Why Trees Matter

By JIM ROBBINS

Helena, Mont.

TREES are on the front lines of our changing climate. And when the oldest trees in the world suddenly start dying, it’s time to pay attention.

North America’s ancient alpine bristlecone forests are falling victim to a voracious beetle and an Asian fungus. In Texas, a prolonged drought killed more than five million urban shade trees last year and an additional half-billion trees in parks and forests. In the Amazon, two severe droughts have killed billions more.

The common factor has been hotter, drier weather.

We have underestimated the importance of trees. They are not merely pleasant sources of shade but a potentially major answer to some of our most pressing environmental problems. We take them for granted, but they are a near miracle. In a bit of natural alchemy called photosynthesis, for example, trees turn one of the seemingly most insubstantial things of all — sunlight — into food for insects, wildlife and people, and use it to create shade, beauty and wood for fuel, furniture and homes.

For all of that, the unbroken forest that once covered much of the continent is now shot through with holes.

Humans have cut down the biggest and best trees and left the runts behind. What does that mean for the genetic fitness of our forests? No one knows for sure, for trees and forests are poorly understood on almost all levels. “It’s embarrassing how little we know,” one eminent redwood researcher told me.

What we do know, however, suggests that what trees do is essential though often not obvious. Decades ago, Katsuhiko Matsunaga, a marine chemist at Hokkaido University in Japan, discovered that when tree leaves decompose, they leach acids into the ocean that help fertilize plankton. When plankton thrive, so does the rest of the food chain. In a campaign called Forests Are Lovers of the Sea, fishermen have replanted forests along coasts and rivers to bring back fish and oyster stocks. And they have returned.

Trees are nature’s water filters, capable of cleaning up the most toxic wastes, including explosives, solvents and organic wastes, largely through a dense community of microbes around the tree’s roots that clean water in exchange for nutrients, a process known as phytoremediation. Tree leaves also filter air pollution. A 2008 study by researchers at Columbia University found that more trees in urban neighborhoods correlate with a lower incidence of asthma.

In Japan, researchers have long studied what they call “forest bathing.” A walk in the woods, they say, reduces the level of stress chemicals in the body and increases natural killer cells in the immune system, which fight tumors and viruses. Studies in inner cities show that anxiety, depression and even crime are lower in a landscaped environment.

Trees also release vast clouds of beneficial chemicals. On a large scale, some of these aerosols appear to help regulate the climate; others are anti-bacterial, anti-fungal and anti-viral. We need to learn much more about the role these chemicals play in nature. One of these substances, taxane, from the Pacific yew tree, has become a powerful treatment for breast and other cancers. Aspirin’s active ingredient comes from willows.

Trees are greatly underutilized as an eco-technology. “Working trees” could absorb some of the excess phosphorus and nitrogen that run off farm fields and help heal the dead zone in the Gulf of Mexico. In Africa, millions of acres of parched land have been reclaimed through strategic tree growth.

Trees are also the planet’s heat shield. They keep the concrete and asphalt of cities and suburbs 10 or more degrees cooler and protect our skin from the sun’s harsh UV rays. The Texas Department of Forestry has estimated that the die-off of shade trees will cost Texans hundreds of millions of dollars more for air-conditioning. Trees, of course, sequester carbon, a greenhouse gas that makes the planet warmer. A study by the Carnegie Institution for Science also found that water vapor from forests lowers ambient temperatures.

A big question is, which trees should we be planting? Ten years ago, I met a shade tree farmer named David Milarch, a co-founder of the Champion Tree Project who has been cloning some of the world’s oldest and largest trees to protect their genetics, from California redwoods to the oaks of Ireland. “These are the supertrees, and they have stood the test of time,” he says.

Science doesn’t know if these genes will be important on a warmer planet, but an old proverb seems apt. “When is the best time to plant a tree?” The answer: “Twenty years ago. The second-best time? Today.”

Jim Robbins is the author of the forthcoming book “The Man Who Planted Trees.”

Press Release

September 2013

As you go about Oriental you may have noticed a lot of young trees along our streets that have black plastic collars on their base. These trees are in the street right of way and were planted by members of the Tree Board. There is a single reason for the collars and that reason is to protect them from string trimmers.

Young trees have thin bark and using string trimmers to cut grass growing next to the trunk severely damages and often kills the trees by girdling them. String trimmers kill the bark and cambium (the layer under the bark that grows wood on the inside and bark on the outside). The tree uses its inner bark to transport sugar down to the roots to feed them and for root growth. Roots below the area where bark has been lost often die of starvation, the result being less stability and less water for the leaves. Less water means less sugar made and this will affect the overall health of the tree.

Most new town trees have three stakes placed around them. While sometimes used to hold the tree in place during predicted high wind, mostly they are intended to keep mowers away from the trunk. Mowers can damage mature trees by mechanically knocking the bark loose and causing the cambium and bark to die resulting in the same problems from string trimmer damage.

