Pruning is important, and ’tis the season for it, but be careful not to hack away and leave only a tree’s skeleton behind.
It’s pruning season, but that doesn’t mean gardeners have to be heavy-handed with our best natural source of shade
Iwas on my way to fetch my grandson from school last week when I passed by workmen busy trimming tamarind trees along Si Ayutthaya Road outside the Chitralada Palace compound. As branches cut from the trees fell to the ground, other workers picked them up and loaded them onto a lorry. They were still busy working on that particular stretch of road when I passed them on the way back.
It was not until the following day that I had a look at their finished work. These workmen must have gone to a different training school from those who prune trees on roadsides in other parts of Bangkok and the provinces. Either that, or they give the trees outside the palace grounds better treatment, in deference to King Rama V who planted them and the royal family who live in the compound.
The latter group of workmen has an affinity for chopping off all branches, leaving the bare trunk sticking out like a sore thumb. In the provinces, they do the chopping at the height of summer, just when the cooling shade of trees is much needed. Even if they are not directly under the trees’ shade, just looking at the greenery has a cooling effect on passing motorists.
The reason for the drastic pruning, I was told, is to prevent trees from toppling over, or branches from breaking and falling on passing cars during a storm. In my 46 years of living in Thailand, I have never witnessed nor heard of a storm strong enough to break off a stem, much less topple a tree, in Bangkok. Storms like Typhoon Gay, which brought havoc to Prachuap Khiri Khan and Chumphon in November 1989, have always been few and far between. At the time fishermen did not know what a typhoon was and went fishing anyway, despite warnings not to venture out to sea.
This practice of cutting back trees to their bare trunks or replacing trees altogether every few years is the reason why Bangkok does not have shady streets. Unlike Singapore, whose streets are shaded by sprawling old trees, with wild ferns and orchids growing naturally on their branches, the only street where Bangkok has big trees is Witthayu Road. Planted in the early 1900s, these trees have been spared only because years ago embassies in the area protested when the axe started falling on them.
The Philippines is visited by no less than 24 typhoons a year, yet trees are not cleared of their branches as they are in Thailand. In Manila, the mahogany trees along Roxas Boulevard looked massive to me when I was a little girl. Sixty years have passed and the trees are still there, looking very grand and even more massive, despite the annual onslaughts of typhoons. At Dasmarinas Village, home to many foreign embassies, prominent politicians and businesspeople, Ficus religiosa ( bho or banyan trees) look imposing with their huge trunks, their branches reaching across the street to form a green archway. These are trimmed every year so that they do not grow very tall.
Trees are planted along roadsides for aesthetic reasons as well as to filter dust and noise, absorb harmful gases, and provide shade and greenery. Cutting them back to their bare trunks, therefore, defeats the reason they were planted in the first place. It is true that most of the trees recover when the rains come, but for some the relentless heat from the sun and the concrete road proves fatal, especially when the rains are late. When the new branches do emerge there is a profusion of growth at the top of the trunk, giving the tree a rounded, top-heavy form.
While this is a successful way of controlling the spread and height of a tree, it is not the ideal way. Like those who trim the old tamarind trees along Si Ayutthaya and Ratchadamnoen roads, workers responsible for pruning trees in Bangkok and the provinces should follow one rule: Never remove more than one third of a tree’s total leaf area during pruning.
For most trees, only maintenance pruning is needed. Diseased or dead wood can be removed, and wayward growth and a few side branches cut off to maintain its shape. In cases where controlling the size means reducing the height of the whole tree, remove a main branch by cutting it back to a lateral branch. The tree is then much reduced in size, but its original shape is maintained.
There are two conflicting schools of thought as to when pruning should be done. Some gardeners think that it is best done after the rainy season when the trees are dormant, while others say it should be shortly before the rains come because the tree can heal itself more quickly when it is actively growing. I belong to the last group, which means that we should bring out our pruning shears now to create well-proportioned, healthy trees in our yards or gardens.
Check your trees for diseased or dead wood and cut it out cleanly. Branches that cross others, creating bark wounds when they rub in the wind, must be removed because these wounds can make the tree susceptible to disease. It is also a good idea to thin branches in the centre of the tree to allow air to circulate and light to penetrate the whole tree.
From time to time, a stem may shoot off into space, spoiling the shape of the tree, or a tree with variegated leaves develops a stem with plain green leaves. Cut off both the wayward growth and the reverted stem with green leaves to preserve the shape and the integrity of the trees. Epicormic shoots, that is, shoots that appear around the wound where a branch has been removed, should be rubbed out at their base. Likewise, shoots that appear under the graft union in grafted trees should be removed, as these will be different from the rest of the tree.
The pruning of mature ornamental trees is usually carried out for cosmetic reasons, but for fruit trees it is a necessity. Fruit trees like mango, durian, longan, rambutan, marian plum, orange, lime and lychee need annual pruning if they are to crop reliably.