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Muir Woods: Learn About the Impressive Coastal Redwoods and More!


Muir Woods: A Little History First!

President Theodore Roosevelt proclaimed Muir Woods a National Monument in January of 1908.  John Muir (1838-1914) was a mountaineer and naturalist.  He spent much of his life wandering in the wilderness.  Muir was a strong advocate for the natural world and encouraged others to be too.  He fought for the conservation and preservation of places such as Yosemite National Park, Sequoia National Park, and Glacier Bay.  Because of this, the park was dedicated to John Muir.  Muir was also the founder of the Sierra Club, which is still active today!

         “And into the forest I go, to lose my mind and find my soul.”   – John Muir


Muir Woods: The Coastal Redwoods

I must say, I felt like Muir as I walked among the coastal redwoods!  There is something so peaceful and awesome about walking in the woods.  Muir Woods is one of the last old-growth coastal forests on Earth.  These redwoods are the tallest living things.  The tallest redwood in this forest is 258′ tall and 14′ wide!  The oldest tree in the forest is at least 1,200 years old!

Old Growth Forests Usually Have Three Layers

Muir Woods is much like a rainforest.  The forest has three layers.

  • The canopy, where light is readily available.  Most of the photosynthesis that occurs happens here, in the treetops.
  • The understory, which is protected from the wind.   Smaller trees and shrubs grow in the understory.
  • The herbaceous layer.  This is the layer closest to the ground.  Smaller shrubs, ferns, fallen logs, and mosses are found here.

Muir Woods Redwoods Depend on the Fog

Muir Woods is cool all year.  The temperature ranges from 40°F to 70°F year-round.  Summers are dry.  This dry air meets the cold, moist ocean air.  The air cools rapidly creating fog.  The moisture in the fog condenses on the leaves.  Then the water drips down to the roots and other plants.  The fog also helps reduce evaporation, keeping the water where it is needed.

Life Cycle of a Redwood

Redwoods can reproduce in two ways.


  • Sexually, by seed.  At about 10 to 15 years redwoods start producing cones.  These cones are only about an inch long.  The seeds in the cones are about the size of tomato seeds.  Surprising, seeing as how huge the trees are!

  • Asexually, by sprouting buds.  Redwoods can sprout from their roots, stumps, and even their crown.  If they sprout from the roots, the sapling can benefit from the nutrients and energy already in place in the adult’s roots.  Buds can sprout from burls on the redwoods, too.  Burls are made of thousands of bud cells.  Most cells in the burl remain dormant in a healthy tree.  When the tree becomes damaged each cell has the ability to produce a clone of the parent tree.

The Importance of the Redwoods

  • Redwoods clean the air we breathe.  According to an article published by the Yale School of Environment, “California’s ancient redwood trees store more carbon dioxide per acre than any other forest in the world.”  This helps to slow climate change.



At first, I thought we were looking at giant clover!  But, when we asked a naturalist in the forest, she told us that it is sorrel.  Each redwood sorrel can be anywhere from 2.5 to 7 inches across.  Sorrel uses low levels of light for photosynthesis.  When sunlight hits the leaves directly, they actually fold down.  They open up when the light diminishes.  This happens so quickly that you can see it!  In the spring, they have purple flowers.

Banana Slugs


I was one of the few lucky ones on the tour to see a banana slug!  Apparently, these slugs are usually active at night but can be seen on cool, moist days.  This slug was about 6″ long and 3/4″ wide.  They can grow to be over 9″ and are the biggest land slug in the world.  These decomposers, like other decomposers, eat leaves, dead plant material, and waste from animals.  Then, they recycle what they eat, and put it back into the soil.  Banana slugs also spread seeds and spores through their waste.  However, they don’t eat redwood seeds because they taste bitter.  The slime on them is mucus that the slug secretes.  The mucus has a chemical in it that can numb the tongue of predators, like raccoons or ducks.  This slime also helps them stick to surfaces.

Muir Woods: Inspiration for Teaching

While walking in the woods (and afterward), I was thinking of all the things that can be taught based on what was there.

  • Researching redwoods.
  • Comparing redwoods to other trees.
  • Comparing the layers of an old-growth redwood forest to the layers of a rainforest
  • Researching animals of Muir Woods.  Here is a downloadable checklist to get you started.
  • For older students, the National Park Service has a science and research page for happenings in and around Muir Woods.
  • Counting tree rings.
  • Learning about condensation and evaporation.
  • Studying how ocean currents affect the weather.
  • Reading about climate change.

Some of Our Resources that You Will Find Helpful


Find out about the science of another walking adventure we had: Our Walkabout Experience in the Blue Mountains:  The Benefits of Nature.

And remember, it’s all science!


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