The amphibians of the Sourlands are migrating to their vernal pools and I finally got to see a Spotted Salamander, Ambystoma maculatum!!! I don’t think I can truly convey how excited I was to be part of the Sourland Amphibian Crossing Guard program. I would label myself a plant nerd, but I have a real soft spot for my amphibian friends. Catching frogs and red-backed salamanders was a favorite past time of mine growing up. It is still a favorite past time that I regularly share with my lovely wild boys. This blog post will be a little different than the usual because I want to share some stories from my fellow amphibian crossing guards. We are a group of nature lovers that run out the door on rainy “warm” (45 degree F) nights in February, March and sometimes April to witness the Amphibian migration across roads, help usher them to safely and document those who made it to safety and those who unfortunately do not.

Wood frog – photo by Carolyn

During the winter, amphibians of all kinds hibernate and those first “warm” spring rains in late February and March wake them up and stir the deep primal urge to procreate. Amphibians return to their vernal pools every spring to find mates and interestingly enough they almost always return to the vernal pool from which they came. Vernal pools are critically important for amphibians because vernal pools do not support resident fish populations which would devour all of the frog and salamander eggs. Unfortunately, having a vernal pool alone is not enough. The habitat around the vernal pool needs to have high quality forest cover. The poor drainage of diabase rock on the Sourland ridge provides for many vernal pools and the large contiguous forest provides an excellent forest canopy.

Spring peeper – photo by Carolyn

The amphibians that the Sourland Amphibian Crossing Guards typically cross are Wood frogs, Rana sylvatica, Green frogs, Lithobates clamitans, Spring peepers, Pseudacris crucifer, American toads, Anaxyrus americanus, Red backed salamanders, Plethodon cinereus and Yellow spotted salamanders, Ambystoma maculatum. During the rainy spring nights, hundreds to thousands of these amphibians migrate to their vernal pools and unfortunately for some populations, a road lays between their adult habitat and their breeding habitat. The Sourland Conservancy always encourages folks to stay home on these rainy nights. Studies have shown a relatively low traffic rate of 1 car passing through a migration area every 4 minutes can wipe out 70% of the population of breeding amphibians. Each female wood frog holds almost 2,000 eggs and a female Yellow spotted salamander can lay 200 eggs. Frogs and salamanders are food sources for many other animals and birds, so if their population size is greatly reduced due to road mortality, it could have a profound impact on the rest of the forest community. I am continually impressed with the dedication and enthusiasm of the Sourland Amphibian Crossing Guards. They truly are the guardians of the night.

Thoughts from Sourland Amphibian Crossing Guards

Photo by Bruce Michael

“I have participated in the amphibian crossing now for several years. I think I might be known as “the Old Guy”. It’s always amazing to see a creature like the Spotted Salamander that stays hidden underground all year, except for those first warm rainy nights of late winter and early spring when they emerge after dark to somehow travel to and find the vernal pools, along with the Spring Peepers and Wood Frogs.  Truly one of the amazing feats of nature. It never gets old for me” – Bruce Michael

Photo by Yvonne S.

“I had no knowledge of spotted salamander and wood frog migrations until the end of spring 2019. These animals are doing what they have done for centuries but now local populations are in danger of being wiped out by traffic. Volunteers can help save these populations by standing on roadsides in the dark, wet, miserable, cold nights of early spring? Sign me up! Watching a salamander wiggle or a wood frog hop itself across a road so focused on the directions its internal compass is providing is fascinating. Being able to gently lift it out of the way of danger for a brief moment so it can finish it’s journey? Priceless. Doesn’t hurt that these critters are absolutely adorable!” – Yvonne S.

Photo by Ann P.

“It was an amazing night and all that joy and wonder carried through the whole day today. I am very blessed to have been a part of it.” – Carolyn Wolfermann

Photo by Eric Teitelbaum

“It’s hard to put a finger about what feels so special about the Sourlands, but somehow the concept of a ridge with such ecological diversity and in tact hardwood forests existing in the middle of New Jersey adds to its draw. We saw so many salamanders last night that it was almost hard to walk at times and safely keep an eye on the amphibians in our vicinity. These moments were concentrated to a rain event from about 8:30 – 9:00 PM, and thankfully no cars came through at that time. But it really demonstrated ecosystem fragility, since in those moments a car would have wiped out an enormous fraction of the amphibians that crossed the road last night. We had no DOR at our location, but in our walk home up the road, there was a squashed female wood frog presumably from one of the three cars that passed throughout the night. But regardless, there are these critical moments on the order of minutes that without stewardship can really impact a species that has existed for geological time, and it was really inspiring to witness firsthand the culmination of all the planning and coordination efforts that went into last night. It was wonderful to be a part of.” – Eric Teitelbaum

The morning after our big night in the Sourlands, I took my littlest out for a walk in the woods to see how the frogs were doing. He was just as over the moon as I was the night before and wanted to hold “all the frogs”. I see a future Sourland Amphibian Crossing Guard!

Sourland Mountain Hunterdon County Preserve – a staff hike through the snow.

The Sourland Mountain Hunterdon County Preserve is located on Rileyville Rd.

Link to trail map.

The Sourland Conservancy staff started a new tradition at the end of 2020 by initiating all staff hikes once a month. Our office closed back in March 2020, and even though we talked almost daily, by the end of the year we were all zoomed out. We all needed some time to reconnect as a team as well as enjoy the beautiful mountain that we work so hard to protect. I love our hikes, sharing our experiences in the Sourlands and brainstorming ideas for new projects and problem solving.

Sourland boulders buried deep in the snow! There was almost two feet of snow when we went out for our hike.

