December Wisdom from the Trees 2013

Tree of the Month

Eastern White Pine • Pinus strobus

Another favorite for use as a Christmas tree

by Lesley Bruce Smith

ISA Certified Arborist


Eastern White Pine by Lesley Bruce SmithPines, in general, are a favorite tree to use for Christmas trees and Eastern White Pine, in particular, is one of our favorite species of Pine to plant for ornamental purposes in the Chicago area.  It was also depicted as a symbol on the first Revolutionary War flag and thousands of 200 foot tall Eastern White Pines were felled and used as ship masts for the British Navy.  To the indignation of the American colonists, the crown claimed the tallest trees and any settler caught using them might have all his land confiscated.  However, it should be noted that no pine species is actually native to the northeast corner of Illinois.  All the pine species capture our imagination and so we plant with abandon.  Recognizing that pines are out of their comfort zone, however, helps us to understand that we need to treat them with a bit more care and tender loving.  Eastern White Pines are no exception to this rule.  They need to be planted out of the clay soil in northeastern Illinois, up high, in a well mulched organic soil environment where they respond best to being permitted to self mulching of their needles and cones.  They are tough only when they live in well drained environments.

I love many traits of the Eastern White Pine including it’s lovely soft needles and gentle yet potentially towering presence in the landscape.  Hands down my favorite attribute of the Eastern Whites is the lovely sound that the wind makes through its branches.  We purposely planted them outside our bedroom windows to help lull us to sleep.  


Pines have a wonderful history of being a living pharmacopoeia. Pines in their native habitats exist in some of the most extreme conditions on the globe, including drought, heat and elevation.  Similar to other medicinal herbs, the naturally stressed, super tough survivors will have a greater medicinal value, possibly due to the higher levels of isomers and anti-oxidants produced by them.  Pines are the source for many essential oils and the use of the Pine knot goes back to the Romans who used them as torches that they knew had both antiseptic and antibiotic properties while burning.  The Cayuga peoples used the Pine knots in the treatment of tuberculosis, creating a tincture from carefully selected knots and utilizing the antibiotic, pinosylvin carried within the pith tissue.

Probably the most popular use for Pines is in the treatment of respiratory ailments.  They release terpenes which have expectorant, antitussive and anti-inflammatory properties. It has been suggested by some that every hospital should have a Pine grove on its grounds where the healing properties of these magnificent plants could be fully utilized.1

1Arboretum America,  Diana Beresford-Kroeger, copyright 2003

What Does Maple Syrup and Anti-freeze Have in Common? OR

Why don’t trees freeze in the winter?

Backyard Wisdom by Gilbert A Smith 

ISA Certified Master Arborist


This is not an easy question to answer because though it has been studied a great deal, plant scientists still don’t completely understand the mechanisms that allow trees to survive in the cold.  When trees go dormant they don’t really stop growing.  They continue to function including photosynthesis, (yes, even without their leaves) they just slow way down. Living plant cells never stop creating sugars, using energy, building, transporting, and protecting their system.  Most of the cell is water. When water freezes it crystalizes and expands and would rupture the cell walls, killing them.  Still, trees in the Boreal Forests can survive in temperatures as low as -76℉.


Winter Oak Tree by Lesley Bruce SmithThe vast majority of cells in trees are dead.  Yes, that’s right!  The “inside” of temperate climate trees, the xylem, consists of dead cells penetrated with a few living cells, called ray cells, which use this dead heartwood for storage, structure and transport.  The only 100% living cells are in the cambium, a thin layer just a few cells thick, just beneath the bark.

 The tree protects itself against freezing by:

  1.  Closing down the “breathing tubes”  stomates and lenticils in the needles and stems.
  2.  Sending water into the already dead xylem structure where it can’t do any damage.
  3. The living cells partially dehydrate, sending some of their water into the areas between the cells.
  4. Life still needs some water to keep living. When they dehydrate, those extremely smart tree cells have increased their concentration of sugars, and like antifreeze, those sugars lower the freezing point of the H2O.
  5. The final protection that the trees utilize is impossible for scientists to replicate because they kill the living cells. So when it freezes outside this thick cellular soup does not crystalize or expand so the living cell wall is not damaged, thus saving the tree.  

