Black spruce

Black Spruce (Picea mariana)

Identity

Botanical and Chemical Names

Picea mariana, commonly known as black spruce, is a North American species of spruce tree in the pine family (Pinaceae). It has carried several synonyms in the scientific literature, including Pinus mariana P. Mill. and Picea nigra (Ait.) Link. The genus name Picea derives from the Latin pix, meaning "pitch" or "resin," in reference to the resinous nature of the tree. The species epithet mariana is Latin for "of Maryland," although the black spruce does not grow in the state of Maryland; it was named by English botanist Philip Miller, born in 1691, to whom "Maryland" epitomized North America. Common alternative names include bog spruce, swamp spruce, and shortleaf black spruce.

Natural Source and Distribution

Black spruce is widespread across Canada, found in all 10 provinces and all 3 territories; it is the official tree of Newfoundland and Labrador. Its range extends into northern parts of the United States: in Alaska, the Great Lakes region, and the upper Northeast. It is a frequent part of the biome known as taiga or boreal forest.

The tree is a slow-growing, small upright evergreen coniferous tree, having a straight trunk with little taper, a scruffy habit, and a narrow, pointed crown of short, compact, drooping branches with upturned tips. Through much of its range it averages 5–15 m (15–50 ft) tall with a trunk 15–50 cm (6–20 in) in diameter at maturity. Black spruce occupies the wettest sites, such as boreal bogs, and co-mingles with tamaracks.

Common Forms and Preparations

Black spruce is used across several distinct commercial and traditional preparations, each derived from a different plant part:

• Essential oil (needle/twig distillation): Black spruce essential oil is obtained through steam distillation of the needles and twigs of the Picea mariana tree.
• Essential oil (bark distillation): The essential oil of black spruce bark residue can be obtained using steam distillation (SD) and water distillation (WD), both giving similar yields and compositions as analyzed by gas chromatography and mass spectrometry.
• Bark extracts (polyphenolic/hot water): Reported for its antioxidant, anti-inflammatory and non-toxicity properties, hot water extracts of Picea mariana bark have been demonstrated to contain highly valuable bioactive polyphenols.
• Hydrosol (aromatic water): A co-product of the distillation process; essential oils of white and black spruce exhibit significant differences in composition compared to their hydrosols, with hydrosols containing alcohols and esters not found in essential oils.
• Resin (crude oleoresin): Used topically and historically as a chewing gum and sealant.
• Needle/bark tea (decoction or infusion): A traditional preparation consumed as a beverage or medicinal tea.

Traditional and Historical Use

Indigenous North American Peoples

The Cree, Ojibwe, Algonquin, and other northern nations used virtually every part of the tree. The inner bark was consumed as an emergency food and prepared as medicinal tea for colds, respiratory ailments, and vitamin C deficiency (scurvy).

The Ojibwa historically used black spruce for medicinal purposes by infusing the roots and bark to treat trembling and fits and stomach pain. The Potawatomi made a poultice from the inner bark and applied it to inflamed skin.

The Algonquin used the gum of the black spruce as a salve. The Cree mixed the pitch of the black spruce with grease and used it as an ointment for burns and skin rashes; they also used a decoction of cones as a gargle for sore throats and chewed the cone for toothaches.

Woodland Cree used black spruce as an anti-diarrheal medication by making infusions from the cones. At other times the needles and cones were used to treat diabetes.

Black spruce has been used by Native Americans for thousands of years. They used it in ointments, salves and lotions for healing skin problems such as boils, burns, sores and wounds. They also used the resin as a chewing gum and smeared it on their skin to protect against insect bites.

A poultice of the inner bark of black spruce was traditionally used as a topical anti-inflammatory, whereas the resin was used on sores to promote healing.

Utility and Food Uses

Spruce gum and spruce beer were made from this species and red spruce. Native Americans used the roots to make trays, buckets, dippers, and spoons. The roots were also used to sew canoes, snowshoes, and birch baskets. The wood was used to make canoe paddles and the pitch to seal seams on birch bark canoes.

Listing in Herbal Pharmacopoeias

In the British Herbal Pharmacopoeia, black spruce is listed as being helpful for diarrhea, cystitis, gingivitis, uterine prolapse, and pharyngitis (sore throat). This listing reflects traditional use rather than formal clinical validation.

