When Trees Become Lethal

Hurricane Sandy has shown us it's not just old and dying trees that we should worry about

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Tracy A. Woodward / The Washington Post / Getty Images

A tree felled by Sandy in Alexandria, Va., Tuesday, October 30th, 2012

And then they kill us. A large number of fatalities from Hurricane Sandy were caused by falling trees—two teenage boys in North Salem, NY; a man killed in Pearl River, his family injured; a young couple walking their dog in Brooklyn.

We all know we’re supposed to be careful about old and dying trees, but somehow there’s nothing worse than paying a large bill to remove a maple on its last legs. With Sandy creating winds up to 90 MPH, many of the trees that fell weren’t old; all over the tri-state area, young trees have snapped in two, or dropped large limbs. So like this storm itself, whatever we thought we knew about trees and how to protect ourselves may in fact be changing.

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The biggest problems are twofold: healthcare for trees, and planting viability.

People tend not to prune, feed, and stay on top of tree health. Trees can be expensive to maintain, but it is critical that they be cared for. Rot begins to spread, and once it is working its way unseen through a trunk or a limb, trouble can hit by surprise. People also hire pruners who are cheap but who don’t know what they are doing, and bad pruning jobs, with limbs lopped off midway, contribute to bad tree health.

And then there’s the places we plant them. As a rule, in this day and age, large trees shouldn’t be hanging over a house, unless you don’t mind living dangerously. Trees near a house are okay, so long as they have lots of space for their roots. But all too often we’re squeezing trees into lousy spaces, especially trees on the strips next to sidewalks in cities and towns alike, or the trees growing out of rocky outcroppings, whose roots are compromised.

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What usually makes these trees vulnerable is poor drainage. The ground gets very wet, water doesn’t drain properly because there’s nowhere for it to go, and then the trees lose their footing, so to speak. Up and over they go. Tree roots are surprisingly shallow. If you go look closely at an overturned tree, you’ll be amazed at how little root system there is for such a big creature. Especially if the roots have been constricted by substructure concrete for roadbeds. Trees need to spread their roots to be more stable.

Stick with trees that are suitable for the area you live in; trees that aren’t hardy in freezing temperatures may look okay for a couple of winters, but their growth will be compromised and you’re asking for trouble down the line. And even though we all love instant gratification, you are better off choosing a smaller tree and letting it establish itself over time into its patch of earth rather than trying to plant a large tree whose roots might not take hold for a while. Don’t stake your trees for too long; trees need to sway in the wind and make other adjustments to weather conditions — it actually helps their root systems grow more stable.

We need to learn how to better live with our trees and move away from our simplistic understanding of them. Yes, trees are pretty and useful but they’re also a responsibility that too often people shirk. We’re well aware that cars can be dangerous and take safety precautions not to drive recklessly or in risky conditions. We have to show similar respect to these giant, powerful beings around us. They do so much for us. Let’s do more for them.

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I know we're all shell-shocked from the storm.  I am - I still have no power at my house, where at least a dozen large trees fell, and an old friend was hit in the face by a branch and died.  But it still amazes me that so few people can look at the sheer magnitude of downed trees - dead people, crushed cars and houses, and lost power - and not ask WTF??  New Jersey where I live looks like the ecopocalypse has arrived.  This is far out of the range of normal - and it's not being explained by the media, or the "experts".

Sandy's monumental surge is no doubt a result of climate change, and has caused epic misery. However, the flooded coast cannot explain the extent of lost power inland.

What is being ignored in this storm (and Irene) is the real source of power loss - trees on the power lines. They didn't used to fall with regularity on people, cars and houses. The winds in both those storms were nothing that a healthy tree shouldn't withstand.

Why are they falling now?

Just look at them! Every species, of every age, in every location is dying. Symptoms are broken branches, cankers, splitting lichen-covered bark, holes, thin crowns, early leaf drop, lost autumn color, yellowed needles.  Note - none of this can be explained by age.  Most trees are genetically suited to live for centuries, some well over a thousand years.  They are dying prematurely.

Foresters have documented tree decline globally but blame climate change drought and/or invasives - which doesn't fit the empirical evidence. Native pests, disease and fungus have also run amuck, while young trees watered in nurseries exhibit identical signs.

Most people don't realize that the invisible background level of tropospheric ozone is increasing. Ozone precursors travel across oceans and continents, and the persistent concentration, more than double the pre-industrial amount, has now passed a threshold that vegetation can tolerate.  The USDA has on their own website that ozone causes significant reduction in annual agricultural yield and quality - what must it do to trees that suffer cumulative exposure season after season?

Scientists know ozone debilitates plants, shrinking roots and rendering them vulnerable to drought and wind...AND impinges on their natural immunity to attack from pathogens.  This has been demonstrated in field surveys and controlled fumigation experiments for decades, by many academic institutions and government agencies around the world.

And yet we choose to ignore this existential threat because it derives from our current unsustainable consumption and population.

Most of the trees that fell were rotted.  Just wait for the next storm - many more are just waiting to topple.   Photos and links to research: http://witsendnj.blogspot.com


I used to live in the Sierras in California.  Not only did we clear large trees next to our homes, but PG&E, power corp., cleared trees in close proximity to power lines.  One year, to save money, PG&E didn't and power lines went down throughout the area. In the dead of winter, we had no power for a week., that included no water as well. They learned.  We need to learn from history and past experiences, not emotions.


Where I live in southwestern Michigan, I have called our city over and over and over asking for the removal of or at least the pruning of a huge Norway ("junk") Maple on the city curblawn overhanging my house. They never do anything about it because it's apparently too much trouble and too expensive for them.And, it's a non-issue since it's still appears healthy and they don't want to do anything they don't have to do. I cannot do anything about it because I don't have the money for it and furthermore it's illegal for me to do anything to a tree in our city's curblawn. These junk trees are notorious in the midwest for dropping limbs, upheaving sidewalks, and general interior decay. Now that they've reached their peak after being planted as ornamentals 60-80 years ago, they are going to come down en masse during the powerful storms near the Lake Michigan corridor.



Maybe we should do the same as the Brazilians and cut as many trees as possible, or prune and top them until they look like some distorted vegetable monster...

The  path to hell is made with good intentions. This seems to be one example: to scare people as much as you can about the "dangers" of trees and in no time our cities will be  like deserts.


As I have walked around NYC most of the trees I've seen that have fallen bear signs of disease or rot inside. The problem is that years of rising surface ozone concentrations are toxic to plant life. Notice that usually in the autumn leaves of deciduous trees turn bright colors, then fall to the ground; this fall the leaves are turning brown while still on the trees.  Everywhere I see spotting and curling and signs of disease. Unfortunately, with our focus on the human effects of climate change, we are not paying attention to the death that is taking place all around us--and imperiling human life from another angle.   I'm not the only one to have noticed this; see http://witsendnj.blogspot.com/2012/11/what-happened-to-power.html.


Very good point about these trees being poor choices.

Why not use coniferous trees? Their roots grow vertically, rather than horizontally. This would mean that not only would they hold better in storms, they would be less likely to tear up sidewalks.