Contemplating trees and allergy season

I have a terrible tree pollen allergy so I was amused to see that Olivia Judson picked the tree for her Life-form of the month for April.

Trees figure in our mythologies and metaphors — the tree of life, the tree of knowledge — and we often imagine them to harbor spirits and sprites. They also figure in a big way in our reality: forests (still) cover about 30 percent of the planet’s land, and may make up as much as 80 percent of Earth’s biomass. That is, if you were to put all the organisms on the planet on a giant set of scales, trees would account for 80 percent of the total.

Better yet, trees harbor plenty of non-imaginary beings. Birds like starlings or blue tits nest in tree holes; others, like magpies and crows, build their nests high in the branches. Chimpanzees sleep in trees. A number of fungi — truffles, anyone? — associate with tree roots. Insects like wasps make houses (galls) in the leaves. And so on.

Until last November, we had a huge Norway maple tree which covered the entire front of the house and reached to the 4th floor.  Over a hundred years old, it as beginning to learn away from the house and over the street.  It was also rotting from an old wound.  It had to come down.  I was wondering if taking it down would lessen my allergies, but so far it doesn’t seem to have made a difference.

Olivia Judson again

Yet although trees are familiar to all of us, many aspects of their biology remain enigmatic: because they grow slowly and live for so long, they’ve been hard for us to study in the laboratory. Which is why they are my nomination for Life-form of the Month: April.

What, then, is a tree? Precise definitions vary, but most of them mention the words “tall” and “woody,” and add that a tree has a single self-supporting stem (i.e., a trunk) that branches well above the ground.

The first trees appeared more than 375 million years ago, in several different plant lineages, in a burst of evolution that some authors have termed “the scramble for the sky.” If you’d been walking through the Earth’s early forests, you might have seen club mosses that were 40 meters (131 feet) tall, as well as giant horsetails. Both types of tree are now extinct. But what’s interesting about them is that they made wood differently from, say, pine trees. Pine trees grow outwards, forming a solid woody cylinder. In contrast, the trunks of tree-horsetails were hollow tubes, like bamboo. Tree-club mosses produced trunks with a hard outer casing, and a softer interior. Meanwhile, tree-ferns evolved a fourth type of woody structure: they grow several stems that are bound together by other tissues.

However you define a tree, they are beautiful, provide shelter, and are a renewable resource if harvested carefully.  I find looking at them restful – even if they make me miserable for a couple of months a year.

Two Birthdays

Two hundred years ago on February 12, two extraordinary men were born.  One on the American frontier and the other in England.  Besides their day of birth, what do Abraham Lincoln and Charles Darwin have in common?  Quite a bit it seems. 

Both men were family men who loved and cared for their childen.  Olivia Judson writes about Darwin

At the same time, he was a humane, gentle, decent man, a loving husband and father, and a loyal friend. Judging by his letters, he was also sometimes quite funny. He was, in other words, one of those rare beings, as likeable as he was impressive.

For example, after his marriage, Darwin worked at home, and his children (of the 10 he fathered, seven survived to adulthood) remembered playing in his study. Later, one of his sons recounted how, after an argument, his father came up to his room, sat on his bed, and apologized for losing his temper. And although often painted as a recluse, Darwin served as a local magistrate, meting out justice in his dining room.

Darwin is best known for the theory of evolution while Lincoln is known for his own political evolution.  Again, Judson on Darwin

The “Origin,” of course, is what he is best known for. This volume, colossal in scope yet minutely detailed, laid the foundations of modern biology. Here, Darwin presented extensive and compelling evidence that all living beings — including humans — have evolved from a common ancestor, and that natural selection is the chief force driving evolutionary change.

Eric Foner writes this about Lincoln in The Nation

Until well into the Civil War, Lincoln was not an advocate of immediate abolition. But he was well aware of the abolitionists’ significance in creating public sentiment hostile to slavery. Every schoolboy, Lincoln noted in 1858, recognized the names of William Wilberforce and Granville Sharpe, leaders of the earlier struggle to outlaw the Atlantic slave trade, “but who can now name a single man who labored to retard it?” On issue after issue–abolition in the nation’s capital, wartime emancipation, enlisting black soldiers, amending the Constitution to abolish slavery, allowing some blacks to vote–Lincoln came to occupy positions the abolitionists had first staked out. The destruction of slavery during the war offers an example, as relevant today as in Lincoln’s time, of how the combination of an engaged social movement and an enlightened leader can produce progressive social change.

Finally, both Darwin and Lincoln opposed slavery.  First, Judson on Darwin

Moreover, while many of his contemporaries approved of slavery, Darwin did not. He came from a family of ardent abolitionists, and he was revolted by what he saw in slave countries: “Near Rio de Janeiro I lived opposite to an old lady, who kept screws to crush the fingers of her female slaves. I have stayed in a house where a young household mulatto, daily and hourly, was reviled, beaten and persecuted enough to break the spirit of the lowest animal …. It makes one’s blood boil, yet heart tremble, to think that we Englishmen and our American descendants, with their boastful cry of liberty, have been and are so guilty.”

And Lincoln, while not initally supporting immediate abolition did oppose slavery

“I have always hated slavery,” Lincoln once declared, “I think as much as any abolitionist.” He spoke of slavery as a “monstrous injustice,” a cancer that threatened the lifeblood of the American nation.

So let’s wish them both a very happy birthday!