Accidentally Damaging Trees
In 1998 U.S. botanists Elisabeth Schussler and James Wandersee defined what they called “plant blindness”. In the arborist community, we often refer to something similar as “tree blindness”. In our case, people tend to look at trees (often the trees on their property) and not see what we, the arborists, see. We often find this situation when looking at tree roots that have been cut.
Unlike people and animals trees do not audibly react when people damage them. In most cases, trees don’t even show meaningful reactions for months or several years. As kids, some of us damaged trees by cutting our initials into the bark of a tree, as adults we may have bumped a tree with our car/lawnmower/trailer/etc. In both of these cases the tree has been injured, but since the immediate impact seems minimal people rarely appreciate the challenge they’ve given the tree.
The damage from the examples above could be small or the beginning of a cycle of decline that leads to the tree dying or becoming hazardous and needing to be removed. The size, species, degree of damage, time of year, availability of nutrients and water to the tree, post-impact care, and other factors would determine the severity of damage from one of the above examples.
Trees can and do put up with a lot. They are resilient plants that often have incredible energy reserves stored in them. Everything has a threshold of what it can handle though and we often are pushing trees past that threshold without even noticing. One of the most common areas we see this is with construction damage. Damage from equipment scraping roots and trunks, digging up root systems, and compacting soil all happen with high frequency on construction sites. Even when the contractor has specifically offered to save the tree through the process. The contractor’s “tree blindness” often keeps them from seeing the damage done to the tree because the results do not appear for years afterward. When the house or construction project is finished the tree is still standing and may have all of its leaves on it depending on the time of year, all too often however, an arborist will be looking at dead or dying tree(s) in 18-36 months.
Good rules of thumb:
-Consult an ISA Certified Arborist if you are planning a project that will be done near a tree you want to preserve. Sometimes very simple steps (and often free!) can be taken to avoid longterm impact on your tree.
-What’s below the ground is just as important as what’s above the ground. Any roots that you dig/cut and any soil that you change/compact will have an impact on the tree close by.
-If you look up and there is a branch above you, there is probably a root below you. Consider the impact to the tree if you are building, digging, or compacting the ground below you even if you aren’t close to the trunk.
The images below are of a large tree that had its root system cut to install an irrigation line. Many alternatives could have been done with no added cost to install the irrigation line, if someone had known. Instead, 2 years later a costly removal of the tree was neccessary.
