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A Pine for Independence Day

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The Appeal to Heaven flag of 1770

As we celebrate Independence Day and the signing of the Declaration of Independence in 1776 we should pay homage to the magnificent tree that was an importance cause of our conflict with Britain – eastern white pine, Pinus strobus.

In 1605, a British ship captained by George Waymouth* sailed down the coast of Maine exploring for sites for future settlements. Waymouth was astonished to find enormous trees reaching to the sky. “Upon the hilles grow notable high timber trees, masts for ships of 400 tun…”  Waymouth understood that these giant trees might be a solution for a problem that vexed the Royal Navy.  Naval battles were won by the largest ships of the line that could be built. These ships required enormous masts, but Europe had run out of large trees.

White pine was a perfect solution to the Navy’s problem. The trees were as tall as 150 feet, 5 feet in diameter and could weigh 10 tons.  The wood was strong, flexible and light weight. White pine made the best and largest masts in the world.

The first major industry in the Colonies was the export of white pine trees for the Royal Navy.  Trees for masts had to be felled carefully, because the soft wood would shatter into splinters if the tree landed on a hard surface. Sawyers cleared a path to fell the tree, covering the ground with pine, spruce and fir branches to cushion the tree’s fall.  The trees were left until winter, when snow cover created a slick roadway. Large numbers of men and oxen were required to slowly move the tree to the nearest river or port, where they were loaded onto specialized mast ships. Even the shape of New England towns was influenced by the mast trade. Instead of town squares, towns like Freeport Maine had (and often still have) triangular centers large enough to allow the turning of the giant masts.

White pine was also needed to build the colonies. With its soft, easily sawn or hewn wood, white pine was a perfect construction wood. Conflict soon arose between the Royal Navy and the colonists for pines, especially the largest trees.  The British administration declared all white pines larger than 2 feet diameter with straight clear stems to be the property of the King. Colonists risked fines and jail for cutting the largest white pines.

As long as the supply of pine was adequate, there was little conflict.  As harvesting reduced the availability of pine, surveyors were sent to mark trees suitable for masts with the three axe strokes known as the King’s Broad Arrow.  Landowners then had to get permission to cut other pines, and even then they had to pay a hefty license fee.

The colonists began to rebel. Mast trees were mysteriously burned or felled onto rocks, splintering them and making them useless for masts. Operators of many saw mills defied the King’s decrees and processed pines, including some marked with the King’s Broad Arrow.  Sheriffs attempted to imprison the miscreants. Rather than succumb, a gang of men disguised with blackened faces attacked the King’s men, beating them with switches and poles and destroying timber records. Eventually the men were arrested and tried, but the judge, sympathetic to the colonial cause, levied minimal fines and the men went free. This came to be known as the Pine Tree Riot, and preceded the Boston Tea Party by a couple of years.

As insurgency spread throughout the colonies, the white pine became a symbol of freedom, appearing on flags and banners.  One of the most prominent flags was emblazoned with a white pine and the words “An Appeal to Heaven.” This flag, and others like it, appeared on colonial ships. Vermont placed a white pine on its colonial flag that is still on the state flag today.

There were other causes of the rebellion, but there is little doubt that for the New England colonies, white pine was an important factor leading to the  Declaration of Independence and American Revolution. As we celebrate Independence Day, we should remember the white pines that fueled the revolution.

*In Europe, eastern white pine is called Weymouth pine after Lord Weymouth who imported the tree to England in 1696. Lord Weymouth is not related to George Waymouth. This is a source of confusion in some references.

This story is based on a chapter in my forthcoming book The Lives of Trees. Engravings are from Manning, 1979, New England Masts and the King’s Broad Arrow.

HMS Victory

HMS Victory, 1759, the oldest serving ship in the world. Masts are white pine.

Marking trees

Marking white pines with the King’s Broad Arrow. Source: Manning, 1979

Felling a mast tree onto a prepared cushion. Source: Manning, 1979

Felling a mast tree onto a prepared cushion. Source: Manning, 1979

Turning mast logs through a Maine village, Source: Manning, 1979

Turning mast logs through a Maine village, Source: Manning, 1979

Tree with Treegator bag

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Water your young trees!

Update: This story is originally from 2016, but the same conditions are starting to prevail. It is very likely that your young trees need water.

We are having a spell of beautiful weather, at least for people.  This weather may be fine for people, but it can be stressful to trees.  Trees lose more water from their leaves when humidity is low. If the soil is dry, the trees may soon wilt or die back. Even without obvious wilting, trees may be stressed. 

We have had plenty of rainfall, and are not currently in drought. As the graph shows at the end of the article shows, soil near the surface has become very dry.  This is the problem for newly planted trees – they are not yet firmly established in the deeper layers of soil where moisture is plentiful. The risk to trees is compounded by our wet spring. In wet conditions, roots tend to form near the soil surface, and when dry conditions replace the wet spring, trees can quickly become stressed.

We can see this all over Lexington – and it is true in many other eastern cities as well.  Newly established trees are wilting. If current weather patterns continue, many more trees will begin to suffer. Some will be stressed enough to eventually die.  Many landowners have spent a lot of money planting trees, but their investment will be lost if trees are stressed. For larger landowners, including city governments, water stress in newly planted trees can result in the loss of thousands of dollars for planted trees that don’t survive or thrive.

You need to water your young trees, but you don’t want to waste water. Instead of watering on a schedule, let the soil tell you when to water.  The easiest way to know when to water trees is to use a trowel to dig a small hole near the tree. If the soil feels dry, it is time to water.

How should you water? It is not sufficient just to water your lawn – for trees, soil needs to be watered deeply. Irrigation systems often do not provide deep enough watering for trees. Drip irrigation is very effective, but is costly and can require a lot of maintenance.

It is easy to water your trees with a hose. Place the hose end at the base of the tree and turn it on to a trickle for an hour or two. This method often results in overwatering and wasting water, especially if you are forgetful.

Another way to ensure that your valuable trees get adequate water is to use a 5-gallon bucket, available at most hardware stores. Poke a nail hole in the bottom of the bucket, put it next to your trees (but not touching the tree) and fill it with water. Refill the bucket once or twice a week.  Here is a good video on watering.

