The Life Expectancy of a Tree

I can go out into my backyard and put my hands on a big post oak tree that's been growing in that same spot since before I was born. Then I can step over about 40 feet, and lean against a pine that is perhaps half that old, though the two trees are the same height. In the best possible world, my oak tree will be around for a hundred years, and can be expected to outlive its neighbor by a quarter of a century.


Long-lived eastern red cedar.

But just across the fence stands an eastern red cedar—a wildly invasive pest that has taken over millions of acres of  grasslands in the Southern Plains, and is choking out vast areas of native deciduous woods. Hypothetically, that cedar could outlive both the post oak and the pine by a good 700 years.

Obviously, when it comes to trees, there doesn't always seem to be a lot of justice in the age distribution of different species.

So how do the trees in your own landscape measure up? Have you ever even thought about how long you can expect your valuable anchor plants to continue to fulfill their important roles? Perhaps you should. Because a  desirable long-lived specimen might be well worth the cost of restoration if it is damaged by an extreme-weather event, while a short-lived tree might warrant removal and replacement (preferably, with a long-lived species).

The ubiquitous Bradford pear is a classic example of a remove-and-replace tree, should it become seriously damaged or simply begin to "age out." The life span of a Bradford pear is 15 to 25 years—and the last five years are apt to look sad indeed as its lollipop shape tends to open out and spread. So...the first five years are devoted to establishing itself and taking shape, followed by a maximum of 15 years in good-looking prime time (if a severe-weather event doesn't substantially shorten that period—a distinct possibility), ending by at least five years of decline.


Short-lived Bradford pears.

If it seems that I spend a lot of time dissing Bradford pears, well, I certainly do. To that, I could add the river birch, despite the fact that the species' "Heritage" cultivar was named 2002 Tree of the Year by the Society of Municipal Arborists. In 2007, I saw many, many river birches destroyed by an ice storm in my community. Five years later, many more remain out there in landscapes, their severely damaged crowns still sporting visible signs of damage.

In this age of increasingly extreme weather, planting a tree that can't "take the heat" (or ice or wind or flood or whatever your region dishes out) makes about as much sense as packing a bikini on an expedition to the South Pole. A little forethought can save you from a lot of grief.

Every part of the country has its rogue's gallery of tree species that are vulnerable to the specific forms of extreme weather common to those areas. Some trees just don't have the structural habit or strength to stand up to the assaults that landscapes across the country are being subjected to these days.

So what does a tree's life expectancy mean to you and your landscape?

First of all, keep in mind that a long-lived species won't necessarily live out its full life span if  it is planted outside its desired growing conditions. And that means more than just its hardiness zone. You also need to take into consideration a species' soil and moisture preferences, as well as what extreme-weather conditions it can tolerate.

Over the ages, a tree species that is native to your area has evolved an ability to withstand most of the types of extreme weather likely to strike you landscape. (Tornadoes and powerful hurricanes are an exception— they have the capacity to uproot even long-lived native trees.) If these native species hadn't developed their weather-specific strengths, they could never had continued to survive and evolve the capacity to live very long lives.

So when I plant trees, I shoot for species that have a "normal" life expectancy of at least 75 to 100 years. These include oaks, maples and ginkgoes. Yes, these trees will outlive me. But I also know they will grace the places where I've lived for generations after I'm gone—a concept that I rather fancy.

Long-lived oak.

The benefits can be striking.

When the ice storm of 2007 struck, my heavily-treed neighborhood was hit particularly hard. Debris-removal trucks trundled up and down the streets week after week, hauling away shattered tree branches and trunks. The roar of stump grinders made pesky leaf blowers sound like wind chimes. But over on the next block, the sturdy oak shown at the right stood unscathed. The tree is probably about 40 years old now, and Nature-built for our heavy-duty weather extremes. With proper care, this tree should live on for generations longer.

You can learn the life-expectancy of your own trees—or that of a tree you think you might like to plant—by googling the species and "lifespan." For an overview of several dozen species, check out this site.

Then, before you buy another tree, pick up the phone and talk with your local cooperative extension agent or municipal forester (if you community has the latter) to find out if your chosen species is suitable for the growing conditions and extreme-weather events common to your location. (Besides longevity, you'll be wanting to know if your soil, drainage, hardiness zone, and other factors are compatible with your choice.

And don't be shy. It's perfectly okay to go out and hug your trees.

