as a method of "hugelkultur", by putting them in the soil either under or around whatever you are planting, hollow side up. This would create little "buckets" to hold water, and slowly rot away over time, normally by which time the tree will be more able to retrieve its water from deeper in the subsoil. Cheers.
If you’re going through hell, keep going. - Winston Churchill / tiny ad
try a month in the "gardening gardeners" program to see if it soothes your soul