Few species of trees have been celebrated and revered throughout history by humanity as much as the species of Quercus, the Oak Trees. Jewish, Greek, Celtic, Baltic, Slavic, Nordic, and many other ancient people, all held a very sacred notion related to this gorgeous tree. Till this very day, Oaks are commonly found depicted in many national and regional emblems and symbols of various sorts; while they are designated as the official national tree of many European countries and the Unites States as well.
This prestige the Oaks have been enjoying among human societies has mainly resulted from the subtle uses humans managed to make out of its various parts, most notably its wood. When strength and endurance are in question, few trees’ wood can rival the rocklike-hardness of the one of Oaks; which has been used since time immemorial in edifition, shipbuilding, and manufacture of diverse instruments. Apart from “heavy” usage, humans have also found a more delicate use for Oakwood in coopering; wines and spirits are commonly stored in barrels made of Oakwood, so to extract their unique flavor from it; while whiskey, in particular, in order to be legally called “whiskey”, must have been aged for a minimum of three years in an Oakwood barrel. Another part of the tree which has been used excessively by humans is its galls. These, mixed with water, iron sulfate, and gum arabic, were used for centuries in the making of iron gall ink: the ink in which -from the first post-Christian years and up to the 19th century- the greatest bulk of western thought has been impressed.
Another reason -which is not related to their immediate convenience- that prompted humans to venerate this tree in such a degree must have been its imposing structure and its symbolic, unique ability to overcome hardships and survive throughout the centuries, in a seemingly miraculous manner. The age of “miracles” having, however, by now, well receded in favor of the age of “understanding”, humans are today much better able than any time before to investigate and comprehend the mechanisms underlying this tree’s remarkable surviving ability…
I recently bumped into an amazing documentary film, directed by British entomologist George McGavin; in which, comprehension of Oak Trees is taken a long way further than it had ever been before. What those guys did: they chose a prosperous, 400-year-old, 19-meter-tall Oak somewhere in the English countryside and, by means of the most sophisticated technologies of our era, they studied it throughout an entire year.
The experiment started in late August, when they surrounded the tree with cameras to film it the whole year round. They also used a special device which, by shooting over 2 billion pulses of laser to the tree, created an incredibly accurate, virtual model of it. By examining the model, they estimated the tree had a whole 700,000 of leaves on it! And now, it was just about to discard them all…
Autumn is coming. The tree knows that by sensing (through sensitive to red light photoreceptive pigments called Phytochromes) the diminishing amount of sunlight reaching its leaves; it’s time to start preparing for the upcoming harsh winter. It first absorbs every useful nutriment contained in its leaves (thus the leaves turning red), and then it gets rid of them altogether. Meanwhile, all its cells release the most of the water contained in them (basically, deliberately dehydrating themselves!), so avoiding freezing down and being permanently damaged.
Having so, in a kind of a lethargic state, made it unscathed through the winter, spring is once again coming… time to wake up!
In order to produce new leaves and keep growing, our Oak is going to need enormous amounts of water and minerals. All these, it will, of course, obtain from the ground, through its vastly intricate root system. The scientists behind the film tied some special device around the tree’s trunk, which was able to measure the exact volume of water conveyed through it. As the spring was progressing, and more and more leaves were sprouting out of the tree’s branches, the water supply of the tree kept increasing steadily until it reached a peak of nearly 70 liters of water in one hour; and a total of 58,822 liters during the 71 days the measurement lasted!
For the sake of examining the tree’s roots, they chose another, young Oak Tree and excavated its entire root system perfectly intact. They managed to do that by first cutting a 1,5 m deep trench around the tree, and then meticulously digging the whole thing out by hand; a laborious task which took ten people two weeks to complete. Even though it was only a very young tree, its roots were comprised by a miles-long network. And that was only as far as it concerns the visible parts of the roots; the actual ingestion is done by immense networks of microscopic fungi attached to the tree’s roots, thin enough to even penetrate rock, called Mycorrhizae; of which the overall length could easily suffice to embrace the whole globe!
Still in springtime, besides the Oak Trees, a vast array of other living things are in search of resources to grow and propagate themselves; and a great many of them happen to call “food” the Oak itself. The Oak, surely not wishing to be eaten, had to develop an ingenious defensive mechanism in order to cope with its aspiring devourers. As an enemy raid begins, the first leaves to be attacked will identify which particular kind of pest is attacking by recognizing the characteristic kinds of chemicals emitted by each one of them possible invaders. They will then communicate the information to every other part of the tree and the Oak forest as a whole {quite sociable trees!} by releasing chemical signs in the air. The trees can then produce the appropriate poison and exterminate the invader.
By the end of the experiment year, it was found that the tree had, in its ca four-hundredth year, added a whole 230 kg of new wood to its volume; and had exhaled 234,000 liters of oxygen (enough to sustain a human for a year). This is the instance when the “may you live a thousand years!” wish is sincere and perfectly realistic!
