This is not something new. But I feel the need to write a blog about it when someone expressed the concerns of shallow roots with TreeDiaper^® treemats. 

Plants grow roots to seek moisture AND nutrients. When plants are super stressed, they would grow roots only for water as a way to survive. TreeDiaper^® allows deep watering and therefore plants shall not grow shallow roots unless their genetics tell them to do that or it is in super stressed condition. 

In 2017, I created a simple demo kit to show that TreeDiaper^® allows deep watering and therefore it should not cause shallow root problems. The picture shows two extremes: clay and sand. Most soils are in between in terms of permeability and porosity. Soil samples were dried in oven before putting in this demo kit. In the clay soil, moisture reached 7" deep 16 hours after TreeDiaper^® sample mat was placed on top of the soil. In sandy soils, it reached 7" deep in 40 hours. You may wonder why it is slower in sandy than in clay. That is because the mechanism of water movement. In contrast to the gravity-driven water movement of liquid water watering, TreeDiaper^® treemats mainly releases water by osmosis. Gravity-driven moisture movement is secondary force. The large pore sizes in the sand makes it harder for the osmosis to work. So it relies mainly on the secondary gravity-driven moisture movement, which makes it slowly. To learn more about the fundamenntals of TreeDiaper^® check this youtube video: https://youtu.be/NaDh3q2TKag  

Compacted soils are common reasons why tree grow their roots to the surface because they can't penetrate the compacted soils and there is not much soil oxygen for the roots to use. Below is a picture I took on a site where the right-of-way soil is heavily compacted when the roads were constructed.

TreeDiaper^® treemats would not solve the soil compaction problems. However, TreeDiaper^® treemats do protect and promote earth worms and earth worms can help to loosen compacted soils. Check out this video on youtube.