The Pitch Pine Forest: A Rare Ecosystem – by Laurie Gorham
On a ridge in Groton, Connecticut lies a fragile ecosystem where pitch pine exists in unusually large numbers. The ridge resides within the Candlewood Hill Wildlife Management Area, a 200 acre preserve recently acquired by the state. Both the name “candlewood,” and the vulnerability of the ridgetop ecosystem reflect this species relationship with fire.
Pitch pine, Pinus rigida, occurs naturally on sandy soil and ridge tops favoring nutrient poor, dry, and acidic environments where other species cannot survive. One of the most drought tolerant of the trees, pitch pine is common throughout Cape Cod and is the dominant tree of the Pine Barrens of New Jersey. Yet despite its preference for areas other species avoid, seeing a large stand of these trees in Connecticut is rare. In fact, the pitch pine forest has been identified by the Connecticut Department of Environmental and Energy Protection (CT DEEP) as one of the 13 most critically endangered ecosystems in Connecticut.
The noun “candlewood” has been used to name all sorts of places: streets, health spas, mountaintops, and undoubtedly others, but the word was originally coined to denote any “resinous wood used for torches or as a substitute for candles.” Pitch pine is highly resinous which made it valuable as a source of illumination in colonial times. Colonists used slivers in place of candles and the knots as torches. In addition to being flammable and useful as lighting, resin could be mixed with other substances or refined, yielding products such as tar, pitch, and turpentine. Across the two-lane highway from the wildlife management property an aptly named Candlewood Street connects routes 184 and 117. Could the street be so named because of a former prevalence of pitch pine in the area?
Ironically, the tree that served humans as a source of fire is also one of the most highly evolved to survive it. The thick bark, for example, (as much as 2 inches thick on a mature tree), insulates the trunk against fire damage. The bark has another secret too, for underneath the bark lies dormant, epicormic buds which can sprout should a fire burn away all its needles. The tree can also regenerate from its basal roots which sink deep into the soil. And finally, pitch pine’s cones provide what writer Charles Fergus describes as the tree’s “ace in the hole.” The tree produces some cones that are serotinous — sealed from the inside with resin that require heat to open them. Should a fire kill the tree and its roots, it will also cause the serotinous cones to split open, scattering the seeds on freshly fire cleared soil.
And therein lies the fragility of the pitch pine ecosystem. Although the trees are highly adaptable and can grow almost anywhere if planted by humans, they require open sunny ground to regenerate from seed. Wildfires, which would periodically clear an area of underbrush, are now suppressed, allowing shrubby undergrowth to flourish and more shade tolerant trees to creep in, crowding out the pine. Currently, within the CHWMA, black huckleberry provides the understory, blanketing the ridgetop in a near mono-culture, although it is intermixed with lowbush blueberry and a shadbush here and there, as well as drought-tolerant bear oak. All these species can regenerate from underground roots in case of fire. In the absence of it, pitch pine seedlings are shaded out by other vegetation.
Bear oak, occurring frequently with pitch pine, hosts several endangered moth species. Pink ladyslipper and wintergreen dot the shaded area beneath the shrubbery. Many birds of interest including ruffed grouse, worm-eating warbler, scarlet tanagers, and rufous-sided towhees call this place home.
Pitch pine-bear oak forests were once common along the sandy coastal plains of the northeast. Development and fire suppression have degraded pitch pine stands by an estimated 95% in Connecticut. Candlewood Hill hosts the largest contiguous stand of pitch pine in the state; yet even here, red and chestnut oak, sassafras, and the black huckleberry are quickly overtaking the pitch pine. It is hoped that once the state completes its management plan for the area, DEEP officials will begin controlled burns to protect this special habitat.
Written by Laurie Gorham
Fergus, Charles. Trees of Pennsylvania and the Northeast. Mechanicsburg: Stackpole Books, 2002
Many thanks to Whitney Adams for sharing his notes and sources, and to Bruce Fellman for the birds.