Trees and typhoons

As I write this, Typhoon Glenda is on its way out to the West Philippine Sea. In its wake, lives have been lost and Luzon has been pummeled by winds of destruction, albeit not as strong as Yolanda’s 300-kph gusts. The lessons from that disaster made for better preparation and less fatalities, but there is much to improve by way of disaster-risk management and preparedness.

One of the effects of typhoons that could be mitigated is the loss of trees, especially in urban areas. Just outside our house, I count three large trees uprooted or badly damaged: a young balete, a mango and a kaimito. Out in the street, several fell, damaging one parked car and missing the vehicle of my eldest by inches.

Around the metropolis, the same situation is evident vis-a-vis felled trees; even the Malacañan complex was not spared. Ivan Mandy, a fellow trustee at the Heritage Conservation Society, posted on Facebook, “How can we save these trees?”

Here are 10 main points regarding that query, and other issues connected with trees and typhoons:

1. A good number of these felled trees can be saved. Smaller uprooted trees can be put upright again and survive, so long as their root systems are fairly intact. The tree’s branches and foliage should be trimmed to lighten the task (trees are heavy) and the trees guyed once upright. A tree with a broken trunk and uprooted roots is hard to save but miracles have been known to happen.

2. Some felled trees can be recycled. More damaged trees can be recycled. Certain species like ficus (balete) can find new life as rooted cuttings. Branches can be cut and made to develop root systems by simply sticking it into the ground or processing them in a nursery to develop a root system at one end and replanted as “rooted cuttings.” Singapore’s initial greening program used rooted cuttings of narra. The only downside is that trees grown from rooted cuttings are a little more brittle compared to those grown from seed.

3. Before a strong typhoon it’s not just those awful billboards that have to be prepared for the winds but also trees. Preemptive pruning should be done before a big one or even before the typhoon season. Village associations can already identify areas where trees may endanger parked cars and pedestrians. Trees already leaning or in danger may already be guyed down or braced. Golf courses and parks in other countries prone to storms do this.

4. Utility cables and trees don’t mix. In a better world, all our utilities would be buried so fallen utility poles won’t cut power to districts. Fallen trees would also not bring down utility cables with them. In our reality, pruning would be the only preventive measure. It would help, too, if power and cable companies ensure their poles are upright and stable. Many poles are obviously overburdened by the black spaghetti that is the curse of many of our streets.

5. The reason why a number of street trees fall is because they are shallow-rooted. Few of these trees are planted according to rational selection and spacing by a licensed landscape architect or trained arborist. Many are just the result of “greening” programs that are more photo-ops than long-range initiatives based on proper parameters of urban greening.

Trees should be selected according to goals of function and aesthetics — columnar trees or palms for narrow streets, spreading trees for larger avenues and wide planting verges. It’s not just the trees that need preparation. Tree holes must be of the proper size to receive these trees or saplings as they are planted. These holes must be between two to as much as six cubic meters in volume and back-filled with good garden soil to ensure proper development of the tree. Most tree-planting initiatives I’ve observed in the metro use small holes half a meter square and deep. Root systems are then prone to be shallow as a lot of the locations for these planting are in soil as hard as concrete.

6. Our urban trees, save for those in a few large parks, are essentially not maintained or monitored properly, if at all. Most progressive cities or metropolises have parks departments that look after and maintain trees. Paris and Singapore even embed their larger and important trees with electronic sensors that monitor the health of each tree.

7. Few of the existing parks departments in individual local government units in Metro Manila have trained personnel or landscape architects in their staff complement. Only the National Parks Development Committee has a licensed landscape architect — its current head, Elizabeth Espino. There is clearly a need for capacity building and the employment of trained and experienced professionals (landscape architecture is a regulated profession, you need a license from the PRC).

8. Metro Manila has few parks of sufficient size to cater to the needs of the population and to serve as nurseries for urban trees. Such parks in other cities abroad also act as refuge zones for people in calamity. Many parks also function as flood-mitigation elements with detention ponds and the fact that open green space absorbs flood waters more than concrete or asphalt.

9. Trees in large numbers can directly mitigate the disastrous effects of typhoons. Mangroves planted (or actually replanted) along coasts can absorb the energy of storm surges. Hills and mountains around cities should be reforested to bring back the absorptive capacity of uplands and therefore reduce flooding down-slope.

10. Reforested uplands and in large parks can also mitigate strong winds and gusts. Tree planting is normally part of highway design and streetscape layouts — also to channel winds for ventilation or for storm mitigation — again depending on proper spacing and specification for their planting.

Trees have an important role to play in climate change adaptation and disaster mitigation. If used properly, they can change from obstructions that have to be cleared after a typhoon into essentials to ensure sustainability for urban development. The key is learning to use them properly, specify and space them (using the expertise of professional landscape architects), planting them in the right numbers and in the correct context, and finally, maintaining them so they live to bring us both pleasure and protection for the long term.

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Feedback is welcome. Please email the writer at paulo.alcazaren@gmail.com.