The Architecture of Trees

 

A towering Giant Sequoia (Sequoiadendron giganteum) in
Yosemite National Park, California.  Giant Sequoias are among the
largest trees in the world.  The huge trunk of this tree reaches about 200 feet
before branching. 

Winter is a great time to admire the architecture of trees.  Deciduous trees dropped their leaves in the fall and their structure is on display for all to admire.  The variety of tree shapes is astounding.  Some trees have towering trunks with their branches high in the air.  Others are small with multiple trunks.  Some trees look like vases or columns or pyramids, some weep.

 

A Bald Cypress (Taxodium distichum) with the pyramid shape. 
Like Christmas trees, this Bald Cypress is widest 
at the bottom and tapers toward the top.
Rowan County, North Carolina. 

A Red Maple (Acer rubrum) with many trunks growing from the base
giving it a vase-like shape. Rowan County, North Carolina.

Dwarf Weeping Cherry (Prunus subhirtella).  This small tree has
a short trunk and numerous contorted branches. The terminal branches
hang down and the tree appears to weep.
Rowan County, North Carolina. 

The branching pattern of trees has much to do with their shape.  Leonardo da Vinci, when he was not painting the Mona Lisa, designing helicopters or making breakthroughs in human anatomy, considered the branching of trees.  His fundamental insight about trees is that the cross-sectional area of the trunk is equal to the cross-sectional area of the branches.  So, if the main trunk of a tree has a cross-sectional area of 100 square inches and it branches into two main limbs, those two limbs will have a cross-sectional area of about 50 square inches each.  This pattern continues with all subsequent branches.  If you measure the cross-sectional area of the twigs they will still have a cross-sectional area of 100 square inches. 

 

Black Gum (Nyssa sylvatica) with a main trunk
and many limbs with branches. Rowan County, North Carolina,

Consider the branching of trees.  A branch may divide into two branches and each of those branches could branch into two more branches.  This pattern is repeated many times in a tree.   Iterative branching goes a long way in explaining the shape of trees.  Trees are natural examples from the field of mathematics called fractal geometry.  The Polish-French-American mathematician Benoit Mandlebrot coined the term fractal in the late 20^th century to describe objects that have similar structure at different scales.  If you look at a whole tree, you find the same basic pattern in the limbs, branches and twigs. 

 

A fractal tree. Virtual trees like this can be produced by a
couple of dozen lines of code. This mathematical tree bears
a striking resemblance to a biological tree. 
https://commons.wikimedia.org/wiki/File:Fractal_canopy.svg

The fractal branching pattern of an American Sycamore
(Platanus occidentalis). Rowan County, North Carolina.

Fractal tree canopy in winter. Rowan County, North Carolina

The reason a tree makes all those branches is to provide the scaffold for the leaves.  A large tulip poplar tree (Liriodendron tulipifera) may have over 100,000 leaves.  Each leaf weighs only a few grams but during summer, particularly when the leaves are wet and the wind is blowing, they put a tremendous stress on the tree.  This load is supported by up to fifteen tons of wood in the trunk, limbs and branches. 

 

Leaves of Tulip Poplar (Liriodendron tulipifera) in high summer.
The hundreds of thousands of leaves are supported by the many
small branches of the tree.

Some trees have tall straight trunks and limbs extending out to the side.  Pine trees (Pinus sp.) are good examples of this structure. When a side limb dies or is broken off, the tree continues to grow in diameter until the broken limb is entirely overtaken and is now inside the trunk.  This old limb may be invisible from the outside but, if the tree is converted to lumber, the old branch is seen as a knot in the wood. 

 

Shortleaf Pines (Pinus echinata) with tall, straight
trunks and limbs branching off.
Rowan County, North Carolina. 

A dead limb on a Shortleaf Pine.
Rowan County, North Carolina.

The knot in a pine 2x4 is a branch the wood grew over as the
tree increased its girth.
Rowan County, North Carolina. 

Spring is coming on and soon the trees will be cloaked in green.  But the deep structure, the architecture of trees, will still be there.

Nothing Like a Beach

A stormy day on the beach at Spanish River Park, Boca Raton, Florida.
This part of Floirda is called the Gold Coast because the sand takes on a golden hue
from shell fragments mixed with the white quartz sand. 