Key Constituents and Active Compounds

Essential Oil from Needles and Twigs

The needle/twig essential oil is the most commercially common form. Bornyl acetate (34.2%) is the main compound identified in the Picea mariana needle essential oil, distinguishing it from the bark-derived oil. Additional major components include β-pinene (14.2%), α-pinene (13.7%), camphene (8.1%), and (+)-limonene (5.2%), as cited in Essential Oil Safety, 2nd Edition.

In a 2024 GC-MS analysis of Picea mariana essential oil used in a pharmacological study, the main active ingredients were identified as (−)-bornyl acetate (44.95%), γ-terpinene (14.17%), and β-pinene (10.12%).

Essential Oil from Bark Residue

The bark residue essential oil composition is turpentine-like, with the predominance of α-pinene (40.6% by SD; 40.5% by WD) and β-pinene (33.9% SD; 25.9% WD), followed by the hydrocarbon monoterpenes β-phellandrene, 3-carene, and limonene. These bark essential oils differ in composition from those from needles, which are commercially available and rich in bornyl acetate.

Hydrosol Composition

The hydrosol's composition is rich in oxygenated compounds, with α-terpineol (29.3% SD; 33.5% WD) as the dominant component, followed by trans-pinocarveol, terpinen-4-ol, verbenone, borneol, and pinocarvone.

Bark Polyphenols

The bark extract represents an entirely distinct phytochemical profile from the essential oil. A comprehensive characterization identified 28 compounds, among which were five neolignans, seven lignans, trans-resveratrol, three phenolic acids, and four flavonoids. Several compounds were reported for the first time in the Picea genus. P. mariana dry bark contains at least 104 μg g⁻¹ dry weight of trans-resveratrol and could therefore be considered a new accessible source of this molecule.

Trans-resveratrol was found in black spruce bark extract in greater concentration than in common food sources such as red wine, grape skin, or cocoa. Several other active compounds identified in black spruce bark extracts — such as taxifolin, pinoresinol, isolariciresinol, and mearnsetin — are known for their strong antioxidant and anti-inflammatory properties. Stilbene phytoalexins isorhapontin, astringin, isorhapontigenin, and piceatannol were reported to be associated with antimicrobial properties, as well as therapeutic potential as antioxidant, cardioprotective, anti-inflammatory, and anticancer agents.

A hot water extract (HWE) from Picea mariana bark was evaluated for its antioxidant and anti-inflammatory activities. HWE was fractionated into an oligomeric proanthocyanidin-rich fraction (OPF) and a polymeric proanthocyanidin-rich fraction (PPF). OPF exhibited the highest antioxidant and anti-inflammatory activities. OPF was richest in total polyphenol but lowest in total proanthocyanidin content. Thiolysis coupled with HPLC-DAD showed that the proanthocyanidins of black spruce bark were of the procyanidin type, with mean degrees of polymerisation (DPm) of 6.0 (HWE), 3.3 (OPF), and 7.6 (PPF).

Quantification of phenolic metabolites showed higher flavonoid and proanthocyanidin content (greater than 27.88 mmol catechin equivalents per 100 g of bark extract and greater than 3.90 mmol CE/100g respectively) in black spruce extracts compared to balsam fir, quaking aspen, and white birch.

Proposed Mechanisms of Action

Anti-inflammatory (bark polyphenolics, NF-κB pathway): The ethyl acetate fraction from Picea mariana bark extract showed inhibitory effects on cytokines, chemokines, adhesion molecules, nitric oxide, and prostaglandins produced by keratinocytes under TNF-α activation through down-regulating the NF-κB pathway. The study demonstrated that this extract could be a potential anti-inflammatory agent capable of improving psoriatic skin.

Serotonergic and GABAergic modulation (essential oil, CNS): In a mouse model of insomnia triggered by chlorophenylalanine administration, Picea mariana essential oils at different doses effectively inhibited weight loss, shortened sleep latency, and significantly extended overall sleep duration. Nissl staining showed that the oil reduced neuronal damage in insomnia mice. Immunohistochemical staining further revealed that the oil increased the expression of GAD65, GABAAα1, 5HT-2A, and 5HT-1A in insomnia mice.

Antidepressant mechanism (serotonin receptor modulation): Immunohistochemistry tests showed that moderate and high doses of Picea mariana essential oils activated cortical 5HT-1A receptors on par with fluoxetine, and medium doses even surpassed fluoxetine in activating the receptors in the hippocampus. Fluoxetine upregulated 5HT-2A receptors significantly in the cortex and hypothalamus, and the essential oil also mainly enhanced receptor expression in these regions. The protective mechanism on the nervous system may be related to the regulation of the levels of 5HT-1A and 5HT-2A in different sites by different doses.

