State Symbols & Fire – Mountain Laurel the State Flower

Small pinkish white blooms appear in May and June. Photo by Joe Vatter

Every person who has spent even a little bit of time in Pennsylvania’s forests knows what mountain laurel is. Hikers are familiar with it as it impinges on trails and seems to reach out and grab at packs and clothing. Hunters are familiar with it for many of the same reasons and its ability to hide game. Tourists flock to areas where it is prevalent to see it in bloom. And wildland firefighters are familiar with it for not only its propensity to burn, but also for its thick matted roots that resist line building. It is a pretty, but not fragrant flower that blooms in May and June. It is a wonderous event to visit a forest when the laurel is in full bloom. The town of Wellsboro even has a festival “The Laurel Festival” in June to celebrate the plant, complete with a Laurel Queen, parade and all the other events found in small-town festivals of that sort. It is so popular in Pennsylvania that 84 out of 9835 small watersheds have ‘Laurel’ in their name (second only to Mill at 121). There are even 18 places named in the Pennsylvania Gazetteer referring to Laurel.

The plant blooms are a major tourist attraction. Photo by Joe Vatter.

Mountain Laurel (Kalmia latifolia) is sometimes referred to as calico-bush, or spoonwood. It is a broad leaf shrub that retains its leaves throughout the winter. It is a member of the heather family, Ericaceae, that is native to the eastern United States. The family of plants contains many common shrubs including huckleberries, blueberries, azaleas, cranberries and rhododendron. It can be found throughout the Appalachian Mountains from Maine to Florida and west to Indiana.  Mountain Laurel is sometimes erroneously called Sheep Laurel, however sheep laurel is recognized as a distinctive species Kalmia angustifolia. The easiest way for a non-botanist to identify the two species is during the bloom. Mountain Laurel has light pink flowers and Sheep Laurel has darker, magenta blooms. The two species may be found in proximity to each other.

Mountain Laurel is the State Flower of Pennsylvania. (It is also the state symbol of Connecticut.) In 1933 the Pennsylvania General Assembly in a fit of indifference could not decide on a state flower. Some legislators favored the Pink Azalea (Rhododendron periclymenoides), others favored the Mountain Laurel. Compromise apparently was not an option. They passed two bills, one naming Mountain Laurel as the state flower, the other bill named the Pink Azalea as the state flower. Then they sent both bills to Governor Gifford Pinchot (a trained forester) and essentially said to him, “Pick one ya like!” Some accounts say that Gifford did not make the choice, but rather passed the decision on to his wife Cornelia. Whoever made the decision, Mountain Laurel became the State Flower of Pennsylvania on May 5, 1933.

The plant spreads by rhizomes sending up new shoots from underground.

WARNING: POISONOUS PARTS: All parts. Highly Toxic, Maybe Be Fatal if Eaten!

If for some strange reason you happen to ingest Mountain Laurel, you should know that symptoms. They include: salivation, watering of eyes and nose, slow pulse, nausea, vomiting, sweating, abdominal pain, headache, tingling of skin, lack of coordination, convulsions, and paralysis. It is an Andromedotoxin, a toxic compound C31H50O10 found in members of the heath family (Ericaceae). Honey made from the blooms of the plant can also impart the poisoning. In short if you eat Mountain Laurel it is going to mess you up.

Mountain Laurel is a heavy, hard and strong wood, but it is somewhat brittle. It has yellow sapwood and a yellow-brown heartwood with red spots. It has a green weight of 63 lbs/ft3. By comparison White Oak is 47 lb/ft3, Eastern White Pine is 22 – 31 lbs/ft3, and Eastern Hemlock is 50 lbs/ft3 when green.

The Janka hardness test measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an 11.28-millimeter (0.444 in) diameter steel ball halfway into a sample of wood. This method leaves a hemispherical indentation with an area of 200 mm2. the measurement is in pounds-force (lbf). The rating for Mountain Laurel is 1,790 lbf., White Oak is 1,360 lbf., White Pine is 380 lbf., and Eastern Hemlock is 500 lbf.

