I find that while teaching Woody Plants and Arboriculture, there is nothing better than taking students off site from Longwood Gardens (where students have an amazing campus of plants to study) to see plants outside the regular garden areas. It is a way to reinforce identification skills while looking at the overall structure and health of the trees.
Our first stop on our journey was to Laurel, Delaware at Trap Pond State Park (Friday, March 16). The park is famous because it holds the northern most stand of bald-cypress (Taxodium distichum) in North America.
The day was bitterly cold and windy with gusts over 25 mph but that didn’t stop the group from botanizing. They really enjoyed looking at the trees from Cypress Point.
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This spot is great in the winter and early spring months to see the cypress because all the surrounding trees on land are bare. Come summer the place to see these amazing giants is from the water. Other plants that are at the site are the less frequently seen sand hickory (Carya pallida) and seaside alder (Alnus maritima subsp. maritima) an endangered species unique to only three locations in the U.S. Bartow County, Georgia, south-central Oklahoma and the Delmarva Peninsula.
The corky bark of the sweet gum (Liquidambar styraciflua) was evident as we looked up into the trees giving its distinctive character. The seedpod with its pointy projections makes this plant easily identifiable. The fruits produce thousands of seeds. We also looked at how trees and other woody plants grow in their natural habitat with their associate plants. Soil type,
The shrubby border begins behind the dune grasses and includes beach plum (Prunus maritima) and northern bayberry (Morella pensylvanica). Then you will begin to see small pine trees beginning to sprout and working their way inland.
Pitch pine (Pinus rigida) grows beautifully inland but grows equally well along the windswept shoreline of the Atlantic Ocean. Seeing it growing along the ocean dunes gives a different visual than growing inland where it is tall and straight in growth habit. Along the coastline sometimes trees are shorter in stature and even “bonsai looking” a form of dwarfing and atypical of what is seen inland. (See photo on the right, Bonsai-like – or windswept appearance of the pitch pine, also known as the Krummholz affect – a twisted and knurled tree).
Mycorrhizal fungi also grow in concert with pines. They help with stabilizing the dunes with their extensive hyphae (collectively mycelium) and assist with nutrient uptake for the pines.
Pitch pine cones have spines on their scales. The spines prevent predators from eating the seeds inside. Pitch pine is classified as a fire species and the stems (peduncles) of the cones are non-existent (sessile) to make sure that during a fire event these cones do not fall off the tree. After a quick moving cool fire the cones open up to release their seeds to begin their life on the charred floor of the woodland. The seeds quickly sprout and begin to grow to cover the woodland floor and to provide habitat for birds and other creatures. If there is no fire, the cones will eventually open after several years of drying.
On this dune we found Japanese black pine (Pinus thunbergii) growing happily with other native pines. This was not surprising to find this non-native tree because many shore homes years ago would plant this pine in their landscapes. They have since seeded into the dune habitat and in some cases have hybridized with other pines. Some have purposely been planted because they come from a similar environment in Japan making it wind and salt tolerant.
Below, pitch pine grows with other associates like loblolly pine (Pinus taeda) and poverty pine (Pinus virginiana) along with scattered Japanese black pine (Pinus thunbergii).
Where there was a soft duff layer of pine needles, the students found this Northern Fence Lizard or pine lizard (Sceloporus undulatus hyacinthinus). He was sunning himself on this nice warm spot. The scales are made of keratin, which helps in protecting the lizard from drying out through evaporation. These characteristics help this cute creature to live in some of the most difficult environments – especially dry ones.
Alnus maritima subsp. maritima
Beachgrass invasion in coastal dunes is mediated by soil microbes and lack of disturbance dependence
Allison Brown, Ph.D.
Information on the Telephora fungus
Cape Henlopen, Lewes, Delaware
Dune Ecology: Beaches and Primary Dunes
Dune Ecology: Secondary Dunes and Beyond
Eastern Fence Lizard or Pine Lizard
Krummholz – Banner and Flag Trees
Promise of Place
Trap Pond State Park, Laurel, Delaware
“What is Place-Based Education and Why Does it Matter?”