There is nothing like a beach.  The infinite horizon, the ever changing light, the sound and even the smell make beaches irresistible.  About 40% of the US population lives near the coast.  But, even at a beach lined with high-rise hotels, if you turn you back on the buildings there is a wet wilderness running to the vanishing point.  This interface between land and ocean is harsh.  Abundant water, salt and light mean unique plants and animals are found on beaches.  Some are sea creatures that wash up.  Some are denizens of the land that occupy the last real estate before the ocean.  Others are highly adapted to living on this demanding edge of the continent.  

I grew up in South Florida, a mile and a half from the Atlantic.  The beach was part of the fabric of my life. Now I live hours from the nearest beach and it is always special when I get to a beach. This blog will examine some beaches and the creatures on them.  

Florida

Lesser Black-backed Gull (Larus fuscus) on Lake Worth Beach, Florida.
This large gull winters in the Southeastern United States where its
numbers are increasing. 

Royal Tern (Thalasseus maximus) on Lake Worth Beach, Florida. 
Royal Terns are year-round residents from North Carolina to the tropics.

Sandwich Tern (Thalasseus sandvicensis) at Spanish River Park, Boca Raton, Florida.
This tern is smaller than the nearby Royal Terns.  It has characterisitc yellow tip on
its beak, as if the bird dipped its bill in mustard.  

Two White Ibis (Eudocimus albus) feeding in the surf at Canaveral National Seashore,
Florida. These waders are found in fresh, barckish and salt water.

Portugese Man-o-War (Physalia physalis) at Boynton Beach Park, Florida.
This relative of corals and jellyfish is the bane of swimmers. 
It has an irredescent blue float and trails tentacles in the water
that bear stinging cells.  A person unlucky enough to
brush against a tentacle will receive a painful sting.

South Carolina

Sunset at Surfside Beach, South Carolina. The sand on the South Carolina
beaches is gray and made of sand washed into the Atlantic
from rivers. 

Ring-billed Gull (Larus delawarensis) on Surfside Beach, South Carolina.
This is the most common gull in the Southeast.  

Sanderlings (Calidris alba) in the sunrise surf at Huntington Beach State Park,
South Carolina. Sanderlings are small, gray and white shorebirds that run up and down the 
beach like a windup toy, following the breaking waves.  The name Sanderling comes from
Old English and means "sand plower".  And they do plow the sand, looking for 
 the small animals they eat. 

A dead Common Loon (Gavia immer) washed up on the sand at Huntington Beach
State Park, South Carolina.

Ghost Crab (Ocypode quadrata) at Huntington Beach State Park,
South Carolina.  These crabs are sand-colored and make burrows 
on the beach above the high tide line.  They usally feed at night but
this one was out on a cloudy day.  The genus name, Ocypode, means
swift footed and so they are.  

This may look like an aerial view of the Sahara Desert but these
dunes are only two inches tall.  Huntington Beach State Park,
South Carolina. 

West Coast

The rocky shoreline of the Monterey Pennisula, California. 

Bull Kelp (Nereocystis luetkeana.) on a sandy beach, Monterey Pennisula,
California.  These giant Brown Algae may reach 100 feet in length.
Kelps make extensive forests in the Pacific off California.  The round
structure is a float the alga fills with gas including carbon monoxide. 
The float keeps the kelp near the surface so it can carry out photosynthesis. 

 

Cannon Beach, Oregon has a sandy beach with sea stacks, large
rocks produced by coastal erosion. This location was used in the great
kid's adventure movie, The Goonies.

The most amazing thing I have ever seen on a beach was a Walrus
(Odobenus rosmarus).  This giant marine mammal was hauled out on the shore of
the Bering Sea, south of Nome, Alaska.  Walruses use their tusks to open breathing
 holes in sea ice and pull themselves up onto ice floes. 

Hawaii

The Hawaiian islands are ringed by beautiful beaches. 
I think the most spectacular are the black sand beaches. 
They are made of eroded sand and stones from lava. 
This black sand beach was at Punalu'u County Beach Park
on the Big Island. 

A Green Sea Turtle (Chelonia mydas) sunning on a black beach.
Punalu'u County Beach Park, Hawaii. 

Black sand beach backed by Coconut Palms (Cocos nucifera).
Punalu'u County Beach Park, Hawaii. 

When I was a kid going to the beach with my family, we would swim and snorkle, body surf and beach comb.  Now, I am not swimming or body surfing or snorkeling as much.  But I still like to walk the beach, looking at the water and seaweed and all the animals at the end of the land.