The wood has been used for utensils (hence the nickname Spoonwood) furniture, bowls and other household goods as well as ornamental wreaths and roping. Until the 1960s, when man-made materials became widely used, the Mountain Laurel furnished root burls that could be substituted for expensive imported briar in the making of smoking-pipe bowls. The wood of these burls was far heavier, harder, and denser than that in the tree above ground, making it slow to burn from smoldering tobacco. Laurel briar is said to be inferior to the imported variety, but it still works for pipe bowls.

An “Old Hunter’s Tale” is that you will only find Mountain Laurel growing on the north side of the mountain. That’s pretty much false. If you use that as a guide to help you find your way out of the woods there is a good chance you will be spending the night in the woods, probably in a laurel thicket.

Mountain Laurel is usually an understory plant. During the past 100 years Mountain Laurel has spread and grown pervasively. After the Pennsylvania forests were turned into the “Pennsylvania Desert” at the beginning of the Twentieth Century, Mountain Laurel had been subjected to fire, and destruction from timber harvesting. The regrowth

of the forests into the infamous “red brush” kept the laurel from being able to compete and its growth was stunted. As the middle of the century arrived the forest canopy reached above the maximum height of the laurel, and space became available for it to begin to grow with abandon. Destruction of the canopy by the oak leaf roller, gypsy moth and other forest pests allowed additional light to reach the laurel permitting it to grow and exclude other plants, notably trees.  While the plant is poisonous to humans, it seems to have little effect on white tail deer, who will browse it as a food of “last resort.” As 

Mountain Laurel is an understory plant that will often grow better when the canopy has been removed.a result, Mountain Laurel is not prone to overbrowsing by deer. It does, however make excellent cover for game. Many a young or novice hunter earned his stripes by following the directive to “Go through that laurel patch over there and kick something out.”


Mountain Laurel will burn hot and fast, due to the waxy leaves and relatively dry thin branches and stems. However, it will survive, and in many cases thrive after a fire. The plant grows reproductive rhizomes some up to 30 inches into the soil, where they are isolated from even the most drastic fire effects. Some prescribed fires have shown that Mountain Laurel will re-establish itself quickly after a fire and outgrow laurel in unburned areas in as little as 8 or 9 years. Sometimes in areas where canopy mortality has been the greatest due to fire the Mountain Laurel will grow best.

Mountain Laurel has matted roots and will grow over and among loose rocks. Trying to cut a fire line through a patch of laurel, even with modern mechanized machinery is a difficult task. In drought conditions fire can travel along the roots and rhizomes deep underground, beneath a fire line cut to mineral soil, and cause fire to break out across the line.

In some forests, prescribed fire is being utilized to thin if not outright kill Mountain Laurel, but like the hardy Pennsylvanians who settled in the forests where the laurel blooms, it is here to stay.


PA State Symbols & Wildfire

Pennsylvania has several state symbols. A state tree, a state bird, a state fish, and so on and so forth. Most if not all are somehow affected by wildfires. The next few blog entries will explore how wildfire affects – positively, negatively, or some combination of both – these symbols. You might even be surprised to learn that in some cases, state symbols may be responsible for wildfires.

The Eastern Hemlock (Tsuga canadensis)

A stand of young hemlocks in a swampy area.

First and foremost, among them is the state tree, the Eastern Hemlock (Tsuga canadensis). Adopted as the state tree on June 23, 1931, the hemlock has played a prominent role in forestry and forest products and other industries in Pennsylvania.

To be clear, the Eastern Hemlock is not the same as the infamous hemlock that Socrates drank. That is a member of the genus Conium, an herbaceous plant from the Mediterranean region. From this point on when hemlock is referred to, it is the Eastern Hemlock (Tsuga canadensis) that is being identified.

The hemlock is a coniferous tree found in valleys, swamps and the dark, shaded understory of mature forests. It is a long-lived tree and can attain heights of more than 150 feet. From early surveys it is believed that hemlock once comprised as much as 19 percent of the undisturbed Allegheny Plateau forests.[1] The tannic acid in the bark of the Eastern Hemlock has a tannin content of between 8 and 14 percent. This made the bark of the tree valuable for the tanning of leather.

