The Forest
Redwood forests generate the world’s greatest volume of living matter per unit of land surface.

Redwoods tend to dominate their environment because of their resistance to fire, drought, shade and disease and their ability to reproduce from burls. They will survive all but the very worst floods or fires and they can live with very little sunlight for decades. On floodplains they will often grow almost exclusively. In areas where they grow less vigorously such as on steeper slopes or after logging, many other plant species have learned to live alongside the redwoods. Douglas firs are one of the most common and may rival the height of the redwoods in some drier areas. The Broad-leaf tan Oak is the most successful tree under the canopy - it grows very well in the shade and will grow in the decaying leaf matter, not tolerated by most other plants. Other trees include the Western hemlock, California laurel, maple, alder, huckleberry, Sitka spruce and rhododendron.

The forest floor is covered in ferns, evergreen huckleberry, salal, and the western azalea. Wildflowers include redwood violets, trilliums, Douglas iris, calypso orchids, and redwood sorrel.
The floor is covered in ‘duff’ – the decaying leaves and twigs. This duff absorbs much of the water and keeps roots moist as well as protecting them from erosion. This layer contains many fungi and bacteria, which convert the dead plant and animal matter into nutrients. A fallen redwood tree may survive for hundreds of years on the forest floor.

Reproduction
One of the reasons the Coast Redwood has survived is its ability to reproduce in two different ways: seed or sprout

Seed Reproduction:
This is the primary means of reproduction in an old-growth forest, and it allows the genetic variation which is necessary for the long term survival of the species. If the tree is exposed to enough sunlight it can produce seeds at around 20 years of age. Seed production peaks at 250 - 1000 years. Redwoods have both male (pollen) and female (ovulate) cones, which grow on separate branches of the same tree. They form on the tips of high branches on mature redwoods in the fall. Pollen from the peppercorn-sized male cones is released in streams in the fall. It drifts and descends through the canopy to settle in the female cones. Fertilization will happen 4-8 weeks later.

Over the next year, the female cones mature into hard-sided cones from .5 to 1.5 inches in length. Protected by the hard scales are anywhere from 60 to 150 seeds. The seeds of the redwood are tiny, about the size of a small oatmeal flake. The will remain viable for up to a year. Some seeds are released from the cone while the cone is still on the tree, drifting down to the ground or blown by the wind. Most will settle within a few hundred feet of the tree. Other seeds remain until the cone falls to the forest floor, dries, and opens.

Less than 1% of these seeds will ever produce a tree. Many seeds cannot penetrate the leaf litter or duff to reach the soil. Some will land in water or on animals and will be carried away from the redwood forest. Many more will reach the soil but will be destroyed by fungal attack, bacteria, and insects. Many will be washed away by rain, and some will be eaten by animals. Probably fewer than one in a million seeds will ever become mature trees.

Seedlings will grow best under shady conditions, under the protection of larger trees. When larger trees fall, opening light gaps, seedlings will spring up to fill the void. They can grow roots of over an inch after just one day. Most seedlings will die within 3 months. Lack of moisture is the most likely cause, although many seedlings will also be washed away, eaten by animals or attacked by fungi. Their best chance of survival is after a fire, flood or fallen tree, when most of the competition is gone.

After a year the roots will be around 1 ft deep and the stem around 5 inches. After their first few years, redwoods can grow very rapidly, 2 to 3 feet in height and up to one inch in diameter a year. The trees can be 30ft (10m) at 20 years, 100ft (30m) at 50 years and fully grown at 200-300. After 300 years the tree will grow wider but not taller.

Sprout (burl) Reproduction:
Redwoods are one of a very few coniferous trees that can also reproduce by sprouting. As early as one year after beginning to grow, a redwood can begin to produce bud collars, most commonly referred to as ‘burls’. These dormant root buds will continuously form, sometimes creating large bulbous growth on the tree's roots, base, or trunk. Hormones within the tree keep these burls from sprouting until the tree faces some form of stress. Fire, erosion, flooding, browsing, or other injury to the tree will trigger a release on the buds, causing them to begin to grow within a few weeks.
Redwood sprouts, or suckers, can grow rapidly, receiving their early nutrition from the roots on which they grow. They are genetically identical to their parent tree, often forming "family circles" around the parent tree. Under optimal conditions, sprouts may reach heights of 8-10 feet in their first year. Eventually the tree will grow its own root system and can survive even if the parent tree should topple. After a fire trees will often sprout in such proliferation that many of the sprouts cannot compete and die back. Some day these sprouts will grow their own burls and produce their own sprouts. Most sprouting will occur from a tree 200 – 400 years old.

Fire
Frequent fires ignited by lightning are an essential part of the forest ecosystem. These fires will remove less fire resistant trees, recycle nutrients, and modify the ground vegetation. The 12 inch thick bark will protect the tree from all but the most intense fires. The foliage is protected from fire by its distance from the forest floor. Major fires occur anywhere from every 100 to 500 years depending on the local conditions. The last significant fire in the Muir Woods was around 1845. Most damage is done to seedlings and young trees, which lack the defense of the mature trees.
It is a matter of debate whether the forest requires these fires to survive (Unlike the Giant Sequoias which cannot reproduce without fire). After a fire the redwood seedlings will usually be the first to grow. They will take advantage of the reduced competition for moisture and sunlight.

Fire ecology has changed throughout the years. It used to be assumed that all fires were bad – they were either prevented or extinguished as soon as possible. However, in the last few decades, the value of fire has been recognized, as it burns up the fuel, reducing the chance of a canopy fire and it returns many important nutrients to the soil. Today, there is a fuel break surrounding the National Monument. This break stops fires from spreading into Muir Woods from the surrounding Mt Tamalpais. The break is maintained through controlled fires, which are set in cool weather the burn the ground debris.

Flood
The redwoods are also excellent survivors of the frequent floods through the valleys. The floodwater will clear out much of the groundcover, leaving new alluvial deposits, rich in nutrients for the new seedlings to thrive. A severe flood can often bring up to 4ft of new sediment, which will suffocate the roots of most trees. Redwoods have the almost unique ability to grow a new layer of roots from the trunk to penetrate the new soil.

Logging
The Coast Redwood has long been a popular target for the lumber companies. The trees along with the Douglas fir are the most important in the state. Redwood lumber is very popular due to its rich color, durability and resistance to termites and decay. Partly because of it commercial value, lumber companies have done a large amount research into the redwood. Most of today’s redwoods are now protected from logging but only 5% of the original old growth redwoods exist today.