{
 "title": "Growth factors: the years per inch of trunk the tree age estimator uses, by species",
 "page": "https://bluewhaletrees.com/articles/tree-age-factors/",
 "license": {
  "name": "Creative Commons Attribution 4.0",
  "short": "CC BY 4.0",
  "url": "https://creativecommons.org/licenses/by/4.0/"
 },
 "attribution": "Blue Whale Trees, https://bluewhaletrees.com/articles/tree-age-factors/",
 "updated": "2026-10-22",
 "row": "one growth factor from one source for one species",
 "rows_count": 125,
 "columns": [
  {
   "name": "species",
   "means": "the species id the tree age estimator uses: a plant page's address word, or the id of a common native the nursery does not grow"
  },
  {
   "name": "name",
   "means": "the common name"
  },
  {
   "name": "botanical",
   "means": "the botanical name"
  },
  {
   "name": "in_catalog",
   "means": "true where the nursery grows the species and it has a plant page"
  },
  {
   "name": "factor",
   "means": "the growth factor: the years of age for each inch of trunk diameter at 4.5 feet, for a tree grown in the open"
  },
  {
   "name": "used",
   "means": "true where the estimator applies this factor; false where the figure is recorded for comparison and not applied"
  },
  {
   "name": "kind",
   "means": "chart where the source prints a table of factors, text where it gives the figure in prose"
  },
  {
   "name": "source",
   "means": "the publisher's short name"
  },
  {
   "name": "source_name",
   "means": "the source as the estimator's page cites it"
  },
  {
   "name": "url",
   "means": "its address"
  }
 ],
 "rows": [
  {
   "species": "american-basswood",
   "name": "American Basswood (Linden)",
   "botanical": "Tilia americana",
   "in_catalog": true,
   "factor": 3,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "american-beech",
   "name": "American Beech",
   "botanical": "Fagus grandifolia",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "american-beech",
   "name": "American Beech",
   "botanical": "Fagus grandifolia",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "american-elm",
   "name": "American Elm",
   "botanical": "Ulmus americana",
   "in_catalog": true,
   "factor": 4,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "american-holly",
   "name": "American Holly, select line",
   "botanical": "Ilex opaca",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "american-hornbeam",
   "name": "American Hornbeam (Musclewood)",
   "botanical": "Carpinus caroliniana",
   "in_catalog": true,
   "factor": 7,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "american-sycamore",
   "name": "American Sycamore",
   "botanical": "Platanus occidentalis",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "american-sycamore",
   "name": "American Sycamore",
   "botanical": "Platanus occidentalis",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "atlantic-white-cedar",
   "name": "Atlantic White Cedar",
   "botanical": "Chamaecyparis thyoides",
   "in_catalog": true,
   "factor": 8,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "bald-cypress",
   "name": "Bald Cypress",
   "botanical": "Taxodium distichum",
   "in_catalog": true,
   "factor": 1.5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "bald-cypress",
   "name": "Bald Cypress",
   "botanical": "Taxodium distichum",
   "in_catalog": true,
   "factor": 1.93,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "balsam-fir",
   "name": "Balsam Fir",
   "botanical": "Abies balsamea",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "balsam-poplar",
   "name": "Balsam Poplar",
   "botanical": "Populus balsamifera",
   "in_catalog": true,
   "factor": 5.56,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "bigtooth-aspen",
   "name": "Bigtooth Aspen",
   "botanical": "Populus grandidentata",
   "in_catalog": false,
   "factor": 2,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "bitternut-hickory",
   "name": "Bitternut Hickory",
   "botanical": "Carya cordiformis",
   "in_catalog": true,
   "factor": 5.38,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "black-cherry",
   "name": "Black Cherry",
   "botanical": "Prunus serotina",
   "in_catalog": true,
   "factor": 5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "black-gum",
   "name": "Black Gum (Tupelo)",
   "botanical": "Nyssa sylvatica",
   "in_catalog": true,
   "factor": 2.22,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "black-locust",
   "name": "Black Locust",
   "botanical": "Robinia pseudoacacia",
   "in_catalog": true,
   "factor": 3.75,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "black-maple",
   "name": "Black Maple",
   "botanical": "Acer nigrum",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "black-maple",
   "name": "Black Maple",
   "botanical": "Acer nigrum",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mndnr",