BLOG EXTRA! When Autumn Leaves...Pack With Snow

Wow. Just...wow. Right when you're all set to enjoy the colorful fall foliage, along comes a freaky autumn snowstorm of deep-winter proportions.

Of course, the results are predictable. Leaves hold onto snow, adding tremendous weight to tree branches that would otherwise shrug off the frozen stuff. The sound of breaking limbs reverberates through neighborhoods, accompanied by cold darkness as shattered tree parts bring down power lines. At last count, something like 3 million households and businesses have been left without power.

Clearly, Halloween has delivered all Trick and no Treat.

My agent, Gina Panettieri, reports from Connecticut that she has a tree in her swimming pool, and no one in the area has gas or hot water.

Courtesy Alexandra Owens

In New Jersey, American Society of Journalists and Authors Executive Editor Alexandra Owens has trees down all over her neighborhood, including in her own front yard where her Callery pear split down the middle. (The species is notorious for buckling under stress.)

There isn't much you can do to save large, leafy trees from damage when a storm dumps not just inches, but feet of wet, sticky snow. If you've taken preventive measures by pruning trees to create stronger branching habits, whether your tree then comes through unscathed will depend on how much of a weight lifter it's become.

Some tree species just naturally have branch angles better able to carry greater weights. Others—such as Alexandra's pear—don't.

But there is something you can do to help shrubs. Wade out in the snow with a broom and start brushing off the frozen stuff, beginning at the bottom and working your way up. Don't bat at it—just brush and lightly jiggle the branches. If the weight has already warped the shrub, it will often resume its proper shape over the next few days if branches haven't been broken.

Once power has returned to the area, the daunging job of cleanup begins...

This posting will be updated as other photos and stories arrive. And do leave comments on what the storm has done to your area!




Since You Asked...Nancy Hugo About "Seeing Trees"

I've loved a lot of trees in my lifetime. Truth be told, I've even hugged a few...and not just metaphorically. But it took nature writer and lecturer Nancy Hugo and photographer Robert Llewellyn, to teach me how to really see the trees that are such an important part of the scenery of our lives.

Courtesy Nancy Hugo/Robert Llewellyn

With their book, Seeing Trees: Discover the Extraordinary Secrets of Everyday Trees [Timber Press, 2011], Nancy and Bob have given the world something very special, indeed.

Rather than dealing with the gorgeous, perfect specimens shown in most books about trees, the 245 pages of this volume are devoted to the ordinary. Once you've soaked up the contents of Seeing Trees (I found it to be a real page-turning), you can walk right out into your own backyard and see your perhaps-imperfect trees with a depth of appreciation that you might not have thought possible.

And the photos...I am not exaggerating when I say they will take your breath away. (You can find out how Bob Llewellyn produced these amazing pictures by viewing the video on the book's Amazon site. Believe me, it's well worth a couple of minutes of your time.)

So I'm delighted to have an opportunity to chat with Nancy Hugo about Seeing Trees.


Photo by Robert Llewellyn

Q. Nancy, when did your fascination with trees begin?

A. As a child, I helped my mother plant trees. My favorite was a Deodar cedar, and I swore I was going to name my first child Deodora. (I didn't; my daughter's name is Kate!) I remember walking through pine forests (grown for lumber, I now know) and being struck by their symmetry, and reading Longfellow and loving references to things like "the murmuring pines and the hemlocks." I won $10 in a Keep Virginia Clean contest when I was 10 (for a forest picture I did in pastels), and that, no doubt, launched my tree watching career!

All gardeners (and I am an avid gardener) come around to loving trees best eventually, because they are the biggest and best plants. I see them as symbols of perseverance—strength in adversity—slow, inexorable growth. I love comparing my small, puny, short-lived self to their large, strong, long-lived selves. And of course, trees have been around about 397 million years longer than people, so there is enormous wisdom in their biological adaptations.


Courtesy Robert Llewellyn

Q. Clearly, Seeing Trees was a challenging book to write and photograph. How long did it take you and Bob to put it together?

A. We worked about two years on Seeing Trees, but some of what we learned doing Remarkable Trees of Virginia [University of Virginia Press, 2009] also seeped into this book. The interesting thing is that, as Bob observes, he and I experienced no fewer "wow" moments in our two years of viewing our backyard trees up close (and traveling nowhere) than we did from viewing Virginia's most remarkable trees (and traveling almost 20,000 miles over four years)!