Another solution is to use a watering device like a Treegator. This is a bit more expensive but provides excellent results if done properly.  The bags slowly leak water into the soil, watering deeply and effectively.  The bags have to be refilled at least weekly, and this is often a problem.  I have seen Treegators that were not refilled for months – as if they had magic properties.  If properly used, Treegators are very effective and will last for years. Be sure to remove and store that Treegator when the watering season is finished.  Some people find Treegators unsightly. There is another solution for small trees called the Treegator Jr.  that is less visible, looking like a small donut around your tree.

Whatever method you use, it is also important to choose the right tree for the right site. Dogwood trees never do well in full sun. No matter how much you water the tree, it will lose water faster than it can take it up.  Dogwoods in full sun may look nice for a couple of weeks when they are in flower, but most of they year they look droopy and stressed.  Red maples also do poorly in very sunny locations, though they may recover after a rain.

Soil moisture in Lexington KY. Source: Kentucky Mesonet, June 9 2018

 

Young tree with dead top

Young tree with a dead top due to water stress.

Red maple wilting

Red maple wilting due to water stress

Irrigation systems often don't adequately water trees.

Irrigation systems often don’t adequately water trees.

Wilting dogwood

Dogwoods never do well in full sun, even if watered.

Tree with Treegator bag

Newly planted trees with Treegator controlled watering bags.

Dying street trees

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A declining urban forest

It is that time of year when our urban forest seems to be lush, vibrant, and green.  Trees have finished leafing out, many have flowered and, with recent heavy rains, many are growing well.  To the casual observer, the urban forest looks like it is thriving.  People are planting trees all over town and nurseries are doing a brisk business.  I am talking here about Lexington, Kentucky, but you could probably say this about any city in the rainy eastern US and Canada.

But all is not well.  A stroll down any street shows numerous trees in dire condition. The first photo shows a street near my office. Ash trees along the street have not been treated and are dying from emerald ash borer infestation.  At least 11% of the trees in the city are likely to succumb over the next few years.  The honeylocust trees are declining due to the fungus Ganoderma lucidum, which decays roots and lower stems of many trees. Honeylocust is especially susceptible.

Ash  and honeylocust trees are widely planted in urban areas. They grow well, require relatively little maintenance and tolerate a wide range of urban stresses. These two tree species are among the most abundant in our urban forest. Yet they are disappearing rapidly and will leave great holes in our urban canopy.  We have repeated the common mistake of the past – overplanting of individual species that do well for a time, and then succumb to a new insect or disease.

The loss of ash and honeylocust might be acceptable if other trees were doing well, but they are not.  Young street trees, regardless of species, have very high rates of mortality. Typically, especially in developments, poor quality nursery stock is planted in poor soil. These trees have little chance of survival. They represent a significant waste of money. Trees have enormous economic and environmental benefits, but only if they live a reasonably long time. When the majority of newly planted trees die within a few years of planting, they have negative value – the planting costs are not recouped by environmental benefits.

The most valuable trees in a city are the largest. These provide the most shade, store a lot of carbon, cool the city and provide psychological benefits. Yet even here, we are losing. Old trees are not receiving adequate care and are being lost to development, mower damage, soil compaction and lightning damage.

As much as we enjoy the beauty of our urban forest, especially on hot summer days, we need to recognize that most of us live in cities where the health and value of the urban forest are declining.  There are solutions, but they require substantial changes in how we manage trees.  We place great emphasis on tree planting but very little on tree health and maintenance. Planting smaller trees, creating better soil conditions, and spending part of our tree budget on maintenance will extend the lives of our trees.

The loss of so many trees over a short period of time is a tragedy, but it is also an opportunity for us to rethink how we plan, plant and maintain our urban forest.

Dying street trees

Decline of street trees. Honeylocust infected with Ganoderma root rot (foreground), white ash killed by emerald ash borer (background)

Dead mature oak

Dead mature oak

Dying street trees

Dying street trees

Lightning struck tree

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Death of an Oak

This beautiful old oak tree was struck by lightning last September. Within 2 days, it had completely wilted and showed no signs of life. Sudden death due to lightning is uncommon in trees, especially after the end of the growing season. Several experts recommended leaving the tree until spring to see if it showed any signs of recovery. Sadly, the tree did not leaf out this spring. Because the tree is in a public park next to a popular basketball court, it had to be removed promptly. The photos below show the tree before and after death and the process of removing it.  We have collected a section of the trunk and will use it to determine the tree’s age.

Before it was hit by lightning, this was a remarkably vigorous tree with no signs of death or decline. Within days after being struck, the leaves had wilted, twigs were dead and the fungus Biscogniauxia atropunctata had popped out on the major branches.  Biscogniauxia is an endophytic fungus, living quietly within the bark of healthy trees and fruiting rapidly when the tree is stressed.

bur oak tree

The tree before being hit by lightning.

Felled tree

The tree after felling

Section of a tree

Section of the tree for ring counting

Lightning struck tree

The tree three days after it was struck by lightning

Slicing the tree to count rings

Slicing the tree to count rings

Fungus on a log

The gray material is the fungus Biscognauxia atropunctata

Emerald Ash Borer-2254-Edit

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The green terror emerges

The emerald ash borer, a shiny green beetle, is emerging from ash trees all over the eastern US and Canada.  The beautiful little beetle, part of a group called “metallic wood boring beetle” was introduced in packing material from China around 1990.  Carried throughout the region by people moving firewood, the beetle threatens to eliminate white, green and black ash.  There is some hope that parasitic wasps introduced from China by the USDA may spread quickly enough to slow the beetle, but this is far from certain.  Below you will find a slide show of the beetle and the damage done. 

A female emerald ash borer feeds on leaves and will soon deposit eggs on the bark of an ash tree.

A female emerald ash borer feeds on leaves and will soon deposit eggs on the bark of an ash tree.

A female ash borer ready to lay eggs

A female ash borer ready to lay eggs

The adult borers eat ash leaves before they lay eggs on the bark.

The adult borers eat ash leaves before they lay eggs on the bark.

The borer larvae make wandering galleries in the cambium, xylem and phloem. This is what kills the tree.

The borer larvae make wandering galleries in the cambium, xylem and phloem. This is what kills the tree.

