Thursday, July 30, 2015

Halibut Point Conifers

Eastern red cedars (juniperus virginiana)
Your first thought about conifers at Halibut Point likely includes the cedars that preside over scrubby fields around the quarry. They're evergreen, conical, piney-looking, so 'conifer' seems to fit. And indeed they are conifers, but solely for the botanical reason that they 'bear cones.'

Cedar cones (juniper berries)
If you look closely at the matter, as botanists do, you find that our 'cedars' are actually junipers, juniperus virginiana. The non-scientific link with cedars probably derives from similarities in fragrance of the wood rather than from genetic ties. Amusingly our juniper has a ground-hugging cousin juniperus communis on Halibut Point that is more closely related to it than any upright plant.

Common spreading juniper, juniperus communis
All the species of the genus juniper fall within the cypress family Cupressaceae . Notice the similarity of the foliage to arborvitaes, another member of the family.

Arborvitaes, thuja occidentalis
Arborvitaes in our area are a non-native introduction. At least two groves of them are still prominent at Halibut Point from earlier ornamental plantings. Both they and the junipers have somewhat frond-like leaves and diminutive cones.

Arborvitae leaves and cones
The arborvitae leaves are brighter green and flatter than the more prickly juniper. Arborvitae cones are more conical than berry-like and mature to a brown color.
The largest family of conifers represented at Halibut Point is the pinaceae. Its largest genus is the pines. Some of them do quite well on challenging sites.

Pitch pine, pinus rigida
Close to the shore pitch pines tolerate wind, salt, and sparse soil. Their location and dwarfish dimensions offer preliminary clues to identification.

Pitch pine branch
The pitch pine is the only tree exhibiting three needles per bundle on its branches and twigs. Occasionally you may encounter Japanese or Austrian black pines with a similar dark stiff appearance to the pitch pine, but larger proportions, and two needles per bundle. Red pines (also two-needled) once planted near the parking lot are now in poor condition.

Scotch pine, pinus sylvestris
The other sizable non-native pine in the neighborhood distinguished by two needles per bundle is the Scotch pine, with a bluish cast and distinctly orange bark.

White pine, pinus strobus
White pines, our tallest-growing New England trees, thrive in more protected situations away from the shoreline.

White pine needles
Even at a distance you can recognize its soft bluish impression given by needles clustered five to the bundle.

White spruce, picea glauca
All the stately spruce trees at Halibut Point are non-native. The black spruces that originally grew on Cape Ann disappeared in colonial times. White spruces have been planted at scattered locations within the Park. In full vigor they present a classic conical outline with ascending branches.

White spruce detail
Typically spruce trees feature short needles emanating all the way around the twigs, and pendulous cones.

Norway spruce, picea abies
Norway spruces distinguish themselves with frill-like branchlets descending from larger branches with an effect of soft majesty.

Norway spruce detail
Individually the branchlets bristle with leaves all the way around the twigs, as in other spruces.

Blue spruce, picea pungens
Blue spruces handle wind and salt spray very effectively. Their resolute aspect conveys a rather stiff, chunky silhouette.

Blue spruce detail
Their twigs and cones, on the other hand,  have appealing delicacy and color.

White fir, abies concolor
The most stunning conifers in the Park must surely be the white firs, like a more lustrous blue spruce.

White fir detail
Needles surround the fir twigs in a more ascending manner than the spruce and are longer, broader, flatter. Firs can be recognized by their cones born upright on the branches.
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To appreciate the place of conifers in the plant kingdom, follow their lineage in the chart below.
As distinct from the lichens, mosses and ferns previously featured in Notes from Halibut Point, conifers reproduce by seed.
The evolutionary appearance of seeds brought advantages in significant ways:  increased storage of nourishment for the seedling; new strategies for dispersal; and dormancy until optimal germination conditions arrive, possibly spreading its occurrence over time so that a catastrophe after germination does not result in the death of all offspring of a plant.
Whereas most of today's seed-producing plants (angiosperms) flower and produce hard or fleshy structures called fruits to enclose individual seeds, non-flowering gymnosperms do not. Instead the seeds of gymnosperms (primarily conifers) begin their development "naked" in the protection of cones.

1 comment:

  1. Great article! Well written. I would love to see some more :)