Beetles kill Beatle's memorial tree

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The George Harrison Memorial Tree in Los Angeles, planted in memory of the Beatles guitarist, was killed by beetles.

Interactive map of the world's tree loss

Global Forest Watch maintains a current map of worldwide tree loss and gain, based upon satellite and other mapping imagery provided by Google. The "loss" color seems to obscure the "gain" color at further-out zoom levels, but it's very easy to explore. [via Flowing Data]

Beautiful photo: Tree "oasis" in a farmer's field

A lovely entry in Smithsonian's ongoing 2013 Photo Contest, Emma Stephenson's "Perfect Tree in a Farmer's Field" photographed in the North Yorkshire countryside, England.

Turntable that "plays" the rings of a tree

Bartholomäus Traubeck's "Years" is a modified record player that "plays" a slice of a tree, converting (and transforming) year ring data into piano music.

It is mapped to a scale which is again defined by the overall appearance of the wood (ranging from dark to light and from strong texture to light texture). The foundation for the music is certainly found in the defined ruleset of programming and hardware setup, but the data acquired from every tree interprets this ruleset very differently.

"Years" (Thanks, Syd Garon!)

The oldest living tree tells all


"In 1964, a geologist in the Nevada wilderness discovered the oldest living thing on earth, after he killed it." A terrific opening sentence to Hunter Oatman-Stanford's story in Collector's Weekly about bristlecone pine trees, which can live for thousands of years.

By the time of Currey’s survey, trees were typically dated using core samples taken with a hollow threaded bore screwed into a tree’s trunk. No larger than a soda straw, these cores then received surface preparations in a lab to make them easier to read under a microscope. While taking core samples from the Prometheus tree, which Currey labeled WPN-114, his boring bit snapped in the bristlecone’s dense wood. After requesting assistance from the Forest Service, a team was sent to fell the tree using chainsaws. Only days later, when Currey individually counted each of the tree’s rings, did he realize the gravity of his act.
(Image: Inyo Bristlecone Signature Tree, a Creative Commons Attribution (2.0) image from usfsregion5's photostream)

Why do trees fall over in a storm?

The more accurate version of this question would really be something like, "Why do some trees fall over in a storm while others stay standing?" The answer is more complex than a simple distinction between old, rotted, and weak vs. young, healthy, and strong. Instead, writes Mary Knudson at Scientific American blogs, trees fall because of their size, their species, and even the history of the human communities around them.

“Trees most at risk are those whose environment has recently changed (say in the last 5 – 10 years),” Smith says. When trees that were living in the midst of a forest lose the protection of a rim of trees and become stand-alones in new housing lots or become the edge trees of the forest, they are made more vulnerable to strong weather elements such as wind.

They also lose the physical protection of surrounding trees that had kept them from bending very far and breaking. Land clearing may wound a tree’s trunk or roots, “providing an opportunity for infection by wood decay fungi. Decay usually proceeds slowly, but can be significant 5-10 years after basal or root injury.” What humans do to the ground around trees — compacting soil, changing gradation and drainage “can kill roots and increase infection,” Smith warns.

Read the full piece at Scientific American Blogs

Image: West Philly Storm - Trees Down, a Creative Commons Attribution (2.0) image from kwbridge's photostream

The life and death of a 125-year-old tree (video)

Standing, and Falling, two short films by Casimir Nozkowski about the life and death of a big, beautiful, very old tree.

Attack of the zombie maples

Last month, I spent several days in Harvard Forest, 3500 acres of woods dedicated to scientific research. The forest is home to dozens of research projects, some short-term, others stretching over decades.

Read the rest

What's your diameter breast height?

Scientists measure trees for a wide variety of reasons. When I visited the Harvard Forest last week, I measured them as part of studying carbon sequestration by plants. But you can't just go out into the woods with any old tape measure and expect to collect some significant data.

That's because where you measure the tree matters. If you want to compare the diameters of two trees, you have to make sure you're measuring them in the same place. If you measured one tree at the wide base and the other further up the trunk, where trees usually get narrower, the comparison wouldn't mean much.

That's where diameter breast height (DBH) comes in. It's a way of standardizing the measuring process.

As the name implies, DBH is meant to be a diameter measurement of a tree trunk taken at, roughly, breast height on an adult. Of course, where exactly "adult breast height" is varies greatly from person to person. So DBH has been set to a standard height—1.4 meters in the United States.

In a research forest, you'll often see some kind of marker on the trees showing where this official "breast hight" is, so people can quickly move through the woods, taking diameter measurements, without having to measure vertically on each tree. In some cases, DBH is marked with yellow spray paint. In others, metal bands. These metal bands actually help measure diameter, too. Set with springs, the bands expand as the tree does, so all researchers have to is measure the distance between two dots on the band and see how far apart the dots have moved since last time.

Read all the Dispatches from Harvard Forest

Climbing a rickety stair to the top of the forest

Seventy-one feet above the Harvard Forest, you can stand on a plywood platform attached to a slightly swaying tower of metal scaffolding, and look out over miles of hemlock groves. On the ground, the trees are massive—trunks reaching up and up and up. From the top of the tower, though, the view feels a bit like hanging out in a Christmas Tree farm. All you see are the friendly, conical tops.

The Hemlock Eddy Flux Tower is one of four research towers in the Harvard Forest. Since 2001, data collection systems on the top of this tower have measured carbon dioxide, water vapor, and wind currents. These measurements are made five times every second.

Thanks to this system, we now know that even a relatively old forest like this can still capture and store a decent amount of carbon dioxide. The hemlocks around the tower are pushing 230. That's not terribly old by tree standards, but it's old for this part of North America—most of which was once clear cut. It's also old enough to challenge some previously held conventional wisdom about what kinds of forests are best for carbon sequestration. Previously, scientists thought only young forests, where the trees were still growing rapidly, did that job very well. Sites like the Hemlock Tower have shown a different story.

Also: It's rather terrifying to climb. The tower lives, it is not stationary. A network of steel cables keep it from toppling over, but you can still feel it tilting one way and then the other underneath you. And, at every landing on the stairs, there's a precarious little gap you have to step over. I took my camera with me in one hand as I made the ascent. About partway up, the filming quality takes a notable turn for the worse as I found myself clinging a bit more tightly to the hand rails. How's that for an awesome tool of science?

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