spore: profile
id: hard-maple
spore_version: '0.2'
family: wood
name: Hard maple (Acer saccharum)
role: Hardwood for floors, musical instrument parts and turned items
category: living
type: bio-grown-building-materials
summary: Hard maple is the wood of the sugar maple (Acer saccharum), a tree native to the hardwood forests of eastern North America. The Wood Handbook gives a clear-wood bending modulus of elasticity of 10,700 MPa when green and 12,600 MPa at 12% moisture. The wood is used for flooring, musical instrument parts and turned items, and its dust is a recorded cancer hazard.
best_for: Floors, instrument parts and turned items where a dense, hard hardwood is wanted
weakest_at: 'Decay and insect resistance: the Wood Database rates it non-durable to perishable and susceptible to insect attack'
identity:
  formula: Wood of Acer saccharum, with a cellulose structure and lignin resin
  source: wikipedia-sugar-maple
  where: 'Timber section: ''the cellulose structure of the wood'' and ''the lignin resins'' (torrefied guitar wood)'
tags:
  applications:
    - structures
properties:
  - benchmark: density
    label: Average dried weight
    value: 705
    unit: kg/m3
    scope: material
    conditions:
      moisture: not stated for this row on the page
      printed: 44.0 lbs/ft 3 (705 kg/m 3)
    method: Value printed on the Wood Database hard maple page; the page gives no test method
    status: ground
    source: wood-database
    where: Properties block, Average Dried Weight
  - benchmark: specific_gravity
    label: Specific gravity, two values printed under 'Basic, 12% MC'
    value: 0.56
    value_high: 0.71
    bound: range
    unit: '-'
    scope: material
    conditions:
      printed: .56, .71 under the label Specific Gravity (Basic, 12% MC)
      assignment: the page does not say which value is basic and which is at 12% MC
    method: Values as printed on the Wood Database hard maple page
    status: ground
    source: wood-database
    where: Properties block, Specific Gravity
  - benchmark: janka_hardness
    label: Janka hardness
    value: 1450
    unit: lbf
    scope: material
    conditions:
      printed: 1,450 lb f (6,450 N)
      moisture: not stated for this row
    method: Value printed on the Wood Database page; the page does not name the test standard
    status: ground
    source: wood-database
    where: Properties block, Janka Hardness
  - benchmark: shrinkage_radial
    label: Radial shrinkage
    value: 4.8
    unit: '%'
    scope: material
    conditions:
      basis: shrinkage basis not stated on the page
    method: Value printed on the Wood Database page
    status: ground
    source: wood-database
    where: Properties block, Shrinkage (Radial 4.8%)
  - benchmark: shrinkage_tangential
    label: Tangential shrinkage
    value: 9.9
    unit: '%'
    scope: material
    conditions:
      basis: shrinkage basis not stated on the page
    method: Value printed on the Wood Database page
    status: ground
    source: wood-database
    where: Properties block, Shrinkage (Tangential 9.9%)
  - benchmark: shrinkage_volumetric
    label: Volumetric shrinkage
    value: 14.7
    unit: '%'
    scope: material
    conditions:
      basis: shrinkage basis not stated on the page
    method: Value printed on the Wood Database page
    status: ground
    source: wood-database
    where: Properties block, Shrinkage (Volumetric 14.7%)
  - benchmark: specific_gravity
    label: Specific gravity, green
    value: 0.56
    unit: '-'
    scope: material
    conditions:
      moisture: Green
      basis: weight when ovendry and volume when green (table footnote b)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; tests on clear specimens (table footnote a) under ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row
  - benchmark: flexural_strength
    label: Modulus of rupture, green
    value: 65000
    unit: kPa
    scope: material
    conditions:
      moisture: Green
      printed: 65,000 kPa
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; tests on clear specimens (table footnote a) under ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Modulus of rupture column
  - benchmark: flexural_modulus
    label: Modulus of elasticity, green
    value: 10700
    unit: MPa
    scope: material
    conditions:
      moisture: Green
      measurement: simply supported, center-loaded beam, span to depth 14/1 (table footnote c)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; tests under ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Modulus of elasticity column
  - benchmark: work_to_maximum_load
    label: Work to maximum load, green
    value: 92
    unit: kJ/m3
    scope: material
    conditions:
      moisture: Green