Q. This book is a terrific teaching tool. But it must have been a tremendous learning process for you, as well. What surprised you during the research?

A. Too much to tell! I guess my two favorite moments were when I saw the pollination droplets on the ginkgo ovules (in my windowsill), and when I heard American beech bud scales falling in my woodland. The sound of the latter is almost imperceptible, but it's real and will now, forever, be something I listen for in spring.

I enjoy doing research, and have lots of experts I call with questions. But I also enjoyed, over and over, hearing even experts say (about some of the things Bob and I were observing): "Well, you know, I've never seen that myself!" And these weren't unusual things, they were things that happen every year, like the "birth" of a red cedar cone. There is just so much that goes on outside our awareness.


Courtesy Robert Llewellyn

Q. You have magnificently revealed the extraordinary in ordinary trees. (I love the way you refer to a tree "behind the Burger King.") How has this book changed the way you see trees?

A. For one thing (and this is more a result of Remarkable Trees than Seeing Trees), I am forever looking for places where a 600-year-old tree can grow. Or a 200-year-old tree for that matter. There are just such few places you can trust to remain undisturbed for centuries. Cemeteries and some college campuses are good.

Also, once you see the kinds of things Bob and I discovered in Seeing Trees, you'll never not see them again (I love that double negative!). Once you've seen, say, the spear-like resting buds of the beech or the spur shoots of the ginkgo, you don't forget them. They are now part of your natural universe and just another way of connecting with nature.

[NOTE: Here is another brief video of Nancy Hugo, with more information on her website.]

Blowing In The Wind

This past week or so, wind has been tough on trees. First, a mile-and-a-half-high sandstorm turned day to night in West Texas. Then high winds hammered the Upper Midwest at the same time a tornado plowed through Florida.


Whatever form of extreme-wind event you experience, the trees in your landscape are at risk, as many of you have no doubt discovered. Wind speeds of around 40mph can snap off twigs. Tack on another 10mph, and weak limbs can come down. Once winds reach 60mph—such as Chicago experienced this week—entire trees can be uprooted.

National Oceanic & Atmospheric Administration/
Department of Commerce


And those velocities don't hold a candle to tornadic winds that, at their worst, can rip a full-grown tree out of the ground and carry it away. Less powerful tornadoes often strip limbs, leaving particularly ragged torque injuries.

During the past 18 months, several heavy-duty tornadoes have torn through this area. And just last spring, we experienced 60 to 90 mph straight-line winds from a storm downburst. Under those conditions, there isn't much you can do to protect trees. In fact, there isn't anything you can do except pick up the pieces and make repairs in the aftermath.

But those repairs—or lack of them—can make the difference between life and death for a tree. So can getting the right repairs.

Several years ago, a major storm left one of the most beautiful oaks in our community severely damaged. While other property owners trimmed away broken limbs from their trees, often bringing in certified arborists to make sure the job was done properly, this poor tree stood draped in broken, dead branches, like a car-crash victim cast off to the side of the road.

Year after year went by, during which the tree received no post-disaster care at all. None. Zero. Its many wounds remained open, providing ready access for any pest or disease that came along. I ground my teeth every time I drove past.

In the meantime, trees that had been properly pruned following the storm were able to devote all their energies to callusing over their neatly trimmed wounds and recovering from the shock they had suffered. These specimens are now well on their way to regaining much of their past glory.

Then, in the middle of last summer's record-breaking heatwave and drought, a tree-trimmer struck.

I didn't see it happen, but I know the so-called "expert" in question was no certified arborist. Why? Because he topped the oak, sawing back all the major limbs, leaving them with blunt ends. As if that weren't bad enough, he even removed every last lateral branch, so the drought-stressed tree had to use all its depleted energy to produce leaf-bearing sprouts just to stay alive. And it had to do this not in spring, but in mid-summer.

Undoubtedly, in his own eyes, the inept tree trimmer was making the damaged oak tidy—and it is, if a dying  tree does it for you. The sprigs of growth that the tree managed to put out along its stumped-back limbs make me think of that  neglected car-crash victim, gasping his last breaths. Unfortunately, the once noble oak's injuries have now gone from survivable to mortal. I no longer grind my teeth when I drive past. How I feel about this "deadly pruning" goes well beyond that.

