Q.Meyer Lemon Tree
More of a freak of nature observation than a question. The Meyer Lemon tree next to my mom’s driveway was there when my parents bought the house in 1975. The soil is red clay, the tree is next to the house (north facing and partially under the eve), and has NEVER been watered or fertilized. We are in Redding, CA where it frequently gets over 105 degrees in the summer and below freezing in the winter. This year we must have had 500 lemons on the 9 foot tree. From everything I have read, this tree must be a freak of nature. Any thoughts?

By chance did you receive some extra rainfall this year?
I checked with the rainfall in your area, and it does appear that your rainfall amounts are higher then normal.
This certainly could account for an increase in fruit production.
There certainly can be other reasons; including temperatures and pollination.
Enjoy the bounty!
https://www.gardeningknowhow.com/edible/fruits/lemons/how-to-grow-a-lemon-tree.htm
https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-not-fruiting.htm
https://www.gardeningknowhow.com/edible/fruits/lemons/learn-about-fertilizer-for-a-lemon-tree.htm