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Spruce

life science Maturity 11-13 Next article →

Spruce trees belong to the genus Picea. They are coniferous evergreen trees within the Pinaceae family. There are approximately 37 different species of spruce found in the Northern Hemisphere. These trees thrive in northern temperate and boreal regions, also known as the taiga. Spruces are vital to many ecosystems and human industries. They provide essential timber for construction and pulp for paper production.

Pinetum woburnense (Spruce, page 146) (cropped)
Pinetum woburnense (Spruce, page 146) (cropped)

Spruces possess unique physical traits that distinguish them from other Pinaceae. Their needles are evergreen and have a square cross-section. Each needle is attached to a small, persistent peg-like structure called a pulvinus. When the needles fall off after four to ten years, these pulvini remain on the twigs. This process leaves the twigs feeling very rough to the touch.

495 Picea abies (cropped)
495 Picea abies (cropped)

The growth patterns of spruce trees vary by species and age. Young trees often feature a conical crown shape. As they grow older, the shape often shifts into a cylindrical column. Most spruces have straight trunks, though wind or insect damage can cause irregular shapes. Branches grow in regular whorls around the trunk. Young branches typically rise above the horizontal, while older branches grow more level.

Spruce in the park of Peterhof
Spruce in the park of Peterhof

Spruce trees are monoecious, meaning they have separate male and female cones on the same tree. The cones contain seeds that possess a large wing for dispersal. The size of these cones varies significantly between species. For example, Picea mariana has cones between 2 and 3.5 cm long. In contrast, Picea abies produces much larger cones reaching 10 to 20 cm. The specific shape and color of the cone scales are key for scientists identifying different species.

Cathaya argyrophylla leaves and cones
Cathaya argyrophylla leaves and cones

Spruces have a very deep history in the fossil record. The Picea lineage began appearing around 130 million years ago. The oldest specific spruce fossils date back to the Early Cretaceous period in western Canada. These fossils are about 136 million years old.

Picea ugoana National Museum of Nature and Science, Japan (cropped)
Picea ugoana National Museum of Nature and Science, Japan (cropped)

While the lineage is ancient, the modern crown group diverged only about 30 million years ago. This means the biology of modern spruces may differ from their ancient ancestors.

These trees are known for their impressive lifespans. Most spruces live between 100 and 600 years. One recorded Engelmann spruce lived for 852 years. Some spruce groups can exist for much longer through clonal reproduction. A Norway spruce clone in Sweden, named "Old Tjikko," is estimated to be 9,550 years old. This age refers to the clonal group rather than a single individual tree.

Spruce in the park of Peterhof
Spruce in the park of Peterhof

Humans have utilized spruce in many ways throughout history. The wood is a standard material for acoustic guitar soundboards. This is because of the specific qualities of the timber.

Politiko Laouto
Politiko Laouto

Native Americans have used the roots of certain species for weaving baskets.

Tlingit spruce root basket, Southeast Alaska Discovery Center
Tlingit spruce root basket, Southeast Alaska Discovery Center

The Norway spruce is also the most common choice for Christmas trees. Even artists have captured their beauty. Augustin Hirschvogel painted them in the 16th century, and Edvard Munch depicted them around 1900.

495 Picea abies (cropped)
495 Picea abies (cropped)

Modern science uses DNA to study the complex relationships between spruce species. This research often conflicts with older methods based on physical shapes. Scientists look at mitochondrial DNA and chloroplast DNA to map the genus. There is evidence of reticulate evolution, where species hybridize and mix their genes. For example, Picea abies and Picea obovata can create a natural hybrid called Picea × fennica. Understanding these genetic links helps scientists map the entire Pinaceae family.

Cathaya argyrophylla leaves and cones
Cathaya argyrophylla leaves and cones
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🖼️ Images & Media (13)
File:495 Picea abies (cropped).jpg
495 Picea abies (cropped).jpg
File:Picea ugoana National Museum of Nature and Science, Japan (cropped).jpg
Picea ugoana National Museum of Nature...
File:Abies alba - Köhler–s Medizinal-Pflanzen-001.jpg
Abies alba - Köhler–s Medizinal-Pflanzen-001.jpg
File:Pinetum woburnense (Douglas firs, page 185).jpg
Pinetum woburnense (Douglas firs, page 185).jpg
File:395 Larix europaea DC.jpg
395 Larix europaea DC.jpg
File:Cathaya argyrophylla leaves and cones.jpg
Cathaya argyrophylla leaves and cones.jpg
File:Pinetum woburnense (Spruce, page 146) (cropped).jpg
Pinetum woburnense (Spruce, page 146)...
File:496 Pinus silvestris.jpg
496 Pinus silvestris.jpg
File:Kuuse-kooreürask ja tegutsemisjäljed Ips typographus.jpg
Kuuse-kooreürask ja tegutsemisjäljed Ips...
File:Wood picea abies (horiz).jpg
Wood picea abies (horiz).jpg
File:Politiko Laouto.jpg
Politiko Laouto.jpg
File:Spruce in the park of Peterhof.jpg
Spruce in the park of Peterhof.jpg

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