{
  "spore": "profile",
  "id": "douglas-fir",
  "spore_version": "0.2",
  "family": "wood",
  "name": "Douglas fir (Pseudotsuga menziesii)",
  "abbreviation": "Douglas fir",
  "role": "Softwood conifer timber used for construction lumber, plywood and light aircraft wood structure",
  "category": "living",
  "type": "bio-grown-building-materials",
  "summary": "Douglas fir (Pseudotsuga menziesii) is a softwood conifer from western North America. At 12% moisture content, Engineering ToolBox gives a density of 460 to 500 kg/m3 for Douglas-fir, and the USDA Wood Handbook gives a modulus of rupture of 85000 kPa for Coast Douglas-fir. Its strength and density vary by growth region, so the figures in this profile are kept side by side rather than merged.\n",
  "best_for": "Structural construction lumber and plywood where a light-to-medium softwood with a strength close to spruce is needed",
  "weakest_at": "Moderate decay resistance in damp service, and it is hard to work with hand tools (FAA)",
  "identity": {
    "formula": "Wood of Pseudotsuga menziesii: cellulose, lignin and hemicelluloses in a cellular structure",
    "designations": [],
    "source": "vt-dendro",
    "where": "Title line: Pseudotsuga menziesii (Mirb.) Franco, family Pinaceae; common names list Douglas-fir"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Average dried weight",
      "value": 510,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "basis": "average dried weight as printed in the species data table",
        "moisture": "no moisture condition stated on the page"
      },
      "method": "Printed on the Wood Database page as Average Dried Weight, with 32 lbs/ft3 shown alongside",
      "status": "ground",
      "source": "wood-database",
      "where": "Species data table, Average Dried Weight row",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Modulus of rupture (bending strength)",
      "value": 86.2,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "basis": "value as printed on the Wood Database page, shown with 12,500 lbf/in2",
        "moisture": "no moisture condition stated on the page"
      },
      "method": "Printed on the Wood Database species page under Physical and mechanical properties",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Modulus of Rupture",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus",
      "value": 12.17,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "basis": "value as printed on the Wood Database page, shown with 1,765,000 lbf/in2",
        "moisture": "no moisture condition stated on the page"
      },
      "method": "Printed on the Wood Database species page under Physical and mechanical properties",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Elastic Modulus",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "crushing_strength",
      "label": "Crushing strength (compression parallel to grain)",
      "value": 47.9,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "basis": "value as printed on the Wood Database page, shown with 6,950 lbf/in2",
        "moisture": "no moisture condition stated on the page"
      },
      "method": "Printed on the Wood Database species page as Crushing Strength",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Crushing Strength",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "janka_hardness",
      "label": "Janka hardness",
      "value": 2760,
      "bound": "exact",
      "unit": "N",
      "scope": "material",
      "conditions": {
        "basis": "Janka hardness as printed, shown on the page as 620 lbf",
        "moisture": "no moisture condition stated on the page"
      },
      "method": "Printed on the Wood Database species page as Janka Hardness",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Janka Hardness",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "shrinkage_radial",
      "label": "Radial shrinkage",
      "value": 4.5,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "shrinkage as printed; no condition stated on the page"
      },
      "method": "Printed on the Wood Database species page under Shrinkage",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Shrinkage (Radial)",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "shrinkage_tangential",
      "label": "Tangential shrinkage",
      "value": 7.3,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "shrinkage as printed; no condition stated on the page"
      },
      "method": "Printed on the Wood Database species page under Shrinkage",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Shrinkage (Tangential)",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "shrinkage_volumetric",
      "label": "Volumetric shrinkage",
      "value": 11.6,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "shrinkage as printed; no condition stated on the page"
      },
