old growth forests


An old-growth forest is a large area of forest that has been growing for a long time without any major changes. These forests can be classified based on the forest’s structure, function, and composition.

old-growth forest structure

(i) Old-growth Forest Structure:

  • In old-growth forests, the structure is all about how many, how big, how old, and how well-placed trees are.
  • Old-growth forests are made up of snags (dead trees that still stand), tree debris, and fallen logs.
  • Structure can also be shown by how many trees there are in the landscape.
old-growth forest function

(ii) Old-growth Forest Function:

  • Forests play a big part in an ecosystem, and their function is to help the ecosystem work together.
  • Species live in old-growth forests.
  • They also help with biogeochemical cycles. Examples of biogeological cycles are the oxygen cycle, the hydrologic cycle, the nitrogen cycle, and so on.

(iii) Old-growth Forest Composition:

  • There are a lot of different types of plants in an old-growth forest.
  • Trees and other plants grow in old-growth forests. The forest floor is made up of grasses, shrubs, and other plants that grow there.
  • The plants that live in an old-growth forest can help you figure out what kind of forest it is.
old-growth forests


(Research from Encyclopedia.com)

  • Old-growth forests have unique features that make them different from other forests.
  • Old-growth forests have multi-level canopies that are made up of both live and dead trees, making them very interesting. Also, because of the forest’s pit-and-mound topography, canopies may also grow there, as well.
  • For a forest to be old growth, it must be at least 120 years old. However, some of the trees may be older than the forest itself, which is why we need to be careful.
  • Old-growth forests also have trees with big diameters that are either standing or down. Every single tree in the forest has an important job to play, even if it’s dead.
  • They have both young and old trees in them. The older trees have more stems than the younger ones. Because they are so tall, they cover a lot of ground in a forest.
  • The barks of trees found in old-growth forests are often covered in moss and lichens.
importance of old-growth forests


Old-growth forests play an important role in the world around us. They give animals food, shelter, and a lot of other good things:

  1. Sustains Biodiversity

Old-growth forests add more species to an ecosystem. These forests are home to both plant and animal species.

The canopies in old-growth forests let sunlight reach the ground. There are a lot of different plants in the forests, so there is a lot of vegetative covers.

Old trees also have a lot of different kinds of animals, including some that are in danger.

The dead trees and fallen logs add nutrients to the soil. This lets soil microbes grow.

  1. Supports Ecosystem Functions

In terms of ecosystem services, these forests are very important because they do a lot for the whole world.

They help plants and animals live together in an ecosystem by giving them food and shelter.

In addition, they use the hydrologic cycle to filter water.

The trees also clean the air, which means that animals can breathe.

  1. Carbon Storage


Older trees take in a lot of carbon from the air each year. This makes old-growth forests a good place to store carbon for the Earth.

There is even more carbon dioxide in the air as the forest grows old.

When old-growth trees are cut down, carbon is released into the air. This can have a very bad effect on the environment.


The United States has about 8% of the world’s forest cover. (Research from World Atlas)

Forests cover 33% of the country. Almost no one lives in old-growth forests. The largest area of old-growth forest in the United States is found in the state of Alaska.

  • Old-growth forest Oregon

Most of the forests in Oregon State are run by the federal government. This helps protect the old-growth forests in the area.

Many different types of old-growth forests can be found in Oregon, and each one is unique. This area used to be covered in old trees, but their numbers have since dropped.

Around the Clackamas River, you can find some of the oldest old-growth forests in the world.

These forests are some of the largest old-growth forests in Oregon. Winema National Forest has about 712,000 acres, and the Willamette National Forest has 1,675,407 acres, so they are about the same size.

  • Old-growth forest in Michigan

If you go to Michigan, you’ll only find a few old-growth forests. During the 1800s, the area had a lot of old trees cut down.

People living in Northern Michigan and the Upper Peninsula have a lot of trees that are old enough to be called “old growth.”

-The forests in this area are mostly made up of pine trees and trees that are still standing.

If you go to Hartwick Pines State Park, you can see some of the oldest trees in Michigan.

  • Old-growth forest Washington

There aren’t a lot of old-growth forests in Washington State like there are in Michigan.

All of the old-growth forests that are still there are protected so that trees and animals can stay alive and grow.

If you live in Washington, you should visit the Mount Baker–Snoqualmie National Forest. It is one of the largest old-growth forests there. It’s about 644,000 acres.

These old trees and plants are home to a lot of different kinds of plants and animals.

  • Old-growth forest Pennsylvania

-Pennsylvania has up to twenty places where old-growth forests still stand. Most of the trees were cut down in the late 1800s, but the government has been able to save some areas.

In the United States, there is a forest called Cook Forest that has been around for a very long time. Most of the trees are around 300 years old.

This area is mostly made up of pines and hemlocks that grow tall.


The world’s old forests are under threat. Areas that used to be covered by old trees have been left empty by people who do things that hurt them. Old forests are not only beautiful, but they also have a lot of sentimental value to the people who lived there before.

But the most important thing is that old-growth forests are carbon sinks. They play an important role in reducing the amount of carbon dioxide in the air around the world.

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