Arborist b 480-969-8808Excessive trimming in many cases is not only unnecessary but can be harmful. Some trees like mesquites need to be trimmed regularly to prevent wind damage, but others like pines need very light if any trimming ever. Remember when talking to most arborists, that trimming trees is how they make their money. Please Beware!


Plant Biology -


Trees create energy in their leaves, and store it to be used for growth, reproduction, to fight disease, and for self-defense.  

Trees have a storage network which takes time to deplete and restock - lots of time – in some cases years.

To better understand the relationship between tree health, energy reserves, and the abundance of leaves on a tree please read on, and watch the videos on this page.


The amazing ways plants defend themselves

As shown in the video above plants, and in our case trees, create energy in there leaves, and store it to be used for growth, reproduction, to fight disease, and for self-defense.  

Trees have a storage network which takes time to deplete, and restock - lots of time – in some cases years.

When the energy reserves are depleted the plants and trees can’t do all of the amazing things they usually do to defend themselves from insect attack, and the diseases they carry.


Hear are two examples that illustrate my point.

Citrus Trees:

I know through personal observation that citrus trees take between three to five years to deplete there energy reserves, and it takes two to three years to restock those reserves.

It used to be that the most common ways a citrus tree would lose stored energy was ether someone not fertilizing there citrus trees, or they would over prune them on a regular bases. These practices would case the trees to notably suffer, and in a few years I would be called upon to fix them.

Now because of the arrival of the Asian Citrus Leafminer all of the citrus trees in the phoenix area are suffering from severely depleted energy reserves.

To make matters worse three spices of whitefly’s are also atacking citrus trees in every neighborhood I visit.

Pine Trees:

The Pine Trees first line of defense against boring insect attack is its sap. If a Pine Tree has enough sap the majority of insects that bore in are trapped and never get out to breed. The sap of course is made from energy made in the pine needles.

When a pine is over pruned (pine trees need very little if any pruning) the amount of sap that can be made is reduced and the Pine Tree is susceptible to insect attack.

For a deeper look at the amazing process going on just below the surface of plants please watch the videos I compiled below.

As you can see there is a lot of really complicated stuff going on in plants, some of it we understand but there is a lot we don’t.

One thing is clear to me though, and that is - that except to protect trees from wind damage - excessive pruning doesn’t help promote tree health. In fact in many cases it makes things worse, leading to increase susceptibility to tree disease, sunburn damage, problems with insects and sometimes – although it may take years, as in the case of pine trees -  tree death.

In the last 52 years I have been working as an arborist and as a Tree Doctor, I have seen this mistake repeated over and over.

I saw it again just yesterday with a 30 year old Alepo Pine, and last week I saw at least 20 pines severely over trimmed, in an association in Sun City West.

When I’m faced with these situations, all I can do is treat the trees with substances that will increase energy production, and kick start the immune system, then I get the owners trained in how to protect the trees from insects, how to fertilize, water, and anything else that may be wrong.

For more information please see Plant Disease and Resistance

This was written February 25, 2018 by Warner Working.

Warner’s Tree Surgery is a family business. Our business consists of my wife Pat, who manages the office and answers the phones and me - Warner Working
We currently serve - Mesa – Gilbert - Tempe - Chandler - Scottsdale – Paradise Valley - East phoenix.