      "method": "Printed on the Wood Database species page under Shrinkage",
      "status": "ground",
      "source": "wood-database",
      "where": "Physical and mechanical properties, Shrinkage (Volumetric)",
      "source_detail": {
        "title": "Douglas Fir, Wood Database (softwood species profile)",
        "id": "Wood Database, Douglas fir page",
        "url": "https://www.wood-database.com/douglas-fir/",
        "kind": "database",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, four Douglas-fir regions (range)",
      "value": 460,
      "value_high": 500,
      "bound": "range",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "moisture": "12% moisture content (table note: values for wood with 12% moisture content)",
        "basis": "Douglas-fir Coast, Interior West, Interior North and Interior South printed as one range"
      },
      "method": "Range printed in the Wood, Panel and Structural Timber Products table",
      "status": "ground",
      "source": "et-timber",
      "where": "Clear Wood table, Douglas-fir row, Density column",
      "source_detail": {
        "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
        "id": "Engineering ToolBox, Clear Wood table",
        "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Fibre stress at elastic limit (modulus of rupture)",
      "value": 82,
      "value_high": 90,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "moisture": "12% moisture content (table note)",
        "basis": "Douglas-fir Coast, Interior West, Interior North and Interior South printed as one range"
      },
      "method": "Range printed in the Wood, Panel and Structural Timber Products table; the column is headed Fibre Stress at Elastic Limit (Modulus of Rupture)",
      "status": "ground",
      "source": "et-timber",
      "where": "Clear Wood table, Douglas-fir row, Fibre Stress column",
      "source_detail": {
        "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
        "id": "Engineering ToolBox, Clear Wood table",
        "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity (range)",
      "value": 10.3,
      "value_high": 13.4,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "moisture": "12% moisture content (table note)",
        "basis": "Douglas-fir regions printed as one range"
      },
      "method": "Range printed in the Wood, Panel and Structural Timber Products table",
      "status": "ground",
      "source": "et-timber",
      "where": "Clear Wood table, Douglas-fir row, Modulus of Elasticity column",
      "source_detail": {
        "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
        "id": "Engineering ToolBox, Clear Wood table",
        "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "compressive_strength_parallel_to_grain",
      "label": "Compressive strength parallel to grain (range)",
      "value": 43.1,
      "value_high": 51.2,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "moisture": "12% moisture content (table note)",
        "basis": "Douglas-fir regions printed as one range"
      },
      "method": "Range printed in the Wood, Panel and Structural Timber Products table",
      "status": "ground",
      "source": "et-timber",
      "where": "Clear Wood table, Douglas-fir row, Compressive Strength parallel to Grain column",
      "source_detail": {
        "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
        "id": "Engineering ToolBox, Clear Wood table",
        "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "shear_strength_parallel_to_grain",
      "label": "Shear strength parallel to grain (range)",
      "value": 7.8,
      "value_high": 10.4,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "moisture": "12% moisture content (table note)",
        "basis": "Douglas-fir regions printed as one range"
      },
      "method": "Range printed in the Wood, Panel and Structural Timber Products table",
      "status": "ground",
      "source": "et-timber",
      "where": "Clear Wood table, Douglas-fir row, Shear Strength parallel to grain column",
      "source_detail": {
        "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
        "id": "Engineering ToolBox, Clear Wood table",
        "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, seasoned and dry wood",
      "value": 530,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "moisture": "seasoned and dry wood (page wording)",
        "basis": "single Douglas Fir value in the species table"
      },
      "method": "Printed in the Wood Species Densities table",
      "status": "ground",
      "source": "et-density",
      "where": "Wood Species - Densities table, Douglas Fir row",
      "source_detail": {
        "title": "Density of Wood Species (Engineering ToolBox)",
        "id": "Engineering ToolBox, Wood Species - Densities table",