Witch hazel, Hamamelis virginiana, seed capsules and buds. Witch hazel disperses its seed by means of ballochory, which is a forceful expulsion out of the seed capsule. I have never been so lucky to witness it happen, but I always check the capsules to see if I might get lucky. The buds of Witch hazel are not really obvious, but to me they look sort of like a fuzzy butterknife.

We saw lots and lots of tracks in the snow. This was one of the more common tracks we saw. My guess is that it is a mouse because it looks like someone hopped with their long tail dragging behind them.

Green briar, Smilax spp., berries! I am not sure which species this is, I need the leaves to tell the two most common species (Smilax glauca and Smilax routundifolia) apart.

Where there is a will there is a way! This tree had been damaged, but it sent up two “waterspout” branches that made it all the way to the canopy.

I loved seeing the streams meander through the snow.

Spice Bush, Lindera benzoin, buds getting ready to burst with chartreuse flowers. I always recommend people plant Spice bush if they want yellow spring flowers like Forsythia. Forsythia is not native, but Spice bush is and is a host plant to many pollinator species and a great nesting shrub for birds.

Beech, Fagus grandifolia, seed capsule! It was nearly impossible to photograph with the snow behind it.

The inside of a Beech nut seed capsule.

The seeds of the mighty Tulip poplar, Liriodendron tulipifera. It always amazes me how these small seeds can grow into such enormous trees.

We were on our way out and these little galls caught our eyes. I used this picture in the “Inaturalist” app and the ID suggestion was Oak Rough Bulletgall Wasp, Disholcapsis quercusmamma. I know there are quite a few ecologists and naturalist that turn their noses up at Inaturalist, but I like it. Yes, I have had it suggest wrong plant species, but, most often it at least gets me in the ballpark (plant family or genus) and then I can use a good field guide to confirm the plant’s identity. Prior to Inaturalist, I think I would have seen this gall and thought it looked interesting, but wouldn’t have the faintest idea on how to start to identify it. I think apps like Inaturalist really help bring people of all backgrounds into the folds of being an outdoor enthusiast. If you don’t know your land, you won’t feel passionate about protecting it. Walking through the woods, getting to know the plants and animals and the unique character of this region, is what makes me feel passionate about protecting it for generations to come.

Woosamonsa Ridge Trail – A new year and a new trail.

The Woosamonsa Ridge Trail is located on Woosamonsa rd in Pennington, NJ.

Link to trail info and map

The Wild Boys bundled up in snow pants to keep them warm in the 27 degree F temperatures!

The sentiment of “good riddance” I think many of us feel towards the year 2020. It was a year of immense sadness, loss, struggle, loneliness and change. As we move into this new year, let’s not forget 2020, but instead take with us what we learned from the hardship of the year and celebrate the moments of joy, love and reflection that 2020 gave us.

The forest is quiet except for the winter-time residents of cardinals, tufted titmice, chickadees and woodpeckers going about their business. Taking deep breaths of the cold air reminds me to be grateful for where I am and the stillness of the winter forest draws me into a restful calm. Looking around at the forest in winter, I absorb the quiet into my mind and let go of all the thoughts of later.

This January morning is below freezing, so we bundled our Wild Boys in snow pants much to their initial protest. “Why snow pants if there isn’t snow?” Experience has taught me that if I top off their bellies with snacks on the ride over to the preserve and bundle them up excessively, we are able to enjoy ourselves for an hour or two in the frigid January forest.

Common Privet, Ligustrum vulgare, is a non-native invasive species. It can be confused with Blackhaw Viburnum, Viburnum prunifolium, a native shrub. The shrubs can be similar size, both have opposite branching patterns and black fruit. One way to tell them apart is that the fruit of Privet are rounded at their ends and the fruit of Blackhaw have a more elongated shape with a somewhat pointed end. If you were to squish these seeds between your fingers you would find seeds that are rounded and pointed versus the seeds of Blackhaw are flat. Another way to tell these two shrubs apart is by looking at the buds. In this picture it is a little difficult to see, but the bud scales of Privet are imbricate, which means that there are multiple scales overlapping one another. The buds of Blackhaw are bivalve and pointed, hinging together to form two pieces closed almost as if in prayer.

Lichens and moss always catch my eye, especially in the browns and grays of winter.

Christmas ferns, Polystichum acrostichoides, laying low during the winter. Christmas fern is my oldest’s favorite fern and so we purchased one to have in our front garden during one of our many visits to Bowman’s Hill Wildflower preserve this year. He often goes outside the front door to check on it. I dream of one day a sea of Christmas ferns across our front yard. Slowly, we are chipping away and replacing our grass with native plants and watching as our yard fills up with bees, wasps, dragonflies, butterflies, moths and birds. This year we had dragonflies and screech owls for the first time. The excitement in my children’s eyes reflected my own. The forest had been calling to us so we answered back by filling our grass with natives plants so we too could be wild.

The seta of moss reaching skyward.

Wild Boys walking on water!

Right now in the forest, the only red berries we saw belonged to the invasive species Multiflora rose, Rosa multiflora, Japanese Barberry, Berberis thunbergii, and Oriental Bittersweet, Celastrus orbiculatus. Someone had been eating these fruits and unfortunately spreading these plants around.

American Beach, Fagus grandifolia, is one of the easier trees to identify in winter. The buds are long, imbricate and look like a rolled cigar. Many times on young Beech trees you will see the phenomenon of marcesent leaves.

The bark of American Beech, Fagus grandifolia, is tight, light gray and unfortunately it is often a favored tree for those who wish to leave their love notes and statements of existence.