α-Pinene and β-pinene (monoterpene mechanisms): α- and β-pinene are well-known representatives of the monoterpene group and are found in many plants' essential oils. A wide range of pharmacological activities have been reported for these compounds, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects. Additional reported effects include cytogenetic, gastroprotective, anxiolytic, cytoprotective, anticonvulsant, and neuroprotective activities.

Scientific Evidence by Area of Use

1. Skin Health and Dermatological Conditions (Bark Polyphenolics)

Background and traditional basis: Picea mariana bark has been traditionally used by North American natives for treating topical inflammations, and it has also been suggested to improve various inflammatory skin disorders like psoriasis vulgaris.

In vitro evidence — psoriasis: Based on the capacity of polyphenolic compounds to modulate functions of normal human keratinocytes, one laboratory study was set up to decipher the mechanisms of action of a chemically characterized polyphenolic extract from Picea mariana bark (BS-EAcf) on lesional keratinocytes of skin with psoriasis vulgaris, a disease in which TNF-α plays a significant role. Conclusions from this study found that the ethyl acetate fraction showed inhibitory effects on cytokines, chemokines, adhesion molecules, nitric oxide, and prostaglandins produced by keratinocytes under TNF-α activation through down-regulating the NF-κB pathway, suggesting it could be a potential anti-inflammatory agent capable of improving psoriatic skin.

In an earlier study, the ethyl acetate fraction at 500 μg mL⁻¹ (a non-toxic concentration) suppressed interleukin (IL) IL-8 production by normal and psoriatic keratinocytes stimulated with TNF-α cytokine. A further study showed that 250 and 500 μg/mL of the polyphenolic extract from Picea mariana bark could decrease the nitric oxide production induced in normal and psoriatic keratinocytes by TNF-α.

Evidence strength: Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. All dermatological evidence to date is preclinical (in vitro, cell culture). No human clinical trials have been conducted.

2. Antioxidant Activity (Bark Extracts)

The hot water extract of Picea mariana bark has been reported for its antioxidant, anti-inflammatory, and non-toxicity properties, and demonstrated to contain highly valuable bioactive polyphenols. The oligomeric proanthocyanidin-rich fraction (OPF), obtained by ethyl acetate fractionation of the hot water extract, was identified as the most potent antioxidant fraction. One study reported no cytotoxicity of hot water extract of Picea mariana on normal keratinocytes at concentrations lower than 55 μg/mL.

In contrast, when the essential oil itself was assessed: balsam fir, black spruce, white spruce, tamarack, and eastern white cedar oils exhibited very poor antioxidant activities in DPPH assay testing. This underscores the distinction between the polyphenol-rich bark extract and the volatile essential oil with respect to antioxidant capacity.

Evidence strength: Antioxidant evidence is in vitro and biochemical in nature. No human intervention studies exist.

3. Sleep / Hypnotic Effects (Essential Oil)

Picea mariana essential oil has been reported in preclinical studies to possess anti-insomnia and antidepressant effects; however, research on the molecular mechanisms underlying its action remains limited.

One study investigated the effect of different concentrations of PMEOs on sleep improvement in mice exhibiting p-chlorophenylalanine (PCPA)-induced insomnia. The main constituents of PMEOs were analyzed by GC-MS. The mice were weighed daily, and sleep latency and duration were measured in an inverted reflex experiment. The number of neurons in the mouse brain was measured using Nissl staining, and the expression levels of 5-HT1A and GABAARα1 were detected by immunohistochemistry, western blotting, and RT-qPCR. The study concluded that PMEOs acted through both GABAergic and serotonergic modulation.

Evidence strength: Preclinical animal studies only. No human clinical trials have evaluated black spruce essential oil for sleep.

4. Antidepressant Effects (Essential Oil)

A study aimed to investigate the principal components of Picea mariana and its effect on reserpine-induced depression mice, with focus on its relationship with brain central transmitters and related proteins. The main constituents of PMEO were analyzed by GC-MS spectrometry, and the quiescent time in the tail suspension test (TST) and forced swim test (FST), along with weight change, were detected. PMEOs effectively improved the retardation and weight loss due to anorexia in depression-like mice.

