From The Garden of Ed. Submitted for publication in The Towne Crier on June 28, 2006
Trees! Good News and More...
I am happy to report that after last year's spring and early summer defoliation of oaks and many other valued tree and shrub specimens, this date of reporting indicates that the gypsy moth caterpillars are on the decline and likely their progeny should be much less troublesome next year.
The adequate rainfall that I hoped for in my April 19th column has come in time to favor the Entomorphaga maimaiga fungus, one of our important allies against these leaf-eating caterpillars.
Also helping out have been the large, hairy (annoying but not biting) flies that like landing on anything, including us and our hair. They are Tachinid flies and have been very helpful in parasitizing adult caterpillars. The defoliation is greatly reduced and many trees will have ample time to re-leaf and build up stores before winter. Trust to nature and nature will provide. Gypsy Moth Caterpillars at all growth stages have been controlled fairly well by now. This has not been without some widespread defoliation in several areas of Ulster, Orange and Sullivan counties, but still less than last year for most.
This provides me with the inspiration for today's column. Trees are many things to many people, and I thought it was time to explore and share some of this. I note that this is but an introduction to a vast world of large plants that serve as the managers and directors of much of our landscape as well as our forests. We easily remember that many trees provide shade, air conditioning of a sort, a place of respite on a hot day.
But, more than that, trees are our pollution controls, the anchors that hold our soils, our water managers, both in time of drought and deluge.
Trees are habitat for all manner of wildlife, providing food and shelter. They are carbon storage units taking in huge amounts of carbon dioxide and keeping it in a safe useable form for the future and at the same time generating our essential oxygen in the process.
Trees are employed as living fences, property screens, and boundary indicators. They are also employed as landscape focal points, places for the eye to rest and linger and marvel. They are objects of great beauty and symbols of enduring vitality. Their majesty serves as inspiration for the ages.
Their abundance, size and variety surely make them man's most important natural resource. Because trees are the most conspicuous plants on the planet, they have been the most studied from the earliest of times. We, the sentimental beings, make note of the differences among the flowers and fruit, the fall colors, the bark textures. We fall under their sway as lovers and observers of the biological world. We admire the habit, leaf characteristics, and blossoms. We see through a lens of potential landscape adaptability.
Well, some of us do. Those that do not, rely lightly or heavily on those that do: garden designers, landscape architects, horticulturists, garden center operators, nurserymen, and, of course, fellow gardeners. Appreciating beauty and harmony in nature sometimes requires another more experienced. Time and money well spent.
This leads me to the point of my article. I want to help the reader make some enlightened decisions regarding trees. My focus for this article will be to help you to enhance and embolden the landscape, not for immediate gratification but for the future.
The basic needs of a tree to maintain health and vigor are acceptable soil structure, texture and drainage, and appropriate pH (acidity or alkalinity). There should be a sufficient nutrient supply, proper room for root and top expansion, adequate moisture and light, and reduced negative impacts from insect, disease, mechanical and environmental damage.
Let's take a look at a hypothetical tree with perfect form and structure. Say it's a white oak, okay? As tall as it grows, seventy to eighty feet is not uncommon; its crown is often wider than its height. Its symmetry is near perfect when in leaf and when showing its internal architecture in winter. Approximately 60% of its mass is its trunk (2 to 4 feet in diameter), 20 % roots (15 % huge transport roots, often 10 to 12 inches in diameter, and 5 % fine feeder roots less than ten thousandths of an inch in diameter), 15 % branches and about 5 % leaves (hundreds of thousands).
How does one achieve growing a perfect tree? One doesn't. It's a bit like raising a child. You take the steps that you can and hope for the best. Be available to intervene if and when needed, but not everything is in your control. Starting at the beginning, as if you did all your homework, checked your soils, chose a tree cultivar resistant to most pests and tolerant of most stresses, you make your purchase.
Once correctly planted, about the only thing you can do, assuming it's a young healthy tree, is to train it in its early years. If purchased from a reputable nursery, it has already benefited from quite a bit of training before coming to market. Training sets out to achieve two goals: To correct growth and to correct structural weaknesses. Little action on your behalf is required the first growing season with the exception of supplying sufficient water if rainfall is lacking. Two inches a week from you or Mother Nature will be enough.
A sharp eye will, with careful pruning in late winter or early spring, when healing is at its most efficient, help you select a central leader, and select some permanent scaffold branches (these should be as near to horizontal as possible). And so the process begins of training a tree to become all it can be. To the degree that you take an active part, to that same degree will stresses and problems be dealt with or kept at bay.
If you have inherited a more mature tree, a little study will indicate any structural problems and these can be remedied if not too major or serious. A certified arborist can be consulted, if you have questions or doubts.
To keep your tree growing healthy and strong, make sure you do not change any drainage pathways in the area. Anywhere under the canopy of the tree (young or more mature) be sure not to compact the soil or drive any heavy machines that might pack the soil and result in oxygen deprivation of the roots.
Be sure not to bury the roots with additional soil. Some folks want to put in a flower garden underneath the tree. A shade garden would be perfect, they think. The way to accomplish this is not by adding six inches of soil over the root zone. The oxygen exchange they require will be impaired.
Most tree roots spread several times their canopy's diameter and are shallow and near the surface. More mature trees have visible roots at the surface. Disturbing these roots can cause major problems. Keep lawn mowers and weed whackers away. Every root cut or injured and every scratch on the trunk is an entry point for pathogens and diseases.
Mulch the root zone with organic matter to a depth of three inches or so. No deeper. Compost, well-composted manures, aged shredded bark or pine needles all work fine. Pull a bit away from the trunk so that in winter field mice and voles won't eat the bark and cause injury. It is acceptable to plant some shade loving ground covers in the mulch. This will keep away anxious mowers and weed whackers.
If your chosen tree or "adopted" senior loved one is in a lawn area, be especially mindful of the tree's needs. Lawns like lime. Excessive lime in the vicinity of your tree's roots might stress it. The same is true for any heavy inputs of fertilizers, salts, and pesticides.
Most stresses to trees are not a result of improper care or neglect. You are off the hook when it comes to things you have no control over. You can water when there is no rain, yes. But, when it comes to snow load, ice damage, heat waves, wind shear, floods and drought, squirrels, insect pest population explosions, there is little you can do. It is not a perfect world where everything goes your chosen way. As the old saying goes, compost happens, and Mother Nature rules.
There are lots of issues I haven't touched on, but I must leave you with two caveats. One: trees are autotrophs. They are self-feeders. They manufacture their own sugars and carbohydrates. Once established, they require no additional food. Overfeed them and you invite a host of insect and disease organisms to feed on abnormally tender growth. Not unlike we humans, an underfed tree is healthier than an overfed one.
Caveat two: Stressed trees are more vulnerable to attack from those organisms that are competing with them because their immune systems are compromised. Keeping your tree in the highest vigor will insure it is best equipped to fend off any environmental assault, including insect and disease attacks.
I hope I've supplied you with some groundwork for keeping your special tree in good health. Sometimes a strong spray from a garden hose is preferred to an assault of chemicals used for no good reason. Remember, Mother Nature rules.
From The Garden of Ed. Submitted for publication in The Towne Crier on June 28, 2006
© 2006 Ed Mues. All Rights Reserved.