Do you know about trees? 🌲

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Speaker 1: You're listening to sleep Tight Science. Did you know that trees are able to communicate and defend themselves against attacking insects? Wow? Hello friends, and welcome back to sleep Tight Science, a bedtime show that answers the questions you have about science. In this episode, we are going to learn about trees. Trees are tall, wooden plants that usually have a stem called a trunk. Trees are the largest and oldest living things on Earth. Some trees live for hundreds or even thousands of years. There are more than eighty thousand species or types of trees. Some well known types of trees include birches, firs, maples, palms, and pines. Scientists divide trees into many different groups. They group them based on how they reproduce or make a new tree. Some trees reproduce with spores or particles that grow into new plants. They are called tree ferns. Most trees reproduce with seeds. Some seed bearing trees grow their seeds in cones, and they are called conifers. Most seed bearing trees grow their seeds in fruits or pods, and they are known as broad leaved or flowering trees. Scientists also group trees based on whether or not they lose their leaves. Trees that keep their leaves year round are called evergreens. Trees that lose their leaves during the winter are called deciduous trees. Trees help people to stay healthy, and we are going to talk about that a bit more later. Trees keep us cool and give us food, from apples to oranges. Fruit trees feed people. Trees help stop erosion or the wearing away of the earth. Their root systems slow and stop rain runoff by absorbing at excess water. This reduces the amount of soil that is washed into streams and lakes and decreases erosion. For this episode, I asked Craig Tupper for help with the answers to our questions. Craig Tupper is a forester who looks after trees and forests for families and small wood lot owners in the area where he lives in New Brunswick, Canada. Thank you, Craig for all your help. Have you ever walked through the woods and thought about the trees around you? Have you ever wondered how they grew so tall? Why was it's so cool and refreshing in the woods, How did those trees start growing. Why are trees so important to us? In this episode, we will learn about how a seed becomes a tree, what types of trees use cones as seeds, what is an evergreen, what do the rings in a tree mean? And why are trees important to us? How does a seed become a tree? According to Craig, seeds grow on trees throughout the growing season, and seeds are either formed in cones or on small stems on the tree. Those seeds are then shed and they drop to the soil at different times of the year for different species. Those seeds, once they have the right amount of sunlight, moisture, or water and heat, will germinate and that means that they are starting to grow. A seed contains a miniature plant called an embryo that can grow into a fully grown plant. The outer shell of a seed, called the seed coat, protects the embryo. Inside the seed, you can find a nutritious material that provides food to the embryo. So the seeds are like a tiny tree that is wrapped in a coat, and when the conditions are right, that means that the seed has enough water, sunlight, and heat. The tiny root of the embryonic tree breaks through the coat on the shell and starts to grow into the soil. Once it starts to gather nutrients and water from the soil, then the small leaves that are also in the seed break through the top and continue to grow. At the end of the first growing season, that small tree will form a bud on the top, and inside that bud is another miniature set of leaves that will continue all of the growth for the following growing year. What types of trees use cones to house their seeds and what does it mean if a tree is an evergreen. Evergreen trees or coniferous trees are trees that use cones to house their seeds. An example of an evergreen would be spruce or pine trees or balsam firs, which you might think of as being used for Christmas trees. The cones these trees produce have many scales to protect the seeds. After a while, the scales open and the seeds fall to the ground to grow where they fall, or they might be carried away by wind, birds, squirrels, or other small animals. An evergreen tree is a tree that keeps its needles all year long, and therefore is always green. These trees, such as the spruce pine or balsam firs, are ones that keep their leaves small needlelike shaped leaves all throughout the year. Large trees are the only trees in Eastern Canada that lose their needles every winter and grow new needles each growing season. What does each ring in the trunk of a tree represent? Each ring in the trunk of the tree represents the growth of the tree over one growing season or usually one year. These annual rings show the amount of wood produced during one growing season. The ring of the tree has two types of wood in it, early wood and lightwood. In Canada and the North United States, the growing season begins in the spring. At first, the cambium, a thin layer