Forest Restoration Through Selective Thinning


What Is An Old-Growth Forest?

A forest that has never been logged is called "old-growth". It is a forest rich in diversity of plants and animals, and has a very different look, feel and character from a forest that has been logged. Old-growth forests are healthy habitats for a wide range of species.

Old-growth redwood forests have...

1) A small number of giant redwoods in each acre (from 5-15 mature redwoods).
2) Lots of different plants on the forest floor.
3) Epiphytes and animals living in the canopy of the redwoods.
4) Open space where light reaches the forest floor.
5) Fallen logs that act as "nurse trees" for centuries.
6) Dead and broken standing trees that provide habitat for lots of wildlife.

What is a Second-Growth Forest?

If a forest has been logged once and has grown back it is called second-growth. In creating Redwood National and State Parks, tens of thousands of acres of second-growth forest were purchased from logging companies. These second growth-forests are now dominated by Douglas-fir trees that were seeded by private helicopters and planes. The density of these trees can be more than a thousand trees per acre.

Second-growth forests have...
1) Un-naturally high density of trees.
2) Very little light reaching the forest floor.
3) Thin, skinny trees that are not able to get light and grow wide, or as tall as they can.
4) Little diversity of forest floor plants, or food for wildlife.
5) No nurse logs, or dead old-growth trees to provide habitat for wildlife.
6) Stumps of giant redwoods.

Where are the Parks' Second Growth Forests?

Second growth forests are all over the parks, and for hundreds of miles around us. You will drive through them on the way to all of the redwood groves and park destinations that you visit. Specifically, you will find second-growth forests at Mill Creek campground, on the road to Gold Bluffs Beach, on the drive up to Lady Bird Johnson Grove, and on the road to Tall Trees Grove.

Places like the Mill Creek watershed at Del Norte Coast Redwoods State Park were logged as recently as the the late 1990s. Parts of Redwood Creek, Skunk Cabbage, Berry Glen Basin, and Lost Man Creek - all now in Redwood National Park - were clearcut in the 1960s and 1970s. Second growth forests are also found in the Prairie Creek watersheds of Prairie Creek Redwoods State Park.
Second Growth Forests: Before and After Thinning.
Too many Douglas fir and redwood trees struggle for light. A healthy number of trees per acre get light and space to grow.
2012: Douglas fir and redwood trees in unnatural densities struggle for light. NPS: Jason Teraoka
2015: After some Douglas firs were removed, a healthier canopy (and forest floor) exists. NPS: Jason Teraoka
Photos of the forest canopy at Holter Ridge that show the positive impact of forest restoration and selective thinning.

Montage of machinery used in thinning projects.


Restoration thinning does use some of the same machines that once clear-cut redwood groves - but the goals, techniques and outcomes are very different.

How Does Forest Restoration Occur?

This is complex, and since the 1990s we have been adapting and improving our restoration techniques.

Restoration of second-growth forests requires the removal of logging roads, thinning and removal of selected trees, stream restoration, and solving erosion problems. All of this work is based on building partnerships and trust between a wide variety of private, tribal, government, non-profit, and academic organisations.

There is no replacing all the old-growth forests that were logged, but future generations of visitors (and wildlife) will have more old-growth redwoods than were around when the parks were established.
comparison of old-growth(left) with second growth forest
Examples of old-growth forests (left) and second growth forests (right) in Redwood National Park.


Why Are Old-Growth Forests Important?

Old-growth redwood forests are what millions of visitors travel from around the world to see. Under these towering giants, people find all sorts of experiences and emotions. The complex ecosystems of these forests go from inter-connected roots ten feet underground, to niche habitats more than 350-feet up in the canopy. Wildlife large and small; on land, in the air, and in the rivers rely on the the old-growth forests for their survival.

Another reason old-growth redwood forests are important is their ability to store massive amounts of carbon. The old-growth redwood forests located here have the highest bio-mass per acre of any forest ecosystem. That means they are storing more tons of carbon per acre than any terrestrial habitat in the world. You can learn more about redwoods and carbon storage.

Last updated: December 12, 2018

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