Trees: One type of natural history book

TREES are all around us. We like their beauty, their shade for our homes, their wildlife benefits, and in many cases for their long term benefits as part of conservation plans. And when they are mature, wood products for lumber become another use. And trees are a renewable natural resource where planting new ones insures the long term viability of a forest, woodlot or landscape setting. The key is to allow the right mix of trees to grow in the right places. Mom Nature does a pretty good job of this in natural setting. Mankind can manipulate wood lands for a wide range of desires or outcomes.

Along with the good comes the bad. But a word of caution when we humans place a tree in the “bad” column base upon our misinformation or outright lack of knowledge. We can overcome these shortfalls with expert advice from private and/or public foresters. Iowa DNR forestry has several folks employed in this category to assist landowners with all kinds of forestry related questions. Depending upon the land owners wishes or long term desires, trees can be managed.

A recent program offered the public a chance to hear the latest information about the Emerald Ash Borer, a small insect that is slowly spreading its way across eastern North America. Forester Joe Herring recently presented a slide show to an audience of 25 folks. He illustrated how the disease was originally detected in the Detroit area. It is thought the little emerald colored beetle was in the wood of shipping crates. The bug found its host trees in America to be our native species of ash, black, white, green, white and purple. Since the 1990s, Herring’s maps showed how confirmation sites are now found in most eastern states, eastern Canada and now in the Midwest.

There is no effective cure for the disease at this time. A little wasp imported from Asia is a predator on the ash borer. The wasp can detect the boring activity deep under the bark of an infected tree, drill through the wood and make a direct hit on the borer whereupon it lays its eggs. The success of this wasp is not keeping pace with its assigned task. Chemical treatment by licensed applicators for ash trees 20 inches or more in diameter can be attempted. Home or property owners can treat trees much smaller if they first get good advice and know their ash trees are worthy of this long term care.

An alternative to trees that may be lost from emerald ash borer is to plan now for selective removal, and replanting with a wide mix of species. We should have taken a hint from Mom Nature to not put all our eggs in one basket. Community streets of nothing but once majestic elms are long gone. Since then lots of city streets were planted predominantly to ash trees. Now they may face the same fate. So, it is best to mix the species of trees by picking from a long list of shade trees, low growing trees and conifers suited to growing conditions in Iowa. The organization TREES FOREVER, INC., is based out of Marion. Call them at 319-373-0650 or 800-369-1269. The website is

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BALD CYPRESS TREES are good record keepers. If you want to know what the weather was like hundreds or 1,000 years ago, University of Arkansas’ David W. Stahle is the person to ask. He has studied this species for the last 30 plus years. At sites in Virginia’s coastal swamps, he finds big cypress trees, drills out a small core and examines growth ring patterns. In one case he found the tree to be alive and growing in the year 934, before the first Norsemen reached American shores.

Stahle has looked for evidence of past weather patterns. Since our detailed instrumented record collection and data keeping is only about 100 years old, tree rings can help fill in long ago events of lots of rain, long droughts and everything in between. One of his discoveries can be summarized this way: The East Coast has been lucky with rainfall during the last 100 years. Cypress tree rings tell the story and provide the evidence of long lasting mega-droughts long ago, even worse than the 1930s Dust Bowl experiences of North America.

Tree rings reflect the material added each year. Lean years of moisture equals thin rings, and normal to abundant rains see more material added for those seasons. One of Stahle’s tree samples for a cypress shows it had 1,650 rings from a gnarled hollowed-out specimen on the Black River in North Carolina. He pinpointed a drought that began in 1587 and lasted two years. At this same time frame British settlers on an island disappeared, now explained by the drought. Move or perish were the settler’s options. The year 1587 was the worst single-year drought in the last 1,072 years in the Tidewater. Additional data was so precise that it confirmed tree growth in 1901 with known 1901 precipitation.

More data showed how long droughts were far more common and far worse than recent historical accounts. In the 1960s, Washington, D.C. experienced a shortage of rainfall that lasted for five years. Brush fires broke out in suburban settings and the Potomac River was running very low. But as bad as that time frame was, cypress tree growth rings tell of worse droughts 1,000 years ago and again 1,400 years ago, each lasting 30-50 years. This proves that Mother Nature has her own plans that do not take into account modern day human desires. She moves at her own pace without regard as to how it affects humans. Our choices are to adapt, adapt or adapt. The take away point I’m making is that we must not be lulled into thinking that wet conditions, or drought conditions, or any short term mixes of the two are to be construed as a definition for normal. Our timeline is way too short compared to the infinite time line of earth’s 4.567 million year old history.

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North America has about 1,000 species of trees. World wide the number grows to at least 10,000. One Banyan “tree” in India has 2,880 trunks, which are actually prop roots which makes this species a wonderful example of the complexity of woody plant types that can be found. Trees and other green plant take in carbon dioxide and give off oxygen. One large tree can provide the equivalent of one day’s supply of oxygen for up to four people. More than 20 percent of the world’s oxygen is produced in the Amazon Rainforest. Here is another tree trivia that is not so trivial. Forested watershed provide quality drinking water to more than 180 million Americans. Trees properly placed can reduce a household’s energy consumption for heating and cooling by significant amounts, estimated at between $100 and $250 annually. Trees properly placed enhance homes and when the house is put up for sale, it sells quicker and for more money than an equivalent home without trees.

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Advice from a tree: Stand tall and proud, Sink your roots deep into the earth, Be content with your natural beauty, Go out on a limb, Drink plenty of water, Remember your roots and Enjoy the view.


Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at P.O. Box 96, Albion, IA 50005.