      printed: kJ m-3 (metric table header)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Work to maximum load column
  - benchmark: impact_bending
    label: Impact bending, green
    value: 1020
    unit: mm
    scope: material
    conditions:
      moisture: Green
      definition: height of drop that causes complete failure, using a 0.71-kg hammer (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Impact bending column
  - benchmark: compression_parallel_to_grain
    label: Compression parallel to grain, green
    value: 27700
    unit: kPa
    scope: material
    conditions:
      moisture: Green
      definition: maximum crushing strength (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Compression parallel to grain column
  - benchmark: compression_perpendicular_to_grain
    label: Compression perpendicular to grain, green
    value: 4400
    unit: kPa
    scope: material
    conditions:
      moisture: Green
      definition: fibre stress at proportional limit (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Compression perpendicular to grain column
  - benchmark: shear_parallel_to_grain
    label: Shear parallel to grain, green
    value: 10100
    unit: kPa
    scope: material
    conditions:
      moisture: Green
      definition: maximum shearing strength (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Shear parallel to grain column
  - benchmark: side_hardness
    label: Side hardness, green
    value: 4300
    unit: 'N'
    scope: material
    conditions:
      moisture: Green
      definition: hardness measured when load is perpendicular to grain (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, Green row, Side hardness column
  - benchmark: specific_gravity
    label: Specific gravity, 12% moisture
    value: 0.63
    unit: '-'
    scope: material
    conditions:
      moisture: 12%
      basis: weight when ovendry and volume at 12% moisture content (table footnote b)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row
  - benchmark: flexural_strength
    label: Modulus of rupture, 12% moisture
    value: 109000
    unit: kPa
    scope: material
    conditions:
      moisture: 12%
      printed: 109,000 kPa
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Modulus of rupture column
  - benchmark: flexural_modulus
    label: Modulus of elasticity, 12% moisture
    value: 12600
    unit: MPa
    scope: material
    conditions:
      moisture: 12%
      measurement: simply supported, center-loaded beam, span to depth 14/1 (table footnote c)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Modulus of elasticity column
  - benchmark: work_to_maximum_load
    label: Work to maximum load, 12% moisture
    value: 114
    unit: kJ/m3
    scope: material
    conditions:
      moisture: 12%
      printed: kJ m-3 (metric table header)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Work to maximum load column
  - benchmark: impact_bending
    label: Impact bending, 12% moisture
    value: 990
    unit: mm
    scope: material
    conditions:
      moisture: 12%
      definition: height of drop that causes complete failure, using a 0.71-kg hammer (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Impact bending column
  - benchmark: compression_parallel_to_grain
    label: Compression parallel to grain, 12% moisture
    value: 54000
    unit: kPa
    scope: material
    conditions:
      moisture: 12%
      definition: maximum crushing strength (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Compression parallel to grain column
  - benchmark: compression_perpendicular_to_grain
    label: Compression perpendicular to grain, 12% moisture
    value: 10100
    unit: kPa
    scope: material
    conditions:
      moisture: 12%
      definition: fibre stress at proportional limit (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Compression perpendicular to grain column
  - benchmark: shear_parallel_to_grain
    label: Shear parallel to grain, 12% moisture
    value: 16100
    unit: kPa
    scope: material
    conditions:
      moisture: 12%
      definition: maximum shearing strength (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Shear parallel to grain column
  - benchmark: side_hardness
    label: Side hardness, 12% moisture
    value: 6400
    unit: 'N'
    scope: material
    conditions:
      moisture: 12%
      definition: hardness measured when load is perpendicular to grain (table footnote a)
    method: Clear-wood test value from Table 5-3a (metric), row Maple, Sugar, 12% row; ASTM D 143 procedures
    status: ground
    source: wood-handbook-2010
    where: Table 5-3a (metric), Maple, Sugar, 12% row, Side hardness column
corrosion:
  - environment: Service exposure to decay and insect attack (rot resistance)
    headline: Rated non-durable to perishable, and susceptible to insect attack.