A dying Ash, Fraxinus spp.. To be honest, I am not great at telling Green Ash, Fraxinus pennsylvanica and White Ash, Fraxinus americana apart unless I can see their buds. My guess is that this is a White Ash, but I can’t say with certainty unless I can get a glimpse of the bud. Whenever I see these giants with their crowns dead and their bark scrapped off, my heart sinks. I learned about the Emerald Ash Borer, Agrilus planipennis, in my urban forestry class in 2006. At that time it was making its way south and east from Michigan, but it seemed like a problem that was so far away from me. I couldn’t comprehend the catastrophic damage this shiny green beetle would cause. Staring at these dying trees throughout the Sourlands I fear for the future of the forest. With the over-abundance of white tailed deer eating all the native seedling trees and herbaceous plants and invasive species that create thick impenetrable thickets, unpalatable to the deer, what will happen to my forest? What will happen to my herbaceous plants that depend on the dappled shade of the forest to grow and thrive? What will happen to my streams, with their banks held tight with thick, strong roots and branches that shade the water keeping it cool? What will happen to many of the birds that depend on the forest for a place to rest, feed, and rear their young? What will happen to the insects, mammals, reptiles and amphibians? It can become paralyzing to stare at the impending loss of over 1 million Ash trees in the Sourlands. It will be a monumental effort from the state, municipalities, organizations, residents and every person that loves this mountain ridge. But I am heartened about the work of the Sourland Conservancy (and many other organizations and individuals) that are working hard to develop plans, apply for grants, create partnerships and engage the public to replenish the forest before all of our Ash trees are gone.

I love this blanket of moss. It looks like it could be the soft bed of a forest fairy.

I am always delighted to come upon an American Holly, Ilex opaca, in the woods. It always feels like such a treat to see this ever green beauty standing with its lustrous green leaves in sharp contrast to the brown canvas of winter.

Sometimes little legs need a rest.

Guest Post – Proust in Hopewell Borough Park by Lois Marie Harrod

Proust in Hopewell Borough Park by Lois Marie Harrod


GreatFieldI sometimes think of Marcel Proust’s warning, “Habit is the enemy of perception,” when my husband Lee and I walk in Hopewell Borough Park.  Since we walk it almost daily, the park is certainly a “habit,” and often we are so addicted to talking or to thinking our own thoughts that we don’t notice the daily changes in our park, a part of our daily 4-mile trek through Hopewell Borough.

Fifteen or more years ago, we used to come upon a rather famous local writer doing her slow jog on the trails with her husband lagging behind.  Neither looked up when we or anyone else passed. They were in their own worlds, not the natural world they were walking through.  We understand that kind of concentration or perhaps I should call it oblivion; we are academic types.


But habit or not, Lee and I keep walking the park.  Walking is more environmentally friendly than driving off to a stinky gym where there is little chance we will surprise a fox or send a catbird mewing, and most of July, once we crossed the southern bridge over Bedens Brook and entered the Great Field, we paid close attention to the wild black raspberries slowly ripening. Since their June blooming, we watched our tiny berries grow a little larger, turn white, a bit pinker, definitely pink, red and finally—after weeks—black. Of course, they are not “ours”—but most people don’t want to pick them—even for jam. The usual nasty suspects:  thorns, ticks, poison ivy, time.


I took on the nasties last year, July 2019, while my husband conveniently had volunteer work to do.  Armored in blue jeans and denim shirt I spent a prickly morning picking black raspberries for his jam.

This year the same thorns, but Covid-19 cancelled my husband’s volunteer work, so he picked too.  If he wanted jam, he was going to have to suffer.

And this year’s picking provided one of those Proustian perceptions my husband likes to talk about, especially now that he is revving up to teach A la Recherche du Temps Perdu again—those petite madelaines that trigger memories, that rouse us from habit, that allow us to see.

Croppedscarletbergamot (1)

Picking those raspberries this year (and there were still a few ripening in early August) triggered the memory of picking those four quarts a year before when the temperature was in the comfortable 80’s instead of the noxious 90’s.  It triggered the memory of listening to parts of Salman Rushdie’s Quichotte on my iPhone as I picked.  In Rushdie’s novel, his Don Quixote is a traveling salesman of pharmaceutical products, and the novel satirizes, among many other things, Purdue Pharma that caused the opioid-overdose epidemic—which seems to have been both overshadowed and worsened by the present Covid-19 pandemic.


So while we were amassing our berries for this year’s jam, I was wondering how Rushdie would treat the Covid-19 Epidemic, which has been very much with us since March.  I was thinking how the epidemic has changed everything including our habitual walk, which used to take a little over an hour, but now takes longer. Depending on when we set out, we see the 7-am or 8-am habituals, the motley crew that uses the park:  the runners, fast or slow, slim and stocky; the dog walkers with Scout, Chester, Rusty, Pearl, Ruby, Romeo or George; the solitary walkers stretching their legs before Zooming.

And we often stop and socialize at a distance.  We tell each other what or whom we have just seen in the park—the fawn, the rabbits, the bluebirds, the tree swallows, the tiger swallowtail on the scarlet bergamot, the rock sculptures children must have built yesterday in Bedens Stream.   We talk about isolation and loneliness, our distant children and grandchildren, the books we are reading, the TV series we are watching, the birds we are missing. Where are the gangs of goldfinch we saw last summer? The thistle is just about to bloom for them. We are sad and worried for most of us walkers care deeply about the environment, and the pandemic seems to have obliterated public consciousness of, I suspect, a worse problem, climate change.


And, of course, by the time my essay gets in print, the black raspberries I photographed will be completely dried up, forgotten.  The Queen Anne’s just opening will be drying into its little bird cages. The first golden rod opening today will be holding sway.  We are 77.  As we eat our raspberry jam, we are trying harder to pay attention to everything in spite of habit.





Part 2: Stone Walls

By Ian Burrow (burrowintohistory@gmail.com)


My first blog was mostly concerned with trees, and how they can help tell the story of people on Sourland Mountain.  Now I want to introduce you to an artifact (= a thing made, modified or used by humans): the Sourland stone wall.

