I have a lychee tree that I just planted about a month ago. It was doing well until about 2 weeks ago when I noticed the leaves were drying up and turning brown. Now, all the leaves are brown and many have started to fall off. I guess very soon, all the leaves will fall off the tree. I am wondering if the tree is dead? Will it sprout new leaves, or should I have it uprooted and plant a new tree? I had purchased this tree from a nursery and planted it under the canopy of a large oak tree. The tree itself is about 2-3 feet tall. I watered regularly - alternating days - but for some reason, it seems to be dying. I am also using regular citrus fertilizer. Someone please help.