In spring, the adult beetles emerge by tunneling through the bark, leaving little piles of sawdust.

In spring, the adult beetles emerge by tunneling through the bark, leaving little piles of sawdust.

The adults emerge through the bark, making a characteristic D-shaped exit hole.

The adults emerge from the stem, making a characteristic D-shaped exit hole.

The borer begins at the top of the tree and works its way down, sometimes taking several years to kill the tree.

The borer begins at the top of the tree and works its way down, sometimes taking several years to kill the tree.

When the beetle is done, cities and forests alike are left with dead trees.

When the beetle is done, cities and forests alike are left with dead trees.

Holly leaf

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A Question of Timing

Leaf exchange in holly

We know that trees usually lose their leaves in autumn, which is why we sometimes call the season fall. A few trees do things differently, though. One of those is American holly, Ilex opaca.

Holly is a tree that we usually call evergreen because it stays green year-round. But if you look carefully at this time of year, you will see yellow leaves on holly just as the new leaves are emerging. Have a look at the pictures to the right. You will see the young developing shoot of this year’s new growth, but you will also see yellow fading leaves on the tree and on the ground.

This unusual pattern is called leaf exchanging. The new leaves are emerging as the old leaves die. The tree is evergreen in the sense that it is always green, but the leaves are replaced each spring.

For the next couple of weeks, you should be able to see this pattern in our American holly and some of the ornamental hollies.  [Scroll down for the story of a fly with good timing]

American holly

Leaf Exchange in American holly. The yellow and dark green leaves are from last year, the pale green shoots are this year’s growth

A Fly With Good Timing

The timing of leaf exchange in holly is interesting to us, but for a one insect, it is a matter of life and death.  The native holly leaf miner, Phytomyza ilicicola, is a tiny fly. The fly larvae live inside the holly leaf, protected from enemies by the tough, leathery holly leaf.  The problem for the female fly is how to get her eggs into the leaf.  It is not possible for the fly to penetrate the mature leaf with her ovipositor, as it is too tough. She needs to deposit her eggs in the young leaves as they develop. Perfect timing is essential. The fly spends the winter inside the leaf, in the mine made the previous year. As soon as spring comes, the mature fly needs to emerge from the leaf, mate, and deposit eggs in the young leaves. If she emerges too soon, there will be no young leaves. If she emerges too late, the leaves will be too tough. Like the porridge in Goldilocks, the leaf must be just right.

Reference: Kimmerer and Potter 1986 Oecologia 71:548-551

 

 

Holly leaf

The track of a native holly leaf miner larva in a mature holly leaf

Holly leaf with a leaf miner track

Holly leaf with a leaf miner track

Norway Spruce

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How old is Old Tjikko?

Old Tjikko is one of the internet’s favorite trees. A Norway spruce growing near the treeline in Sweden, it is said to be the oldest tree in the world at 9,558 years. Over 26,000 web pages tell us about Old Tjikko, including the usually reliable National Geographic. As is common for such stories on the internet, the tale was immediately seized upon as fact.  The truth is that Old Tjikko is a fairly ordinary Norway spruce of about 80 years of age.

Trees are the largest and longest lived organisms on the planet. They are also photogenic and inspiring. It is no surprise that the internet is filled with pages that trumpet the largest tree, the strangest tree, the oldest tree and all manner of tree stories. Some of them are even true.

In science, extraordinary claims require extraordinary evidence. It is certainly extraordinary to claim that a tree is almost 10,000 years old. Is there extraordinary evidence to support the claim?

Prof Leif Kullman and his student Lisa Öberg published a number of papers about treeline changes in boreal Sweden. Some of these include observations about Old Tjikko. Many of the papers are obscure and hard to find, and some are in Swedish. When I first read Kullman’s papers, I was skeptical, particularly of the connection between very old wood in the soil and the tree (see below). However, I did not have access to all the papers.  Fortunately, Dr. Gordon Mackenthun, General Secretary of the European Champion Tree Forum has analyzed all of Kullman’s work and summarized it in a recent paper in the New Journal of Botany.

So, how old is Old Tjikko? Some trees are unitary, producing a single stem on a single root system. When a unitary tree dies, both the stem and the root system die. The age of a unitary tree can be determined by careful analysis of its annual rings. Other trees are modular (or clonal), with a long-lived root system supporting younger stems. When stems die, they are replaced but the root systems remains alive. Counting the rings of a modular tree only tells us the age of the stem, not the age of the entire clone.

Kullman acknowledged that the stem of Old Tjikko was not old, probably about 80 years.  This is the stem seen in the well-known photo to the right. Around the stem, and visible in the picture, is krummholz (crooked wood), formed when branches low on the tree are pushed down by snow but continue to grow. Kullman and Öberg obtained wood from the soil beneath Old Tjikko and used radiocarbon dating to determine that the wood was about 9550 years old.  The assumption was that the wood was from the same tree and that Old Tjikko is an ancient clone.

This result was only reported in a paper in Swedish, so until Mackenthun translated and analyzed the paper, it was difficult to assess the validity of the result. In several papers, Kullman and Öberg state that for this tree and several others, it was evident that the trees were reproducing clonally and that the wood pieces must be genetically identical to the stems.

There are several problems with this conclusion:

  • The pieces of wood were collected under the tree, but it is never shown that they were connected to the tree. This could have been old wood from previous trees. In cold, wet boreal soil, fragments of wood can persist without decay for thousands of years.
  • The conclusion that the tree is part of a clone and that therefore the wood fragments are genetically identical to the tree is unsupported by any evidence. When I read the Kullman papers which contained the assertion that the wood fragments were genetically identical to the tree, I assumed that the evidence was in one of the papers I could not obtain. Mackenthun shows that this is not the case. No genetic analysis on either the wood or the stem appears to have been conducted.

It is pretty clear that there is no solid evidence that a 9550 year old piece of wood in the soil bears any relationship to a nearby 80 year old tree.

Mackenthun also points out that there is evidence that the population of trees in the area of Old Tjikko had reproduced sexually during warm periods in the past. If trees could only reproduce clonally, then it might be reasonable to conclude that the wood and the stem were genetically the same. If sexual reproduction has been happening in the past, there is no reason to conclude that the tree and the wood bear any relationship to one another.