You will encounter stone walls on many of Sourland Mountain’s preserved areas.  Sometimes they can be quite impressive, like this massive and well-built wall beside the Rock Hopper Trail near Lambertville (Figure 1).

Fig 1 Walls Blog

Figure 1. Rock Hopper Trail. Well-built revetment wall on north side of Rock Road: Panoramic View looking north from the roadbed of Rock Road.  Photograph: Ian Burrow, 2019.

Some examples are just a line of low, tumbled stones winding through the woods (Figure 2).

Fig 2 Walls Blog

Figure 2.  A poorly constructed “wall” on the Mount Rose Ridge in Hopewell Township.  Photograph: Ian Burrow 2019.

Others look more like banks or ramparts (Figure 3).

Fig 3 Walls Blog

Figure 3.  Wall along western side of the 1850’s Rock Road to Lambertville-Rocktown Road connector, showing the hollow-way character of the road on the left.  View facing south towards intersection with Rock Road.  Near the Rock Hopper Trail. Photograph: Ian Burrow, 2019.

Some are very well made (Figure 4), others much less so (Figure 5).

Fig 4 Walls Blog

Figure 4.  Cross-Section of an argillite stone wall on the Cedar Ridge Preserve.  The wall has been constructed from wedge-shaped slabs, and the wall narrows with height.  The flat “capstone” indicates that this is the full intended construction height of the wall, about two and half feet.  Photograph: Ian Burrow, January 2018.

Fig 5 Walls Blog

Figure 5.  A massive but roughly constructed diabase wall on the east side of the Rock Road north of Swan Creek on the Rock Hopper Trail. Photograph: Ian Burrow, 2019.

What are they all about? Are they special to the Sourlands? When were they built and by whom?

The easy answer to the first question is that most of them are field walls, sometimes called stone fences, built to create a boundary around a field or a group of fields.  That seems straightforward enough, but when we delve a little deeper we find it leaves a lot of other questions unanswered.  Why, for example, do most agricultural fields in central New Jersey lack stone walls? Many fields have no boundary around them at all, others may have boundaries in the form of hedges, treelines, or wooden fences.

It turns out that Sourland Mountain is one of the few areas in New Jersey where stone field walls are present. Stone walls are actually a rare cultural resource in the state.  How do we know this? In 1871 the U.S. Department of Agriculture helpfully published statistics of field fencing types in the United States. In New Jersey only 5% of the recorded fences were stone walls, most of them in the northern counties. 62% were post-and-rail, 29% were wooden zig-zag or “worm” fences, and 4% were made of boards.  Compare this to Connecticut, where one third of all the fencing in the state, or 20,505 miles, was of stone.  In Massachusetts 50% of all fences were of stone. In Rhode Island most of the 14,030 miles of fencing in the state were stone walls. New York State had an astonishing 95,364 miles of stone walls!

As you might guess, the geographical distribution of stone walls has something to do with geology and topography. In sandy southern New Jersey stone useful for walls is very hard to find.  The New England states, by contrast, are very rocky.  So it seems to make sense that if you find yourself in a stony part of the world you will build stone walls around your fields.

In many parts of New England, stone walls were created as a result of clearing the fields of rocks for cultivation or for pasture.  The collected rocks were dumped around the edges of the fields, sometimes as well-constructed walls, but often as rough linear piles of stone.  The mechanics of this meant that the most efficient field was a square roughly 300 feet on a side, and covering about 2 acres.  Is this an explanation for the stone walls we see on Sourland Mountain? The answer is sometimes, but not always.


Walls of Argillite Stone

My study of the Cedar Ridge Preserve in Hopewell Township showed differences from this New England model.  Cedar Ridge is composed of argillite stone.  This rock type breaks quite easily into slabs useful for building.  It is sometimes exposed in outcrops (Figure 6), and can also be recovered from the beds of the streams and brooks along the southern slopes of Sourland Mountain.

Fig 6 Walls Blog

Figure 6.  Argillite outcrop, Cedar Ridge Preserve.  A substantial field wall lies about 30 feet to the south. Photograph: Ian Burrow, March 2018.

However, unlike the glacial rocks and boulders of New England, argillite is not found lying on the surface.  In fact, you have to dig about four feet down into what soil scientists call the Chalfont Silt Loam in order to reach argillite bedrock.  This means that if you want to build a wall of argillite on Cedar Ridge you have to either dig down for the stone, or bring it from somewhere else.

On the Cedar Ridge Preserve I have noted about 4500 feet of argillite stone walls.  There were probably more at one time.  Studying these walls I noticed that almost 75% of them run along long-standing property boundaries which are often modern lot lines.  In addition, in most places these lot/property boundary walls are associated with a substantial ditch on one side.  The best way to see feature this is to start at the parking lot on Van Dyke Road and head west along the trail which runs just south of the stone wall.  This wall runs almost continuously for about 2000 feet, and for much of that distance there is a ditch on its southern side.

I have concluded that these ditches were used as the source for the stone for the walls.  They probably also served a drainage function on the poorly drained soils of the locality.  My guess is that the walls were built by the person on the ditch side of the wall.

There are two substantial lengths of stone walling which do not have associated ditches.  These lie close to the argillite outcrop shown on Figure 6, so perhaps the stone for these walls came from there.

One of these is not on a modern lot line, but does form the boundary between two of the largest fields in the area.  Like the others, however, it is very well built (Figure 4)

So what does all this tell us?  I predict that in argillite bedrock areas on Sourland Mountain, stone walls will only be found marking important, long-lasting boundaries.  This is because the effort of both quarrying/hauling and building the walls was very considerable.  In 1858 it was estimated that one man could erect three rods (about 50 feet) of stone walling in a day. This figure assumed that the stone had already been gathered and brought to the construction site, tasks that probably entailed an equal amount of labor to the construction itself.  If we halve the amount that could be built in a day to 25 feet (to allow for the quarrying), that means that it would have taken one man about six months to build all the stone walls observed at Cedar Ridge.

