Tree Preservation

If talking to your plants helps them, what about hugging your trees?


In this context "hugging your trees" means taking special care of them, especially during excavation and construction activities.

Over the decades, we've witnessed the death of dozens of majestic trees that could have easily been preserved with the proper precautions taken around their trunk and root zone.


Doing the tree 2-step

A few simple precautions will help most trees survive construction activities. These precautions can be narrowed down to 2 basic principles:
   1. Protect the tree trunk
   2. Defend the root zone

   Trunk wounds like this can be deadly to a tree.

Trunk wounds like this can be deadly to a tree.


Protecting the tree trunk

It's just wood, isn't it? No!

People tend to think of tree trunks as just being wood. After all they say, how can you hurt a board? It's only wood!

Even though the center core of most tree trunks is just wood (Heartwood), the inner bark consists of living cells. These layers are known as the Phloem (FLOW-em) and the Cambium, with the Cambium being the actual growth layer. The Cambium produces Phloem cells in front (toward the exterior of the trunk) and leaves Xylem (Zi-lem) behind (toward the center core of the tree trunk).

These tree layers are similar to a human being's arteries and veins, with the Xylem transporting water and nutrients up the tree, and the Phloem transporting the products of photosynthesis back down to the roots.

Since these layers of conductive tissue are just inside the often rough, outer bark, it's very important to protect these tree tissues from wounding, just as you protect your own skin from abrasions, because in both cases, wounds provide an opening for disease pathogens to enter.

So, protect a tree trunk like it's your arm!

tree-trunk-cross-section.jpg

"Defending" the Root Zone

Roots don't breathe, or do they? Yes!

Most people think tree roots can live without air since they are buried in soil. However, as seen on our soil webpage, half of a soil's volume is made up of pore space. Tree roots use this pore space to exchange gases and "breathe." If the root zone of a tree is covered with a foot or two of soil, that's usually enough to suffocate the roots and eventually kill the tree. Some trees are adversely affected by as little as a few inches of soil fill over their rootzone.

   To create a level parking area, soil fill was carelessly graded right up against this tree trunk.

To create a level parking area, soil fill was carelessly graded right up against this tree trunk.


Protecting tree roots

Cutting a few roots can't hurt, right? Wrong!

Most tree roots aren't as deep in the ground as most people think -- most roots are within two feet of the soil surface. Cutting roots in this area can cause serious harm to trees.

A worst case scenario is digging a deep trench close to a tree's trunk, which can effectively remove 40% of the root system. This reduces the tree's stability, nutrient and water uptake, and it leaves open root wounds that provide an entryway for disease pathogens.

   Dieback of a tree crown is a sure sign of trouble, often beginning at the roots.

Dieback of a tree crown is a sure sign of trouble, often beginning at the roots.

   Bad sign: Dieback at branch tips.

Bad sign: Dieback at branch tips.


Tree preservation summary:

Protect your trees during construction!

Prior to excavating your new building lot, decide which trees you want to preserve. In some cases, it won't be feasible to save trees that are in the way. But for trees that fit nicely on the building lot, and provide some nice shade or screening, take some early steps to provide protection:
   
  1. Keep heavy equipment and big trucks off the root zone
  2. Don't pile soil against the trunk or over the root zone
  3. Avoid cutting trenches for utility lines close to the tree
  4. Protect tree bark from heavy equipment and construction damage


   Dead trees are known as "widow makers" due to the deadly threat of falling branches and increased risk of blow-over.

Dead trees are known as "widow makers" due to the deadly threat of falling branches and increased risk of blow-over.