If the wood samples that Kullman collected still exist, it should be possible to do the kind of genetic analysis that would confirm whether the wood and the tree are a clone. Kullman declined Mackenthun’s invitation to comment on his paper.

Old Tjikko is most like a fairly ordinary Norway spruce of around 80 years of age, with fragments of wood nearby that may be 9550 years old. No evidence exists that it is part of a clone.  There is no evidence to support the conclusion that this tree is any older than 80 years.

Norway Spruce
Old Tjikko Norway Spruce (source: Wikimedia commons)
Huge bur oak

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Field Course – Airdrie Stud

Venerable Trees, Inc. offers frequent Field Courses to introduce people to the amazing woodland pasture ecosystem of the Bluegrass and Nashville Basin.  Recently, we were able to visit the amazing Airdrie Stud Farm at the gracious invitation of Mrs. Elizabeth Jones, the Owner. Airdrie Stud is one of the premier horse farms in the Bluegrass. It is also the location of one of the best-preserved and most extensive woodland pastures and some of the finest trees in the Bluegrass.

Below is a slide show of our course. The photos were taken by Rick Showalter and are used with permission. Thanks Rick and Sallie! Click pictures for a slide show.

flowering dogwood inflorescence

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When is a flower not a flower?

Many trees are full of showy flowers at this time of year. A close look at these flowers can be quite rewarding. Flowering dogwood is one of our most popular flowering trees, but those beautiful white blossoms hide a secret. Take a close look at a dogwood tree and you will see that the showy white “petals” are not actually petals. Instead, these are white bracts that direct the attention of a pollinator – bee or moth – to the center. Now look at the center and you will see a cluster of tiny green flowers.
Each of these tiny green flowers is a “perfect” flower, containing both male and female organs. Pollinators are attracted by the showy bracts, but it is the tiny flower that is pollinated. Soon, you will see a cluster of small fruits developing, though dogwood usually loses all but a few fruits before they ripen.
Trees are huge and easy to look at from a distance, but they also reward a closer look.flowering dogwood inflorescence

Inflorescence of flowering dogwood. The white bracts (not petals) surround a cluster of flowers

Flowering dogwood inflorescence

Flowering dogwood inflorescence. The arrow points to a single flower

Evening trees

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Street Lights and Tree Growth

Urban trees live with all kinds of stresses that their forest cousins do not – road salt, soil compaction, lawn mower strikes. They also live in a different light environment, one in which it is never completely dark.  Spend the night deep in the woods and the only light you will see is from the stars and moon. This is what trees experience – bright light in the day, complete dark at night.  Trees evolved with a regular, predictable transition from day to night. They have developed exquisitely sensitive ways of measuring light so that they know the exact day length. They also measure shadows so they know the distance to other trees.  Pollinators of trees like moths and bats also depend on the dark of the night.
What happens when we suddenly (in evolutionary time) add bright lights to our cities and plant trees? The use of gas lanterns for lighting streets began around 1816 and spread to cities throughout the world. People soon noticed trees doing very strange things near these lights – losing leaves in midsummer, or growing strange branches, or roots growing on stems. Many trees died. Observers soon realized that it wasn’t the light but the illumination gas causing these effects. Dimitry Neljubow, a graduate student in Russia, realized that illumination gas was causing abnormal growth and in 1901 published the discovery that ethylene, a component of illumination gas, was causing abnormal growth. By 1935, scientists had realized that ethylene was a plant hormone, produced by plants in the normal course of growth. Ethylene is what makes bananas ripen and apples rot.
With the advent of electric lighting, the gas problem went away. But light itself has powerful effects on tree growth. Watch the trees on your street and you may notice that trees near street lights sometimes hold their leaves longer on the side facing the light.
There is not enough light in street lighting for photosynthesis. Instead, the effect of street lights on trees can be to change their sense of time. Trees tell time with a molecular clock that is very sensitive to red light and far red (nearly infrared) light. Many processes in trees, such as leaf drop or the formation of buds, depend on the tree’s exquisite sense of day length. Light at night can interrupt this clock. The more red light in a street lamp, the more it will affect a tree’s growth.
The problem with coming up with some general rules about street lights and trees is that there are too many variables. Distance between a light and a tree is most important – light intensity falls off as the fourth power of the distance, so a light four feet from a tree is 0.0001 times as powerful as a light 1 foot away. We are constantly changing the color of street lights. We used to use fluorescent (almost no red), then went to sodium vapor (very red) and now to white LED (very little red).
Overall, I think that street lights do affect the growth of trees but in subtle ways that are hard to observe. An effect on flowering and seed set, which is very likely would not typically be noticed in street trees. I suspect that if we paid closer attention, we would find a wide variety of effects.
There is, perhaps, a more important but indirect effect of street lights on trees, and that is on the nocturnal insects and bats that pollinate trees and on nocturnal mammals that use trees as habitat. For example, street lights enhance the ability of insect predators to find their prey. City trees by moonlight and street light

City trees by moonlight and street light

City trees by moonlight and street light

City trees by moonlight and street light

Woodland pasture, Woodford County

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Great Trees of Jessamine County

 
Jessamine County is one of the fastest-growing counties in Kentucky. A bedroom community for Lexington, it is also increasingly a center for business and manufacturing. In spite of this growth, much of Jessamine County retains its rural flavor. Some of the finest woodland pastures in the Bluegrass can be found in northern Jessamine County.  Locations like the Robinson Farm and Chaumiere des Prairies are home to magnificent ancient trees. Our research has recently shown that some of these sites are probably unchanged for thousands of years. Remarkably, the farmers who settled these locations saw no need to disturb the woodland pastures or the deep, rich soils.
To whet your appetite, here is a gallery of trees from around Jessamine County.  On March 19, Venerable Trees will hold a Field Course in Jessamine County and will reveal, for the first time, some of the remarkable history of the woodland pastures and farms of the county. Please join us.
Scroll down for a gallery of Jessamine County trees.
Jessamine

Jessamine County, Kentucky

Bourbon County-0082-Edit

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Bourbon County Field Course

Saturday, February 27, was a beautiful day to spend with friends old and new exploring the woodland pastures of Bourbon County. We had 23 guests who had lots of great questions and observations.  Special thanks to Jim and Kellye Pikul for their hospitality and enthusiasm. A special thanks to Jim for helping with navigation and path clearing – it is useful to have a Marine along.

