Why Does Your Christmas Tree Smell Bad? The 3 Likely Causes!

Christmas trees are known to have rich, piney scents that most people cannot celebrate the holidays without. So what exactly could cause the tree to smell bad? With the help of science, this is what I’ll be unwrapping with you today!

Bad smells in Christmas trees can be due to the tree variety, mold, and root rot. To prevent this, it is recommended to buy fragrant trees, provide them with adequate water and mask any unpleasant odors from the tree.

The smell of musty, rotting Christmas trees is not the most cheerful thing in the world. Thankfully, there are ways to handle it. At the end of this article, you’ll know exactly how to spruce up a bad-smelling Christmas tree, so let’s get into it!

1. Tree Variety

Certain Christmas trees like junipers and spruces will naturally release foul odors whenever they are damaged for defense. These odors are not harmful but can be persistent and unpleasant. Lingering scents can be masked with an air freshener.

There are over 600 species of conifers or cone-bearing seed trees, and many of them smell quite lovely. But there are some species of Christmas trees with less-than-pleasant scents.

Some varieties of Junipers, such as the Juniperus foetidissima, are known to have an unpleasant smell. To help protect themselves from herbivores, the plant tissues will release a putrid aroma when it is damaged.

It’s not harmful to breathe in and the essential oils in the Juniper tree have been found to repel multiple pests. So luckily, you don’t have to worry about this smell causing any harm.

Spruce trees are another type of Christmas tree that some people find repulsive, so beware!

If you’ve accidentally bought a tree that naturally smells unpleasant, avoid bruising the foliage as much as possible. The smell might eventually dissipate with time. But if it doesn’t, you might be able to cover up the scent with some air freshener.

2. Mold

Mold can cause Christmas trees to smell bad by releasing gasses or microbial volatile organic compounds into the air. Adding 2 tablespoons of white vinegar can eliminate mold in the tree’s water. If mold is growing on the tree, it is safer to buy a new one, as regular exposure to mold can cause respiratory issues.

One of the reasons why a Christmas tree could smell bad is because of mold. If these trees were frequently left outdoors in the rain or snow, mold can develop on the trunk and branches of the tree.

Molds are likely to develop on Christmas trees that are frequently misted or placed in a room with high humidity as well.

You might be wondering how this could impact such a large and richly-scented tree. Aside from looking disgusting, microbial volatile organic compounds are released into the air by mold and are highly unpleasant to smell.

Mold can also be found in the water of chopped Christmas trees, especially if they’re not taking in any water.

Cutting 1–2 inches off the trunk can help prevent this. A couple of tablespoons of white vinegar can be placed in the water as well to help eliminate any mold.

Serious mold growth can cause respiratory issues and can be incredibly dangerous to breathe in, especially for children or people with compromised immune systems.

If you suspect that the Christmas tree itself has mold, it might be safer for you to just buy a new one.

3. Root Rot

Christmas trees suffering from Phytophthora root rot will release more putrescine, a naturally foul-smelling compound. This odor is not harmful but can attract fungus gnats. Replace the trees or decorate them with air fresheners to mask the smell.

Another reason why a potted Christmas tree might smell bad is that it is suffering from root rot. One of the most common symptoms of these is when the needles turn a reddish brown.

This is due to Phytophthora root rot, a disease that commonly affects Douglas firs, Balsam firs, pines, and spruces. The trunk may also begin to rot, contributing to the smell.

Phytophthora Root Rot in Christmas Trees

But let me briefly introduce you to putrescine, one of the main compounds found in a wide range of terrible odors, like rotting flesh.

If the roots of this tree are consistently left in water, the Phytophthora pathogen will lead to the plant producing more putrescine that will make the tree smell like it’s rotting.

The smell of root rot isn’t harmful but the saturated and diseased roots of the tree can potentially invite pests, like fungus gnats, into your home.

Flies and rotting smells are definitely not the first things you want to encounter on Christmas morning. Decide whether you want to replace the tree or if you’re willing to mask the smell before you toss it out.

The presence of putrescine isn’t necessarily bad. It can even be found in many plant tissues. But to keep us safe, our brains are hardwired to interpret its smell as something disgusting, which I will discuss further in the next section.

Why Do Christmas Trees Have Such a Strong Smell?

The bark, leaves, and seeds of Christmas trees contain resin filled with compounds like pinene and terpene, making them highly fragrant. Bacteria can contaminate the resin and overpower these fragrances, causing the tree to smell unpleasant. But unless it is due to mold, these odors are not harmful to breathe.

If you ask how much resin Christmas trees have, the answer is a lot! Numerous rows of resin pockets and resin canals are found on conifer trunks, inside their leaves, and even in their seed cones.

Resin canals are internal tubes filled with oleoresin, a combination of resin and essential oils. Compounds like terpene and pinene can be found in the oleoresin and are responsible for the iconic, refreshing smell of Christmas trees.

It’s difficult to explain the chemical processes behind every compound and smell, as the chemical composition is different in every species.

One thing we know for certain though is that the extreme fragrance of resin helps protect the Christmas tree from predators and disease.

However, if your tree smells bad, the resin has probably been contaminated by bacteria, resulting in the release of new, awful odors.

These odors aren’t always bad for our health but once we pick up on certain scent molecules, like putrescine, our brains will recognize the odorous compounds. To be safe, our brains will interpret these smells as foul to help us stay away from them.

If your tree is suffering from root rot or is just naturally unpleasant to smell, it probably won’t cause you any harm. But how do you get rid of it?

3 Ways to Get Rid of & Prevent Bad-Smelling Christmas Trees

The 3 best ways to control and prevent bad smells in Christmas trees are to buy fragrant trees, provide them with adequate water, and mask their smell.