But, as one might expect, these walls were not all built at the same time.  With the help of a friend, I cleared away the fallen stones from the area around the T-shaped junction of two walls (Figure 7).

Fig 7 Walls Blog

Figure 7.  Investigation of the junction of two argillite walls on Cedar Ridge.  View looking north.  The west and east sections of Wall 8A survive to close to original height, while the area of the intersection with Wall 8B in the center is much lower.  Large slabs mark the east face of 8B, which was built later than 8A. Photograph: Ian Burrow, April 2018.

Here we could clearly see that the north-south wall forming the stem of the “T” was later than the east-west wall which it joined.  The north-south wall had been roughly keyed-in to the existing wall, and had actually caused the latter to bulge outwards on its northern side.

Walls of Diabase Rock

The main spine of Sourland Mountain is composed of diabase rock.  This is the geological formation which produces the interesting and sometimes spectacular rock outcroppings and boulder fields to be seen at the higher elevations.  It is a dark, dense, hard, fine grained volcanic rock.  The Rock Hopper Trail and the surrounding preserved area around the Swan Creek Reservoir just southeast of Lambertville lie almost completely on diabase.  Much of the preserve is very stony, but areas north of the reservoir are less so.  Some parts here are still farmed, and the present woodland north of the reservoir lies on former farm fields for the most part.

Much of the Rock Hopper Trail follows the route of the Rock Road, abandoned in the mid-20th century. It is chiefly along or close to this road that we find walls made of diabase. As you walk the trail from east to west you encounter a narrow stone bridge (Figure 8).

Fig 8 Walls Blog

Figure 8.  Stone-arched bridge carrying Rock Road across Swan Creek on the Rock Hopper Trail.  Photograph: Ian Burrow, 2019.

A couple of hundred yards beyond that and you meet this dramatic wall on your right (Figure 1).

This wall extends for about 500 feet along the top of a slope on the north side of Rock Road The base of the wall is about five feet higher than the bed of Rock Road, and the wall itself is typically about five feet high.  Rather than being a free-standing wall, this is actually the retaining wall for a terrace, so the top of the wall is almost level with the ground surface at the rear (northern) side (Figure 9).

Fig 9 walls blog

Figure 9. Rock Hopper Trail. The eastern end of the Revetment Wall, looking west. Note that the ground surface on the right (north) side is about two-thirds of the way up the wall at this point. The roadbed of Rock road lies about 20 feet to the left (south) and five feet below the base of the wall. Photograph: Ian Burrow, 2019.

The wall was finished off with vertical “coping” stones. Where these survive, it can be seen that the overall height of the wall was intended to be about six and a half feet.  The wall itself is well built of massive stones, many of them far too large for one person to handle (Figure 10).

Fig 10 walls blog

Figure 10. Close-up view of a section of the Revetment Wall with vertical coping stones still in place. Note the large scale of many of the diabase stones used for the body of the wall. At this location the wall is close to six feet high. The ground surface behind the wall is at the level of top of the scale pole. Photograph: Ian Burrow, 2019.

As with all the Sourland stone walls, we ask the following questions of this one:

When was it built?

Who built it?

What was it for?

It turns out that we can partly answer the “when” question: This wall was probably constructed no earlier than 1851.  We reach this conclusion in the classic cultural landscape history way: by looking at the landscape itself, and by consulting historical documents.

The western end of the wall curves around a corner at the intersection of Rock Road with an unnamed and long-abandoned road which connects Rock Road with the Rocktown-Lambertville Road (Figure 11).

Fig 11 walls blog

Figure 11. Rock Hopper Trail. The western end of the revetment wall, view facing southeast from the road-bed of the 1850’s Rock Road-to-Lambertville-Rocktown Road connector. Note how the wall is continued around the corner from Rock Road to the east side of the connector, indicating that the revetment is of the 1850’s or later. Photograph: Ian Burrow, 2019.

This road is very similar in character to the Rock Road, especially in its southern portion, where it is a moderately deep hollow-way.

Now, it is clear that the wall could not have been built before the connecting road was in place.  Fortunately, historic map evidence strongly suggests that the road was built after 1851 and before 1860, because it is shown on a map of 1860, but not on a map of 1851. So all we can strictly say is that the wall is later than 1851, but that in itself is worth knowing.  Supporting this dating is the fact that one of the stones at the end of the wall has a drill hole in it of a type probably not in use in this area until after about 1830.

So, what about the who and the why?  Detailed historical research on the owners of the property that includes the wall might give us a clue to the who. As for the “why”, it seems clear that this is no ordinary field wall.  It would be quite useless for keeping animals in fields and off the road.  The wall is so low on its northern (terrace) side that nimble sheep would easily get over it and scramble down to the road.  Cattle or horses might simply fall over the edge and injure or kill themselves.  So the land behind the wall was used for something else.

Seen from the road, however, there can be no doubt about the message sent by this wall.  The message is “Keep Out”.  Anyone wanting to climb the wall from the road had first to scramble up a steep grassy slope and then find footholds and handholds in the face of the wall.  Then that individual would have to negotiate the upright capping stones in order to get across the wall.  It would be clear to that person, and to anyone else, that they had crossed a line that was not meant to be crossed.  This, and the resources that were put into to building this wall, indicate very strongly that this was the boundary of a person of means who intended to maintain an exclusive privacy, particularly from people travelling along the road.

These examples will, I hope, give you some idea of the interesting stories built into the stone walls of Sourland Mountain.


Next Time: Puzzles and Mysteries





Part 1.