Frost Crack on Maple Tree by Lesley Bruce SmithTrees are amazing survivors!  If the temperature swings rapidly between hot and cold as it does in late or early frosts, tree cells rupture and can die, killing all or part of the tree.  An example of this which we see in forests and in landscapes is frost cracks.  Usually on the south side of the tree the winter sun heats thin barked trees, like Maples, during the day.  When the temperature plummets at night the bark splits and remains a weak spot that opens up every winter.  

We can’t manage the weather but here are some things we can do to mitigate freeze damage.

  1. Keep needles and leaves below tree and shrub branches as these  are natural insulators.  
  2.  Plant freeze sensitive plants, like Magnolias, Japanese Maples, Rhododendrons on the North side of structures so they are not “heated up” by the southern or western sun in the winter and then super cooled at night.
  3. Keep evergreens further away from the house and drives, especially near glass or on South and West exposures.  Again, the building or drive heats and or reflects the solar radiation in the winter causing the plants to heat up and lose their cold hardiness.

Think of your trees on a cold winter day, because your trees always appreciate your thoughts, and know that your trees are prepared for the freezing cold weather.

December Reprise

Mother Nature's Moment

by Lesley Bruce Smith ISA Certified Arborist


Douglas Fir by Lesley Bruce SmithBecause Gil’s article on Trees and Freezing and my tree of the month article on Eastern White Pines are both a bit long winded  (we try to hold these posts to brief informative articles) I am going to just reference the helpful information from last year’s Mother Nature’s Moment December entries for those of you that wish to read more.

Just a reminder that using a real, cut Christmas tree is in fact an environmentally sound thing to do.  Christmas trees are a totally renewable resource and the trees harvested each year end are replaced 3 fold with young saplings in the spring.  Click here to see article from December 2012 Newsletter, Wisdom from the Trees dedicated to live/cut Christmas trees.


Poinsettia by Lesley Bruce SmithWilt-Pruf is a non-toxic spray on anti-desiccant, and a great way to preserve the cut greenery, including your Christmas trees, from early dry out while they are inside or out, decorating our homes.  It is available at Pasquesi’s and Chalet Garden Centers.

Click here to read the article on Poinsetta’s and learn that they really are not poisonous as so often is thought.  It is also available in the December 2012 Newsletter in Wisdom from the Trees.

Don't forget to take advantage of the marvelous holiday exhibitions at both the Chicago Botanic Garden and the Morton Arboretum.  It is a great way to enjoy the winter weather and the wonder of the season. 

December - Wisdom from the Trees

Tree of the Month - Christmas Tree
Balsam Fir - Abies balsamea

Is it an environmentally sound thing
to buy a real Christmas tree?

The answer is an emphatic YES!  

Balsam Fir (Abies balsamea) by Lesley Bruce SmithChristmas trees are a totally renewable resource, and the trees harvested each year end are replaced 3 fold with young saplings in the spring.  Christmas trees are grown on farms in the USA that are dedicated for that purpose and employ over 100,000 people here.  Christmas tree farms are providing oxygen, reducing soil erosion, creating habitat for wildlife and sequestering carbon.  The farmers that grow Christmas trees usually also grow blueberries or other fruit crops keeping jobs at home. Three of our closest neighbors are among the top Christmas tree producing states in the nation: Wisconsin, Indiana and Michigan.  We have been producing Christmas trees commercially in the USA since the mid 1800‘s.  Artificial trees are manufactured overseas.

If keeping a fresh cut tree in the house, the best way to help it from drying out is to put it into a cooler room.  We put ours on our porch where the temps stay a bit cooler than the rest of the house, also making clean-up a breeze.  When you bring your tree home cut about a 1/4” off the bottom to open the cells that take up water.  Then use a tree stand that has a reservoir of at least 1.5 gallons.  A freshly cut, averaged sized tree can use up to a gallon of water each day.  Also turn the lights out when you are not home, for safety and to help prevent drying out.

 If you still aren’t convinced that a fresh tree is a good idea because you hate the idea of cutting down a tree, you can do what we have done many times.  Buy an actual live tree  from a garden center, in a root ball or pot and plant it outside when you have finished with it.  This is a great way to commemorate a baby’s first Christmas or some other special family event. To do this you need to do a little planning ahead.  We usually dig a hole before the ground freezes (which this year is now).  You can’t keep it inside for more than a few days and you need to keep it protected, if you didn’t dig a hole ahead, until the ground is thawed enough to plant.  Otherwise it will dry out.  (Request our planting abstract for more details on this.)

