The End of Trees

When the eponymous John Winthrop and the English Puritans founded this town it was all trees. Winthrop is not like that now.

Stresses against Winthrop trees are plenty. The biggest and oldest trees were planted long before global warming, paved roads, pollution, salt, soil compaction, and strikes by cars and trucks. Think what would happen if you stood by the curb day and night for sixty years. Eventually you would be hit by a vehicle or poisoned by pollution or die of thirst. Most old trees lining Winthrop’s busy streets have been hit. Some are now dying of hunger and thirst in our current drought.

As you look at the trees in town you will see at least two types with dead branches on top of their crowns. Look for them. There are Crimson King maple cultivars of Acer platanoides that can no longer gather water and nutrients with their roots that are largely under crushing concrete and asphalt. They give up their extremities. Imagine if when you were thirsty and could not move to get a drink that your fingers and later your hands, feet, and arms would die and fall off. Since our trees cannot sidle up to a local bar for a drink, we have to bring water to them. We can help and save some by watering them. We can’t save them from voracious, invasive insects.

Our town’s ash trees are doomed to die because they are all infected by the invasive emerald ash borer. It is a tiny, shiny, pretty green insect that lays its eggs under the bark of the tree. Larvae eat the living cambrium layer that gives rise to the vascular cells, the xylem and phloem, that transport water and nutrients up and down the tree. Imagine a little worm eating your veins and arteries! These ash trees (they have a compound leaves with 5 to 11 leaflets) die from the top. You can see them all over town.

Trees shade us from the hot sun. They tug water to their leaves, where it evaporates and thus cool the air. Trees shade the black asphalt. In full sun the asphalt heats and retains the heat, which is a serious health threat. Heat kills more people than cold.

Trees remove dust and pollution from the air. Winthrop is cauldron of air pollution. The airport is our biggest hazard. Jet fuel combustion releases particles smaller than 1 micrometer in diameter. Truck and bus diesel produce exhaust comprising even smaller particles of hydrocarbons, sulfuric acid, carbon, and metallic ash. They are so wicked tiny that we breathe them deep into our lungs, where they do the great damage. We also breathe the soot from the airplane tires that burn at every touchdown. The dampness of tree leaves will catch and hold many of these particles, until the next rain and not get into our houses and lungs.

Trees grant us an economic benefit by increasing the re-sale value of properties in their proximity. A house on a tree-lined street often commands a high price. Trees are beautiful and so help us relax and reduce our own stress.

Entire ecosystems live in the tree canopy. Birds feed on the insects in the trees, and insects feed on each other and on fungi and bacteria, all by grace of the energy gathered and stored in tree leaves and bark. Also pretty birds, cute squirrels, and bandit raccoons frolic in trees.

Trees nourish an equally complex system underground where their roots bring the carbohydrates created in their leaves to bugs, worms, and fungi that live in perpetual darkness. Fungus underground lives in a symbiotic relationship with trees by helping them find water and nutrients through their fine filaments to the wood of the tree roots. The tree provides them with carbohydrates photosynthesized in their leaves. This mycorrhizal fungus connects trees with each other so they can share water and resources over a wide area. The mushrooms that appear on the lawn are often the fruiting bodies of a huge and extensive beneficial underground fungal mycelium communication system. Arborists and tree wardens jokingly call this the “wood wide web.” Trees need to be many and close to each other to flourish.

But all this wonder is in peril. If trees die, our town loses. The end result, the function, of trees is the benefit to us, to enrich the town and the ecosystem. We can save the trees and save these benefits. We can replace dead, dying, dangerous trees with new ones. Which will it be?

When the ash trees die we will have to remove them because their brittle, dead branches often fall without warning. Public safety is the tree warden’s first responsibility.

We cannot save the ash trees but we can save the function–the benefit and beauty–of trees for each of us in Winthrop to enhance the tree canopy of Winthrop for the next 100 years. The town will plant trees at your request on the homeowner’s side of the sidewalk where their chances of survival will be much greater than if they are imprisoned in hardscape. Contact the tree warden at tderderian@winthropma.gov to see if you have a spot that will qualify for a public tree. The shade will serve us all.