How Does Drought Affect Trees?
Before we can begin, let’s first understand what drought is. Drought is a severe and prolonged shortage in water supply. That is, drought can be defined as a long-term condition of low water supply and high demand.
Many people in the South have seen firsthand the devastating effects of drought. This is especially true for those who live in Florida between 2011 and 2017. The drought has caused many changes in our lives, from mandatory water restrictions to more dusty conditions. Many people don’t realize how devastating drought can be to trees that depend on Mother Nature in both natural and domestic settings.
Drought in Natural Setting
Let’s start with the trees in their natural environments. Native trees and plants, from the deserts to mountains, need irrigation to grow and protect themselves against pestilence.
Wait a second. Just now, we heard the expression “defend themselves”. What does this mean? What does that mean? If you don’t get enough rest or nutrition, your defenses will eventually fail. Next thing you know, the flu or common cold is here. Everyone around you notices that you’re ill. You start to sneeze, sniffle and blow your nose. Guess what? Trees do the same.
Ok, so we have never heard of a tree sneeze. However, when stressed, it releases chemicals like ethanol, acetaldehyde and ethylene. These chemicals are catnip to ambrosia beetles and “secondary” bark beetles. We’ll be discussing the secondary bark beetle effect as our topic.
Bark Beetles
The bark beetle attacks weakest trees first, just like the Serengeti lion attacking the slowest antelope. The bark beetle does not have a long, flowing tail or a long mane. It measures only 1/8″ to 1/38″ in length. It’s not a huge size. Don’t let this fool you.
These beetles work together to burrow through the tree’s vascular system, cutting off nutrients flow.
Ever sipped through a straw with a hole or slit and ended up with air? This is exactly what’s happening.
The tree can’t distribute nutrients throughout its canopy so the trees at the far ends of the tree will starve. This eventually leads to the whole tree dying. These bark beetles fly off to infect their next victims while they reproduce. This is not a pretty image.
Urban Drought
Let’s now talk about trees in urban settings. Many cities imposed watering restrictions in areas that were not essential, such as landscaping, when the drought became severe. Many people reduced or eliminated irrigation in landscape areas to comply with these restrictions. This had a negative impact on the trees that live in these areas.
Although these trees initially didn’t seem to be affected by the reduction, they began going through the same stress processes as trees in natural settings.
These are signs that a tree is stressed.
- Reduced leaf production
- Defoliation is increasing
- Interior thinning/dieback
- smaller leaf size
Do you remember the bark beetle that attacked native trees? They targeted trees of similar species, while their cousins attacked other types. This is a complete assault on the urban greenscape.
The Effects of Drought Tolerant Landscape Escaping
Many people chose to go with native/drought-tolerant landscapes that needed minimal irrigation, in order to reduce the drought water restrictions. They laid fake turf or plastic on top of which they added material like gravel, bark, or decomposed granite. The material covered the roots of trees and deprived them of oxygen, water, and nutrients. They were also baked under extreme heat. Imagine you are trying to carry a bag of plastic over your head all day. You get the idea.
What You Can Do
Even though the drought has been over for years, trees are now falling over in urban areas. The public is at risk as houses and cars are destroyed, homes damaged, and their lives put in danger. What can we do?
First, contact an Arborist for a look at your trees and to give you an evaluation of what he/she sees. As a doctor would, he/she will ask questions about the tree and your history. This will allow him/her to provide a more accurate assessment and make better recommendations.
The drought’s effects will continue for many years, even decades. Protect your trees and prevent potential hazards to property and people.
This post was written by a professional arborist at Arbor Wise Professional Tree Care. Robert Miller is the owner of Arbor Wise Professional Tree Care, a locally owned and operated tree service company that offers superb lawn care by the most experienced arborist largo. Arborwise Tree Services is a tree removal company that offers stump removal, tree pruning, stump grinding, fertilization, and tree restoration. We have an extraordinary lawn care industry notoriety covering the Pinellas county area.