   "source_name": "Minnesota Department of Natural Resources, Project Learning Tree, Growth Factor Worksheet, the Internet Archive's copy of 2020-12-01",
   "url": "https://web.archive.org/web/20201201145939/https://files.dnr.state.mn.us/education_safety/education/plt/activity_sheets/growthfactorworksheet.pdf"
  },
  {
   "species": "black-maple",
   "name": "Black Maple",
   "botanical": "Acer nigrum",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "black-maple",
   "name": "Black Maple",
   "botanical": "Acer nigrum",
   "in_catalog": true,
   "factor": 4.23,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "black-oak",
   "name": "Black Oak",
   "botanical": "Quercus velutina",
   "in_catalog": true,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "black-spruce",
   "name": "Black Spruce",
   "botanical": "Picea mariana",
   "in_catalog": false,
   "factor": 12,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "black-walnut",
   "name": "Black Walnut",
   "botanical": "Juglans nigra",
   "in_catalog": true,
   "factor": 4.5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "black-willow",
   "name": "Black Willow",
   "botanical": "Salix nigra",
   "in_catalog": false,
   "factor": 2,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "boxelder",
   "name": "Boxelder",
   "botanical": "Acer negundo",
   "in_catalog": false,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "boxelder",
   "name": "Boxelder",
   "botanical": "Acer negundo",
   "in_catalog": false,
   "factor": 2.6,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "bur-oak",
   "name": "Bur Oak",
   "botanical": "Quercus macrocarpa",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "bur-oak",
   "name": "Bur Oak",
   "botanical": "Quercus macrocarpa",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "texastrees",
   "source_name": "Texas Trees Foundation, Tree Measurements: The Urban Forest, Grades K-8, 2026",
   "url": "https://texastrees.org/wp-content/uploads/2026/07/3.1-Tree-Measurements.pdf"
  },
  {
   "species": "bur-oak",
   "name": "Bur Oak",
   "botanical": "Quercus macrocarpa",
   "in_catalog": true,
   "factor": 6.5,
   "used": false,
   "kind": "table",
   "source": "friends",
   "source_name": "The Friends of the Wildflower Garden, Minneapolis, Tree Age Calculation, 2015",
   "url": "https://friendsofeloisebutler.org/pages/photosubpages/photoinfopages/treeagecalculator.html"
  },
  {
   "species": "bur-oak",
   "name": "Bur Oak",
   "botanical": "Quercus macrocarpa",
   "in_catalog": true,
   "factor": 6.51,
   "used": false,
   "kind": "rate",
   "source": "morton",
   "source_name": "Marlin Bowles, The Morton Arboretum, How old is that oak?, The Land Conservancy of McHenry County, 2012",
   "url": "https://conservemc.org/how-old-is-that-oak/"
  },
  {
   "species": "bur-oak",
   "name": "Bur Oak",
   "botanical": "Quercus macrocarpa",
   "in_catalog": true,
   "factor": 3.8,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "carolina-silverbell",
   "name": "Carolina Silverbell",
   "botanical": "Halesia tetraptera",
   "in_catalog": true,
   "factor": 9.5,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "cherrybark-oak",
   "name": "Cherrybark Oak, Wye Island line",
   "botanical": "Quercus pagoda",
   "in_catalog": true,
   "factor": 2.22,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "common-hackberry",
   "name": "Common Hackberry",
   "botanical": "Celtis occidentalis",
   "in_catalog": true,
   "factor": 2,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "common-hackberry",
   "name": "Common Hackberry",
   "botanical": "Celtis occidentalis",
   "in_catalog": true,
   "factor": 3.63,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "eastern-cottonwood",
   "name": "Eastern Cottonwood",
   "botanical": "Populus deltoides",
   "in_catalog": false,
   "factor": 2,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "eastern-hemlock",
   "name": "Eastern Hemlock",
   "botanical": "Tsuga canadensis",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "eastern-red-cedar",
   "name": "Eastern Red Cedar",
   "botanical": "Juniperus virginiana",
   "in_catalog": true,
   "factor": 9.43,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "eastern-redbud",
   "name": "Eastern Redbud",
   "botanical": "Cercis canadensis",
   "in_catalog": true,
   "factor": 7,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "eastern-white-pine",
   "name": "Eastern White Pine",
   "botanical": "Pinus strobus",
   "in_catalog": false,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "eastern-white-pine",
   "name": "Eastern White Pine",
   "botanical": "Pinus strobus",
   "in_catalog": false,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mndnr",