By Ian Burrow (burrowintohistory@gmail.com) 

eroding Dam

Fig 1.  Eroding Mill Dam 

If you have taken a hike on any one of the preserved areas on Sourland Mountain, chances are that you have noticed a tumbled stone wall, an earthen bank by a stream, A huge tree standing out among its smaller neighbors, a rusting piece of farm machinery, rocks with holes drilled into them, the rotting trunks of cedar trees, the bed of an abandoned road, or perhaps even the foundations of a long-forgotten building. For me, each of these features tells a piece of the story of the Mountain, and how people have interacted with it over hundreds and even thousands of years.  

Figure 2

Figure 2. Old road trace and wall

I would like to share with you what I am learning about this history, and to help and encourage you to discover it for yourself.

People go the Sourland woods for many excellent reasons.  Some watch and record wild birds, others search for the native plants, lichens and fungi unique to this place.  On cold rainy nights in early spring, hardy souls help amphibians cross the roads to vernal pools.  Some folks are on a mission to seek out and destroy invasive plants.  Many others are there for the peace and beauty of the trails, to enjoy the open air, to be strengthened and replenished by nature, and perhaps to seek out the mysterious rocky outcrops and giant boulders that litter the landscape.

I’m an archaeologist.  That means I’m interested in studying and understanding the physical evidence that people from the past have left behind.  This evidence can take many forms.  Most people immediately think of Indian arrowheads and other old and unusual artifacts when archaeology is mentioned (some people also think of dinosaurs, but those beasties are for the paleontologists).  Artifacts are an important part of the archaeological record, of course, but for Sourland Mountain we are talking mostly about a rather different kind of archaeology.

It goes by various names. In the UK, where I come from, it’s called “Landscape Archaeology”.  That term has a slightly different meaning here in the United States, where it has come to be chiefly associated with the study of the formal landscapes and gardens of the powerful.  So I tend to call what I do “Cultural Landscape History”.  Let me explain what I mean.

It is easy to imagine that when we are out in the woods, or in wild or wilderness areas, that we are in unspoiled nature.  We can readily think that we are seeing places where human hands (and feet) have not changed the environment.  There are still places like this in the World, but not as many as you might think. Very few of them are in Eastern North America, hardly any are in New Jersey, and none at all are on Sourland Mountain.  Almost everything that you see in the Sourland Landscape is in some way the result of what people have been doing here in the past.  So this is what is meant by a “cultural landscape”: land that has been altered from its original, pristine appearance by the activities of human beings.  Some of the alterations can be very obvious, others more subtle.  Cultural landscape historians try to peel back the layers of this history to see how things have changed through time.

So, let’s look at some of the features in the Sourland Landscape that will give up some of their secrets if we ask them the right questions. We’ll start with


They are hard to miss on the Mountain! One thing that you will notice is that in many places the trees are all much the same height and size, with the tree trunks rising straight up for many feet before the branches open out.  The tree trunks are often slender: 18 inches in diameter or less. 

Figure 3

 Fig 3. Young deciduous forest 

If we could talk to these trees they would say something like this: “We all started growing at the same time a few decades ago.  The trees that were here before us were all cut down and cleared away at one go, leaving open ground for us to colonize together.”

How Old?

That’s all very interesting, we may say, but exactly when did you all start growing? In order to learn this from the trees themselves we need to do two things.  

The first is to learn how to identify tree species from their bark, leaves, and overall appearance.  There are many Sourland-lovers who are much more knowledgeable about this than me, so it’s a good idea to have them on hand as teachers.  There are also lots of good reference books you can take out with you.  One of my favorites is Bark: A Field Guide to Trees of the Northeast by Michael Wojtech. I like this because I tend to be out in the woods in fall, winter and early spring, when the leaves are unhelpfully lying on the ground instead of being attached to their trees.

Once you have identified your tree species, you then do a little measuring, using the measuring tape that you have remembered to bring with you.  Otherwise you will have to go back to the car to get it. 

This is what you do:

  1. Measure the circumference (distance around) of the tree at a height of 4’ 6” above the ground.
  2. Using your geometry and math skills, work out the diameter of the tree.  Remember pi? Pi is your friend.  Divide the circumference of the tree (in inches) by the magical value of Pi, which is 3.14.  Make a note of the result.
  3. Now you consult a Tree Growth Factor Chart like this one:

FIgure 4


Fig 4. Tree-Growth Factor chart

Find your tree species on the chart and make a note of the “growth factor” number

  1. Multiply the diameter of the tree by its growth factor.  The result is the approximate age of the tree in years.  Magic!  Impress your friends and family!

You may rightly ask where these “growth factors” come from.  The International Society of Arboriculture is where.  They know what they are doing as far as trees are concerned, so we may rely on them.

Wolf Trees

Every so often you will see a tree quite different from the slender ones we have just been talking about:

Figure 5

 Fig 5. Wolf Tree

This tree is not only big, with a thick trunk, it also has many branches spreading out widely in all directions, starting quite close to the ground.  It may not be much taller than the trees that surround it, but it is much more massive.  Landscape historians call this a Wolf Tree.  

Let’s ask it a couple of questions: “Hello, wolf tree, why are you so different from most of the other trees around here, and why do they call you ‘wolf’?”

“These other trees are much younger than me.  Measure my trunk and you’ll see.  For a long time I was the only tree around here.  I was surrounded by pastures and meadows where cows were grazing.  The cows sheltered from the summer heat under my spreading branches, and could also browse the leaves from the lowest branches.  Farmers cleared the other trees to make the pastures and meadows, but left me as a “lone wolf” to give shade to their livestock.  After a while the cows went away, and these other trees grew up around me on the abandoned fields.”

So these lovely trees take us back to the time, a hundred years ago and more, when much of Sourland Mountain was open grassy fields.

