In this brief overview, I will cover the basics of a tree’s life—what it is, what it needs, how to keep it happy, and what it doesn’t want.
A tree is a plant, generally with one woody trunk over 10 feet high. Its body consists of three main organs and many types of different tissues, all made from cells. Cells are produced at different times by special cell generating tissues called meristems. The three organs are the roots, the trunk/branches, and the leaves.
The roots supply the support to hold up the trunk and leaves. They are the organ solely responsible for the uptake of water and approximately 20 essential elements, minerals similar to your multivitamin supplement. The vast majority of water that enters the tree’s body is absorbed through the roots. The water is then drawn up to the leaves and any other tissue that needs it. The absorptive roots are called root hairs and they are smaller in diameter than your own hair.
The main job of the trunk and branches is to support the leaf mass above and act as a conduit for the movement of fluids through thousands of tiny pipes that make up the majority of the bulk of the trunk. The pipes that supply water and nutrients to the leaves are called vessels in broadleaf trees and tracheids in evergreen trees. The pipes that move the sugars produced in the leaves are called the phloem. The phloem tissues supply sugar in solution to any part of the tree that needs energy. Working growing roots, growing shoots and leaves above, also supply sugar for energy for defense and sugars that are stored in special cells as starch grains, for when energy is needed. The phloem tissues are an inner bark tissue, found between the wood of the trunk and the outer bark.
The last major organ is the leaves. The leaves are the tireless worker bees of the tree’s body. They produce all the sugars, which are the energy and building blocks for all of the life processes of the tree. It is in the leaves that photosynthesis occurs. This is a chemical process where CO2, water, and the energy from sunlight combine to produce sugars and release oxygen and water vapor. All of this happens in the green cells inside the leaf. CO2 is allowed into the leaf through pores in its surface called stomata. When enough water is present, the stomata are open and allow the free movement of CO2 into the leaf. If the tree is water-stressed, the stomata remain closed, conserving water but shutting down photosynthesis. Yes, you can starve your tree by not supplying enough water.
So we have three main parts or organs: roots, trunk, and leaves, all performing different actions and contributing different materials to the whole of the tree. They are in balance. All are essential, all necessary. There are no extra leaves on trees; they are all needed. Keep this in mind when pruning; go light. The tree, like all living things, has a basic economy. You make so much, your costs of upkeep cost so much. Trees in Calgary have it tough, they work for less than six months when they have leaves, but the costs of life go on every second, every day. This is why it is so important to maintain their overall health, mainly by supplying them with enough water to be successful.
The tree needs a few basic materials to thrive. They are air (CO2), soil with its mineral content, sunshine, and water. Water is always the limiting factor. Keeping a steady available supply of these four basic ingredients will guarantee your tree will thrive. That’s how you keep a tree happy.
What doesn’t your tree want? What hurts it? Too much pruning is the most common mistake. The leaves are 100% essential for ongoing energy production and none are designed as extras. Go light with the pruning. Too much fertilizer is another common mistake. Fertilizers in overabundance bond with water in the soil, making it hard for the tree to remove the water. They also force unnaturally long growth that can later be weak. Injections, the latest wave of commerce for the tree care industry, are completely unnecessary when the tree is kept well-watered and then is in good health. None of these tree care providers ever speak of water, which is the number one concern.
In a nutshell, any tree in Calgary that gets the water that it wants will be healthy, grow well with little deadwood, and will be able to defend itself from insects and disease, without the use of fungicides, pesticides, or insecticides, which are all poisoning the planet.
May 10, 2024, written by Kevin Lee, consulting arborist at krltreeservice.com.