I'll be glad when the tree's struggles are finally over and it's been taken down. Because, really, that grand old oak that has stood there for generations is just too painful to look at now.

What I'm getting at is this: If you've had horrific weather—wind, ice, snow, whatever—and need help with your trees, call someone who won't leave you worse off than you started. To find a qualified arborist in your area, go toThe Tree Care Industry Association (TCIA).

With Respect to Rotten Trees

Millions of you have seen it in the movie, or read about it in Harper Lee's book: the big old tree in To Kill a Mockingbird, where reclusive "Boo" Radley left presents for Scout in a hole in the trunk.

While I'm a strong proponent of growing the healthiest trees possible, there can be magic in the imperfections of old trees. Besides providing hidey-holes for stashing treasures, hollow trees are prime nesting sites for woodpeckers and many other species of birds, as well as squirrels and other small mammals.

In my own backyard, a single hole in the trunk of an old post oak alternately housed squirrels in winter, and titmice and chickadees in summer. So tree hollows are definitely important habitat for wildlife, whether in urban or rural settings.

At least one rotten tree I knew went well beyond nesting-site status. It was merely a six-foot, one-sided snag of cambium layer and bark, with a single short, gnarly branch. For more than thirty years, this remnant of a once large specimen produced enormous blackjack oak leaves—proof that trees really do want to live, given half a chance. (Sadly, the snag was finally clipped by a truck and toppled.)

I admit, I do have a soft spot for needy plants. But there is a limit...and that limit comes up hard against safety. A hollow tree that might fall on a neighbor's property, or otherwise threaten property or lives, is a serious candidate for removal. And if a tree is downright ramshackle, with major dead and dying limbs that make an arborist shake his head, then it needs to come down. (I recently spotted one tree in my community with a hollow that went all the way through the trunk at the base—large enough for a small child to crawl through.)

[Note: for information on the legal liabilities involved with ramshackle trees, refer to the book, Weatherproofing Your Landscape: A Homeowner's Guide to Protecting and Rescuing Your Plants.]

Of course, a hollow tree that you've chosen to keep as long as possible needs extra care and attention. An annual inspection by a certified arborist will help assure that your tree isn't infested, diseased or unstable. While he's at it, the arborist can prune away weak limbs and keep the tree as sturdy as possible. Even so, I certainly wouldn't park my favorite birdbath—much less, my vehicle—beneath the limbs of a hollow tree, especially when bad weather threatens.

All that said, a hollow but still-stable tree is both a treasure and a delicate balancing act—in a way, a fitting symbol of our own life condition. In an age where perfection is the ideal, I rather fancy the idea of celebrating imperfection. And so, apparently, does Nature.

These days, I can stand at my door from spring through early summer and watch birds that are in a family way come and go from a hollow tree in my front yard. So far, the old oak tree remains robust—last spring, it withstood 60 to 90 mph winds without losing so much as a twig.

Of course, with their protective shield of bark compromised, such trees are always vulnerable to invasive organisms and other maladies that can bring them crashing down. But if the old post-oak snag was any indication, this tree could be around for a long, long time.

Since You Asked...Pablo Solomon

Record-setting dry conditions continue to take an ever-growing toll on landscape trees and shrubs in large parts of the nation this year. So this week, we're having a chat with widely recognized artist and environmental designer Pablo Solomon, who lives in one of the most drought-stricken areas of the country. He has been a prominent figure in the environmental movement since the 1960s.

Break out your copy of Weatherproofing Your Landscape: A Homeowner's Guide to Protecting and Rescuing Your Plants, and you will find Pablo's striking photo of his "tumped tree"—with his wife, Bev—on page 5.

Courtesy Pablo Solomon

Q. Pablo, water has become an urgent global issue. But how much responsibility can and should we as individuals take in conserving water literally in our own backyards?

A. I am a big believer that everything of value starts with the individual taking responsibility for whatever he/she has some control over.

As a well-known artist and ecologist, I travel a lot. I find it annoying when people want these big plans instituted, while doing nothing on a personal level.

So if you want to save the planet, save your backyard, and then move on to bigger challenges.

Q. As outspoken as ever, I see. So what do you think is the most important tool for landscape owners who want to conserve water?

A. The most important tool is actually your mind. You must first want to conserve water. Then you must apply your time, energy and creativity toward that goal.