The main focus of this Field Course was on conservation and on what we need to do to ensure a future for Bourbon County woodland pastures. The woodlot that we explored showed that the woodland pasture species can regenerate themselves under the right condition. However, without good management the woodland pasture will quickly revert to forest as we saw.  

In addition to learning about conservation of woodland pastures, we had an opportunity to explore many aspects of tree biology. Nancy Barnett starred in the role of the vascular cambium, we had a contest to see who could accurately guess the height of a tree (not as easy as it sounds), and we talked about the life-time of unitary and clonal trees.  One of the highlights was the discovery of a substantial stand of very large sugarberry, Celtis laevigata. 

We hope that the folks who attended the course will become the nucleus of a sustained effort to ensure a future for the woodland pastures of Bourbon County.  We are beginning additional projects in Woodford and Jessamine Counties.  Check our Events page to find out what is coming up.

 

 

 

 

Sugarberry treeBur oak and sheepGoatChinkapin oakChinkapin oakWoodland pastureChinkapin oakYoung woodland pastureWoodland with large bur oakAll-age stand of chinkapin oakBur oak, 72" diameter, with Jim Pikull

Old chinkapin oak

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The Wolf Trees of Nashville

When you hike through the woods in Nashville, you don’t expect to encounter wolves. If you keep your eyes open, though, you may see some wolf trees.

Foresters used the term ‘wolf tree’ to indicate a very large tree with a broad crown and a short main stem.  These trees were considered wolves because they were so large that they devoured sunlight that other trees might need.  These trees were often killed because they had no market value.

Today, we have a changed opinion of these huge trees. They are now understood to be very important as wildlife habitat and also in regenerating a new forest after harvesting or damage. Harvesting rules, especially on state and federal forest land, often require that wolf trees be left in place.

Wolf trees serve another important purpose: they can tell us a lot about the history of a forest. On a recent walk through the Warner Parks of Nashville, I noticed something striking. Throughout these hilly, dense woods were many huge wolf trees. A closer inspection showed that these were species typical of the woodland pasture habitat:  chinkapin oak, Shumard oak, blue ash, and kingnut (I have not yet seen any bur oak).  

Their enormous size and low, spread branches tell us that these trees did not grow up in a forest, but in either an open woodland or woodland pasture.  The level ground surrounding the Warner Parks has a large number of woodland pasture tree species and several intact woodland pastures.  I suspect that this part of Nashville represented a continuum from woodland pastures on level ground to open woodlands and the slopes and denser forest on the upper slope. 

The Warner Parks are about to lose their large population of white ash to emerald ash borer. I made a quick estimate of the stocking (timber density) of white ash in the Warner Parks and estimated it to be more than 20%.  As these trees die over the next few year, conditions may favor the ability of the wolf trees to reproduce.

I look forward to learning more about this beautiful area.

Old chinkapin oak

A magnificent wolf tree – an old chinkapin oak in Warner Parks, Nashville

Old oak tree

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How Old is that Tree?

Everyone wants to know how old a particular tree might be. We will discuss this complicated and important subject in two stories. This month we will talk about unitary trees, and next month we will tackle the complex problem of aging clonal trees.  

A unitary tree is like a person – a single, integrated organism. Unitary trees have one or a few stems on a single root system. The stem is the same age as the root system. Most tree species are unitary, although some, such as oaks, beeches, and red maples, will create a new stem or a few stems when the original one is lost so that the root system is older than the stem.Clonal trees are colonies of many stems, sometimes thousands, on a single root system. The entire clone, including all the stems and the root system, is a single organism.  Over time, some root connections may be lost and the tree no longer functions as a single organism, even though the separated parts are genetically the same as each other.

Clonal trees are colonies of many stems, sometimes thousands, on a single root system. The entire clone, including all the stems and the root system, is a single organism.  Over time, some root connections may be lost and the tree no longer functions as a single organism, even though the separated parts are genetically the same as each other.

As most of us know, trees in temperate climates generally produce a single ring of wood each year, growing fast in the spring, slowing down in the summer and producing a distinct ring.  It should be a simple matter, then, to count the rings and find out the age of the tree. We can do this either by cutting the tree down or by taking an increment core, a narrow cylinder of wood from the bark to the pith at the center of the tree. This is not as simple as it sounds. Obviously, we don’t want to cut down ancient trees unless they are dead or in danger of falling and doing harm.  Increment cores are very labor intensive both to obtain the wood sample and to prepare the sample and count the rings.  Very large trees like our bur oaks are extremely difficult to core.

Determining the age of an old tree by carefully counting and cross-dating the rings using valid methods, followed by publication of the results in a peer-reviewed journal is the gold standard for determining and confirming the age of a tree.  On that basis, the oldest known tree in the world is a bristlecone pine, Pinus longaeva, originally collected by Ed Schulman in the 1950s but only analyzed by Tom Harlan in the past couple of years. This tree, now 5065 years old is still alive and growing well in the White Mountains of California. Understandably, its location is kept secret.  This tree is accepted as the oldest unitary tree known in the world.

In the Bluegrass and Nashville Basin, the majority of our very old trees are hollow.  You can’t count the rings in a hollow tree unless you take a sample above the hollow part, and then you may miss many years of growth. 

In Europe and Asia, the age of very old trees may be known from historical records, such as the date a yew tree was planted in a churchyard, or a sacred bodhi tree was planted at a temple. We rarely have that luxury in North America with its very short written history. A number of trees planted by Thomas Jefferson, William Bartram and other botanists and enthusiasts survive today and we can date them precisely. William Bartram planted a yellowwood (Cladrastis kentukea) at his garden in Philadelphia in 1805. Badly damaged by a wind storm in 2010, the tree recovered and is thriving today at age 210. 

Any other method of determining the age of a tree is very imprecise. The relationship between tree size and age, especially in our open-grown hardwoods, is not a strong one.  Trees growing slowly in poor conditions often outlive trees in better conditions.  

