What are the rigs inside a tree trunk called?

What does the seed coat do? How can I effectively plant burlap-wrapped trees to ensure their successful growth and establishment in my garden? Why is my eggplant turning brown? What do you feed lilac bushes? Why are my strawberry plants dying? What is milagrosa plants? What colors do magnolias come in? How can I successfully grow tomatoes in a vertical garden? How much sun do pothos need to thrive? Does petals have cells? What states has poison oak? Are lilies of the valley poisonous? How can I ensure the successful growth of an English walnut tree in my garden? Another name for a cardboard jungle from Bud Not Buddy? How much does 1 cubic meter of bark weigh? How cold hardy are Roman Chamomile plants? How does adding sulfur to soil affect plant growth and soil health? What are the conditions for a spruce tree to grow? Where does the phrase trim the x mas tree originate? Are zebras ectothermic or endothermic?