        "url": "https://www.engineeringtoolbox.com/wood-density-d_40.html",
        "kind": "web",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Modulus of rupture, Coast Douglas-fir",
      "value": 85000,
      "bound": "exact",
      "unit": "kPa",
      "scope": "material",
      "conditions": {
        "moisture": "12%",
        "basis": "clear wood, Coast Douglas-fir (Oregon and Washington west of the Cascade summit), as printed in the metric table"
      },
      "method": "Printed in the Wood Handbook metric strength table, Douglas-fir Coast row, 12% moisture content line",
      "status": "ground",
      "source": "wh2010",
      "where": "Table 5-3a (metric), Douglas-fir Coast, 12% row, modulus of rupture column",
      "source_detail": {
        "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
        "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
        "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
        "year": 2010,
        "kind": "report",
        "license": "US government publication"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, Coast Douglas-fir",
      "value": 13400,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "moisture": "12%",
        "basis": "clear wood, Coast Douglas-fir, as printed in the metric table"
      },
      "method": "Printed in the Wood Handbook metric strength table, Douglas-fir Coast row, 12% moisture content line",
      "status": "ground",
      "source": "wh2010",
      "where": "Table 5-3a (metric), Douglas-fir Coast, 12% row, modulus of elasticity column",
      "source_detail": {
        "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
        "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
        "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
        "year": 2010,
        "kind": "report",
        "license": "US government publication"
      }
    },
    {
      "benchmark": "compressive_strength_parallel_to_grain",
      "label": "Compression parallel to grain, Coast Douglas-fir",
      "value": 49900,
      "bound": "exact",
      "unit": "kPa",
      "scope": "material",
      "conditions": {
        "moisture": "12%",
        "basis": "clear wood, Coast Douglas-fir, as printed in the metric table; the table footnote calls compression parallel to grain the maximum crushing strength"
      },
      "method": "Printed in the Wood Handbook metric strength table, Douglas-fir Coast row, 12% moisture content line",
      "status": "ground",
      "source": "wh2010",
      "where": "Table 5-3a (metric), Douglas-fir Coast, 12% row, compression parallel to grain column",
      "source_detail": {
        "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
        "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
        "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
        "year": 2010,
        "kind": "report",
        "license": "US government publication"
      }
    },
    {
      "benchmark": "shear_strength_parallel_to_grain",
      "label": "Shear strength parallel to grain, Coast Douglas-fir",
      "value": 7800,
      "bound": "exact",
      "unit": "kPa",
      "scope": "material",
      "conditions": {
        "moisture": "12%",
        "basis": "clear wood, Coast Douglas-fir, as printed in the metric table"
      },
      "method": "Printed in the Wood Handbook metric strength table, Douglas-fir Coast row, 12% moisture content line",
      "status": "ground",
      "source": "wh2010",
      "where": "Table 5-3a (metric), Douglas-fir Coast, 12% row, shear parallel to grain column",
      "source_detail": {
        "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
        "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
        "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
        "year": 2010,
        "kind": "report",
        "license": "US government publication"
      }
    },
    {
      "benchmark": "specific_gravity",
      "label": "Specific gravity, Coast Douglas-fir",
      "value": 0.48,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "moisture": "12%",
        "basis": "table footnote: specific gravity is based on ovendry weight and volume at 12% moisture content"
      },
      "method": "Printed in the Wood Handbook metric strength table, Douglas-fir Coast row, 12% moisture content line",
      "status": "ground",
      "source": "wh2010",
      "where": "Table 5-3a (metric), Douglas-fir Coast, 12% row, specific gravity column",
      "source_detail": {
        "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
        "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
        "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
        "year": 2010,
        "kind": "report",
        "license": "US government publication"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Damp service where decay fungi and wood-boring insects are present",