Over time, a number of biologists have developed criteria to assess whether a tree is very old.  Neil Pederson summarized the most important characteristics of very old hardwood trees:  1) balding bark – bark smoother than younger trees of the same species; 2) low stem taper – the main stem is cylindrical, not narrowing with height; 3) sinuous, winding stems and branches; 4) crowns with few, very large and twisting branches; 5) low crown volume relative to the stem diameter; 6) low leaf area to trunk ratio. For the ancient trees of the Bluegrass and Nashville Basin, two additional characteristics are 7) leaves tufted at the ends of branches; and 8) main stem rarely present, with the top of the tree damaged and decayed.  While these sound complicated and difficult to analyze, with a little bit of practice, it is not difficult to separate our oldest trees from younger ones. 

Using these criteria and a knowledge of the terrain and land use history, we can usually sort our trees into categories.  For example, an extremely large bur oak growing at the top of a slope that shows the above characteristics was probably growing before the area was settled. That would make it somewhere in the range of 300-500 years old, possibly older (we have found some older trees but have not yet published the data).  A bur oak of similar size, growing along a creek with good access to water and showing fewer of the old-tree characteristics may be half the age of the one at the top of the hill.

I know this answer frustrates a lot of people anxious to know the age of their favorite trees,  but the plain answer to “how old is my tree?” is usually “I don’t know but I think it is several hundred years old.  Based on the limited scientific evidence that we have, plus some historical data, I am often comfortable saying that our biggest old trees are “probably 300-500 years old, maybe older.”

And as to all the claims of the great age of trees that we see on the Internet, we should treat them with a great deal of skepticism.  That 6,000-year-old baobab?  It might be 1,000 years old.  The Angel Oak said to be 1,500 years old?  More likely to be 400-500 years old. These trees are still very old and deserving of our respect and veneration, and there is really no good reason for people to make such wild claims.  And what about that 9,000-year-old spruce called Old Tjikko, the subject of thousands of Facebook claims and blog posts?  As we will see in our next story on old trees, that claim does not hold up either.

 

Old oak tree

Veteran’s Park Oak in Lexington, a very old unitary tree

National champion smooth sumac, Rhus glabra, Anacardiaceae

National champion smooth sumac, Rhus glabra, Anacardiaceae

Old chinkapin oak

A chinkapin oak that was growing in Lexington before 1779. This is at 14′ off the ground because the base was hollow.

Hollow tree

Hollow trees cannot be aged with accuracy. Hackberry.

Bur oak, 72" diameter, with Jim Pikull

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Young Woodland Pastures

Those who have read my book or heard my presentations know that one of our major concerns about the future of our rare and ancient woodland pastures is the failure of trees to reproduce. With trees succumbing to age, lightning and poor management, the population of ancient trees is declining. While we are constantly on the lookout for young trees, they are quite rare. As anyone can readily see, if death rate > birth rate, the future of our trees is grim.

On January 1, we had the opportunity to explore woodland pastures and a large woodland in Bourbon County, thanks to the hospitality of Jim and Kellye Pikul. We wandered their property and several adjacent properties in search of woodland pasture trees, especially bur, chinkapin, and Shumard oak as well as kingnut and blue ash.

What we found was astonishing and a revelation. All over the area were huge old venerable trees, including a 72″ diameter bur oak. There were exceptionally large bur, chinkapin, and Shumard oaks and blue ash, with a few kingnuts. There were also many immense sugarberry trees (Celtis laevigata).  Sugarberry is primarily a bottomland tree in western Kentucky and the south. It is found on upland limestone sites but has apparently not previously been reported in Bourbon County.

The most astonishing part of our ramble was the very large number of young trees of all the woodland pasture species. This indicates that there is the potential on this site for a self-sustaining woodland pasture.  We found young trees mixed with very large trees in three sites. In the large woodland, most of the younger trees were chinkapin oaks, bur oaks, a few Shumard oaks, many kingnuts and blue ash. These trees ranged from pole-size saplings to mature overstory trees.  The woodland is now choked with honeysuckle and wintercreeper, so it is likely that further natural regeneration will not occur.

There is a huge amount to learn from this site, and it is worthy of close scrutiny. If we can learn why this site is reproducing well, we may be able to facilitate natural regeneration in other woodland pastures. We hope to work with landowners and with interested volunteers to learn more about this site, and to work on improving management, especially of the woodland which is badly in need of thinning and invasive species control.

Followers of our website will hear a lot more about this very exciting site in months to come. We will schedule a Field Course there as soon as possible.

 

 

Sugarberry treeBur oak and sheepGoatChinkapin oakChinkapin oakWoodland pastureChinkapin oakYoung woodland pastureWoodland with large bur oakAll-age stand of chinkapin oakBur oak, 72" diameter, with Jim Pikull

 

Butternut twok

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A Winter Tree Walk at Lower Howard’s Creek – Postponed

Postponed: Due to an injury, we are temporarily unable to offer Field Courses. We will reschedule courses as soon as possible.On Saturday, January 23, from 9am to 1pm,  Venerable Trees and the Lower Howard’s Creek Nature Preserve are offering a winter tree walk at the Preserve in Clark County.  This will be a hike in rough, forested terrain. Participants will

  • Learn to identify common Bluegrass trees in winter – it’s easier than you think;
  • Learn what trees are doing in the winter – it’s a lot more than you think;
  • Learn about the importance of Bluegrass creeks as nurseries for woodland pasture trees.

We hope you can join us. Registration is limited to the first 20 people who register.To cost of the course is $20. Click the Pay Now button and make a payment of $20 per person to help cover our expenses. The payments are made through PayPal, but you do not need a PayPal account. If you prefer not to pay online, please contact us and let us know how you would like to pay.

To cost of the course is $20. Click the Pay Now button and make a payment of $20 per person to help cover our expenses. If you prefer not to pay online, please contact us and let us know how you would like to pay.


Butternut twok

Butternut, Juglans cinerea

Trees on Chandler Farm

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Woodland Pastures of Pisgah

Saturday, December 12, 9am to noon. Chandler Farm, Pisgah Pike, Woodford County.