   "source_name": "Minnesota Department of Natural Resources, Project Learning Tree, Growth Factor Worksheet, the Internet Archive's copy of 2020-12-01",
   "url": "https://web.archive.org/web/20201201145939/https://files.dnr.state.mn.us/education_safety/education/plt/activity_sheets/growthfactorworksheet.pdf"
  },
  {
   "species": "eastern-white-pine",
   "name": "Eastern White Pine",
   "botanical": "Pinus strobus",
   "in_catalog": false,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "eastern-white-pine",
   "name": "Eastern White Pine",
   "botanical": "Pinus strobus",
   "in_catalog": false,
   "factor": 2.53,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "florida-maple",
   "name": "Florida Maple",
   "botanical": "Acer floridanum",
   "in_catalog": true,
   "factor": 4,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "flowering-dogwood",
   "name": "Flowering Dogwood",
   "botanical": "Cornus florida",
   "in_catalog": true,
   "factor": 7,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "fraser-magnolia",
   "name": "Fraser Magnolia",
   "botanical": "Magnolia fraseri",
   "in_catalog": true,
   "factor": 2.87,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "green-ash",
   "name": "Green Ash",
   "botanical": "Fraxinus pennsylvanica",
   "in_catalog": false,
   "factor": 4,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "honeylocust",
   "name": "Honeylocust",
   "botanical": "Gleditsia triacanthos",
   "in_catalog": false,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "honeylocust",
   "name": "Honeylocust",
   "botanical": "Gleditsia triacanthos",
   "in_catalog": false,
   "factor": 3.5,
   "used": false,
   "kind": "table",
   "source": "redbutte",
   "source_name": "Red Butte Garden, University of Utah, How Old Is That Tree?, the Internet Archive's copy of 2023-07-05",
   "url": "https://web.archive.org/web/20230705122226/https://redbuttegarden.org/media/documents/calculate-tree-age-activity.pdf"
  },
  {
   "species": "honeylocust",
   "name": "Honeylocust",
   "botanical": "Gleditsia triacanthos",
   "in_catalog": false,
   "factor": 2.35,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "hop-hornbeam",
   "name": "Hop Hornbeam",
   "botanical": "Ostrya virginiana",
   "in_catalog": true,
   "factor": 7,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "jack-pine",
   "name": "Jack Pine",
   "botanical": "Pinus banksiana",
   "in_catalog": true,
   "factor": 6.35,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "kentucky-coffeetree",
   "name": "Kentucky Coffeetree",
   "botanical": "Gymnocladus dioicus",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "kentucky-coffeetree",
   "name": "Kentucky Coffeetree",
   "botanical": "Gymnocladus dioicus",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "mndnr",
   "source_name": "Minnesota Department of Natural Resources, Project Learning Tree, Growth Factor Worksheet, the Internet Archive's copy of 2020-12-01",
   "url": "https://web.archive.org/web/20201201145939/https://files.dnr.state.mn.us/education_safety/education/plt/activity_sheets/growthfactorworksheet.pdf"
  },
  {
   "species": "kentucky-coffeetree",
   "name": "Kentucky Coffeetree",
   "botanical": "Gymnocladus dioicus",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "kentucky-coffeetree",
   "name": "Kentucky Coffeetree",
   "botanical": "Gymnocladus dioicus",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "redbutte",
   "source_name": "Red Butte Garden, University of Utah, How Old Is That Tree?, the Internet Archive's copy of 2023-07-05",
   "url": "https://web.archive.org/web/20230705122226/https://redbuttegarden.org/media/documents/calculate-tree-age-activity.pdf"
  },
  {
   "species": "kentucky-coffeetree",
   "name": "Kentucky Coffeetree",
   "botanical": "Gymnocladus dioicus",
   "in_catalog": true,
   "factor": 2.4,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "loblolly-bay",
   "name": "Loblolly Bay",
   "botanical": "Gordonia lasianthus",
   "in_catalog": true,
   "factor": 4.55,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "pecan",
   "name": "Northern Pecan",
   "botanical": "Carya illinoinensis",
   "in_catalog": true,
   "factor": 4.44,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "northern-red-oak",
   "name": "Northern Red Oak",
   "botanical": "Quercus rubra",
   "in_catalog": true,
   "factor": 4,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "northern-white-cedar",
   "name": "Northern White Cedar",
   "botanical": "Thuja occidentalis",
   "in_catalog": true,
   "factor": 11.29,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "nuttall-oak",
   "name": "Nuttall Oak",
   "botanical": "Quercus texana",
   "in_catalog": true,
   "factor": 2.92,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "overcup-oak",
   "name": "Overcup Oak",
   "botanical": "Quercus lyrata",
