Can you hold your breath for say ten minutes? I doubt if you can. We can go without food or and water for maybe 5-6 0r 7 days but without oxygen we can die in only 5 or so minutes.
According to the The Book of Health, A medical Encyclopedia for Everyone,
our respiratory system has to take in oxygen and eliminate carbon dioxide. Inhaled oxygen enters our lungs and reaches the alveoli. Oxygen passes quickly through the air-blood barrier and into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.
Then the oxygenated blood travels from the lungs through the pulmonary veins and into the left side of the heart, which pumps the blood to the rest of the body . Oxygen-deficient, carbon dioxide-rich blood returns to the right side of the heart through two large veins, the superior vena cava and the inferior vena cava. Then the blood is pumped through the pulmonary artery to the lungs, where it picks up oxygen and releases carbon dioxide.
To support the oxygenenation of a human body and release of carbon dioxide, we need about 5 to 8 liters (about 1.3 to 2.1 gallons) of oxygen per minute to be brought in and out of our lungs, and about three tenths of a liter (about three tenths of a quart) of oxygen is transferred from the alveoli to the blood each minute, even when the person is at rest. At the same time, a similar volume of carbon dioxide moves from the blood to the alveoli and is exhaled.
During exercise, it is possible to breathe in and out more than 100 liters (about 26 gallons) of oxygen per minute and extract 3 liters (a little less than 1 gallon) of oxygen from this air per minute. The rate at which oxygen is used by the body is one measure of the rate of energy expended by the body.
So where do we all get the oxygen to enable us to live? From malls, buildings, roads and plastic pipes? Hell no. We get 97 percent of our oxygen from trees and plants and the remaining 3 percent from phytoplanktons in the ocean.
And in the 67 square km Baguio city, we get most of our oxygen from pine trees so called Benguet or Cordillerean pine (Pinus insularis/Pinus kesiya), the dominant tree species in the region.
In short the pine trees are the lungs of the city. One large pine tree aged ten years and above can supply a day’s supply of oxygen for four people in the city. Qne mature pine tree releases aboutr 45 lbs of oxygen each year.
But more than this, the pine trees clean our already dirty air of smog—mostly composed of dangerous greenhouse gasses carbon di and monooxide, sulphur oxide and methane. Pine trees absorb these potentially harmful gasses from the air and release oxygen. One mature pine tree sequesters 45 lbs of CO2 each year and up to one ton of CO2 by the time it is 40 years old.
Trees take up a variety of other air pollutants, including both ozone and nitrogen oxides, which reduces the ambient concentrations that we breathe. In the atmosphere, nitric oxides are converted to nitric acid, which trees absorb through their pores, or stomata.
Do pine needles have stomata? Yes of course,Like the leaves of all higher plants, pine needles have special microscopic pores on their surface, called stomata, which are important for exchange of water vapor, carbon dioxide, and oxygen. The stomata are usually arranged in rows on the underside of the needles, where they appear as white lines.
The leaves of Benguet pine trees are needle-like and arise from the stem in bundles, called fascicles. Each fascicle is often associated with a fascicle sheath, a special tissue at its base. It has three to sometimes four needles per fascicle. The needles of pines are arranged in a spiral about the stem. Each year, as the branch of a pine tree grows, it produces a whorl of new leaves, called a candle. The needles of pines last about two years and most species are evergreen, meaning they have some needles at all times. Since pines have needles throughout the year, they have the potential to photosynthesize whenever conditions are suitable.
Pine trees provide us water, absorbing as much as 150 liters per mature tree each year which they release slowly to recharge brooks, springs, rivers and ponds. Three of the nation’s biggest mega-dams, San Roque, Ambuklao and Binga generating a combined 1,200 megawatts of hydroelectric power—get their water from pine forests of Benguet and Mountain Province.
The pine trees prevent soil erosion and landslides in the region, serving as the main soil cover thereby protecting topsoil loss. The Cordillera region losses some 100,000 tons of topsoil every year, without the pine trees soil loss would be worse affecting adversely agriculture, settlements, properties and lives.
The pine trees lower temperature. When Baguio had more pine trees, the city was cooler; it deserved to be called the “City of Pines”. Today, the city is not only warm, congested and dirty but also dubbed by World Bank as having one of the cities in the world with the “dirtiest air” as thousands of trees were allowed by the city government to be cut to give way to commercial and residential buildings, roads, tourism and hotels.
Pine trees lower tmperature. Clumps of pine trees and all trees for that matter reduce mid-day temperature from a minimum of 0.2 degrees C to 1.3 degrees C some 1.5 meters to 2.4 meters above ground.
Below individual and small fragments of pine trees over grass, mid-day air temperatures can be reduced to as low as 0.7C to 1.3C degrees cooler than in any open area.
When pine trees respire, they emit oxygen which do not only reduce air temperature, but also absorb radiation and store heat. They also reduce relative humidity, turbulence, and surface albedo of concrete. These changes in local meteorology alter pollution concentrations in urban areas
Pine trees reduce urban island phenomenon and Temperature on buildings Urban Island phenomenon is the heat transferred from cities via highway and roads to outlying communities. Pine tree reduce this, as well as lessen building energy use by lowering temperatures and shading buildings during the summer, and blocking winds during rainy season. When building energy use is lowered, pollutant emissions from power plants are also lowered.
The cumulative and interactive effects of trees on meteorology, pollution removal, and power plant emissions determine the overall impact of trees on air pollution.
There was a time when pine trees were favorite trees cut for Christmas trees. Today, cutting a pine tree is a crime. But pine trees still exude mixed joy on Christmas especially to children. Thousands travel every Christmas to Baguio City and other places in the Cordillera region just to see pine trees.
To any young child who sees a small young pine tree, if anything, he/she is fascinated with joy to reach out and touch the vigorous plant– fantastically rich in its detail, with its thick and sappy shoots bristling, bright new needles, embossed with male and female parts of splendidly original and suggestive design– inviting kids to dapple them.
The trees’ genus Pinus is the pine proper, limited to 100 or so species all over the world, with certain clear and obvious characteristics, of which the easiest to see and remember is the relatively long evergreen needles.
Next time you find yourself walking underneath pine stands, woods or forests, look up. Not many people embrace this view high above our limited ground floor. An awakening and soul-changing world is gifted by a simple tilt of the head as you see the sky through a beautifully complicated and tangled web of pine trees.
That gives life.