Healthy Trees…Healthy Soil
Tree Science is roughly only about 40 years old. The amount of information being produced, has added to create many subjects pertaining to the “urban forest”. One subject that has drawn my attention, is that of soil studies. Healthy tree species, that are tolerant to the environmental conditions, will have two main ingredients; adequate hydration, and soil properties, that each tree species thrives in.
As a professional Certified Arborist for around 15 years, when I consult on projects with sickly, diseased, or trees just underperforming, the first thing that I look into, is the soil and how much hydration are they receiving. A quick note here, is that too much hydration(over watering) using a sprinkler system, is way more common that a drought condition, so keep that in mind. My external studies that include soil, can be very dry and super dorky, so I will keep this simple and raw.
If you want to know what is going on with your trees(both good and bad), and that your trees, are correctly matched to your Geographical USDA Cold Hardiness Scale, start by examining the soil. Take a small hand shovel, or coring device, to dig the soil at various depths, various locations, and place about three handfuls into labeled plastic bags. Then perform a basic examination of each of your samples. A few things to test for would be; color/texture/organic matter/smell/and particle properties (sand, clay or silt). Now decide what samples you want and need to submit to the soil/plant lab and testing facility. There are fees for each sample, so only submit the critical samples, if your budget is limited. There are many labs that you can send your bagged and labeled soil samples, for analysis. The more information that you provide to the testing facility, the better the lab can prepare an analysis that provides recommendations in the report. The lab will provide any soil corrections, amendments, species consideration, and even fertilization. Every Lab provides instructions, on how to harvest a proper soil sample, how to label it, and what information to include when submitting your sample.
If your trees are not healthy, for whatever reason, it is usually directly related to the soil. One thing that is overlooked by property owners as well as, the Arborist Community, is an over compacted soil condition. If your trees are in a heavy clay or high amounts of silt, and the soil around the root plates has been damaged by paving/pedestrian traffic/urban development/vehicle traffic, or any disturbance to the soil causing it to compact, your trees will suffer. Overcompacted soil, destroys the small openings in the soil, that allow for water and oxygen to be absorbed by the trees root system. Once a soil is damaged, it is nearly impossible to re construct the soil properties that were present before it was damaged.
So in conclusion, this is just a tiny and small introduction into soil studies. There is so much more to get into after you receive your lab analysis. In the upcoming months, we will dive deeper into soils because, of extreme importance that there are some soils, that are compatible with healthy tree function, therefore you will have healthy trees! Moreover, there are some soils, that are very incompatible with certain tree species, that simply make trees; underperform/die/lack tree function/are more susceptible to disease or pest infestations and simply show the many signs of tree stresses. The biggest point of this posting is, to examine/know your soil, know your tree species, and identify where unhealthy trees are, as well as, healthy trees are, and what the soil conditions and properties of that soil, are causing your urban forest to either stress or thrive. Overall Tree Health, is very strongly connected to the soil composition, characteristics and properties of that soil!
Brian C Dunlevy
BCDTreeandEnvironmental.com