The Pisgah neighborhood of Woodford County, Kentucky, has some of the finest woodland pastures in existence.  Students in this course will learn to identify venerable tree species; discuss the biology of very old trees, including the role of wood decay; and examine opportunities for natural regeneration and planting of our venerable trees.  The course requires some walking over rough terrain though the total distance will be less than two miles. Adequate shoes, warm clothes and rain gear are necessary.  The course will only be rescheduled or canceled if severe weather is predicted.This course will fill, and registration is required. We will not be able to accommodate people who show up without registration.

To cost of the course is $20 (no charge for children with an adult). Click the Pay Now button and make a payment of $20 per person to help cover our expenses. The payments are made through PayPal, but you do not need a PayPal account. If you prefer not to pay online, please contact us and let us know how you would like to pay.





Elmwood Grove-4377-Edit

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The Conservation Work of Venerable Trees

Venerable Trees, Inc., is focusing our efforts on  five high-priority geographic areas and four high-priority tasks:

  • Woodford County with the greatest extent of original woodland pastures;
  • Bourbon County with several areas where woodland pasture species are regenerating;
  • Jessamine County with woodland pastures threatened by development;
  • Oldham, Jefferson and surrounding counties, with great promise for woodland pasture restoration;
  • The Nashville Basin with great promise for restoration and management of the original woodland pasture habitat.

High-priority tasks:

  • Assessing woodland pastures. The first step in managing a natural resource is to evaluate it. We will begin mapping and measuring trees in woodland pastures.  We will train a cadre of volunteers and interns to locate trees with GPS, measure them and assess their condition.  We will begin in four critical regions of the Bluegrass that have extensive woodland pastures and interested landowners.
  • Developing management plans. We will work with landowners to develop management plans for their woodland pastures that will extend the lifespan.
  • Solving the reproduction problem.  Venerable trees are not reproducing in woodland pastures. Without our intervention, they will disappear in a few years.  We will develop two methods for growing young trees: 1) allowing natural regeneration to take place within protected areas such as tree pens, and 2) establishing small cooperative nurseries and growing trees from locally collected seed.
  • Preserving ancient trees in urban landscapes. We will work with volunteers to map, identify and assess ancient trees on public urban land, and work with homeowners to do the same for trees on private property. We will then develop management plans and carry them out, including protecting park trees from lightnin

Elmwood Grove-4377-Edit

Clark County Wood Pastures

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Woodland Pastures of Clark County

Clark County Kentucky is in the Inner and Outer Bluegrass (map). The Outer Bluegrass farms are on steeper hills than in the Inner Bluegrass and are primarily cattle farms. There are extensive and thriving woodland pastures on many of these farms. However, there is little natural reproduction of the ancient trees. The woodland pastures of Clark County will disappear without strong conservation efforts.  We plan to begin mapping and assessing the woodland pastures of Clark County with the cooperation of landowners.

We are planning a winter field course in the woodland pastures of Clark County and the wonderful nature preserve at Lower Howard Creek. The course will include an introduction to winter tree identification.  We will announce the winter schedule in the next couple of days.  In the meantime, enjoy these photos of southern Clark County.

Venable Farm Wood Pastures-9776-EditClark County Wood Pastures

Persimmons

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How to make beer in 1779

Imagine that you are a settler in the Bluegrass in 1779, the year Lexington was established.  There is no shortage of game, and wild plants. But what do you do if you want a good beer? West Sixth Brewing was not open yet, so what was the thirsty settler to do?  You could make your own, but you would have to use ingredients collected from the meadows and forests.

For nearly 100 years, the most popular beer was made from two abundant fruits – persimmon and honeylocust. Ripe persimmons are sweet and flavorful. Honeylocust fruits (legumes or pods) are packed with a sweet, sticky gum. The gum provided sugar and acted as a thickening agent, and provided some flavor.  Although locally made beer became available in the early 19th century, the tradition of making persimmon beer continued until the Great Depression.

The recipe for persimmon beer, as it was called, was very crude by modern brewing standards.  Technically, the brew was more similar to metheglin, or flavored mead, where the honeylocust gum substituted for honey.

Here is a recipe from Virginia. It was passed down for many generations and published in The Fruit-Grower in 1908:

Get a clean, tight barrel, and place within it a false head four inches from the bottom. Add a pone of bread made of wheat bran and baked very brown; it takes this bread a long time to cook and it is added to give a good color to the beer. Next put in a small armful of honeylocust shucks (legumes) then put in the persimmons in greater quantity than the locusts, and continue in this way until the barrel is two-thirds or three-fourths full. Weight down and add water until all is covered. In three days, or perhaps a week if the weather is very cold, it will be a sparkling drink that will bite the tongue. A few dried apples or peaches will add to the flavor.

Another recipe from 1872 is similar but uses a layer of straw, then persimmon, then honeylocust along with dried apples and wheat bran.

A third recipe calls for baking loaves of persimmons and wheat bran, then breaking the bread into a clean barrel and adding water and either molasses or honeylocust.

It would be interesting to try to make this brew using modern, hygienic methods. We have the key ingredients: persimmon and honeylocust are common in the Bluegrass.

Note: There are many recipes for persimmon beer dating back to the late 1700s, but most are variations on these.

Sources: The Fruit-Grower, 1908; Hill, A. P. 1872. Mrs. Hill’s Southern Practical Cookery and Receipt Book. Univ of South Carolina Press.Persimmons

Persimmon fruits ripening on a cool autumn day.

Honeylocust fruit

Honeylocust fruit

The Fruit-Grower, February 1908

The Fruit-Grower, February 1908

Bur oak leaves

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A Deep Green Autumn

A deep green autumn is rare in Kentucky. By this time of year, our trees usually look forlorn and bedraggled. Dry summers, high temperatures, insects and diseases all take their toll.  Not in 2015, though. Our frequent rainfall and cool temperatures have allowed many trees to maintain lush green leaves and to continue growing. Some trees are still producing new shoot growth.  

Leaves are a bit like tissue paper, designed for use for only a short time and then discarded. From the time a leaf is formed, a tree invests a limited amount of resources into maintaining it.  Shade, drought, insects and fungi all take their toll, so by August, a lot of trees look pretty sad and pale. This is especially true in the Bluegrass and Nashville Basin, where our karst topography leads to water stress even in modest droughts. 