      "headline": "Heartwood is moderately durable against decay but susceptible to insect attack.",
      "effect": "The Wood Database rates Douglas-fir heartwood as moderately durable in regard to decay, but susceptible to insect attack. The page gives no exposure time or test method for this rating.",
      "rating": "moderate",
      "conditions": {
        "basis": "rating as printed on the species page; no exposure test described"
      },
      "source": "wood-database",
      "where": "Decay and durability, Rot Resistance"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Wood Database: Douglas-fir has been reported to cause skin irritation, nausea, giddiness and a runny nose, and splinters are more likely to become infected. Severe reactions are described as quite uncommon.",
        "ghs": [],
        "source": "wood-database",
        "where": "Allergies/Toxicity"
      },
      {
        "text": "Wood Database allergy chart: Douglas-fir is listed as an irritant, with giddiness, runny nose, splinters going septic and nausea. The chart also states that all inhaled wood dust is hazardous to long-term health.",
        "ghs": [],
        "source": "wood-allergies",
        "where": "Allergy and toxicity chart, Douglas-fir row, and the introduction text above it"
      },
      {
        "text": "IARC Monographs Volume 62 (1995) states that occupational exposure to wood dust is causally related to adenocarcinoma of the nasal cavities and paranasal sinuses. The classification applies to wood dust in general, not to Douglas-fir alone.",
        "ghs": [],
        "source": "iarc-v62",
        "where": "Classification statement on the monograph page"
      }
    ],
    "failure_risks": [
      {
        "mode": "Decay and insect attack in damp service",
        "trigger": "Moisture in service together with decay fungi or wood-boring insects",
        "consequence": "Loss of strength and service life; the sources we hold give no rate of loss",
        "severity": "moderate",
        "source": "wood-database",
        "where": "Rot Resistance"
      },
      {
        "mode": "Splitting and splintering during fabrication",
        "trigger": "Hand-working or machining Douglas-fir stock",
        "consequence": "Split and splintered parts; the FAA notes large solid pieces are hard to inspect and should be avoided",
        "severity": "low",
        "source": "faa-ac43-13",
        "where": "Table 1-1, Remarks column"
      }
    ],
    "side_effects": [
      {
        "text": "The wood has a distinct resinous odour when it is worked.",
        "affects": "People working the wood",
        "source": "wood-database",
        "where": "Odor"
      }
    ],
    "handling": [
      {
        "text": "Wood Database allergy page: all woods produce fine dust when worked, so keep dust down when cutting or sanding.",
        "source": "wood-allergies",
        "where": "Paragraph after the allergy chart introduction"
      },
      {
        "text": "FAA AC 43.13-1B: Douglas Fir is difficult to work with hand tools and gluing is satisfactory.",
        "source": "faa-ac43-13",
        "where": "Table 1-1, Remarks column"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "structures",
      "device": "Construction lumber, plywood, piles and engineered wood composites",
      "example": "Douglas-fir is used mostly for building and construction purposes in the form of lumber, marine fendering, piles, plywood, and engineered wood composites.",
      "source": "wh2010",
      "where": "Chapter 2, Species Descriptions, Douglas-fir paragraph"
    },
    {
      "application": "structures",
      "device": "Aircraft wood structure, as a substitute for spruce",
      "example": "Douglas Fir exceeds spruce in strength; it may be used as a substitute for spruce in the same sizes or in slightly reduced sizes, providing the reductions are substantiated.",
      "source": "faa-ac43-13",
      "where": "Table 1-1, Douglas Fir row (printed as Pseudotsuga Taxifolia)"
    },
    {
      "application": "structures",
      "device": "Railroad crossties, poles, mine timbers and fencing",
      "example": "Considerable quantities are used for railroad crossties, cooperage stock, mine timbers, poles, and fencing.",
      "source": "wh2010",
      "where": "Chapter 2, Species Descriptions, Douglas-fir paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Douglas-fir timber (wood feedstock)",
      "producers": [],
      "critical_lists": [],
      "recycling": "No recycling figure for Douglas-fir timber was found in the sources we hold.",
      "substitutes": [
        "FAA AC 43.13-1B: Douglas Fir may be used as a substitute for spruce in the same sizes or in slightly reduced sizes, providing the reductions are substantiated."