    effect: The Wood Database gives this rot-resistance rating for hard maple. No exposure test or time to failure for hard maple was found in any source read for this profile.
    rating: unknown
    source: wood-database
    where: Rot Resistance line
risks:
  hazards:
    - text: Hard maple, along with other maples in the Acer genus have been reported to cause skin irritation, runny nose, and asthma-like respiratory effects. The page refers readers to its wood allergies and dust safety articles, which were not read.
      ghs: []
      source: wood-database
      where: Allergies/Toxicity line
    - text: The page on hardwood dust says it 'is classified as Group 1 carcinogen by the IARC', and that 'Prolonged exposure to hardwood dust can cause cancer in the nose and paranasal sinuses.' These are findings for hardwood dust in general, not for sugar maple alone.
      ghs: []
      source: eu-hardwood-dust
      where: Hardwood dust fact sheet, classification and cancer site
    - text: The NIOSH pocket guide lists wood dust with a recommended exposure limit of 'Ca TWA 1 mg/m3 [See Appendix A]' and the cancer site '[nasal cancer]'. The entry covers wood dust in general, not sugar maple alone.
      ghs: []
      source: niosh-npg-wood-dust
      where: Exposure limits and cancer site rows
  failure_risks:
    - mode: Burning when machined
      trigger: Machining with high-speed cutters, such as in a router
      consequence: Maple has a tendency to burn when being machined with high-speed cutters such as in a router.
      source: wood-database
      where: Workability line
    - mode: Insect attack
      consequence: Hard maple is susceptible to insect attack and is rated non-durable to perishable.
      source: wood-database
      where: Rot Resistance line
    - mode: Blotchy stain
      trigger: Staining without preparation
      consequence: Blotches can occur when staining, and a pre-conditioner, gel stain, or toner may be necessary to get an even color.
      source: wood-database
      where: Workability line
  side_effects: []
  handling:
    - text: Use a pre-conditioner, gel stain, or toner when staining to get an even color.
      source: wood-database
      where: Workability line
    - text: 'The EU sets a binding occupational exposure limit: ''An EU binding occupational exposure limit of 2mg/m³ (TWA) is in place.'' Keep wood dust below that limit.'
      source: eu-hardwood-dust
      where: Exposure limits section
  mitigations: []
uses:
  - application: structures
    device: 'Flooring: basketball courts, dance floors, bowling alleys and residential floors'
    example: 'Common uses: flooring (from basketball courts and dance-floors to bowling alleys and residential)'
    source: wood-database
    where: Comments, Common Uses line
  - application: structures
    device: 'Musical instrument parts: violin-family sides and back, guitar necks, grand piano rims and drum shells'
    example: Maple is widely used in the manufacture of musical instruments, such as the members of the violin family (sides and back), guitars (neck), grand pianos (rim), and drum shells.
    source: wikipedia-sugar-maple
    where: Timber section
  - application: structures
    device: 'Turned and specialty items: cutting boards, butcher blocks, workbenches, baseball bats'
    example: Common uses include cutting boards, butcher blocks, workbenches, baseball bats, and other turned objects and specialty wood items.
    source: wood-database
    where: Comments, Common Uses line
supply:
  - subject: Hard maple wood (sugar maple, Acer saccharum)
    abundance: Native to the hardwood forests of eastern North America and mostly found in the north of its range, according to Wikipedia.