of cells, makes a lot of large cells with thin walls that form the spring wood or early wood. If you look at a cross section of a tree, this is the light colored ring. Then, towards the end of the summer growth slows down. The cells manufactured at this time of the year are small with thick walls. They form the summer wood or lightwood, which appears as a dark ring on the tree cross section. That is why you can see a difference from one side of the ring to the other side of the ring. So if you want to know how old a tree is, you can find and start in the middle of the tree and count the rings all the way out to the bark to see how old a tree is. What part of a tree is important to gather sunlight for photosynthesis. The leaf is the important part of the tree that gathers sunlight for photosynthis the leaves are like food factories for the trees. Coniferous trees have small, needle like leaves, while deciduous trees have broad, flat leaves. Deciduous trees are trees like maple trees and birch trees. The green material in leaves is called chlorophyll and is very important in photosynthesis. Photosynthesis is when a leaf gathers sunlight and water and nutrients from soil and converts them into sugar that provides food to help the tree grow each year. In what ways are trees important to humans? It is easy to talk about trees being important in that they provide us with oxygen in woods like lumber and paper and things that we use every day that are very important to us. But it is also important to talk about trees being a part of a larger community of living things called an ecosystem, and we are also part of that ecosystem. Trees create habitats for plants and animals. Whenever trees are grown, wildlife and other plants are sure to follow, which creates a healthier ecosystem. Trees provide shelter and food for lots of different birds and small animals. Trees improve air quality. Trees are sometimes called the lungs of the earth. They are called this because they soak up pollutants through their leaves, trapping them in and filtering bad things out of the air. Trees also produce oxygen through photosynthesis. Forests also help filter and provide water and help to control flooding. A tree's leafy canopy captures precipitation before it reaches the ground, allowing some of it to gently drip and the rest to evaporate. Tree roots hold soil in place, lowering erosion the wearing away of the earth. One hundred mature trees can catch about one hundred thousand gallons of rainfall per year. If you spend a lot of time in the forest, you will come to understand how important they are as well. Going out into nature is one of the most meaningful things you can do with your family to be happy and healthy. Trees have a positive effect on our health because they create a comfortable, shaded area where kids and parents can play, which encourages active play. Trees also benefit our mental health and well being. Trees have been found to limit stress and promote relaxation in both children and adults. Fun facts about trees. If a birdhouse is hung on a tree branch, it won't move up the tree as the tree grows. Wow. A large oak tree can drop ten thousand acorns in one year. What The amount of oxygen produced by an acre of trees each year equals the same amount of air that is consumed by eighteen people in a year. Awesome. A bristle cone pine tree named Methuselah is believed to be the oldest tree in the world. Its exact location has been kept a secret to protect it from taurus and vandals. Trees make coffee and chocolate yummy. There are four hundred and twenty two times as many trees on Earth as people. In this episode, we learned how a tree grows from a seed that the seed contains a miniature plant and all the things it needs to start growing, and when it gets enough sunlight, water and warmth, it will start to grow. We learned that an evergreen tree is a tree that stays green all year round. These are usually trees that have needles instead of leaves, such as a fir tree. We also learned that each ring in a tree represents one year of growth. There is usually a dark part and a light part in each circle, and they are the early wood which grows in the first part of the growing season, the light colored part, and then the light wood, which grows in the later part of the growing season the dark colored part. We talked about photosynthesis and that the leaves of the tree are necessary to make food for the tree. We also spent quite a bit of time learning about the different ways that trees are important. They improve air quality, they help filter water and prevent flooding, They provide homes and animals, and they also have a positive effect on people who spend time in the woods. I'd like to thank Griffin who sent in a question for this episode. This episode was made with the help of Craig Tupper. I'd like to say thank you to Ivy and Jonah Karthik and Kavish from Shunai, India, shar Aaron Vargas, John and Rhea from California. For your questions, We hope to have a chance to use these ideas in future episodes. If you'd like to send us your questions, please send them to Hello at sleep tightscience dot com