Exploring The Last Green Valley: Mighty oak has glorious past, perilous present, hopeful future
“Since the glaciers last retreated and since humans began to build and settle down, there have been but two versions of the world: the world made of wood and the world made with coal and oil. One lasted twelve to fifteen millennia; the other has lasted about 250 years so far.”
– William Bryant Logan, Oak: The Frame of Civilization
The Last Green Valley National Heritage Corridor and much of Southern New England is forested land – with deciduous tree species the dominant type. They make up 50% of our landscape with conifers 12% and forested wetlands 5%. We are a land of oak, hickory, maple, birch and ash. Every year our multi-colored fall foliage provides the colorful truth to the great variety of deciduous trees in our region.
Of our broadleaf trees, it is our oaks that have the greatest monetary value as lumber wood, far outpacing other tree species for dollar per 1,000 board feet. The durability, hardness and beauty of oaks make them favored species for flooring and other commercial uses.
In his 2005 book, “Oak: The Frame of Civilization”, William Bryant Logan details the importance of oak trees over thousands of years of human development. The genus Quercus has dominated – not because it is the tallest tree or produces the hardest wood – but because oaks are found across the world.
The tall giant redwoods survive only on a cool foggy band of warm coast. The hard, workable ebony requires tropical heat, lots of water, and little variation in temperature. But oaks are found throughout the entire temperate climate zone, coinciding with locations of the settled civilizations of Asia, Europe and North America.
The first Europeans to arrive in North America came by boats made of oak; first the Norsemen followed by the French, Spanish and English. The great explorers and armadas of Europe crossed the oceans and “Britain ruled the waves” in ships made of oak. The most famous war ship in the United States and oldest commissioned naval vessel still afloat is the USS Constitution. Its planks of white oak repelled cannon from British warships thereby gaining the popular name of Old Ironsides.
Recently our region’s beautiful stately oaks have been in the press, and it’s not good news. Successive drought years starting in 2015 and persisting through 2017 along with dramatic gypsy moth infestation (oaks are the preferred food of the gypsy moth larvae/caterpillars) have resulted in extreme stress and death of countless trees. Oak mortality in Eastern Connecticut, central Massachusetts, and western Rhode Island, especially the larger specimens in our forests, has created a regional ecological disaster.
A summertime drive along Interstates 395 and 84, Routes 20, 44 and 6, or along our smaller country roads is all the proof you need. Within stands of foliated deciduous trees, the skeletal dead hulks of large oaks loom over roads, telephone and electric lines and yards. Within deeper forests the scene of dead oaks is even more tragic.
Last August, Thomas Worthley, UCONN Associate Professor of Forestry published “The Slow Storm: Tree Mortality in CT from Invasive Insect Pests”. Linked below, Worthley brings into sharp focus the local and regional costs of dealing with thousands of dead and potentially dangerous trees.
While gypsy moth caterpillars were the primary cause of mortality, stress from drought and native opportunistic pathogens brought about the death of oaks on tens of thousands of woodland acres in Eastern Connecticut
Thankfully, the spring and summer of 2019 has seen a dramatic decrease in the number of gypsy moth caterpillars with reports from around the region of caterpillars dying before reaching full size.
The primary cause of gypsy moth caterpillar death has been the Maimaiga fungus. Originally from Japan, it was released several times in the US, starting in 1910 as a potential biological control against gypsy moth caterpillars. At first the impacts seemed minimal, but starting in 1989, during a very wet spring, the fungus re-emerged and has continued each year, effectively keeping the caterpillars in check. That is until excessive droughts of the past few years.
If you think back to the recent spring season you will recall the cool and wet months of April and May, followed by a wet and hot June – perfect conditions for fungus. The Maimaiga fungus is effective for gypsy moth control since the annual life cycles of the two organisms interconnect. The fungus is in the soil and leaf litter as a “resting spore.” In the spring when there is enough rain and humidity, it activates.
This activation is usually at the same time the gypsy moth caterpillar is in its third growth cycle or “instar” when it spends time on the ground seeking shelter during hot days. While on the ground the spores infest the caterpillar. Some of the caterpillars will attempt to climb back up the tree only to die from the fungus.
This June many people were delighted to see pictures shared from around the region of dead gypsy moth caterpillars still clinging to tree trunks. This was the case in my yard with our single tall red oak tree. It was stripped of leaves last year, but still had enough energy reserves to sprout a second crop of leaves though smaller and not as well formed.
The 2018 the gypsy moth caterpillars pupated, and the adult moths emerged late last summer. This spring our old red oak tree bark was covered with gypsy moth caterpillar egg masses. From the bark I scraped and destroyed all the egg masses I could reach with a ladder. When the eggs in the upper canopy hatched, they began chomping. The fungus hit just in time and I am pleased to report at this writing our tall red oak tree has a full canopy of beautiful healthy green leaves
What will the future hold for the amazing oak trees of our region? The species has proven to be resilient in the past. The beauty and utility of oak is deeply bred in its genes and my guess is, the monetary value will remain as well.
It saddens me to see the standing dead trees – especially the ancient red and white oaks along the roads in my neighborhood. I also feel bad for many forest landowners who have spent decades growing large stands of oak only to see them perish in a few short years. Some landowners have resorted to salvage operations to remove the dead trees, now only suitable for firewood with minimal value as commercial grade saw timber.
Last week while walking the edge of my property, I found a tiny red oak sapling only 12 inches tall with two or three leaves. We only have one acorn-bearing oak tree on our property so certainly this sapling is from our old red oak. I cut back competing vegetation to urge its ascent towards the life-giving sun. My hope is that someday long after I am gone, it will stand proud with full canopy – a fine example of the amazing oaks. My favorite fortune cookie message is “The mightiest oak in the forest is just a little nut that held its ground.” Hopefully my little red oak sapling will hold its ground for generations to come.
We live in a beautiful place called The Last Green Valley National Heritage Corridor. I hope you will join me and so many others as we care for, enjoy and pass on this place we call home.
Bill Reid is chief ranger of The Last Green Valley National Heritage Corridor and has lived in the region for more than 35 years. He can be reached at firstname.lastname@example.org.
Sign up for our newsletter
"*" indicates required fields