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-sugar-maple
    where: Distribution and habitat section
  - subject: Hard maple veneer logs, Lake States (1966)
    abundance: Not stated; the source gives a harvest volume only.
    producers:
      - country: United States (Lake States region)
        year: 1966
    critical_lists: []
    substitutes: []
    source: blyth-1966-veneer
    where: 'Abstract: ''The Lake States hard maple harvest exceeded 13 million board feet, up 1.3 million from 1965.'''
  - subject: Hard maple lumber market (2024, qualitative)
    abundance: No production share found; the 2024 market note reports the trend only.
    producers: []
    critical_lists: []
    substitutes: []
    source: timber-talk-2024
    where: 'Hardwood market section: ''Through January, Hard Maple production has been extremely low.'''
media: []
documents: []
gaps:
  - No space, vacuum, radiation or flight data for hard maple were found in any source read for this profile. The only space-related use filed under structures is the site's own categorisation of wood flooring and instruments, which is not a space test.
  - The Wood Handbook table read here gives green and 12% rows for sugar maple only. No air-dried, 15% or fibre-saturation row was found for this grade.
  - Thermal conductivity, specific heat and thermal expansion for sugar maple were not found in any page read. Only mechanical and density values are recorded.
  - Shrinkage (4.8%, 9.9% and 14.7% on the Wood Database) has no moisture basis printed on the page. The Wood Handbook shrinkage tables for sugar maple were not checked.
  - 'The 12% specific gravity disagrees between sources: 0.71 on the Wood Database and 0.63 in Wood Handbook Table 5-3a. The Wood Database does not say which of its two printed values is basic. Both sources are recorded side by side.'
  - The Wood Handbook table printed here is the 2010 edition (FPL-GTR-190). The 2021 edition (FPL-GTR-282) was not checked.
  - Engineering ToolBox lists maple as one group that includes sugar maple with other maple species. Its group rows are not recorded as this grade's own values.
  - Current production volumes and country shares for hard maple lumber were not found. The 1966 Lake States veneer-log harvest (Blyth) and the 2024 market note (Nebraska Forest Service) are the only supply figures; the 2015 Luppold and Bumgardner paper gives only hardwood-wide figures, not maple-specific ones.
  - No critical-mineral list applies to a wood, so none was checked.
  - NIOSH and EU wood-dust figures cover wood dust in general. No dust limit specific to sugar maple was found.
  - No safety data sheet or GHS classification for hard maple wood was read. The hazards recorded here come from the Wood Database, NIOSH and the EU fact sheet.
  - Wood has no UNS, EN or ASTM grade code. The Wood Database gives the common names hard maple and sugar maple; no separate designation code was listed.
  - 'Property names used here that are not in spores/property-canon.yaml: specific_gravity, janka_hardness, shrinkage_radial, shrinkage_tangential, shrinkage_volumetric, work_to_maximum_load, impact_bending, compression_parallel_to_grain, compression_perpendicular_to_grain, shear_parallel_to_grain and side_hardness. Units are kept as printed (kPa, MPa, mm, N, kJ/m3).'
  - Clear-wood values (no knots or defects) are the basis of the Wood Handbook rows, as the handbook states. Real timber with defects will differ.