I have heard people say that string trimmers won’t harm trees, and that is true for a mature tree that has thick bark such as oaks, pecans or pines, but even these trees will be damaged when young because all trees have thin bark when young. Trees such as crepe myrtle are damaged by string trimmers even when mature because they maintain very thin bark throughout their lives.

A little caution with string trimmers and mowing will go a long way to protect your investment in your landscape trees. If you use a lawn service to care for your property insist that they exercise care with trimmers and mowers around your trees, and to exercise care around street trees planted in the town right of way.

There is a final concern regarding mowing and water quality. When grass clippings are blown into the street they are washed into our creeks and rivers in the next rain. These clippings carry a lot of nitrogen and cause pollution problems for our waterways. Keep them on the lawn where they will fertilize your grass and not our water.

Bob Miller

Oriental Tree Board

Press Release

Oriental Tree Board

September 25, 2009

Being a member of the Oriental Tree Board I am often asked about logging here in Pamlico County, especially the practice of clearcutting.  This concern seems to be primarily based on the unsightly appearance of logged stands immediately following the harvest of timber, and the perceived destruction of the forest. 

First, we need to understand the nature of forests and forest management here in North Carolina.  The Southeastern United States is regarded as one of the global wood baskets due to the abundance of forestland and the favorable climate in which to grow trees.  We have a long growing season with abundant rainfall, factors that make the Southeast an excellent place to practice commercial forestry.  The only place in the United States that grows trees at a faster rate than here in the Southeast is along the Pacific Northwest coast. 

That being said, what about Pamlico County?  Most timber management here is to grow pine trees, primarily loblolly pines that have been genetically selected for rapid growth.  Typically the pines are planted, thinned two times for pulpwood to make paper and other cellulose fiber products, followed with a final harvest of logs destined for sawmills or utility poles.  All of this takes place in less than thirty years.  Where I come from in colder and drier Wisconsin, this would take 20 to 30 years longer. 

Pine trees are typically clearcut for their final harvest because they grow best in full sunlight.  They are replanted soon after harvest so that seedlings can take advantage of the sunlight and so foresters can control the composition of the next forest.  If a stand of timber is logged and not replanted, then a new forest will grow back anyway because forests are the natural land cover in much of North Carolina.  However, the composition of this forest will be mixed and this mixture will depend on what seeds are available to grow following logging.  If a pine forest is not logged other trees (mostly hardwoods) that can tolerant more shade will seed in under the pines and eventually replace them as the pines die of old age. 

Much of the high ground in Pamlico County was covered by stands of longleaf pine at the time of European settlement.  These longleaf forests were maintained by frequent fires that were intentionally set by Native Americans or were caused by lightning.  These forests were kept open underneath and did not seed into hardwoods because the fires killed the hardwood seedlings.  Longleaf pine successfully reproduced itself because of its resistance to fire and because the open nature of these forests allowed sunlight to reach the forest floor.  Longleaf pine also lives a very long time, much longer than loblolly pine. 

This brings us back to logging.  Most forest land in the county is privately owned, and many owners manage these forests to gain income and to produce wood for forest products.  In the seven years I have lived in Oriental three forest stands near my home have been logged.  One was clearcut and planted, and now has pines that are about 15 feet tall.   The second was clearcut but not replanted and now has a young mixed pine/hardwood forest.  The third was cut leaving scattered seed trees and it has a pine/hardwood mix, with pine being dominant. 

Logging is a messy business no matter the method used.  Tops of trees and branches are not usable so they are left in the forest to decay.  This isn’t a bad thing since they will release nutrients into the soil for use by the new trees.  In just a few years in our humid climate most of the material will rot away.  I have been asked why loggers are not required to clean up the debris after logging.  This would be impractical and very expensive, and would keep valuable nutrients from returning to the soil. 

There is also the question of the impact of this kind of forestry on wildlife.  While plantations usually have only one species of tree in the canopy, shrubs, grasses and herbs grow under the pines.  These managed forests will attract wildlife species that do well in recently cut areas and in young forests.  However, wildlife that depends on old forests for their habitat needs will be scarce or absent. 

Pine plantations are more diverse and contain more wildlife than farm fields and housing developments, but the most diverse wildlife habitats here in the county are the wet forests (swamps), and freshwater and salt marshes.  The virgin forests of longleaf pine were extremely diverse in plants and animals.  There are some managed longleaf forests along highway 306, especially between highway 55 and Aurora. 

To sum this all up, most logging here in the county is of managed forests that are soon replanted after harvest.  While they are not as diverse as the longleaf forests of the past, they do provide important wildlife habitat, income for their owners, and forest products we all use. 

Bob Miller

Oriental Tree Board