Rachel Ehrenberg: What Makes A Tree?→

Knowable Magazine:

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“If one is pressed to describe what makes a tree a tree, long life is right up there with wood and height. While many plants have a predictably limited life span (what scientists call “programmed senescence”), trees don’t, and many persist for centuries. In fact, that trait — indefinite growth — could be science’s tidiest demarcation of treeness, even more than woodiness. Yet it’s only helpful to a point. We think we know what trees are, but they slip through the fingers when we try to define them.

Trees don’t cluster into one clear group: They emerge in multiple lineages and have adopted multiple strategies to become what they are. Take longevity. A classic example of the Methuselah-ness of trees is the current record-holder, a 5,067-year-old great bristlecone pine that grows high in the White Mountains of California. (That tree was almost 500 years old when the first pyramids were built in Egypt.) Scientists speculate that the hardy bristlecones owe their endurance largely to location: They avoid fires that sweep through lower elevations and pests that can’t stomach the harsh terrain of the subalpine zone. The giant sequoias, a short way down the mountains from the bristlecones, take an entirely different longevity tack. These beasts — their trunks can be more than 30 feet across — live thousands of years, fighting fire and pestilence with thick, resistant bark and plentiful in-house repellent compounds.

Some 400 miles to the east, a spindly wisp of a tree has both the bristlecones and the sequoias beat when it comes to lifespan — through another strategy altogether. The quaking aspen (Populus tremuloides) — a tree you can wrap your arms around that rarely grows taller than 50 feet — excels at sending up new shoots from its base. This results in giant stands of “trees” that are, in fact, one genetic individual connected beneath the ground. A Utah colony of quaking aspen is estimated to be 80,000 years old. Neanderthals were around back then.”

Speaking of Neanderthals, what makes a human?

Human-Assisted Migration→

Greg Breining, writing for Ensia:

iStockphoto.com/jimkruger

“During the last two springs, contract planters for The Nature Conservancy have spread out through the pine, spruce and aspen forest of northeastern Minnesota. Wielding steel hoedads, they have planted almost 110,000 tree seedlings on public land.

What’s noteworthy about planting trees in a forest? Usually foresters plant seedlings grown from seeds harvested nearby, on the assumption that local genotypes are best suited to local conditions. But these TNC workers were planting red and bur oak (which are uncommon in northern Minnesota) from seed sources more than 200 miles to the southwest, and white pine from as far away as the Lower Peninsula of Michigan, 400 miles to the southeast.

TNC is anticipating a day soon — within the lifespan of a tree — when a changing climate may make the forest unsuitable for some tree species and varieties that now live there. Projections for northeastern Minnesota predict warmer and possibly drier conditions — bad news for the boreal species such as white spruce, balsam fir and paper birch that have defined the forest here for centuries. But a warmer, drier climate would likely make the area better suited for species such as oaks.”

Helping trees move with change, patience you must have my young padawan.

The Health Benefit of Trees→

James Hamblin, writing for The Atlantic:

“It is becoming increasingly clear that trees help people live longer, healthier, happier lives—to the tune of $6.8 billion in averted health costs annually in the U.S., according to research published this week. And we’re only beginning to understand the nature and magnitude of their tree-benevolence.

In the current journal Environmental Pollution, forester Dave Nowak and colleagues found that trees prevented 850 human deaths and 670,000 cases of acute respiratory symptoms in 2010 alone. That was related to 17 tonnes of air pollution removed by trees and forests, which physically intercept particulate matter and absorb gasses through their leaves.

In terms of impacts on human health, trees in urban areas are substantially more important than rural trees due to their proximity to people,” the researchers wrote. “The greatest monetary values are derived in areas with the greatest population density.””

Mr. Moment - Flicker

 For our own health we need more wildness in the urban areas. You will know when you are calm, at peace.

Ancient City Trees→

Andy Sturdevant, writing for MinnPost:

“There are dozens of trees listed in the Minneapolis Park Board’s registry of heritage trees, notable for size, age or cultural importance. Of all of these, there are at least two trees that are both older than anyone who has ever called themselves a Minneapolitan. The first is the remains of the Ancient Oak in Seward, which died in 2010 after approximately 333 years. The second is the Rockwood Oak in Theodore Wirth Park in North Minneapolis. It is at least 314 years old, meaning it first sprouted sometime around the turn of the 18th century. It nearly died a year after the Ancient Oak succumbed to age, in the North Minneapolis tornado, but it still lives.”

Flickr - Wendy

When three hundred years old you reach, look as good, you will not.