The last three years (2013-2015) have been different.  Tree growth has extended well into the fall. Today, the first day of meteorological autumn, sees many trees still growing, and leaves of some trees staying dark green.

2015 is even more exceptional. I have rarely seen trees still growing in September, but some of our bur oaks, even some very old trees, are still producing new flushes of growth.

See what the trees in your neighborhood are doing.

 

Bur oak leaves

Bur oak leaves in August

Eastern redbud leaves

Eastern redbud leaves, Cercis canadensis

The Old Schoolhouse Oak

The Old Schoolhouse Oak in August 2015

September flush of growth in bur oak

September flush of growth in bur oak

Quercus sumatrana in Sumatra

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How many trees species?

When I worked in Borneo, I was fascinated by the immense diversity of trees in the jungles where I worked, even though I could only identify a few species. I did not even know how many different trees I was seeing. They look so much alike, with some exceptions, that I could walk by a rare, unrecognized tree without knowing it.  And that raises the question that has long puzzled biologists: how many kinds of trees are there?

We know that in North America there are about 1,000 tree species, and similar numbers in temperate Asia. Europe has a more limited tree flora, with 250-500 species.  The number of tropical trees has never been known with any accuracy.

Now, a worldwide study lead by Prof. Ferry Slik of Universiti Brunei Durussalam, along with 170 colleagues from all over the world, has come up with the most accurate estimate to date, and it is quite astonishing.  The problem is that most tropical species are rare, and easily missed in species counts. Instead of analyzing species lists or herbarium specimens, the researchers analyzed a database of over 200 intensively studied forest plots worldwide.

Their conclusion is that there are 40,000-53,000 species of tropical forest trees in the world. This is much higher than any previous estimate or calculation, which typically miss rare trees.

This number, and the high frequency of rare trees, has important implications for conservation. If we are to prevent extinction of large numbers of tropical tree species as the world warms up, we need to change our conservation approach. Instead of focusing on conservation of individual species, as is commonly done with wildlife species, tree species conservation will only succeed if we can set aside very large areas of tropical forest. This could allow rare species to maintain self-sustaining populations. Climate change may result in the loss of large amounts of tropical moist forest, and this will inevitably cause extinction of many rare tree species. Addressing climate change and tropical forest conservation are critical if we are to avoid the loss of a large percentage of tropical tree species.Similar principles can apply to temperate forests. Conservation of large tracts of forest land could help prevent the loss of species as the world warms.

Quercus sumatrana in Sumatra

Quercus sumatrana in Sumatra

Tropical forests of West Kalimantan

Tropical forests of West Kalimantan in 1983.

Second flush of growth in Kentucky coffeetree, Gymnocladus dioicus

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The Great Flush of 2015

Have you seen the Great Flush of 2015?  In Central Kentucky,  trees are growing very fast right now, producing new growth that is noticeable for its pale green or yellow colors.  Late flushes are complicated responses to changes in soil moisture. This is the first of several stories about the Great Flush of 2015, but also about weather patterns and, perhaps, about climate change.

What is a flush?  Think of a bud as a package of tiny leaves waiting for spring. The leaves were made late last year.  As the weather warms in spring, the little package begins to open and out come the leaves, quickly growing to capture sunlight.  As the stem grows, the distance between leaves increases. Soon, growth ends for the year. It is surprising that, in most trees, shoot growth ends by June, long before the growing season ends. A new bud sets and the leaves for next year begin to develop.  Here are couple of examples in kingnut and American beech.

Beech bud
A beech bud opening in spring
Soil Moisture Map
Change in soil moisture from June 30 to July 22 2015. Source: NOAA Climate Prediction Center

This is not the only style of shoot growth. Some fast-growing trees like yellow-poplar continue producing and growing new leaves throughout the summer until shortening days or drought bring an end to their growth.

But what happens in a year like 2015?  We are having an exceptionally wet July, setting records in many counties throughout Kentucky and adjacent states.  We are usually in mild to moderate drought at this time of the year, but right now soil is exceptionally moist.  That means that growing conditions for trees are excellent.

How do trees respond?  Instead of waiting out the year and growing again next spring, many trees produce a new flush of growth. Suddenly, it looks like spring again.  We don’t know exactly how this works, and why some trees like dogwood ignore the high moisture and snooze until spring.

For oaks, hackberries and many other trees, the Great Flush of 2015 is easy to see. The pale color of the second flush contrasts with the deep green of the first flush. Some people see these colors as an early sign of autumn, but the opposite is true: it’s a sign of a renewed spring.

The amount of growth can be astonishing.  Here is a bur oak produced a moderate first flush but an huge second flush:

Bur oak stem
Bur oak with two flushes of growth. The spring flush, between the white arrows, was 2.5 inches (6.4 cm) while the second flush (yellow arrows) is 12 inches (30.5 cm)

Why are the second flush leaves so pale? Here are two pictures that provide a simple explanation: On the left is a bur oak, on the right is a black locust. Both are continuing to produce new leaves but the locust leaves are dark green. Black locust is a nitrogen-fixing tree species, continually producing nitrogen in root nodules. The bur oak depends on nitrogen from the soil and can’t make its own. In the spring, the soil contains lots of nitrogen from decay over the winter. The tree also contains a lot of nitrogen stored in the form of protein, which it uses to make new leaves in spring. By mid-summer, both the internal reserves of nitrogen and soil nitrogen are depleted. So, the new leaves don’t have enough nitrogen to make an adequate supply of nitrogen.

Bur oak and black locust leaves
Bur oak (left) and black locust in the same soil on the same day.

In the next part of the story, we’ll talk about the trees that don’t quite growth so early. In the third part, we will talk about the weather and climate factors that great great flushes.

Scenes from the Great Flush of 2015

July flush in bur oak
July flush in bur oak with typical pale foliage
Growth flush on a bur oak
Growth flush across the whole crown of a bur oak
Hackberry trees
A stand of hackberry trees with a pale late flush.
July flush of hackberry with very pale foliage.
July flush of hackberry with very pale foliage.
Growth flush on American elm
Late flush of American elm
Kentucky coffeetree with a second flush of growth
Kentucky coffeetree with a second flush of growth
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