The trees were cut in early spring until about the end of June. This was the time of year when the bark was said to be “slipping,” and thus easily removed. Bark peelers, men who were hired to remove the bark from the fallen trees, used bark spuds and peeling chisels to remove the bark from the logs. The peeled bark, measured volumetrically in cords, was stacked in the woods, with the inside facing up to allow it to dry more easily. When it was completely dry the bark was hauled to the tannery and sold by weight.

As tanneries began to spring up across Pennsylvania the demand for hemlock bark increased. There was a prodigious amount of bark – and thus hemlock trees required to supply the ever-growing need for leather tanning. DeCoster notes:

 “The Pennsylvania harvest of hemlock in 1896 was estimated at 1.3 billion board feet. The peeled bark went to the tanneries, the logs went to the sawmills.”[2]

Stranahan noted the volume of hemlock needed to supply the tanneries.

 “Fifteen hundred feet of hemlock were needed to produce one cord of bark, and the nation’s tanneries were consuming 1.5 million cords of bark annually.”[3]

The Mosser and Keck Company tanneries in Allentown and Williamsport used 700 and 1,200 train car loads of bark respectively each year.[4]

While hemlock lumber was not as easily worked as the white pine with which it shared the forest, it was usable. The invention of the wire nail which replaced the cut nail allowed carpenters to securely fasten hemlock together and its use for framing and crating and other rough applications became more common as the availability of white pine dropped.[5]

Dr. Joseph T. Rothrock noted the use of hemlock in his 1895 report.

“Hemlock came into demand as a result of two causes. First. because the white pine was exhausted here, and second, because the hemlock was exhausted in New York state. It was not recognized as lumber so long as white pine continued abundant, and hence it was cut simply for the bark, which was to be employed in tanning. The logs in most instances were allowed to decay where they fell or to become the fuel to destroy the remaining timber when the next forest fire devastated the region.”[6]

The last sentence however, is a common misconception. The lumbermen who owned the stands of forest and the loggers who cut the timber knew what they were doing. Bennett notes:

“Hemlock trees were relatively easy to hand peel free of bark during an eight to twelve week period during the summer sap flow season. The customary practice was for the cutters to maximize peeled saw log and tan bark production during this limited summer season. The freshly cut slippery logs and bark were left to dry until the fall and winter season when they could more easily and safety be handled and moved to roadside or mill storage yards. This seasonal division of work enabled full use of available experienced woods labor.”[7]

He further notes:

“…mature old growth hemlock timber is thick barked. The bark contents of an unpeeled log amounts to over 20% of its total volume. To cut thru, skid, load, haul, and handle this excess bark fiber only added to the cost of the final lumber product.”[8] 

Simply put, the trees were cut, the bark was removed, and the logs left in the forest to dry in order to haul less weight to the sawmill, where they were eventually sawed into lumber. It is easy to deduce why Rothrock and other forest advocates – even to this day – decried the wanton waste of hemlock logs. Most first-hand accounts that saw the stark white hemlock logs lying in the forests saw them in the summer after they had been cut. Those who viewed the photographs taken of the cutover forests saw photographs that were also taken in the summer. But a picture speaks a thousand words and the logs in the black and white photographs easily gave the viewer a false impression.

Bennett strengthened his case.

“Some 25 years ago [prior to 1986 when the article was published] after I had become convinced the hemlock log waste story was a childish tale, I wrote a short article for the “Northern Logger” magazine. I challenged anybody to show me any hillside or forest area where the rotted logs were supposedly left to rot. I assured readers I could still show them the remnants of the old hemlock stumps where logs had been cut. In return they would have to show me the remnants of the rotted logs. Of course no one ever accepted this challenge – how could they – the logs were never left to rot, except for the odd and overlooked in the skidding operation. 

Even today many of the old hemlock cut stumps still stand two feet high as sentinel spires of those early harvest days. I have yet to find any rotted logs to substantiate this ongoing myth.”[9]

This author can attest to the fact stated by Bennett that even thirty years after the publication of his article, hemlock stumps are still visible in the woods but the logs that were supposedly left are nowhere to be found, even in detrital remnants that have decomposed into the forest floor or partially burned logs that would have left an ash pile.