sources:
  wood-handbook-2010:
    title: 'Wood Handbook: Wood as an Engineering Material, FPL-GTR-190 (Ross, ed.), chapter 5, Tables 5-3a and 5-3b'
    id: USDA Forest Service, Forest Products Laboratory, Gen. Tech. Rep. FPL-GTR-190
    url: https://research.fs.usda.gov/download/treesearch/37440.pdf
    year: 2010
    kind: handbook
    license: US federal government work
  wood-database:
    title: 'Wood Database: Hard Maple'
    url: https://www.wood-database.com/hard-maple/
    kind: web
  wikipedia-sugar-maple:
    title: 'Wikipedia: Sugar maple (Acer saccharum)'
    url: https://en.wikipedia.org/wiki/Sugar_maple
    kind: web
    license: CC BY-SA 4.0
  niosh-npg-wood-dust:
    title: 'NIOSH Pocket Guide to Chemical Hazards: Wood dust'
    url: https://www.cdc.gov/niosh/npg/npgd0667.html
    kind: database
  eu-hardwood-dust:
    title: 'Stop Carcinogens at Work: The facts on hardwood dust'
    url: https://stopcarcinogensatwork.eu/fact/hardwood-dust/
    kind: web
  blyth-1966-veneer:
    title: Blyth, J. E. Veneer-log production and consumption, North Central Region, 1966. USDA Forest Service Resource Bulletin NC-5
    url: https://research.fs.usda.gov/treesearch/10285
    year: 1968
    kind: report
  timber-talk-2024:
    title: Nebraska Forest Service, Timber Talk, March 2024 (hardwood market report)
    url: https://nfs.unl.edu/sites/unl.edu.ianr.nebraska-forest-service/files/media/file/Timber%20Talk%20March%202024.pdf
    year: 2024
    kind: report
  engineeringtoolbox-timber:
    title: 'Engineering ToolBox: Timber, mechanical properties'
    url: https://www.engineeringtoolbox.com/timber-mechanical-properties-d_1789.html
    kind: web
  luppold-bumgardner-2015:
    title: 'Luppold, W. and Bumgardner, M. Examination of worldwide hardwood lumber production, trade, and apparent consumption: 1995-2013. Wood and Fiber Science 47(3)'
    url: https://research.fs.usda.gov/treesearch/49153
    year: 2015
    kind: paper
license: CC-BY-4.0
updated: '2026-11-02'
review:
  status: draft
  method: assistant
  checked_values: 24
  unreachable: 0
  caveats: 2
  note: Written by an AI assistant on 2026-11-02 from the Wood Handbook (2010) rows and the Wood Database page. The 12% specific gravity differs between the two sources and both are recorded.
story:
  why: Hard maple (Acer saccharum, sugar maple) is a hardwood used for floors, musical instrument parts and turned items. The Wood Handbook (USDA Forest Products Laboratory, 2010) and the Wood Database both publish clear-wood values for it. This profile sets those values out row by row and records where the two sources disagree. Hard maple is not a space material; it sits in this collection as a bio-grown building material.
  recipe:
    line: Hard maple is wood, not a single compound. The wood is built from a cellulose structure with lignin resin. No source read gives the share of either part.
    parts:
      - name: Cellulose
        role: The structural component of the wood. The Wikipedia sugar maple article calls it 'the cellulose structure of the wood'.
        share_note: Share not found in any source read
        source: wikipedia-sugar-maple
        where: Cultivation and uses, Timber section
      - name: Lignin
        role: A resin in the wood. The Wikipedia article says some high-end guitar wood is torrefied 'to cook out the lignin resins'.
        share_note: Share not found in any source read
        source: wikipedia-sugar-maple
        where: Timber section, guitar wood sentence
  risk_groups:
    - title: For people
      level: 3
      verdict: Wood dust is a known cancer hazard
      lead: The hazard recorded for hard maple is its dust. The dust sources cover wood dust in general, not sugar maple alone.
      points:
        - label: IARC
          line: The EU fact sheet says hardwood dust 'is classified as Group 1 carcinogen by the IARC'. It adds that 'Prolonged exposure to hardwood dust can cause cancer in the nose and paranasal sinuses.'
        - label: NIOSH
          line: The NIOSH pocket guide lists wood dust with a recommended exposure limit of 'Ca TWA 1 mg/m3 [See Appendix A]' and the cancer site '[nasal cancer]'.
        - label: Latency
          line: The EU fact sheet says the latency between exposure and wood-dust nose cancer is 'estimated to be at least 20 years'.
