Can anyone let me know why the tiny short trunk is dying. I forgot what this plant is called I got it at Home Depot over a year ago.

Your plant is called Yucca cane. The lower cane probably died because of a problem with the roots, most likely improper watering. In general, it needs a thorough watering as soon as the top inch of soil feels dry. Make sure it does not sit in water that collects in the bottom of the outer pot.

If there are no signs of healthy buds emerging from the shorter cane or if the shorter cane feels soft, then you can safely assume it will not revive and it can be removed.

Thank you!!! I don't think it will come back. I'll remove it and make sure the watering is correct thank you

To remove the dead cane, spin it in place to release it from any of the roots, then pull it straight up and out. That will prevent damaging the roots of the other cane and leave the soil intact.