Often overlooked in disaster preparations, especially for tropical storms, are protection for the trees and plants that are planted in home gardens and in public areas around the metropolis.
Typhoon Glenda showed us that a typhoon with strong, unrelenting winds are more damaging for trees than a torrential storm, in particular those that have not been hardened and prepared.
The Calabarzon (Cavite, Laguna, Batangas and Quezon provinces) region where I live suffered serious damages in infrastructure, agriculture, and fisheries amounting to millions of pesos. Many old-growth trees were also uprooted or badly damaged, but one cannot put a price on what was lost here, for they provided beauty, enjoyment, pleasure and history, not to mention shade, fruits and flowers to countless people. It’s a major aesthetic and social loss.
In my own garden in Cavite, a few of my trees were also damaged although none were uprooted. The surviving trees will live on and grow new branches; their shapes changed forever. (See my earlier column, “Glenda reminded us of prepping,” The Manila Times, July 20, 2014).
How could trees that are already old and large get toppled down or its branches split? There are several explanations given out by gardening experts and landscapers.
One is that the trees were not planted deep enough, or the soil wasn’t prepared properly such that their roots failed to anchor themselves firmly on the ground. We saw a lot of these shallow-rooted trees overturned in the main road artery EDSA. The Metro Manila Development Authority (MMDA) should study how to plant trees correctly in order to avoid this, and also to learn how to stake trees to fortify them against an upcoming storm.
Trees planted in public areas in the country appear to receive little care or maintenance. Apart from regular watering, these wonders of nature also need adequate fertilization, regular thinning, and proper staking, to ensure their vigor and resilience when faced with sharp changes in the climate.
Another reason for the fallen trees is that some are already old and weak to begin with, from decay inside the trunk. Experts said that if there are “conks” or bracket fungi that are growing out of the tree trunk (they look like hard mushrooms), this is a sign of a decaying tree.
The most likely explanation that can apply to most trees in public areas is that they did not undergo regular pruning. We typically do not touch large trees and prefer to let nature or the Department of Public Works and Highways (DPWH) have its way with them (a shame, the number of trees they cut in Bicol and Makiling this year, supposedly for the sake of “progress”).
Since we live in a country that is buffeted by typhoons every year, we have to learn how to cut and trim tree branches since this is the key factor in ensuring that they can withstand our regular typhoons.
Closer examination of the damaged trees in my area showed that they had grown what are called “codominant branches,” or those branches that are opposite each other on the stem or trunk.
The codominant branches had become almost as heavy and large as the main trunk, causing their splitting during the recent typhoon. Proper pruning could have made for a more storm-resistant tree.
The perfect analogy for a tree is a boat or ship with masts and sails. To propel the vessel with speed through the sea, the ship’s crew will unfurl the sails and catch the wind.
Imagine now a tree with its many branches acting like sails on the boat; the more branches and leaves there are, the more wind they can catch. Thus, you see the phenomenon of both big and small trees being uprooted, by the sheer force of the wind sail.
In contrast with the heavily masted trees, the araucaria pine trees I saw around my town were still standing despite having tall trunks. The reason: their horizontal branches are spread out flat and in symmetrical form, leaving a lot of space in between branches for the wind to pass through.
Experts recommend pruning trees not only before a storm, but while they are young. They can then be trained to grow in a certain direction and you can plan out a more even arrangement of branches. Gardening manuals recommend that you cut branches before they become one inch in diameter.
I also noticed that trees that grew together orchard or grove style were more resistant to the wind. Studies have shown that trees planted together are less likely to tumble since their roots will interlock at the bottom for a firmer “group hold”.
There are calls to plant less of the acacia trees in major roads and highways, citing the many that toppled down. I think this had nothing to do with the species being weak, just sheer numbers since this was the preferred ornamental tree starting from the turn of the century.
I think than more than the issue of the type of tree, it should be the proper maintenance and protection of them that should be seriously studied and implemented.
For instance, if a major storm is forecast to arrive, the weak and vulnerable trees should already be provided support in the form of stakes, ties, or cables. Ensure that the ties are loose enough that the stem or branch will not be damaged and still be allowed to grow (and yet provide a measure of control against the wind).
Examine trees well to determine how the branches grow. The general rule is to maintain one main trunk growing upright, and for a full branch tree, ensure that the branches are evenly spaced. Cut off while early any branches that will potentially compete with the leader stem.
For top branched tree (one that is clear of branches in the first few feet and ending with a well-branched crown on top) you will want to avoid a lopsided crown. Aim to prune branches to achieve a fairly symmetrical crown.
Look also for the forked branches that are vulnerable to splitting and cut them off. A tree with a steep “V” shape of branches is at serious risk when hit head-on by strong winds.
Our trees are our gift to the next generation of Filipinos. Officials should ensure that they remain strong and vigorous, and protected against our yearly bouts with tropical storms.