   "in_catalog": true,
   "factor": 4.44,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "paper-birch",
   "name": "Paper Birch",
   "botanical": "Betula papyrifera",
   "in_catalog": false,
   "factor": 5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "pignut-hickory",
   "name": "Pignut Hickory",
   "botanical": "Carya glabra",
   "in_catalog": true,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "pin-cherry",
   "name": "Pin Cherry",
   "botanical": "Prunus pensylvanica",
   "in_catalog": true,
   "factor": 2.78,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "pin-oak",
   "name": "Pin Oak",
   "botanical": "Quercus palustris",
   "in_catalog": true,
   "factor": 3,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "pitch-pine",
   "name": "Pitch Pine",
   "botanical": "Pinus rigida",
   "in_catalog": false,
   "factor": 6.5,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "pond-pine",
   "name": "Pond Pine",
   "botanical": "Pinus serotina",
   "in_catalog": true,
   "factor": 6.49,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "post-oak",
   "name": "Post Oak",
   "botanical": "Quercus stellata",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "pumpkin-ash",
   "name": "Pumpkin Ash",
   "botanical": "Fraxinus profunda",
   "in_catalog": false,
   "factor": 1.71,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "quaking-aspen",
   "name": "Quaking Aspen",
   "botanical": "Populus tremuloides",
   "in_catalog": false,
   "factor": 2,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "red-maple",
   "name": "Red Maple",
   "botanical": "Acer rubrum",
   "in_catalog": false,
   "factor": 4.5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "red-pine",
   "name": "Red Pine",
   "botanical": "Pinus resinosa",
   "in_catalog": true,
   "factor": 5.5,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "red-pine",
   "name": "Red Pine",
   "botanical": "Pinus resinosa",
   "in_catalog": true,
   "factor": 5.5,
   "used": false,
   "kind": "table",
   "source": "mndnr",
   "source_name": "Minnesota Department of Natural Resources, Project Learning Tree, Growth Factor Worksheet, the Internet Archive's copy of 2020-12-01",
   "url": "https://web.archive.org/web/20201201145939/https://files.dnr.state.mn.us/education_safety/education/plt/activity_sheets/growthfactorworksheet.pdf"
  },
  {
   "species": "red-pine",
   "name": "Red Pine",
   "botanical": "Pinus resinosa",
   "in_catalog": true,
   "factor": 5.5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "red-spruce",
   "name": "Red Spruce",
   "botanical": "Picea rubens",
   "in_catalog": true,
   "factor": 6.67,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "river-birch",
   "name": "River Birch",
   "botanical": "Betula nigra",
   "in_catalog": true,
   "factor": 3.5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "rock-elm",
   "name": "Rock Elm",
   "botanical": "Ulmus thomasii",
   "in_catalog": true,
   "factor": 7,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "sassafras",
   "name": "Sassafras",
   "botanical": "Sassafras albidum",
   "in_catalog": true,
   "factor": 3.75,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "scarlet-oak",
   "name": "Scarlet Oak",
   "botanical": "Quercus coccinea",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "scarlet-oak",
   "name": "Scarlet Oak",
   "botanical": "Quercus coccinea",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "shagbark-hickory",
   "name": "Shagbark Hickory",
   "botanical": "Carya ovata",
   "in_catalog": true,
   "factor": 7.5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "shellbark-hickory",
   "name": "Shellbark Hickory (Kingnut)",
   "botanical": "Carya laciniosa",
   "in_catalog": true,
   "factor": 8.33,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "shingle-oak",
   "name": "Shingle Oak",
   "botanical": "Quercus imbricaria",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "shingle-oak",
   "name": "Shingle Oak",
   "botanical": "Quercus imbricaria",
   "in_catalog": true,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "shumard-oak",
   "name": "Shumard Oak",
   "botanical": "Quercus shumardii",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "shumard-oak",
   "name": "Shumard Oak",
   "botanical": "Quercus shumardii",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "shumard-oak",
   "name": "Shumard Oak",
   "botanical": "Quercus shumardii",
   "in_catalog": true,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "texastrees",
   "source_name": "Texas Trees Foundation, Tree Measurements: The Urban Forest, Grades K-8, 2026",
   "url": "https://texastrees.org/wp-content/uploads/2026/07/3.1-Tree-Measurements.pdf"
  },
  {
   "species": "silver-maple",
   "name": "Silver Maple",
   "botanical": "Acer saccharinum",