It can feel hopeless to go through all the trouble of preparing for Christmas only to end up with a bad-smelling tree. While it may not be ideal, this can be seen as a learning experience!

To help you avoid going through this hassle again, let’s go over the ways you can get rid of and prevent bad smells from developing in your Christmas trees.

1. Buy Fragrant Trees

The best way to prevent bad-smelling trees is to buy fragrant Christmas trees like Balsam fir, Fraser fir, and Scotch pine. Freshly cut trees with needles that release a strong scent when crushed are ideal. Avoid any trees that smell unpleasant or show any signs of disease.

When shopping for Christmas trees, don’t be afraid to smell each of them to determine their scent! This is, after all, part of the magic of Christmas.

Ask the sellers how fresh the tree is and if it’s possible to take a needle to crush it and smell how potent its resin is.

[quote] Scotch pine, Balsam fir, and Fraser fir are some strong-smelling trees that give a nice piney scent.

The Korean arborvitae, or Thuja koraiensis, has a sweet smell to it that resembles fruit cake. However, this tree is native to Korea and is currently threatened by habitat loss, so this species is quite difficult to come by.

If you know that your local Christmas tree farms and stores tend to sell bad-smelling trees, consider buying from a different location.

Artificial trees are also an option but can be harmful to the environment if it’s used for less than 9–20 years.

Find out more in our article Is My Christmas Tree Bad For The Environment?

2. Provide Adequate Water

Prevent cut Christmas trees from smelling bad by watering them every day to help them stay hydrated and fragrant. Potted trees must be watered when the top 2 inches of soil is dry.

Another good way to make sure your Christmas tree smells good is to make sure they’re properly watered.

This will prevent the tree from drying out and losing its scent and will help ensure the tree is healthy and less prone to root rot.

If you notice the tree isn’t absorbing any water, the stump may have hardened over since it was cut. This will effectively seal the tree off, stopping it from taking in any moisture. Its water can also become stagnant and can even become moldy as a result.

To ensure your Christmas trees smell fresh for as long as possible, be sure to give chopped Christmas trees water every day and give your potted Christmas trees water whenever the top 2 inches (5.08 cm) of soil is dry.

Learn more in our article on What To Do When Christmas Trees Won’t Drink Water

3. Mask the Bad Smell of the Tree

Hang air fresheners on bad-smelling Christmas trees to disguise their odors. Avoid using scented sprays for misting as the moisture can damage ornaments and Christmas lights. Fragrant Christmas trees with pleasant aromas can be placed in warm rooms and trimmed to release more of their scent.

Regardless of how good or bad your Christmas tree might smell, there are some ways to control it and bring out more scents you enjoy while hiding the ones you don’t.

One of the most common ways people mask bad-smelling Christmas trees is to spray them with something more fragrant. While this sounds easy, this can be dangerous.

The excess moisture from sprays could ruin the ornaments and damage the lights and potentially start a fire, so try to avoid this as much as possible!

Instead, it’s best to hang scented air fresheners on the tree or in the room, as these do not have any moisture and tend to last for a couple of weeks.

Pleasant-smelling trees can be placed in a slightly warmer room to encourage the secretion of resin. But do this with care, as this can easily cause the tree to dry out faster too.

Scents can also be extended by occasionally bruising or cutting some needles to release their scented compounds. Use a sterilized pair of scissors or shears to cut the inner needles of the tree and enjoy its fresh, piney fragrance!

FAQs

Why doesn’t my Christmas tree smell?

Some Christmas trees are naturally less fragrant than others and may have less internal resin pockets to release essential oils. It is also possible for the tree not to have any scent as a result of dehydration.

What Christmas tree smells like oranges?

Balsam fir and Douglas fir trees are some of the most aromatic Christmas trees available that are also known to smell like oranges. Grand fir Christmas trees also have dark green needles that smell like citrus when bruised.

Summary of Why Christmas Trees Smell Bad

Some Christmas tree varieties naturally produce unpleasant odors. Examples of this include junipers and spruces. Christmas trees can also develop foul odors as a result of mold and root rot.

Odors that are naturally released from some tree species and those that are emitted due to root rot are generally not harmful to breathe in. Prolonged mold exposure, however, can be dangerous and must be avoided.

To prevent bad smells in Christmas trees, it is essential to buy fresh and fragrant trees like Balsam fir and Scotch pine and to water the trees regularly. The use of air fresheners can also cover any odors from bad-smelling Christmas trees.

Sources

• “Conifers of the World” by James E. Eckenwalder in University of Toronto
• “Chemical Composition of Essential Oils from Leaves and Fruits of Juniperus foetidissima and Their Attractancy and Toxicity to Two Economically Important Tephritid Fruit Fly Species, Ceratitis capitata and Anastrepha suspensa” by Mehmet Kurtca, Ibrahim Tumen, Hasan Keskin, Nurhayat Tabanca, Xiangbing Yang, Betul Demirci, and Paul E. Kendra in National Center for Biotechnology Information
• “What does mold smell like?” by n/a in United States Environmental Protection Agency
• “Phytophthora Root Rot of Christmas Trees” by Ann Joy and Anette Phibbs in University of Wisconsin
• “Phytophthora Root Rot” by Ed Rajotte in Pennsylvania State University
• “What makes something smell good or bad?” by n/a in University of Maryland
• “Why Christmas Trees Smell Good” by Andrew Moore in NC State University
• “Resin-based defenses in conifers” by Michael A. Phillips and Rodney B. Croteau in The Institute of Biological Chemistry, Washington State University