Remember the Golden Rule: Tree roots will grow outwards as far as their branches, and often more than the area covered by their branches (the canopy). With Fir trees this is not likely to be very far, but with Saman trees the spread of roots will be enormous because the head of the tree is enormous. As you stand in the garden under an umbrella in the pouring rain, or make your way along one of the city streets in a deluge, consider these words and look at the trees that surround you. Many of you will have a variety of umbrellas of different sizes to give protection from the elements. So it is with trees, which act in much the same way as umbrellas. In the city of Georgetown many of the trees form such large heads that they have to be pruned regularly to keep them balanced. In other words they have the spread of their canopy reduced. This means that they do not have to send their roots out so far.
Now it is a fact that the area under the canopy becomes dryer than the surrounding area because the main volume of water is shed outside the ‘circle’ formed by the branch system and leaves in the same way as does the umbrella, but with trees their root growth has to match and exceed the growth of their branches to make sure that the tree gets sufficient water to sustain its growth. If it doesn’t, it will die out.
You will all have seen gardens which have large trees with their roots coming to the surface of the lawns. This again is because they have to go searching for water in more open ground. Look at the ground under a Samaan tree. You will find it as hard as a rock throughout the year, and the root spread is just as enormous as the spread of the canopy. This is fairly common in the case of most of the trees found in Guyana. Now in Europe where the vast majority of trees are deciduous, for the winter months the rain will fall onto the ground right up to the main trunk of the trees, because there are no leaves to bounce it well away from the tree. Consequently bulbs such as snowdrops, bluebells and so on are able to get to a water supply in the late winter in order to start off their growing season, and they flower in profusion in the spring before the canopy becomes too dense. During the summertime woods of deciduous trees in Europe suffer from the same water shortage as do trees in Guyana, and have to send out more roots in search of it.
Under large trees in Guyana you’ll find that different kinds of grass establish themselves. Not the fine-leaved grasses we find so desirable for our lawns, but coarser varieties able to stand drier conditions and reduced light levels. They compensate for lack of light by longer and darker green leaves to get as much light as they can. With trees having light foliage like the Jacaranda, for example, their roots are not as invasive, as the foliage is not so dense to prevent water going through it. If you have a smallish garden it is important then to choose only those types of tree that will not develop a massive root system in order to survive. Leave the Samaan and the Flamboyante trees to those that have the space.
One final word dear readers. Don’t take any risks with seedlings, which sometimes have the alarming habit of ‘damping off.’ Patches of seedling suddenly dying are often affected by fungus diseases at soil level, and sometimes whole trays full of youngsters will keel over and die. Use sterilized soil, don’t over water, and water on one of the copper sulphate mixtures tailor-made for the job. Enjoy your garden and may your God go with you wherever you may be.