Contributions of Pine Trees to the Philippine Environment

Contributions of Pine Trees to the Philippine Environment
By Dr. Michael A. Bengwayan
Once again, as we face the coming of Christmas, the most memorable holiday in the Christian calendar, the image of pine trees comes vividly in our minds.

In the Philippines, the most notable is the Benguet pine tree (Pinus kesiya) often referred to as Cordillera pine because the tree grows not only in Benguet but also throughout the Cordillera range covering Mountain Province, Ifugao, Kalinga, Nueva Vizcaya, Abra, including Ilocos Norte and Ilocos Sur.

Pinus kesiya is endemic in the Cordillera region, a relative of the Khasya pines of the Khasya region in Burma. Pine trees in the Cordillera region are the standard-bearers of the Philippine mountain skyline.

The natural range of the pines is enormous. If anything, they favor rugged conditions, from the ecotome of Mount Pulag’s mossy montane forests, to the dipterocarp skyline of Balbalasang, the waterless and extremely exposed rocky crevices of Sagada, the clayey subsoils of Solsona, to the rocky domes high above where there seems to be no soil at all in Mount Santo Tomas.

If pine trees have a headquarters in our era, it is in Benguet and Mountain Province, whose tropical highlands they seem to relish. With their evolutionary tactics of self-pollination and interbreeding, they keep botanists, tree lovers and tree planters busier there than anywhere else in the region.
Pinus kesiya, ever proud and conquering, is symbol of the Cordillera peoples. Whether blanketed in lush cloaks of vibrant green or stripped naked with only their bare trunks remaining, they reveal their beauty throughout the warmest, wettest or rainiest seasons. Their knowledge of time, history and events is timeless and though science, technology and capitalism seem to have combined to end their reign, they continue to remain.

So What Do the Pine Trees Do?
On the surface, what most people see is the economic side of pine trees—lumber for housing, furniture and buildings. Very few are aware of the ecological, social, medical and cultural contributions of pine trees.

As food, pine trees seem unimportant to humans except for birds, insects and a few animals. While some pine tree species’ have seeds big enough to eat, Pinus kesiya’s seeds are, although edible, too small to really satisfy human hunger. Only the Lebanese pine, Korean and Pinon pine have seeds big enough to be harvested for food.

But the trees are more important for something else. There are four direct and uncontested facts that the pine trees do for the Philippine environment. First, the trees help directly contribute to oxygen supply to the environment for humans to breathe, directly affecting local and regional air quality by altering the urban atmospheric environment.

Humans breathe only oxygen which comprises 21 percent of our atmosphere. But oxygen in many parts of the world is being depleted due to pollution wherein dangerous methane, sulphur and nitrous oxides and CO2 and smog are increasing in the air. Trees supply about 70 percent of our oxygen supply.

Second, they provide 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.

Third, the pine trees prevent soil erosion and landslides in the region, serving as the main soil cover thereby protecting soil 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.

Fourth, 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.

Oxygen Supply and CO2 Absorption
One mature pine tree, ten years and above, releases 45 lbs of oxygen a year. At least four trees can supply the oxygen requirement of one human each year.

As pine trees release oxygen, they absorb CO2, a dangerous greenhouse gas. Each mature pine tree absorbs 45 lbs of CO2, following physics’ Boyle’s law of “what element is lost is equally replaced by another element”.

The oxygen released by the millions of pine trees affect air by reducing temperature, remove smog and air pollutants, CO2, methane, sulphur and nitrous oxides thereby regulating microclimatic effects like cooling.

Pine Trees Lower Temperature
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.

Removal of Air Pollutants
Even though pine trees leaves are needle-type, they function as normally as a broadleaf. The needles through their stomata, remove deadly gaseous air pollution primarily by uptake.

Once inside the leaf, gases diffuse into intercellular spaces and may be absorbed by water films to form acids or react with inner-leaf surfaces. The trees also remove pollution by intercepting airborne particles. Most particles like CO2 are absorbed into the tree, and eventually stored in the soil by the roots.

Some particles that are intercepted are retained on the plant surface. These are resuspended to the atmosphere, washed off by rain, or dropped to the ground with leaf and twig falls. Consequently, vegetation is only a temporary retention site for many atmospheric particles.

Reducing 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.

Energy and Medical Relevance
Pine trees are the most popular among all conifers in the world, the most widespread, most varied and most valuable trees of their order. The biggest family of conifers goes by their name, the Pinaceae.
Pine trees are called pine trees basically because it contains the rare and highly expensive Alpha e-pinene chemical content that the tree treasures. E-pinene  contains an important hydro-carbon alkane, the chemical used for lighting and cooking in high altitudes and also ingredient for pharmaceuticals and chemical necessities.

The chemical is contained in the resin of the pine tree which explains why pine wood is highly flammable. The indigenous Cordillera tribes make use of resin-rich pine wood as flint or for starting fires called locally “saleng”.

Pine Trees and the Joy of Christmas
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.

The pine needles and cones are the ones that easily lure people on Christmas time. Pinus kesiya has three needles for each fascicle. The yearly growth of each shoot of a pine needle takes the form of a ‘candle’, which is a defiance of gravity.

The needles are boiled as tea and drank to cure upper respiratory tract ailments. Medical experts recommend to asthma victims to walk under pine trees in the morning because the trees release terpenes which help cleanse the lungs.

Thanking the Pine Trees
To give thanks to the pine trees for their ecological, social, cultural, economic and aesthetic benefits, the environmental group Cordillera Ecological Center conducts yearly the Pine Tree Festival. Already on its fourth year, educational, cultural, music and arts activities by representatives from Baguio city, Benguet, Mountain Province, Abra, Kalinga and Apayao. It attracts thousands of tourists.

Most importantly, it advocates and leads numerous tree planting activities.
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.