Numerous biological properties of P. mariana have been documented, including immunomodulatory, anti-inflammatory, and antioxidant activities. However, the effects of PMEOs on neuroinflammatory indicators and immune-triggered behavioral abnormalities remain largely unexplored. While anti-inflammatory or antidepressant effects of PMEOs have recently been demonstrated in mice, these observations were made in chronic stress models, and there is not any clear pharmacological proof linking PMEOs to immune-triggered depression.

Evidence strength: Preclinical (rodent) studies only. No human studies have been conducted on black spruce essential oil for depression or mood disorders.

5. Antimicrobial Activity (Bark Extracts and Essential Oil)

One study aimed to characterize antimicrobial efficacy of extracts from black spruce bark residues to determine their potential as a natural disinfectant. Quantification of phenolic metabolites showed higher flavonoid and proanthocyanidin content in black spruce extracts compared to balsam fir, quaking aspen, and white birch. Extraction with water followed by fractionation with ethyl acetate yielded a fraction enriched with oligomeric proanthocyanidins.

Stilbene phytoalexins isorhapontin, astringin, isorhapontigenin, and piceatannol were reported to be associated with antimicrobial properties. With respect to the essential oil, the DPPH-based antioxidant/antimicrobial assessments in the systematic review context found that black spruce oil showed only modest activity compared to other boreal species.

Evidence strength: In vitro laboratory work only. No clinical antimicrobial evidence exists.

6. Respiratory Support (Traditional and Aromatherapy)

Respiratory use is one of the most historically consistent applications. Indigenous peoples prepared a medicinal tea from the inner bark for colds, respiratory ailments, and vitamin C deficiency (scurvy). In modern aromatherapy practice, black spruce essential oil is applied via diffusion or topical chest application for respiratory complaints. The modern aromatherapy uses of black spruce essential oil include soothing respiratory problems such as coughs, colds, flu, bronchitis, catarrh, sinus congestion, asthma, and allergies. These applications, however, rest entirely on traditional precedent and inferred pharmacology from its α-pinene and 3-carene content; no controlled human clinical trials have evaluated black spruce specifically for respiratory outcomes.

Body Systems and Health Areas of Association

• Integumentary (skin): Bark preparations have been traditionally used by North American natives for treating topical inflammations and suggested for inflammatory skin disorders such as psoriasis vulgaris.
• Respiratory system: The inner bark tea has traditional use for colds and respiratory ailments.
• Central nervous system / mood: Preclinical research has identified serotonergic and GABAergic interactions, with essential oil demonstrating anti-insomnia and antidepressant effects in animal studies.
• Musculoskeletal system: The bornyl acetate content of the essential oil indicates potential as a beneficial analgesic and anti-inflammatory for musculoskeletal applications such as muscular aches, pains, stiffness, and tension. This inference is derived from the known pharmacology of bornyl acetate rather than specific black spruce clinical trials.
• Immune system: Immunomodulatory, anti-inflammatory, and antioxidant activities have been documented for P. mariana.
• Gastrointestinal system: The Ojibwa used infusions of roots and bark to treat stomach pain. Woodland Cree used black spruce as an anti-diarrheal medication by making infusions from the cones.

Dosage Forms and Reported Dosages

There are no established human clinical dosages for black spruce preparations supported by clinical trials. The following dosage parameters have appeared in the scientific literature in preclinical contexts or as reported in reference works:

• Bark polyphenolic extract (in vitro): The ethyl acetate fraction has been studied at 500 μg mL⁻¹ as a non-toxic concentration that suppressed IL-8 production by keratinocytes.
• Bark polyphenolic extract (in vitro, NO suppression): Concentrations of 250 and 500 μg/mL of the polyphenolic extract decreased nitric oxide production induced in normal and psoriatic keratinocytes.
• Polyphenol extraction optimization: Low temperature (80 °C) and a low ratio of bark/water (50 mg/mL) were determined to be optimal parameters for efficient polyphenol extraction, especially for low molecular mass polyphenols.
• Essential oil (aromatherapy, traditional practice): In aromatherapy literature, black spruce essential oil is used aromatically via diffusion at approximately 3–4 drops per diffuser session, and topically diluted in a carrier oil. One aromatherapy practice guide specifies using a 1:2 essential oil to vegetable oil dilution, gently massaged above the kidneys, twice daily — but this is practitioner guidance, not a clinical dosage.