      ],
      "source": "vt-dendro",
      "where": "Distribution paragraph: range from the Rocky Mountains to the Pacific coast and from Mexico to central British Columbia; production from the coast states of Oregon, Washington and California and the Rocky Mountain states"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Wood Database: Douglas Fir (softwood species profile)",
      "type": "database",
      "url": "https://www.wood-database.com/douglas-fir/"
    },
    {
      "title": "Wood Handbook: Wood as an Engineering Material (FPL-GTR-190, 2010), copy hosted by California Air Resources Board",
      "type": "report",
      "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
      "year": 2010
    },
    {
      "title": "FAA Advisory Circular AC 43.13-1B, Chapter 1 (copy hosted by RAANZ)",
      "type": "standard",
      "url": "https://raanz.org.nz/techproject/FAA%20AC43.13%20b/Chapter%2001.pdf",
      "year": 1998
    },
    {
      "title": "IARC Monographs Volume 62: Wood Dust and Formaldehyde",
      "type": "report",
      "url": "https://publications.iarc.who.int/80",
      "year": 1995
    }
  ],
  "gaps": [
    "No ageing or weathering data for Douglas-fir (greying, UV, moisture cycling) were found in a source we could open; the one search returned only other species.",
    "No country-level production shares or current production volumes for Douglas-fir were found, so the supply entry lists feedstock regions only.",
    "No flight, vacuum, radiation or thermal-cycling data for Douglas-fir were found, and no space application source was found.",
    "Specific gravity of the other Douglas-fir regions was not recorded, because the Wood Database gives two unlabelled values (0.45, 0.51) and the Wood Handbook regions were not matched to them.",
    "Shrinkage values in the Wood Handbook Table 4-3 are printed without an explicit unit on the page, so they were left out; the Wood Database shrinkage percentages are recorded instead.",
    "Thermal conductivity, Poisson's ratio and fatigue strength for Douglas-fir were not recorded from a source we could open.",
    "Moisture effects away from 12% moisture content were not recorded from a source we could open.",
    "Combustion and fire behaviour for Douglas-fir were not found in a source we could open.",
    "No UNS, EN or other standard grade designation applies to Douglas-fir timber, so none is listed."
  ],
  "story": {
    "why": "Douglas fir (Pseudotsuga menziesii) is a softwood from western North America. The Wood Handbook says it is used mostly for building and construction, and the FAA says it may be used as a substitute for spruce in some aircraft wood structures. It is in this collection as a structural timber benchmark, not as a space material: we found no flight data and no space-environment source for it.",
    "uses": [
      {
        "where": "Building and construction",
        "line": "The Wood Handbook says Douglas-fir is used mostly for building and construction, as lumber, marine fendering, piles, plywood and engineered wood composites."
      },
      {
        "where": "Aircraft wood structure",
        "line": "FAA AC 43.13-1B Table 1-1 says Douglas Fir exceeds spruce in strength. It says the species may be used as a substitute for spruce in the same sizes, or in slightly reduced sizes, if the reductions are substantiated. The table prints the older name Pseudotsuga taxifolia."
      },
      {
        "where": "Railroad ties, poles and fencing",
        "line": "The Wood Handbook says considerable quantities are used for railroad crossties, cooperage stock, mine timbers, poles and fencing."
