What are the rigs inside a tree trunk called?

Why are my peace lily leaves turning black and what tips can you provide to prevent this issue? Are nectarines poisonous for goats? How can I effectively keep chipmunks out of my planters? Is elderberry toxic to horses? How can I effectively get rid of tiny black bugs on my vegetable plants? How does a tree growing crooked affect its overall health and stability? How should I store seed potatoes in the refrigerator to ensure their freshness and viability for planting? Is purple fountain grass poisoous to cats? How can I effectively block wind on my patio? How can I successfully grow nectarines in pots? How can I effectively keep black birds out of my yard? What tree misses someone very much? Do a zebra have a backbone? What is eg oak? Is the word iris a common noun? What are 10 examples of aerial plants? Can ants kill your lawn? How tall is the tallest plant? How much topsoil do I need to properly prepare the ground for growing grass? What type of plant has a white stem and coin like iridescent leaves or seeed pods?