No standardized or pharmacopeial dosages have been established for any form of black spruce in human medicine.

Safety Considerations

Essential Oil — Skin Sensitization and Oxidation

Tisserand and Young (Essential Oil Safety, 2nd Edition) do not indicate any special precautions when using black spruce essential oil under normal conditions; however, they caution to avoid use of the oil if it has oxidized. Black spruce essential oil contains monoterpenes (50–55%), including δ-3-carene (up to 16%) and α-pinene; the presence of δ-3-carene can cause the oil to become a strong skin sensitizer when old or oxidized.

Essential Oil — Respiratory Sensitivity

α-Pinene, a naturally occurring component of black spruce essential oil, is a known mild respiratory irritant for sensitive individuals, and responses can be very individualized.

Bark Extract — Cytotoxicity Profile

One study reported no cytotoxicity of hot water extract of Picea mariana on normal keratinocytes at concentrations lower than 55 μg/mL. While these forest extracts function as antioxidants in vitro and may act on signaling pathways, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods.

General Notes on Evidence Gaps

The effects of P. mariana essential oils on neuroinflammatory indicators and immune-triggered behavioral abnormalities remain largely unexplored. While anti-inflammatory or antidepressant effects have been demonstrated in mice, there is no clear pharmacological proof linking PMEOs to immune-triggered depression in humans. The vast majority of biological data for black spruce — across all preparation types — derives from in vitro and preclinical animal studies. Human clinical evidence is absent for all proposed therapeutic applications as of the time of this writing.

References

• Wikipedia — Picea mariana (Black Spruce)
• Francezon N. & Stevanovic T. (2017). Chemical composition of essential oil and hydrosol from Picea mariana bark residue. BioResources 12(2), 2635–2645.
• Garcia-Perez M.E. et al. (2012). Picea mariana bark: A new source of trans-resveratrol and other bioactive polyphenols. Food Chemistry 135(3), 1173–1182.
• Garcia-Pérez M.E. et al. (2013). Picea mariana polyphenolic extract inhibits phlogogenic mediators produced by TNF-α-activated psoriatic keratinocytes: Impact on NF-κB pathway. Journal of Ethnopharmacology.
• PubMed — Picea mariana polyphenolic extract inhibits phlogogenic mediators produced by TNF-α-activated psoriatic keratinocytes (2013).
• PMC — Optimization of Bioactive Polyphenols Extraction from Picea mariana Bark. Molecules 22(12):2118 (2017).
• PMC — Antidepressant Effect and Mechanism of Picea mariana Essential Oil on Reserpine-Induced Depression Model Mice (2024).
• Tang M. et al. (2023). Chemical Composition and Hypnotic Effect of Picea mariana Essential Oils. Journal of Essential Oil Bearing Plants 26(2).
• A Natural Remedy for Insomnia: Picea mariana Essential Oils Exerts Effects through GABAergic and Serotonergic Modulation. ResearchGate (2023).
• Zuzarte M. et al. (2019). Antimicrobial, Antioxidant, and Immunomodulatory Properties of Essential Oils: A Systematic Review. Nutrients 11(11):2786. PMC.
• St-Pierre A. et al. (2019). Chemical Composition of Black Spruce (Picea mariana) Bark Extracts and Their Potential as Natural Disinfectant. Industrial Biotechnology.
• Garneau F.X. et al. (2012). Chemical Composition of the Hydrosol and Essential Oil of Three Different Species of the Pinaceae Family. Journal of Essential Oil Bearing Plants.
• Adirondack Visitor Interpretive Center — Trees of the Adirondacks: Black Spruce (Picea mariana).
• Johnson's Nursery Knowledge Base — Black Spruce (Picea mariana).
• Aromatherapy and Massage — Black Spruce Essential Oil Benefits and Uses. (Citing Tisserand & Young, Essential Oil Safety, 2nd Ed.)
• AromaWeb — Black Spruce Essential Oil (citing Tisserand & Young, Essential Oil Safety, 2nd Ed., 2014, p. 429).
• PlantNative.org — Black Spruce: Native Tree with Edible Uses.
• Base Formula — Essential Oil of the Month: Black Spruce (Picea mariana).
• BoreA Canada — Black Spruce (Picea mariana) essential oil (citing Moerman D.E., Native American Ethnobotany, Timber Press, 1998).