We all know that conifers have beautiful cones. Many of us even take them indoors in the wintertime to liven up our homes with their fragrance and appearance. But have you ever considered their purpose?
Spruce trees get cones so that they can reproduce. Cones are a protective housing for their seeds to prevent animals from eating them before they’re fully developed. Cones drop when the temperature is ready for new trees to grow!
Read on for an extensive guide on the purpose of spruce tree cones and how they work!
Spruce Trees Make Cones For Reproduction
On conifers, you will find both female and male cones on the same tree.
Male cones release pollen. Female cones capture the pollen while it blows in the wind. How cool!
Eventually, the pollen and “megaspore” combine and grow into a baby conifer. The baby conifer is all tucked away in a seed, just waiting to grow into a new tree.
Cones Act As A Protective Housing For Seeds
Now that you know how the baby conifers end up in the seeds, it only makes sense that they need to be protected.
Cones are like the ultimate seed armor. They’re strong and tuck the seeds safely away.
Just try opening up a closed cone and you’ll see how stubborn they are!
Nature is always full of surprises, and the cone is truly a work of art.
Putting It Together
Let’s recap those last two sections into one cohesive story!
- Pollen from male cones gets caught in the wind and captured by female cones.
- A baby tree is formed and tucked away in the seed.
- The cone protects a bunch of seeds by staying tightly shut.
Awesome! Now onto the next stage of the cycle.
When Do Spruce Tree Cones Drop?
We all know the feeling of walking through the woods in awe at all the beautiful cones on the forest floor with their scent floating in the air.
Cones Begin To Drop In Late Summer
Spruce cones ripen between late August and early September.
Cones start to fall after they’ve dried and opened up, releasing their seeds.
Spruce cones dry out when the sap flow gets cut off. Then, the stem that the cone is attached to closes up.
Spruce Trees Tend To Stop Dropping Cones In Early Fall
Once the temperatures start to drop, the dropping stops!
By early fall, most of the cones have dropped and opened up in the hopes of creating new spruce trees.
It Takes Two: A Two-Year Cycle of Cone Production, That Is!
Spruce trees take two years for their cones to mature.
Buds form during the first year. In fact, many species of baby spruce cones are edible in at the beginning of their life cycle!
Then, the cones develop and drop during the second year. This is what leads to the new trees really being established.
Spruce Trees May Drop Cones At Other Times If Weather Patterns Change
So we’ve already learned that spruce trees drop their cones between late August and September.
But if temperatures stay too hot, the spruce trees won’t get the message to drop their cones.
On the same token, if temperatures cool down early, the spruce trees will think it’s time to drop much earlier than they usually would.
High Temperatures And Drought Can Lead To A Lot Of Cones
According to Michigan State University, heat and drought can lead to “bumper crops” of cones.
In response to stress, the trees create excessive buds in an attempt to protect their species and make sure it lives on.
Because of the two-year cycle, many cones will be produced in the year following any stressful weather.
Similarly, other stressful conditions can also stimulate spruce trees to drop more cones. For instance, if they aren’t in their optimal acidic pH soil, they may create more cones.
How Do Spruce Tree Seeds Work In Cones?
Now that we’ve covered cones, let’s talk about the spruce tree seeds! Although they may seem like simple structures, cones can be incredibly complex, and are usually adapted to specific dispersal methods.
Cones Simply Act As Initial Protection
Cones are like the ultimate armor.
Seeds are tucked away as snug as a bug in a rug, surrounded by strong woody material that won’t open even if you try to rip it apart with your bare hands! Try getting through that, squirrels!
It’s quite genius how cones originally act to capture pollen and then go on to close up and protect the baby trees while they do their thing.
When Dry, Cones And Seeds Can Fall To The Ground
Cones fall to the ground once they’ve dried up enough to open.
By drying out, the tension in the cones is released and they open all their treasures into the world.
Once they’re dry, they have no purpose left on the tree and fall to the ground when shaken by the wind.
Especially when the ground is fertilized, they’ll establish themselves in the soil. Read our piece on the 5 best spruce tree fertilizers (and how to use them.)
Falling To The Ground Can Help Disperse Seeds
While the cone is falling, seeds begin to fly out of the cone and sprinkle into the surrounding area. Kind of like a dandelion, except not as extreme.
Likewise, when the cone hits the ground, the pure shock of the impact rattles some seeds around and sends them flying in all directions.
Animal Activity Can Help Seeds Spread
Now comes the best part- the animals!
Squirrels love to collect and bury seeds. Since cones fall during late summer, it’s the perfect time for squirrels to start collecting for the upcoming winter.
Likewise, birds will peck at the seeds and then transport them to different locations (you know how)!
How Long Does It Take Fresh Spruce Seeds To Germinate?
Since the whole point of cones is to protect the seeds (although we may like to think it’s to make us happy), it’s important to go over the germination process.
Most Spruce Seeds Require A Cold Dormant Period
Though spruce trees need more sun than shade, they also require periods of cold to balance out the warm, sunny weather that keeps them energized. Just like many plants, spruce seeds need a period of dormancy in order to germinate.
This is similar to cacti, which need to “winter over.”
You can think of it like hibernation, where the seeds are waiting for the right weather to wake up.
All seeds are technically alive, complete with food reserves and everything!
When Temperatures Rise, It Can Take 1-3 Weeks
Once temperatures rise, this tells the spruce seeds to germinate and “wake up” as discussed before.
A set of enzyme and protein reactions start to take place within the seed, eating up the food reserves and beginning the process of growing roots and a shoot.
Spruce seeds usually depend on animals to bury them or stomp them into the ground in order to germinate.
You can read our article about the 8 best plants to plant under your spruce tree because it makes a difference which plants are sharing your spruce’s soil.
In that same vein, there are also 13 plants not to plant under your spruce tree.
Stored Spruce Seeds Can Last A Long Time
If you store spruce seeds in a cool, dry place, they can last for quite some time!
Knowing how to store seeds is a good skill to have in general. It can save you money in a vegetable garden and make you feel more self-sufficient.
Tightly sealed glass containers are a wonderful vehicle for storing your seeds.
Really, storing spruce seeds is just one more way to reach self-sufficiency! You can use a container like this ZENS Airtight Glass Jar to make sure that your seeds stay properly stored.
Plus, people who are reforesting areas need a way to preserve seeds for their research and environmental efforts.
Quick Recap
Now that we’ve gone over the essentials, there is really only one thing left to do.
Time to recap!
- Spruce trees develop cones in order to reproduce
- The cones contain seeds
- Cones drop and open up in late summer
- Seeds require a period of dormancy
- Seeds store well and can help reforestation efforts
I hope that this piece helped you to feel more informed about spruce trees and their workings. We’ll see you next time, friends.
References
Aniszewska, M., Gendek, A., & Zychowicz, W. (2018). Analysis of selected physical properties of conifer cones with relevance to energy production efficiency. Forests, 9(7), 405.
Kerzenmacher, T., & Gardiner, B. (1998). A mathematical model to describe the dynamic response of a spruce tree to the wind. Trees, 12(6), 385-394.
Huang, J., Hammerbacher, A., Gershenzon, J., van Dam, N. M., Sala, A., McDowell, N. G., … & Hartmann, H. (2021). Storage of carbon reserves in spruce trees is prioritized over growth in the face of carbon limitation. Proceedings of the National Academy of Sciences, 118(33), e2023297118.
Castagneri, D., Storaunet, K. O., & Rolstad, J. (2013). Age and growth patterns of old Norway spruce trees in Trillemarka forest, Norway. Scandinavian Journal of Forest Research, 28(3), 232-240.
