What’s happening to the tree above can sometimes come from what’s happening to the tree below. In this blog we try to explain the importance of paying attention to the soil.
When a tree is in a state of decline, most times certified arborists will look down to the root zone to find clues as to why the tree is declining. There is a direct correlation between what is happening in the root zone of the tree to what is happening in the canopy of the tree. Trees have a rough go of it in suburbia. From soil compaction to lack of nutrients and everything in between. Let’s delve into it.
First of all, soil compaction can lead to lack of oxygen in the root zone. You may think, “Well construction equipment or cars and trucks aren’t parked in the root zone of my tree. My tree is fine.” I hate to be the bearer of bad news, but your quite mistaken. A major cause of compaction on suburban properties, believe it or not, is foot traffic. Yes! It does not take much pressure to compact the pore space of soil.
Another soil issue is lack of water. Well-manicured lawns look great. The issue is when there is turf up to the trunk of the tree. Unfairly, the turf gets a drink every time it rains and the tree itself only gets a drink when there is a deep soaking rain and only when the turf is at full water retention capacity and the water can finally drain into the tree roots.
Sometimes the soil in suburbia and urban area is lacking nutrients. In a natural forest setting that contrasts suburbia, there are plenty of nutrients in the soil. As the leaves and dead branches that have fallen off of the trees are decomposing on the forest floor, they put nutrients back into the soil. In suburbia, lawns are kept neat and clean. Every fall the leaves and tree debris are removed from most sites, so there are no natural soil amendments.
In urban and suburban areas, when trees are planted close to roadways or in planting beds, lack of root space, too much heat and salt damage can all affect the tree dramatically. When trees are planted in between the curb and sidewalk there is a lack of soil volume to properly support the tree. A lot of times when we see these trees uprooted, it is shocking to see how small of a root system has grown because of the lack of soil space that they have. The heat island effect is another problem trees have. Being surrounded by asphalt that absorbs the sun’s heat and consequently heats the root zone and canopy at a greater rate than turf, keep these trees suffering. Salt damage from road salt being pushed into the root zone from plows is also a concern when trees are planted near roadways or parking lots.
What can be done about these issues? To combat soil compaction, we can bring in an air spade or do hydrofracking in the root zone of the tree. These two methods bring back the pore space the tree so desperately needs in the soil. In addition, adding in soil amendments will help by putting beneficial nutrients back into the soil.
We can also mulch the root zone of the tree, instead of planting it with turf, which will allow the tree easier access to water when it rains along with helping to regulate soil temperatures during temperature extremes in summer as well as winter. A natural hardwood mulch will also slowly break down and put nutrients back into the soil. So, as you can see mulching the root zone of the tree provides a multitude of benefits.
Most importantly, selecting the right tree for the site will help mitigate these problems before they happen and resolving these issues can be quite a bit more involved, but we have solutions for all problems big and small. As arborists, we will help you decide how much time, money and effort you should invest into your trees – one of nature’s greatest resources.