Eastern Red Cedars

Juniperus virginiana,  to give it its scientific name, is a coniferous (evergreen) tree that eventually grows to a height of 30 to 40 feet, often in groups or stands.  On Sourland Mountain you will see them in four main settings:

  1. As fairly small trees scattered across grassy pasture fields.  We see them here because they are often the very first tree species to colonize pastureland, once cows have ceased to graze it, or it is no longer mowed for hay.  Eastern red cedars love these old pastures.

Figure 6

Fig 6. Easter Red Cedars

  1. As a dense, dark, almost gloomy, woodland.  This is what happens after 20-30 years of the growth of these trees.  They have successfully colonized the old pasture and are, for now, the dominant species.
  2. As sickly-looking trees surrounded and overshadowed by bigger deciduous trees.  The reign of the cedars is coming to an end as other trees overtop them and cut off their sunlight.  Eventually the cedars die.
  3. As rich red-brown crumbly tree-trunks lying on the woodland floor.  After they die the cedars gradually fall and decay as the other trees continue to grow.


Next time: stone walls!

Guest Post by Laurie Cleveland – Self Quarantine in the Sourlands

Self Quarantine in the Sourlands 

Last weekend, I celebrated successfully passing through another complete set of seasons, and I marked the day with my family in a new way – quarantine!

Though thankfully none of us are exhibiting symptoms of COVID-19, we’re squirreling ourselves away to slow the spread. I’ve set some goals in an attempt to stay mentally and physically healthy while working and living in an old farmhouse with five other people: eat well, stick to a schedule, exercise, play games, learn a new skill, and get outside as much as possible. 

I have set forth a personal quest to hike every one of the twenty-eight Sourland region preserves. So far, I’ve logged seven, accompanied by one or more of my new colleagues (formerly known as my family): Cedar Ridge, Rock Hopper, Woosamonsa Ridge, Omick, Hunterdon County Sourland Mountain Preserve, Rocky Brook and Pryde’s Point. 

I say hike, but I really mean walking with a backpack just big enough for snacks and a water bottle. There’s a first aid kit and a bandana in there, too, because I am a Girl Scout. 

Everyone in our group experiences the trail in a different way: a physical challenge, a meditative journey, an orienteering opportunity, an imaginary adventure, a biology lesson, a photographic expedition, and we all enjoy a picnic. Many days I set out with a specific plan – looking for a certain flower in bloom, checking vernal pool activity, working out some frustration… or working off a little birthday cake. Often I am diverted, but always leave the forest feeling relaxed and accomplished.

I find that sunny mornings and late afternoons are usually best for taking pictures, but rainy days offer a special appeal for fair-skinned photographers who seek more dramatic lighting. On this day, the passing showers suited my mood. 

Faerie partyWhen approaching a faerie house, a polite guest must overlook signs of evening revelry such as discarded dishes and confetti. Does one of the wee folk share my birthday?


This sweet rue anemone popped up at the edge of the trail. It was so small I almost missed it!

Cutleaf toothwort

This delicate cutleaf toothwort was the first I’d found in blossom this year. 

Beech Leaf

The mystery of beech. I’ve heard a few theories about why young beech trees are marcenscent. I’m not sure why last year’s papery leaves hang on through the winter, but I do enjoy wondering. 

Water Skippers

I was surprised and delighted to find playful water skippers creating ripples in the reflection.


Who needs forsythia when spicebush offers four-season interest, cheery yellow blossoms, swallowtail butterflies, fall color, berries for birds – and delicious spices for me?


My passing admiration of moss has developed into a passion since my favorite librarian suggested “Gathering Moss.” I’m not sure what type of moss is growing on this tree stump (or why it hasn’t grown on the little knob) but I do know you can’t unsee the lizard/frog/turtle in the picture once you’ve seen it.

Furry looking moss

This luxurious moss shares a home with a leathery lichen. I don’t think either one has a common name, so I will create my own – and share an old story about lichen, “Alice Algae and Freddy Fungus took a “lichen” to each other, but now their marriage is on the rocks.” We now know that bacteria play a role in this relationship, but that’s a story for another day.

Nightmare Mycelium

Speaking of fungus, here’s the stuff of nightmares (or fairy tales). Don’t linger too long in the forest, children, or the mycelium’s spindly white fingers may claim you, too.


I wonder who might be lurking under this dark umbrella, but I choose not to look.

Mayapple young

Speaking of umbrellas, this tiny mayapple could make an attractive addition to a sprightly spring wardrobe – if you don’t mind accepting a gift from a passing box turtle…

Battered Blood Root

At last, the object of today’s quest: Bloodroot. These showy flowers can be difficult to find as they close on cloudy days and lose their petals within a day or two of pollination. Although I found several intact, I found this weathered one more beautiful.


The author finds that a sturdy walking stick and waterproof boots are essential for squelching through mud or crossing streams on these rainy spring days – especially as her right foot took a refreshing dip shortly after this photo was taken. She would like to thank her son, Will, for choosing not to take the action shot.


Additional Notes:

I have heard people say that they’ve found the preserves crowded, but that has not been my experience. I have passed by a few busy parking lots on weekend days to find quieter preserves. I have met a few families on the trail, but we all respected each other’s personal space.

I would like to remind all hikers to stay on the trail and keep dogs on the leash. It’s important to help ensure the safety of hikers, their dogs – and the wild birds and animals who can be unintentionally injured or burn essential calories as a result of an encounter. Sourland preserves provide a source of respite and renewal for hikers – and critical habitat for many rare and endangered plants and animals who play an important role in our ecosystem and are not always visible to humans. 

And finally, leave no trace, take only memories and leave only footprints.


Sourland Ecosystem Preserve – The blooms are coming!

Sourland Ecosystem Preserve is located on Mountain Road in Hopewell.

Link to hiking map.