      }
    ],
    "can_do": [
      {
        "label": "Density",
        "line": "Engineering ToolBox gives 460 to 500 kg/m3 at 12% moisture content for the Douglas-fir regions. A separate table gives 530 kg/m3 for seasoned and dry wood, and the Wood Database gives 510 kg/m3 as average dried weight. The three figures use different moisture conditions, so they are shown side by side.",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Bending strength",
        "line": "At 12% moisture content, Engineering ToolBox gives 82 to 90 MPa for fibre stress at elastic limit. The Wood Handbook gives 85000 kPa for Coast Douglas-fir, and the Wood Database gives 86.2 MPa modulus of rupture without a moisture condition.",
        "benchmark": "flexural_strength",
        "scope": "material"
      },
      {
        "label": "Stiffness",
        "line": "The Wood Handbook gives 13400 MPa modulus of elasticity for Coast Douglas-fir at 12% moisture content, and Engineering ToolBox gives a range of 10.3 to 13.4 GPa across the regions.",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Hardness",
        "line": "The Wood Database gives a Janka hardness of 2,760 N for Douglas-fir.",
        "benchmark": "janka_hardness",
        "scope": "material"
      },
      {
        "label": "Compression and shear",
        "line": "At 12% moisture content, the Wood Handbook gives 49900 kPa compression parallel to grain for Coast Douglas-fir and 7800 kPa shear parallel to grain. Engineering ToolBox gives 43.1 to 51.2 MPa and 7.8 to 10.4 MPa across the regions.",
        "benchmark": "compressive_strength_parallel_to_grain",
        "scope": "material"
      }
    ],
    "compare": "Against spruce, the FAA table says Douglas Fir exceeds spruce in strength, but it is harder to work with hand tools and splits more readily. The sources give Douglas-fir values at different moisture contents and test regions, so this profile does not rank Douglas-fir numerically against other timbers. The compare rows below use the 12% moisture values from the regional tables.",
    "compare_rows": [
      {
        "label": "Density at 12% moisture",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Bending strength",
        "benchmark": "flexural_strength",
        "scope": "material"
      },
      {
        "label": "Stiffness",
        "benchmark": "elastic_modulus",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep dust down when cutting or sanding. The Wood Database allergy page says all woods produce fine dust when worked.",
      "Douglas-fir splits and splinters during fabrication, and it is hard to work with hand tools, according to the FAA.",
      "Keep the wood dry where you can. Decay is the main risk in damp service, and the heartwood is only moderately durable."
    ],
    "good_for": [
      "Construction lumber, plywood and piles, where a strong softwood is needed (Wood Handbook).",
      "Aircraft wood structure, where the FAA allows Douglas Fir as a spruce substitute if the reductions are substantiated."
    ],
    "watch_out": [
      "Moderate decay resistance and susceptibility to insect attack in damp service.",
      "Splitting and splintering when worked, with large solid pieces hard to inspect.",
      "Dust from the wood is a reported health hazard, and IARC classifies wood dust as carcinogenic to humans."
    ],
    "verdict": "A strong, widely used structural softwood. Keep it dry and control its dust and splinters.",
    "recipe": {
      "line": "Douglas-fir is wood, not a single compound. Its cell walls are built from cellulose, lignin and hemicelluloses, arranged in a cellular structure. The Wood Handbook gives this composition for all wood.",
      "parts": [
        {
          "name": "Cellulose",
          "role": "Long fibres that give the cell walls their tensile strength.",
          "source": "wh2010",
          "where": "Chapter 1, composition sentence"
        },
        {
          "name": "Lignin",
          "role": "Binds the cellulose fibres together and stiffens the cell walls.",
          "source": "wh2010",
          "where": "Chapter 1, composition sentence"
        },
        {
          "name": "Hemicelluloses",
          "role": "Matrix material between the cellulose fibres.",
          "source": "wh2010",
          "where": "Chapter 1, composition sentence"
        },
        {
          "name": "Cellular structure",
          "role": "The hollow cells whose size and arrangement, with the component proportions, make a wood heavy or light, stiff or flexible, and hard or soft.",
          "source": "wh2010",
          "where": "Chapter 1, composition sentence"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The reported hazards are irritation from dust and splinters, and wood dust is classed as a cancer hazard in occupational exposure.",
        "points": [
          {
            "label": "Dust",
            "line": "The Wood Database allergy chart says all inhaled wood dust is hazardous to long-term health. IARC Volume 62 (1995) links occupational wood dust exposure to cancer of the nasal cavities and paranasal sinuses."
          },
          {
            "label": "Skin and splinters",
            "line": "The Wood Database reports skin irritation for Douglas-fir, and says splinters are more likely to become infected. Severe reactions are described as quite uncommon."
          },
          {
            "label": "Odour",
            "line": "The wood has a distinct resinous odour when worked."