As tanneries spread across Pennsylvania the value of the bark escalated and its destruction by wild fires was noted on several occasions.

The New Bloomfield Times, May 18, 1880

Williamsport, May 10. Forest fires are still raging in this part of the State, Sullivan county being the latest sufferer. The hemlock forest of that county have been burning for two or three days, and great quantities of limber are reported destroyed. The latest advices received here to-day are to the effect that two thousand acres are already burned over between Thorndale and Schreyvogels, and over fifteen hundred cords of bark belonging to Thorn McFarland & Co. here have been eaten up by the flames. The fire is still fiercely burning and promises to do still greater damage unless its destructive progress is arrested by rain.

The Forest Republican, July 14, 1886

A dispatch from Sheffield to the Warren Mirror, under date of July 10th, says: One of the most destructive forest fires that ever visited this section of the country is now raging near here in Forest county. The fire originated in a large bark slashing in which was piled several thousand cords of bark. About sixteen hundred cords of bark, together with several lumber camps, are now burned and the fire is not yet under control. Horton, Crary & Co, who own the bark, have a hundred men fighting the fire, and it is thought it will be under control before night.

Pittsburg Dispatch, May 11, 1891


Many Thousand Feet of Logs and Cords of Bark Destroyed.

Special Telegram to the Dispatch 

Keating Summit, Pa., May 10. One of the largest forest fires known for many years is raging south and east of Austin, on the land of F, H. and C. W. Goodyear. The fire has been burning since yesterday noon. It is estimated that 30,000,000 feet of logs and 10,000 cords of bark have been destroyed, besides 10 miles of tram railroad. Telephonic communications are cut off and it will be impossible to get full details until tomorrow. 

Dr. Joseph T. Rothrock reporting for the state forestry commission about which more is to come, noted:

The supply of hemlock is not only very limited, but none are more fully aware than those most directly concerned, that it too, is approaching extinction. The successful handling of large tanning plants makes it imperative that they should be kept at least reasonably active, and this demands a large annual cut of hemlock for bark. This, in turn, gluts the market with hemlock lumber. The end will come, and come suddenly, when both the pine and hemlock as sources of revenue to the capitalist and the wage earner of the State will disappear from within our limits. To the citizens of twenty years hence, it will appear incredible that with these facts before us, the close of 1894 showed no active measures taken for either protection or restoration of our timber resources.[10]

Metal salts eventually replaced hemlock bark as the principal tanning agent and the demand for bark fell.

Bark loading in McKean County

The methods of storing and transporting hemlock bark and logs in the 19th and early 20th centuries were conducive to the rapid spread of fire. Bark and logs were stacked along railroad tracks and sidings and piled as high or higher than the cars to which they eventually were loaded in a continuous line. The huge piles of bark were tinder dry.

Wildfires in the slashings would give off embers that would blow into the piles, or the steam locomotives would give off sparks. Once fire impinged on the piles it was difficult if not outright impossible to stop it.

Hemlock in McKean County

Burning piles of logs and bark caused disastrous losses and the Moores Run fire disaster was caused in large part by logs and bark piled immediately adjacent to the tracks.

Common woods found in Pennsylvania forests have different BTU values.  For example, dry white oak will release 24 Million BTU’s per cord, hemlock will release 15.9 Million BTU’s per cord and white pine will release 14.3 Million BTUs per cord. A cord is a measure of wood that is defined as a stacked pile 4 feet wide, by 8 feet long by 4 feet high.  The website notes that, “A cord is 128 cubic feet but because of air space between pieces the actual amount of solid wood may be only 70-90 cubic feet. This depends on the size and shape of the pieces and how tightly they are stacked.”[11] Because of this discrepancy they further note the weight of the wood in each cord. Considering that the wood is dry and suitable for burning in a woodstove the weights are: White oak – 3,757 pounds per cord, hemlock – 2,482 pounds per cord, and white pine 2,236 pounds per cord. The number of pounds per cord will vary significantly depending on the dryness of the wood. The BTU values will also vary as wetter wood will require more heat to drive out water in wood that is not sufficiently dried.  But these numbers illustrate that denser wood such as white oak will have more energy stored than the softer hemlock and pine.[12]

Despite its propensity to burn hemlock was used in wildfire suppression. Green hemlock branches were used by early firefighters to beat out the flames as fire crept across the forest floor. It may not sound like a good idea today but at the time it was often the best available tool for fire control.