    - title: Skin and breathing
      level: 2
      verdict: Irritation and asthma-like effects
      lead: The Wood Database reports these effects for maples in the Acer genus, which includes hard maple.
      points:
        - label: Reported effects
          line: '''Hard maple, along with other maples in the Acer genus have been reported to cause skin irritation, runny nose, and asthma-like respiratory effects.'''
    - title: Machining
      level: 1
      verdict: Burns with high-speed cutters
      lead: The Wood Database notes a tendency to burn in fast machining.
      points:
        - label: Router
          line: Maple has a tendency to burn when being machined with high-speed cutters such as in a router.
  uses:
    - where: Flooring
      line: The Wood Database lists flooring from basketball courts and dance floors to bowling alleys and residential floors as common uses of hard maple.
    - where: Musical instruments
      line: The Wikipedia article says the wood is used for members of the violin family (sides and back), guitars (neck), grand pianos (rim) and drum shells.
    - where: Sports equipment
      line: The Wikipedia article says bowling alleys and bowling pins are commonly made from sugar maple, and that maple is a popular wood for baseball bats.
    - where: Turned and specialty items
      line: The Wood Database lists cutting boards, butcher blocks, workbenches and other turned objects among its common uses.
  can_do:
    - label: Density
      benchmark: density
      line: The Wood Database prints an average dried weight of 705 kg/m3, with no moisture basis on that row.
    - label: Bending strength
      benchmark: flexural_strength
      line: The Wood Handbook prints a modulus of rupture of 65,000 kPa when green and 109,000 kPa at 12% moisture.
    - label: Bending stiffness
      benchmark: flexural_modulus
      line: The Wood Handbook prints a modulus of elasticity of 10,700 MPa when green and 12,600 MPa at 12% moisture.
    - label: Hardness
      benchmark: janka_hardness
      line: The Wood Database prints a Janka hardness of 1,450 lbf (6,450 N). The Wood Handbook prints a side hardness of 6,400 N at 12% moisture.
  compare: 'Compared with the other maples, the Wood Database says hard maple is ''stronger, stiffer, harder, and denser'' than the other maple species sold as lumber. The Wood Handbook shows the moisture effect: the bending modulus of elasticity rises from 10,700 MPa when green to 12,600 MPa at 12% moisture, and compression parallel to grain rises from 27,700 kPa to 54,000 kPa. The two sources do not agree on the 12% specific gravity, which is 0.71 on the Wood Database and 0.63 in the Wood Handbook.'
  compare_rows:
    - label: Dried weight (density)
      benchmark: density
    - label: Bending strength (modulus of rupture)
      benchmark: flexural_strength
    - label: Janka hardness
      benchmark: janka_hardness
  handling:
    - Use a pre-conditioner, gel stain or toner before staining to get an even colour (Wood Database).
    - Keep wood dust below the EU binding occupational exposure limit of 2mg/m³ (TWA), as the EU fact sheet prints it.
    - Expect burning with high-speed router cutters (Wood Database).
  good_for:
    - 'Flooring: the Wood Database lists basketball courts, dance floors and bowling alleys as uses.'
    - 'Instrument parts: the sides and back of violin-family instruments, guitar necks, grand piano rims and drum shells (Wikipedia).'
  watch_out:
    - 'Dust: hardwood dust is a Group 1 carcinogen per the IARC, linked to nose and paranasal sinus cancer after prolonged exposure.'
    - 'Decay and insects: rated non-durable to perishable and susceptible to insect attack (Wood Database).'
    - 'Stain: blotches can occur when staining without a pre-conditioner (Wood Database).'
    - 'Burning: maple tends to burn with high-speed cutters such as in a router (Wood Database).'
    - 'Specific gravity at 12%: the two sources give 0.71 and 0.63, so check which one your source uses.'
  verdict: Hard maple suits flooring, instrument parts and turned items where a hard, dense hardwood is wanted. Its dust is a known cancer hazard, and it needs protection against decay and stain blotching.