It’s that time of year again — the time to talk about our trees and how to care for them. The most obvious problem for many of the trees in the area is the overuse of mulch around their bases. That is the black stuff that gets piled up, sometimes as much as a couple of feet deep around the bottom of the trunk. The use of mulch piled up around the base of a tree this way is harmful.
In our part of New Jersey over the past few years, many people, and especially businesses, have taken to piling up mounds of mulch around trees so that it smothers the bark. It is well known to arborists and botonists that covering the bark of a tree for more than a few inches at the base is very harmful.
There are many government publications explaining the bad effects and urging people not to do it. For one, the U.S. Department of Agriculture has published a pamphlet titled “Mulch is Killing the Trees of New Jersey.” Some people have referred to the appearance of excessive mulch around a tree as a “mulch volcano.”
The problem is partly due to landscape contractors who know very little about how to grow trees, and also the people who make mulch who want to sell as much of it as possible. The general public needs to be educated on the subject, and, though the West Windsor Shade Tree Commission has been trying to do this over the years, its success has been limited.
If you go to Carnegie Center you will see some of the worst examples of the overuse of mulch around trees. That’s one of those places in West Windsor where the maintenance of the area around the buildings is in the hands of a landscape contractor who relies on mulch as a way to make mowing the grass “easier.” Other areas where excess mulch is obvious are along New Village Road and in almost any major subdivision where the local community uses a single landscape contractor to mow and trim the grass.
In West Windsor it’s easy to trace the origin of the mulch problem. It goes back to when the township shut down the municipal dump around 15 years ago and started making small quantities of mulch available to people who wanted to come and pick it up for use on their garden flower beds. This led to the use and distribution of the mulch by landscape contractors who made the job easier for the homeowner.
The problem was that many of the contractors were good at mowing grass, but knew very little about the cultivation of trees. When they realized that a layer of mulch around the base of a tree would provide an area that was easy to keep free of weeds and helped avoid damage to the tree bark by other equipment such as string trimmers, they started using mulch in great quantities, sometimes piling it up more than a foot deep around the tree.
What happens then is that the mulch provides a place where new rootlets, fungus, and other unwanted harmful growth takes place that interferes with the tree’s normal growth. The mulch not only provides a safe haven for rodents and fungus, it also creates a local “ecosystem” that competes with the natural one that supports the healthy growth of the tree.
Over the ages trees have become very good at supporting their own well being by being left alone, nearly wherever they are. Look at some of the very large trees in downtown Princeton, for example. Many, despite being surrounded by paving stones, are very healthy, and more than a century old. Their roots reach out underground until they find a source of needed water. If they are living today, you can be sure they found it. Unfortunately some trees, no matter where they are, fall prey to disease and either die or have to be destroyed. That happened recently to some of those on Nassau Street.
A major problem with mulch is that its bad effects can take years to show up. There are many places in West Windsor where excessive amounts of mulch have been sitting there surrounding a tree for five years or more with no apparent ill effects. But if the mulch were to be removed it would be found that small, vulnerable rootlets have grown out from the bark in the covered area and that the bark itself has softened to the point that it can no longer protect the tree as it was meant to.
A tree’s normal habitat includes a forest, where the terrain around its trunk is covered with decaying leaves and decaying pieces of tree limbs that have fallen. There is no mulch, unless there are enough leaves in some areas to provide a physical equivalent to the “artificial” stuff. But even then it is distributed in a way that does not interfere with the tree’s normal growth. The “volcanoes” we see around here are anything but normal and do not exist in the forest.
Speaking of trees, they were the feature of the annual Arbor Day Celebration that took place at the Ronald R. Rogers Arboretum on April 30. The program, which was under the direction of the West Windsor Township Shade Tree Commission and hosted by Chairman Ron Slinn, included musical selections played by a group from High School South, an art show and contest, and contributions by Boy Scouts and Girl Scouts.
In addition, seedlings of both Douglas Fir and Swamp White Oak trees were distributed to anyone who wanted one. Planting instructions were provided. Swamp white oak was the species of one of West Windsor’s “champion” trees, — the largest one of its species in the state. It was discovered about 20 years ago by members of FOWWOS.
Unfortunately, not long after its discovery, it fell down because of its unstable location on a stream bank. It was estimated to be have been more than 250 years old. At the end of the Arbor Day event a new, mature swamp white oak was planted near the site the 9/11 Memorial.