Today hemlock accounts for about 6 percent of the forest in the Appalachian Plateau[13] and accounts for about 4 Billion board feet of sawtimber in Pennsylvania each year according to the Pennsylvania Forest Products Association.[14] The bark once so prized for its value in tanning is now used as landscaping material.

Hemlock trees in Pennsylvania are under assault. The Hemlock Wooly Adelgid (HWA) often referred to as simply wooly adelgid, has begun a destructive path across Pennsylvania. According to the Penn State Extension, the insect pest arrived in the western United States in 1924. It first appeared in the east around 1950 and was discovered in Pennsylvania in 1973.[15]

It is a small, soft bodied insect that is barely visible to the unaided eye. The adelgids feed on the nutrients taken from the base of the needles. The needles turn brown or gray and then die. Because the critters are so prolific, infestations can kill a mature hemlock tree in one to four years. The presence of adelgids on the trees can be found by turning over leaves and looking for small white cottony egg sacs at the base of the needles. These sacs will be present all year but are more prominent in early spring.

The death of thousands of hemlock trees from HWA infestation, coupled with gypsy moth mortality of hardwoods, is part of the reason a fire complex in Monroe and Pike counties – the Beartown Fire and the Sixteen Mile Fire burned a collective 8,644 acres in April of 2016.

Foresters and entomologists are looking for solutions but for the large stands of eastern hemlock that have re-grown since the state was subjected to industrial logging a century ago, there is nothing that seems to be adequate in the control of the invasive pest.


[1] Quimby, John W. Value And Importance Of Hemlock Ecosystems in The Eastern United States

Department of Conservation and Natural Resources, Bureau of Forestry, 1995

[2] DeCoster, Lester, A. The Legacy of Penn’s Woods: A History of the Pennsylvania Bureau of Forestry, Harrisburg, Pennsylvania Historical and Museum Commission and the Department of Environmental Resources, 1993

[3] Stranahan, Susan Q., Susquehanna, River of Dreams, The Johns Hopkins University Press, Baltimore, 1993

[4] “Mosser and Keck, Tanners of Union Sole Leather, East Allentown,” 1881,,

[5] Stranahan, Susan Q., Susquehanna, River of Dreams, The Johns Hopkins University Press, Baltimore, 1993

[6] Rothrock, J.T. and Shunk, William F., Annual Report of the Pennsylvania Department of Agriculture for 1895, Part II, The Division of Forestry,   Commonwealth of Pennsylvania, 1895, Official Documents Comprising The Department and Other Reports Made To The Governor, Senate and House of Representatives of Pennsylvania, Volume X, Clarence M. Busch, State Printer of Pennsylvania, 1896

[7] Bennett, Arthur L., lt’s Time to Debunk the Myths of Early Logging Practices, Pennsylvania Forests, Vol. 76, No. 5 Sept.- Oct., 1986.

[8] Bennett, Arthur L., lt’s Time to Debunk the Myths of Early Logging Practices, Pennsylvania Forests, Vol. 76, No. 5 Sept.- Oct., 1986.

[9] Bennett, Arthur L., lt’s Time to Debunk the Myths of Early Logging Practices, Pennsylvania Forests, Vol. 76, No. 5 Sept.- Oct., 1986

[10] Rothrock, J.T. and Shunk, William F., Annual Report of the Pennsylvania Department of Agriculture for 1895, Part II, The Division of Forestry,   Commonwealth of Pennsylvania, 1895, Official Documents Comprising The Department and Other Reports Made To The Governor, Senate and House of Representatives of Pennsylvania, Volume X, Clarence M. Busch, State Printer of Pennsylvania, 1896



[13] Quimby, John W. Value And Importance Of Hemlock Ecosystems in The Eastern United States

Department of Conservation and Natural Resources, Bureau of Forestry, 1995

[14] Pennsylvania Forest Products Association,