Any more than 6 inches and the tree will probably die.
you should never build up dirt around the trunk of a tree (or most plants in general) i would remove the garden immediately and see if you can nurse the tree back. . .you can grow another garden a lot faster than you can grow another tree if you want a garden around the tree it would be a better idea to build a raised platform planter
The average diameter of a tree in a mature forest ecosystem is typically around 12-36 inches.
To create a raised bed around a tree in your garden, start by measuring the circumference of the tree trunk and marking the desired size of the bed. Next, dig a trench around the tree, making sure it is deep enough to accommodate the height of the raised bed. Build a frame using wood or stone around the trench, filling it with soil to create the raised bed. Be careful not to damage the tree roots while constructing the bed.
dirt+dirt=palm tree
dirt+dirt=palm tree
To prop a mature tree that is leaning, you should consider the ground under the tree. You can use another support or use a string to prop a mature tree that is leaning.
a mature tree and after that an old tree
To create a raised flower bed around a tree in your garden, first measure the circumference of the tree trunk and mark the desired size of the bed. Then, dig a trench around the tree following the marked outline. Build a frame using wood or stone around the trench to create the raised bed. Fill the bed with soil and plant your desired flowers. Make sure to water the flowers regularly and maintain the bed by removing weeds and dead plants.
dirt+dirt=palm tree
The pindo palm tree takes 12-24 months to mature. This palm does well in containers and is hardy up to Zone 8.
On a mature healthy tree there are about 200,00 leaves
A mature cherry tree can produce around 200 pounds of oxygen per year, which is enough to sustain two adult humans.