Q. Do water catchment systems, for example, have to be sophisticated or pricey to be effective?

Courtesy Pablo Solomon

A. The photo at the left shows a very simple water collection system—basically a garbage can collecting runoff from my 1856 long tobacco barn, which I use as a bad-weather workshop.

I also have an 8,000-gallon concrete storage tank which is at the other end of the cost spectrum.

And I put plastic dish-washing tubs in my hand sinks and showers to collect any water I can.

Gray water use can be as simple as using bath water for plants or to flush a toilet occasionally. I run a flexible drain hose out to plants from my washing machine (use biodegradable detergents). Some new and retro-fixed homes have more elaborate gray water separation systems. Just do what you can afford and feel comfortable doing.

[Note: For more rules-of-the-road for using gray water, break out Weatherproofing Your Landscape again.]

It really is a state of mind: if you want to save water and it is part of your value system, you will find ways to do it. If every one in America saved just one gallon of water a day, that would supply a city of one million for five days.

Q. How have you addressed the issue of excessive water usage by your plants themselves?

Courtesy Pablo Solomon

A. I live in the beautiful Texas Hill Country, where drought is recurring. Over the eons, the native plants here have developed remarkable tolerance to crazy, extreme weather conditions.

So we use native plants: cacti, mesquite, live oak, western juniper, wild flowers, wild grasses, wild shrubs, etc.

I love to shape plants—it's like doing giant bonsai trees. I studied Japanese flower arranging to understand Zen concepts of balance and harmony—the principles are the same whether doing a miniature tree or a complete landscape.

A. As an environmental designer, what does your crystal ball tell you about water conservation systems becoming standard equipment in new residential and commercial construction?

Q. Amazingly, my crystal ball readings have been somewhat accurate over the years. Unfortunately, the most accurate readings have been the most negative. People continue to waste water...continue to use drinking water to flush toilets...continue to plant Hawaiian gardens in Phoenix.

However, I think that separation of usable gray water from sewage water; rainwater collection systems; runoff retention systems; etc., will be standard features very soon. I am encouraged by how many commercial developments are doing very creative things in water collection, conservation and retention. As we improve desalinization methods, they will become standard for beach houses, resorts, seaside towns, etc.

Honoring The Old Ones

In the world of trees, this past year has been a giant-killer. In Amsterdam, the iconic chestnut tree that young Anne Frank gazed out upon from her attic window during World War II was toppled by a storm. Hurricane Irene brought down a 220-year-old tree that had stood over John F. Kennedy's gravesite  for almost half a century. Even "movie" trees took a hit, as the grand old oak that was seen in a closing scene of the film, Shawshank Redemption, was split in half by yet another storm.

Each year, tens of thousands of people travel great distances to visit historical trees. These Old Ones can hold special meaning to people who might not otherwise consider themselves to be sentimental. And if you stop to think about it, that stands to reason.

The tree that stood over JFK's grave, for instance, was a young sapling when George Washington and our other founding fathers were old men. It had grown to maturity by the time the country was nearly torn apart by the Civil War and the Virginia estate where it stood became Arlington National Cemetery. As the 20th Century rolled through war after war, the tree added 100 more rings as thousands of soldiers and sailors and marines and airmen arrived at their final resting places.

And then, as suddenly as a lightning bolt, the tree was gone.


The Survivor Tree
Oklahoma City National Memorial

Many Old Ones, such as Anne Frank's much beloved chestnut, fall to extreme-weather events because they were already in failing health. Still others get a new lease on life with well-deserved special care—the Survivor Tree at the Oklahoma City National Memorial is an example.

Defoliated, broken, and badly charred by the bombing of the Alfred P. Murrah Federal Building in 1995, the century-old American elm has been lovingly nurtured back to robust health by a team of dedicated state foresters. Today, the Survivor Tree casts a giant shadow, both physically and in a spiritual sense. When I first stood beneath its broad boughs, I couldn't help but feel humbled by this grand symbol of quiet endurance and strength.

Whether they are in the public domain or grow in your own landscape, Old Ones have earned the right to special care. The big oak in my back yard has been carefully manicured by a certified arborist. When its roots were damaged a few years ago, it received additional treatment that could keep it thriving despite last summer's deadly heatwave and drought.

As a property owner, I have become the designated steward of my Old One's life. It is a responsibility that I don't take lightly.

Do you know of an Old One in your community...or your own backyard? I would love to hear about it.