Plants like aloe vera can be grown on mass with very little work they store
water in the dry season. You can dice such plants and
feed them to
trees or whatever you want to help through the dry season. Putting them in a
mulch pit is a good way to put their water content into the soil. You may want to do it before the wet season ends so they can rot a bit. Rotting may cause some adverse effects especially if the roots come into direct contact with the rotting material. It will work well for some plants not so good for others. Dirt
should be put on top and then less saturated mulch on top of that.