Why Did This Tree Topple?

Our initial view of the trouble. I have written 24" because of the diameter, not a box size!

We got a call from an HOA in Scottsdale that a large Blue Palo Verde had tipped over something during the weekend and we needed to clean it up. We were already in the valley, so we headed over after the first job to see what had happened. The tree was about 24″ diameter at the ground and had tipped over onto a common wall. The question was posed – why did the tree tip?

We could see from the gap that this tree was not planted at the correct depth!

 The bottom of the trunk just disappeared into the ground with no root flare obvious. From this we could tell that the tree had been planted too deep. The tree was also sitting in mud! The Flood Control District of Maricopa County automatic gauge nearest this location showed only a little more than 1/2″ of rain from the storm this weekend. The tree sat downhill from some drains under the common wall, but I suspected that these would not have made this much mud…

Emitters near the trunk of the tree compounded the problem!

 Looking uphill from the tree I could see two emitters that were putting out water, making more mud right up against the trunk! They were probably placed 2ft away from the trunk, but the way the hillside sloped, the water ran right down against the trunk. Now we knew where the mud came from! Mud will not support a tree. We want the main anchoring roots to be in firm soil and the water to be applied to the absorbing roots out under the trees canopy. When you pour water up against the trunk of a tree you are asking for trouble!

We cut off what we could from the top of the tree. We used a rope to pull branches away from the common wall as they were being cut so we didn’t damage the wall. We ended up with only one branch inside the wall – everything else we were able to pull up and away. We hopped the wall and got the one branch – no problem!

I then cut up the main trunk of the tree. The bottom 6-8ft were straight and I left them attached to the rootball so we could chain it to my trunk and try to pull the stump out of the ground. You never know what you will run into when you try this. Sometimes the thing doesn’t even move! Jerome asked if I had my trunk in 4-wheel drive. I told him “no”, I was going to see what happened with the first pull.

I put my trunk in reverse and backed up. The chains barely came tight and the trunk stood up and tipped right out of the hole. Here is what we saw:

No Roots!

The tree had either been planted over 24″ too deep, or soil had been added around the tree at some time in the past! It had been struggling to survive against the constant stress for many years! Where the stump broke off, over 24″ below the surface of the ground, there was still no root flare! Either all the roots rotted off, or they were deeper yet! The fresh wood you see in the above picture was the only indication of a root that we could find and it was heading exactly in the direction the tree fell.

The job we were on before this included excavating out some new little Palo Verde trees that had been planted too deep. This post describes another job we were on last week. Is this an epidemic?

The water against the trunk, which caused the mud, only allowed the tree to tip over this past weekend. It would have tipped over sooner or later because it had no roots!

So, the real question is, “Why didn’t this tree topple sooner?”