One last positive thing about buying a fresh Christmas tree is that the Real Christmas Tree industry donates many thousands of trees to our troops and their families each year.  Nothing beats the smell of a Frazier or Balsam Fir tree in the house at Christmas time.

Read more at:

Winter Silhouettes

Backyard Wisdom by Gilbert A Smith
ISA Certified Master Arborist

Oak Silhouettes by Gilbert A SmithMy almost favorite tree is the native Downey Hawthorn (Crataegus mollis).  Not because of it’s leaves, flowers, or fruit and certainly not because of it’s thorns;  I love it because of it’s shapely winter silhouette.

Without leaves you can see that it has sinuous bark which resembles torturously twisted rope or muscles taught to the breaking.  The limbs stretch out horizontally so far from the trunk you’d think they would certainly crack.  Then they cascade almost to the ground and curve back upward again.  However,  you can only see this properly in the winter.  One of my favorite Downeys is on Deerfield Road, the North side just West of Highway 94/41.  All summer this little tree is just a 20 foot, nondescript, green tree. But in the winter she is a stand out specimen especially if snow outlines those graceful, swooping branches.  

So it is with my most favorite tree, the Illinois native Burr Oak (Quercus macrocarpa).  The huge branches are impossibly horizontal making highways in the sky for squirrels and other tree climbers.  Burr Oak branches are favored roosts for Hawks, Owls, and Raccoons to sit and contemplate their next meal.  Again, you can’t really see their true character until the winter.  

This winter, as you drive any of the east-west corridor roads, (Route 60, Route 22, Lake Cook Rd, Dundee, Lake Ave.) through Hawthorne Silhouette by Gilbert A Smiththe forest preserves flanking the DesPlaines River, take a look at the tree silhouettes.  You will see my friends, the Burr Oak, White and Red Oaks, Sugar Maples, and Elms each with a new face.  Each has its own signature silhouette that sets it apart from all other species.  When you do, you may find that it’s as if you’d never seen them before.  After the drama of the striking fall color the winter is a good time to slow down, and to let the trees introduce themselves to you.  

If you would like a friendly introduction, plan a day with your friends, and Lesley and I can take you on a brisk walk through Elawa Farm in Lake Forest, Ryerson Woods in Riverwoods, Fort Sheridan in Highland Park, The Chicago Botanic Garden or The Morton Arboretum.  Call, and let’s make a date.

Poinsettia’s - Facts and Fiction

Mother Nature's Moment by Lesley Bruce Smith
ISA Certified Arborist

Poinsettia's by Lesley Bruce SmithWe sometimes get asked:  Aren’t Poinsettias (Euphorbia pulcherrima) poisonous plants?  The answer is not really.  Both the websites for child and animal toxicity on plants state that if these plants are digested they may cause some intestinal discomfort and the milky white sap they exude could cause some irritation to the skin, BUT they are not lethal!  

I think they get a bad rap because of their name’s similarity to the word poison, however, they are named after Joel Roberts Poinsett who was the botanist, physician, and first US ambassador to Mexico that introduced this plant to our country in 1828.  The only time I have ever seen them growing in the landscape in the US was Hawaii, but I know they grow in many southern regions of the country.  They originate from Central America and are best known there as "La Flor de la Nochebuena" or the flower of the Holy Night.

What we traditionally see in red on the Poinsettia, which is confused as a flower, is actually the leafy part of the plant or bracts.  These plants turn color in the winter months of the year due to day length exposure.  As a matter of fact, when we were in university a situation in a greenhouse filled with Poinsettias shed light on how sensitive the day length requirements are.  A security guard would stop on his rounds in the same place every night and light up a cigarette.  That brief flash of light prevented the plants in that area of the greenhouse from turning red.

The Aztecs used the Poinsettia’s bracts to make a reddish purple dye for fabrics, and used the sap medicinally to control fevers.  The Poinsettas are one of the best selling potted plants in America and most are sold within the six weeks before Christmas.  December 12 is Poinsettia Day marking the death of Dr. Poinsett in 1851.