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TREATMENT IN NURSERY CAN AFFECT TREE'S LATER GROWTH
How trees get planted - and how they were grown previously - have a huge influence on how they're going to grow in the years that follow. Many trees get planted wrong, and the error often doesn't belong to the homeowner.
I recently came across a forestry website that featured an ongoing discussion by urban foresters and tree-planting services. The discussion focused on how many tree problems develop long before trees are set in the ground in a homeowner's yard. I hope these comments will help you ask better questions when you select and plant trees in your yard in the future.
A consulting arborist from the University of Pennsylvania wrote: "When many nurseries plow between the rows of trees, they push dirt up against the trunks and cover the root flares. Then when the balling is done, this dirt becomes part of the root ball. Then, presto! the dirt doesn't hold together when the burlap is rolled back. Numerous root problems start in nurseries, and one of the worst is trees left in containers too long."
From a North Carolina consulting arborist, who says he has bought and planted more than 20,000 trees in the past 10 years: "I am convinced that the most insidious, unrecognized and ignored threat to new trees is that they were planted too deep in the nursery. Ninety percent of the trees I bought last year, all from reputable, established nurseries, came with 2 to 6 inches of excess soil over the crown.
"The problems resulting from this extra topsoil include slow transplant recovery and slow growth. When these trees die sometime during the next 10 to 15 years, it's nearly impossible to relate the mortality back to the root crown at planting time and therefore the nurseries won't accept responsibility for a tree's death."
A tree service operator wrote: "We are finding that balled-and-burlap trees consistently have 4 to 8 inches of excess soil on the top of the root ball. This often means that the tree gets planted 8 inches too deep.
"Another problem is leaving the strings wrapped around the trunk at planting to keep the root ball firm so that the tree doesn't have to be staked. In four or five years, the homeowner is calling for help because the tree died.
"I recommend that the burlap be folded away from the top of the ball and the top half of the wire basket cut away once the tree is positioned correctly in the hole."
A tree-planting instructor advocates removing the upper part of the wire basket if there is one. "In most situations, the strings on non-treated natural burlap should be cut away after the tree is one-third planted and the burlap folded back or cut away.
"Another root ball problem is nursery stock that is so poorly dug and handled that the ball won't hold together when you remove the burlap from the upper part."
The owner of a tree planting service offered this insight into another root situation: "A very common problem caused by mechanically planted nursery liners is j-roots. The machine opens a furrow, the tree is inserted into the furrow, and the soil is plowed back around the plant to finish the operation. (Note: The term "liner" refers to a tree seedling or rooted cutting when it is first planted in rows in a nursery.)
"If the person inserting the liner drags the plant, all the roots are swept to one side. Later, when the plant is dug for sale, roots are bunched on one side of the root ball. If the root system is washed off, the root system resembles the letter j. This problem affects both the early establishment of the tree and long-term performance. Since the roots are present in only half the root ball, the plant fails to establish. If the tree somehow manages to survive, its roots stay in the j-shape forever, which affects the long-term stability of the tree.
"The bottom line is that many modern nursery production practices are labor-saving shortcuts that affect the root system's structural development. The structural root system is established when the tree is in the liner (first transplant) stage. If it is in a pot at this stage, the roots girdle the stem. If the liner is planted deep, it produces secondary tiers of roots. If the liner is j-rooted into the ground, the roots retain that shape.
"Many installation contractors get blamed for planting too deep. I believe that most of the blame lies with the wholesale nursery, which plants liners too deep and mound-cultivates to control weeds. At least the nursery should remove the excess soil rather than balling it. When I plant a tree, I locate the roots in the nursery ball and plant the ball high enough to place the roots at the proper depth."
This rather technical discussion on tree planting illustrates why there isn't always a simple solution to a tree owner's tree problem. It's possible that the cause of a tree's demise could have occurred decades earlier.
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