          }
        ],
        "level": 1,
        "verdict": "Dust and splinters are the reported hazards"
      },
      {
        "title": "If the wood is wet or infested",
        "lead": "Douglas-fir heartwood is rated moderately durable against decay and susceptible to insect attack.",
        "points": [
          {
            "label": "Damp service",
            "line": "Moisture with decay fungi or wood-boring insects is the main threat to the wood. The Wood Database rates the heartwood moderately durable, which gives no exposure time."
          },
          {
            "label": "Splitting",
            "line": "The FAA says Douglas Fir has some tendency to split and splinter during fabrication, and large solid pieces are hard to inspect."
          }
        ],
        "level": 2,
        "verdict": "Moderately durable against decay; susceptible to insects"
      }
    ]
  },
  "updated": "2026-11-02",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 19,
    "unreachable": 0,
    "caveats": 2,
    "note": "Read by an AI assistant on 2026-11-02 from the cited pages and PDFs. Regional values are kept separate; the Wood Database averages are not merged with the regional tables."
  },
  "sources": {
    "wood-database": {
      "title": "Douglas Fir, Wood Database (softwood species profile)",
      "id": "Wood Database, Douglas fir page",
      "url": "https://www.wood-database.com/douglas-fir/",
      "kind": "database",
      "license": "cited, not reproduced"
    },
    "wood-allergies": {
      "title": "Wood Allergies and Toxicity, Wood Database",
      "id": "Wood Database allergy and toxicity chart",
      "url": "https://www.wood-database.com/wood-allergies-and-toxicity/",
      "kind": "web",
      "license": "cited, not reproduced"
    },
    "et-timber": {
      "title": "Wood, Panel and Structural Timber Products - Mechanical Properties (Engineering ToolBox)",
      "id": "Engineering ToolBox, Clear Wood table",
      "url": "https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html",
      "kind": "web",
      "license": "cited, not reproduced"
    },
    "et-density": {
      "title": "Density of Wood Species (Engineering ToolBox)",
      "id": "Engineering ToolBox, Wood Species - Densities table",
      "url": "https://www.engineeringtoolbox.com/wood-density-d_40.html",
      "kind": "web",
      "license": "cited, not reproduced"
    },
    "wh2010": {
      "title": "Wood Handbook: Wood as an Engineering Material, General Technical Report FPL-GTR-190 (2010 edition)",
      "id": "USDA Forest Service Forest Products Laboratory, FPL-GTR-190",
      "url": "https://ww2.arb.ca.gov/sites/default/files/barcu/regact/2014/capandtradeprf14/usfswoodhandbook2010.pdf",
      "year": 2010,
      "kind": "report",
      "license": "US government publication"
    },
    "vt-dendro": {
      "title": "Pseudotsuga menziesii (Mirb.) Franco, Douglas-fir wood technology sheet (Virginia Tech Dendrology)",
      "id": "Virginia Tech Dendrology, woodtech sheet",
      "url": "https://dendro.cnre.vt.edu/DENDROLOGY/woodtech/pseudotsuga_menziesii.pdf",
      "kind": "report",
      "license": "cited, not reproduced"
    },
    "faa-ac43-13": {
      "title": "FAA Advisory Circular AC 43.13-1B, Chapter 1, Table 1-1: Selection and Properties of Aircraft Wood",
      "id": "AC 43.13-1B, dated 9/8/98",
      "url": "https://raanz.org.nz/techproject/FAA%20AC43.13%20b/Chapter%2001.pdf",
      "year": 1998,
      "kind": "standard",
      "license": "US government publication"
    },
    "iarc-v62": {
      "title": "IARC Monographs Volume 62: Wood Dust and Formaldehyde (1995)",
      "id": "IARC Monographs Volume 62",
      "url": "https://publications.iarc.who.int/80",
      "year": 1995,
      "kind": "report",
      "license": "IARC, cited"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/douglas-fir/"
}