Though this winter was not very cold, it just seemed to drag on and on. I have been impatient while waiting for the seasons to change. The breaking of buds signaling that winter has yielded to spring is a comforting sign of normalcy. My family has been quarantined together and we have been getting cabin fever so we headed out for a hike at the Sourland Ecosystem Preserve. We all needed to run, shout in excitement, kneel on the ground to get a better look and get our hands very dirty. The forest offers so much hope and reassurance and we wanted to soak it all in. The buzzing forest brought me the relief that I was hoping for. Buds were opening, spring ephemerals were unfurling, and frogspawn was developing in the vernal pools.


Blackhaw Viburnum, Viburnum prunifolium, fruits leftover from last fall. These fruits can sometimes be confused with European Privet, Ligustrum vulgare, but one of the best ways to tell the difference between these two shrubs is that the seed inside Blackhaw is flat and the seed inside Privet looks like an olive pit.


The forest is celebrating and the Red maple, Acer rubrum, is dropping its flowers like confetti across the forest floor.


A new life has started with this Red Oak, Quercus rubra, acorn that survived the winter and germinated!

IMG_1957 2

Spicebush, Lindera benzoin, flower buds just about ready to open. I absolutely love the chartreuse flowers of Spicebush.


Searching for bugs! He reminds me of a chimp taking his stick and fishing in the log for insects.


This appears to be a European Beech, Fagus sylvatica, rather than our native American Beech, Fagus grandifolia. American Beech usually has a single trunk and grows straight up while European Beech has a shorter trunk with many branches reaching out to create an open canopy.


Important conversations are best had in the canopy.


Littlest and I enjoyed ourselves while we pretended to toast marshmallows over the fire.

IMG_4441 2

Spring Beauty, Claytonia virginica, as beautiful and graceful as it can be.


Blackhaw Viburnum, Viburnum prunifolium, buds bursting open!

IMG_7014 2

American Hazlenut, Corylus americana! In late winter, this shrub really stands out. The large catkins are the male flowering parts of the hazelnut. The female flowers are magenta and so small that you can barely see it. If you look at the three closet catkins, look up slightly and to the left and follow the branch to the end of the twig and you will see the female flowers.


I spy with my little eye a bird’s nest!


Christmas fern, Polystichum acrostichoides, is my oldest’s favorite fern. Whenever we go hiking he is on a mission to find it.

IMG_1281 2

A flowering dogwood, Cornus florida, flower bud about to open. Dogwoods are such underrated shrubs. I love seeing the beautiful pink shine through the dormant forest. Soon, the forest will awaken and I will no longer be able to see the dogwoods behind the shields of Maple, Sweetgum and Oak leaves.


Skunk cabbage, Symplocarpus foetidus, beautiful and vibrant in the muddy stream bank.


As we ended our hike, our family felt refreshed and renewed. I love that the forest can give us both the adventure and the reassurance that we need.

Baldpate Mountain – A family hike in February

Baldpate Mountain is located in Hopewell NJ.

Link to the trail map


There are 10 miles of hiking trails on Baldpate and while I have walked many of the trails, I have never completed the entire Blue Trail. Usually, when we bring the kids, we choose the Red Loop Trail. If I am out with my friends, we will hike the Ridge Trail.

My Littlest just turned 3 years old this week and his desire to show off his speed, climbing, and balance is in over-drive.  We decided to hike a trail with a lot of rocks to hop and climb on so that he could burn off some of his Wild Boy energy.

My oldest was confused asked me, “Why are we parking at this parking lot?” He had been all over Baldpate Mountain with me in the baby carrier as an infant, later as a toddler and now as a “really old” 5-year old.  He was quite distressed and insisted that we were “NOT at Baldpate Mountain”. He loves the vista from the meadow near Strawberry Mansion, which is also one of my favorite places in the Sourlands. After I explained that we would still see the view but we had to climb big rocks to get there, both Wild Boys were ready to go!


Even at my age, I love stepping stones as much as my kids.

IMG_2463 2

I appreciate the whole body effort of my Littlest. He will hop across all those stones just like his big brother.


Horizontal logs are an absolute must when perfecting those balancing skills.


Littlest and I had hiked part of the Blue Trail when he was a few months old and we had stopped at this very same log to look at all of the nutshells. I love how you will see some of the same familiar sights even if you haven’t been on that trail for 1.5 years.


We all get in on the rock hopping fun!




A Sourland boulder must always be appreciated and climbed.


Shagbark Hickory, Carya ovata, is a popular roosting place for many bat species in the Eastern United States. The Indiana Bat, Myotis sodalis, in particular, likes to hide within the loose bark of this tree.


One of the reasons I love winter hikes is that you can discover the hidden views. During the summer when all of the leaves are out, this view will be completely different.


I believe that this is some sort of non-native Buttercup, possibly Winter Aconite, Eranthis hyemalis.


Common Snowdrops, Galanthus nivalis, making an appearance.


I love all of the big trees on this side of the mountain.


Taking a little break.


Multiflora Rose, Rosa Multiflora, is already sending out new leaves – in February! It has been alarming how mild this winter has been and I am so afraid of how this affects our ecosystem as a whole. There is such a thin balance between bloom times, insect emergence, migrations, and breeding season that when one thing starts too early, the whole balance is thrown off.


A hardscrabble up these rocks!


Garlic Mustard, Alliaria petiolata, leafing out early. Unfortunately, this invasive is almost always one of the first plants I see to leaf out in the spring.  But let’s be honest, it is still winter! Garlic Mustard is edible and can be substituted for garlic in pesto. Yum!


Running to the world’s edge – also known as the “septic mound”… We usually travel to the higher meadow but when the Wild Boys saw this wide-open view, they took off.


Rolling down the mountain.


Snacks after a hike well done!