Why Do Some Trees Keep Their Leaves in Winter?

Chloe Effron
Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Have a question? Send it to why@mentalfloss.com.

Have you ever wondered why some trees keep their leaves in winter when all the other leaves fall off? Trees have different life cycles, and are either called deciduous (de-SID-you-us) or evergreen. Trees with flat, wide leaves that turn pretty colors in the fall are deciduous. They will drop their leaves when the weather gets cold. Evergreen trees, on the other hand, lose their leaves throughout the year a little bit at a time.


First, we need to talk about how trees get food, or energy. Trees use the energy from sunlight and water to turn carbon dioxide into a kind of food. This process is called photosynthesis (foe-toe-SIN-thuh-SIS). The days get shorter in fall and winter, so there is less sun energy to use. Deciduous trees close up the little holes where the leaves attach so they don’t lose moisture (MOYS-chur), or water. This makes the leaves drop off. Evergreen trees don’t have to drop their leaves.


Evergreen trees first came from cold climates. (But you can find many in warm tropical rainforests too.) They have very strong leaves rolled up tight, like long, thin needles. This shape allows the evergreens to conserve water, which is needed for photosynthesis. Because they have more water than their deciduous cousins, their leaves stay green, and stay attached longer. Evergreen needles also have a very waxy coating that also helps save water during summer and winter. Christmas trees are generally evergreens like spruce, fir, or pine.

To learn more about the lives of trees, watch this short film at National Geographic

6 Protective Mask Bundles You Can Get On Sale

pinkomelet/iStock via Getty Images Plus
pinkomelet/iStock via Getty Images Plus

Daily life has changed immeasurably since the onset of COVID-19, and one of the ways people have had to adjust is by wearing protective masks out in public places, including in parks and supermarkets. These are an essential part of fighting the spread of the virus, and there are plenty of options for you depending on what you need, whether your situation calls for disposable masks to run quick errands or the more long-lasting KN95 model if you're going to work. Check out some options you can pick up on sale right now.

1. Cotton Face Masks; $20 for 4

Protective Masks with Patterns.
Triple7Deals

This four-pack of washable cotton face masks comes in tie-dye, kids patterns, and even a series of mustache patterns, so you can do your part to mask germs without also covering your personality.

Buy it: $20 for four (50 percent off)

2. CE- and FDA-Approved KN95 Mask; $50 for 10

A woman putting on a protective mask.
BetaFresh

You’ve likely heard about the N95 face mask and its important role in keeping frontline workers safe. Now, you can get a similar model for yourself. The KN95 has a dual particle layer, which can protect you from 99 percent of particles in the air and those around you from 70 percent of the particles you exhale. Nose clips and ear straps provide security and comfort, giving you some much-needed peace of mind.

Buy it: $50 for 10 (50 percent off)

3. Three-Ply Masks; $13 for 10

Woman wearing a three-ply protective mask.
XtremeTime

These three-ply, non-medical, non-woven face masks provide a moisture-proof layer against your face with strong filtering to keep you and everyone around you safe. The middle layer filters non-oily particles in the air and the outer layer works to block visible objects, like droplets.

Buy it: $13 for 10 (50 percent off)

4. Disposable masks; $44 for 50

A batch of disposable masks.
Odash, Inc.

If the thought of reusing the same mask from one outing to the next makes you feel uneasy, there’s a disposable option that doesn’t compromise quality; in fact, it uses the same three-layered and non-woven protection as other masks to keep you safe from airborne particles. Each mask in this pack of 50 can be worn safely for up to 10 hours. Once you're done, safely dispose of it and start your next outing with a new one.

Buy it: $44 for 50 (41 percent off)

5. Polyester Masks; $22 for 5

Polyester protective masks.
Triple7Deals

These masks are a blend of 95 percent polyester and 5 percent spandex, and they work to block particles from spreading in the air. And because they're easily compressed, they can travel with you in your bag or pocket, whether you're going to work or out to the store.

Buy it: $22 for five (56 percent off)

6. Mask Protector Cases; $15 for 3

Protective mask case.
Triple7Deals

You're going to need to have a stash of masks on hand for the foreseeable future, so it's a good idea to protect the ones you’ve got. This face mask protector case is waterproof and dust-proof to preserve your mask as long as possible.

Buy it: $15 for three (50 percent off)

At Mental Floss, we only write about the products we love and want to share with our readers, so all products are chosen independently by our editors. Mental Floss has affiliate relationships with certain retailers and may receive a percentage of any sale made from the links on this page. Prices and availability are accurate as of the time of publication.

The Little News Ears Podcast Helps Keep Kids Informed Without Overwhelming Them

Little News Ears translates current events into kid-friendly terms so parents don't have to.
Little News Ears translates current events into kid-friendly terms so parents don't have to.
Ranta Images/iStock via Getty Images

Kids are often curious about things they overhear on television or in conversations around them, but trying to translate that information into a kid-friendly format isn’t always easy. That’s where Little News Ears can help.

The program, available both as a podcast and as a YouTube video series, explains intriguing news stories to children in a simple, upbeat, and often funny way. In it, a young boy named Bram, a futuristic dog-like being named BoxerBlu, and a loris named Otis cover everything from Prince Harry and Meghan Markle’s decision to step away from their royal duties to people mudlarking (hunting for treasure) along the River Thames. More serious topics, like the deaths of high-profile people, are presented “in the vein of Fred Rogers teaching children about the Kennedy assassination,” as the website explains.

Little News Ears was created by Dan Buck, a former primary school teacher who now serves as the Head of School at Tessa International School in Hoboken, New Jersey. While the focus of the series itself is to express the news in ways that preschoolers and elementary school students can understand without frightening or overwhelming them, the website also includes lesson plans, vocabulary lists, and other resources to help parents and teachers learn how best to educate children on current events.

Usually, Little News Ears is offered as a subscription service—$6 per month or $55 for an entire year—but Buck and his team have made the program, along with the supplemental materials for educators, completely free for as long as the coronavirus pandemic lasts. You can learn more about the site and sign up for free access here.