Why Do Pinecones Open and Close and How Does That Affect Seeds?

September 26, 2025

Aria Zoey Brio

As fall begins, we are starting to find pinecones on the ground, catch whiffs of their earthy aroma, and see their unique, scaled patterns up close. Have you ever wondered why some pinecones are wide open and others are tightly closed? This simple mystery tells a fascinating story about how trees protect their seeds. We were inspired to learn about pinecones based on our Rooted in Time Exhibit.

Let us dive into learning about pinecones and pine trees!

What Are Pine Trees and Which Pine Trees Live in Washington State?

Pine trees are also known as conifers. The word conifer comes from Latin: conus meaning cone and ferre meaning bearing. Which means that pine trees produce seeds that live in pinecones.

There are many pine tree species in the Pacific Northwest, but the ones that are local to the State of Washington are the lodgepole pine, Western white pines, Ponderosa pines, and white bark pines.

These conifers grow to a few hundred feet in height, with the tallest species being the Ponderosa pine at around 260 feet and the smallest being the lodgepole pine at around 130 feet.

Next time you go for a drive, you can identify which pine trees you see. We are, after all, called the Evergreen State!

Are There Different Types of Pinecones?

There are both female and male pinecones!

Female pinecones are what we often see-on the ground during fall. They carry seeds inside their cone scales. Male pinecones are small and hard to see. They contain the tree’s pollen. Male pinecones pollenate female pinecones. Pine trees drop female pinecones to the ground once they have reached mature growth in hopes that a seed will become a tree.

How do male pinecones get pollen to female pinecones? This amazing process is called wind pollination. Wind pollination is when air carries pollen and fertilizes plants or conifers. The male pinecone’s pollen travels by air and lands on the female pinecone to fertilize it, making a seed.

The seed is exposed inside the pinecone scale and is called a gymnosperm, meaning nothing is covering the seed.

Why Are Some Pinecones Closed or Open?

Before we answer this question, we need to learn about the anatomy of a pinecone.

Female pinecones have scales on their exterior. The scales open and close depending on the weather. After pollination, the seeds live inside the scales and need protection. Below is an illustration of the parts of the female pinecone.

Now that we know the anatomy of pinecones, let’s dive into the question at hand: why do we sometimes see the scales of pinecones open and other times closed?

The answer is simple: it’s a protection mechanism for their seeds! Pinecones open in warm, dry weather to release seeds and close in the cold, damp weather to protect them.

In cold weather, both female and male pinecones close their scales because it would be hard for them to pollinate.

How Do Pinecones Know When to Open or Close?

It does not take much for a pinecone to detect a change in weather. In fact, it takes little as a one percent change in humidity for pinecones to respond to their environment. When water reaches the center of the pinecone, they will close their scales. Once the water in the center of the pinecone begins to dry, the pinecone knows it is safe to open their scales again.

This video shows how a pinecone closes and opens:

Image from Warren Photography — *Closed pinecone on the left; open pinecone on the right.*

*Male – Pollen cone; Female – Seed cone*

Can Pinecones Be Eaten?

No; pinecones, though they look beautiful, should not be eaten because some of them are toxic.

Seeds from the pinecone, on the other hand, may sometimes be eaten. For example, some recipes call for pine nuts. Those are the seeds that come from pinecones.

Not all pinecones make seeds or pine nuts that are easy or big enough to pick and eat. The most well-known pinecone for pine nuts is from the pinyon pine. Native Americans have used these pinyon trees for thousands of years. Pinyon tree pine nuts are used for cooking or making butter, and tree sap was also used medicinally as baby powder or on burns and wounds. They would also use the wood from the pinyon tree in construction or to create tools, like hairbrushes.

What Fun Activities Can I Do With Pinecones?

There are many amazing and fun projects to do with pinecones, from creating arts and crafts to conducting science experiments. Here are some ideas of what you can do with pinecones:

Will a pinecone stay open, or will it close when put in water? Find out how to do this fun science experiment

Can pinecones be eaten? NO! But what if we turn it into a bird feeder? Create this fun project here: How to Make a Pinecone Bird Feeder

Grab a pinecone and some paint to make cool pinecone stamps! This project reminded us about our PacSci exhibit, Rooted in Time. Learn more about this cool art project here: Pine Cone Stamps Painting Activity

Learn More About Pinecone and Pine Trees

Loved learning about pinecones and pine trees? These are a few websites to keep the cone conversation going!

Gardener’s Path – Explore more about conifers and their different types: What Are Conifers?

Plant Native – How do pine trees grow and adapt to the environment: Environment and Adaptation

Pro Garden Tips – Learn more about the local pinecones and pine trees in Washington state: 4 Main Types of Pine Trees in Washington State

Discover More at Pacific Science Center

Explore our amazing Digital Discovery Workshops, where we host an amazing virtual workshop, Ecosystem Investigators. See if you can figure out if pinecones would open or close their scales in these ecosystems!

Even though we are currently closed, exploring curiosity and wonder is still open, just like pinecones in warm weather! Visit PacSci to learn more about upcoming events.

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about the author

Aria Zoey Brio is a Guest Services host with a passion for marketing and social media, based in Seattle, working at Pacific Science Center. Through her customer service experience, Aria has learned what content people are curious about and want to explore. When she isn’t working, she enjoys spending time with her two fluffy Samoyed dogs, crocheting, and cooking.