Have you noticed in recent years the method of mulching trees in public places, especially parks? The mulch is deep and is spread right out to the drip tip of the tree (the ends of the branches).

This has two main effects. Firstly, and very importantly especially in traffic areas, the thick layer of mulch aids in preventing soil compaction. Soil compaction is responsible for poor drainage and aeration, definitely something to avoid around your trees. Secondly the thick layer of mulch insulates the soil against heat and wind, protecting the root area and keeping the soil underneath cool and moist. This in turn creates favourable conditions for ‘critters’ in the soil to do their thing and improve structure and fertility. It also means you will rely on irrigation less - if at all.
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