   "in_catalog": false,
   "factor": 3,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "slippery-elm",
   "name": "Slippery Elm",
   "botanical": "Ulmus rubra",
   "in_catalog": true,
   "factor": 6.5,
   "used": false,
   "kind": "table",
   "source": "friends",
   "source_name": "The Friends of the Wildflower Garden, Minneapolis, Tree Age Calculation, 2015",
   "url": "https://friendsofeloisebutler.org/pages/photosubpages/photoinfopages/treeagecalculator.html"
  },
  {
   "species": "southern-magnolia",
   "name": "Southern Magnolia",
   "botanical": "Magnolia grandiflora",
   "in_catalog": true,
   "factor": 3.33,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "spruce-pine",
   "name": "Spruce Pine",
   "botanical": "Pinus glabra",
   "in_catalog": true,
   "factor": 2.25,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "sugar-maple",
   "name": "Sugar Maple",
   "botanical": "Acer saccharum",
   "in_catalog": false,
   "factor": 5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "sugarberry",
   "name": "Sugarberry",
   "botanical": "Celtis laevigata",
   "in_catalog": true,
   "factor": 6.67,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "swamp-cottonwood",
   "name": "Swamp Cottonwood",
   "botanical": "Populus heterophylla",
   "in_catalog": true,
   "factor": 1.25,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "swamp-tupelo",
   "name": "Swamp Tupelo",
   "botanical": "Nyssa biflora",
   "in_catalog": true,
   "factor": 8.5,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "swamp-white-oak",
   "name": "Swamp White Oak",
   "botanical": "Quercus bicolor",
   "in_catalog": true,
   "factor": 2,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "swamp-white-oak",
   "name": "Swamp White Oak",
   "botanical": "Quercus bicolor",
   "in_catalog": true,
   "factor": 6.51,
   "used": false,
   "kind": "rate",
   "source": "morton",
   "source_name": "Marlin Bowles, The Morton Arboretum, How old is that oak?, The Land Conservancy of McHenry County, 2012",
   "url": "https://conservemc.org/how-old-is-that-oak/"
  },
  {
   "species": "swamp-white-oak",
   "name": "Swamp White Oak",
   "botanical": "Quercus bicolor",
   "in_catalog": true,
   "factor": 2.07,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "sweet-birch",
   "name": "Sweet Birch (Black Birch)",
   "botanical": "Betula lenta",
   "in_catalog": true,
   "factor": 8,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "sweetgum",
   "name": "Sweetgum",
   "botanical": "Liquidambar styraciflua",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "sweetgum",
   "name": "Sweetgum",
   "botanical": "Liquidambar styraciflua",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "sweetgum",
   "name": "Sweetgum",
   "botanical": "Liquidambar styraciflua",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "redbutte",
   "source_name": "Red Butte Garden, University of Utah, How Old Is That Tree?, the Internet Archive's copy of 2023-07-05",
   "url": "https://web.archive.org/web/20230705122226/https://redbuttegarden.org/media/documents/calculate-tree-age-activity.pdf"
  },
  {
   "species": "sweetgum",
   "name": "Sweetgum",
   "botanical": "Liquidambar styraciflua",
   "in_catalog": false,
   "factor": 4,
   "used": false,
   "kind": "table",
   "source": "texastrees",
   "source_name": "Texas Trees Foundation, Tree Measurements: The Urban Forest, Grades K-8, 2026",
   "url": "https://texastrees.org/wp-content/uploads/2026/07/3.1-Tree-Measurements.pdf"
  },
  {
   "species": "tamarack",
   "name": "Tamarack",
   "botanical": "Larix laricina",
   "in_catalog": true,
   "factor": 19.27,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "tuliptree",
   "name": "Tuliptree",
   "botanical": "Liriodendron tulipifera",
   "in_catalog": false,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "tuliptree",
   "name": "Tuliptree",
   "botanical": "Liriodendron tulipifera",
   "in_catalog": false,
   "factor": 3,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "virginia-pine",
   "name": "Virginia Pine",
   "botanical": "Pinus virginiana",
   "in_catalog": false,
   "factor": 2.94,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 1, Conifers, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1547.pdf"
  },
  {
   "species": "water-hickory",
   "name": "Water Hickory",
   "botanical": "Carya aquatica",
   "in_catalog": true,
   "factor": 4.17,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "water-oak",
   "name": "Water Oak",
   "botanical": "Quercus nigra",
   "in_catalog": false,
   "factor": 3.33,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "water-tupelo",
   "name": "Water Tupelo",
   "botanical": "Nyssa aquatica",
   "in_catalog": true,
   "factor": 3.33,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "white-ash",
   "name": "White Ash",
   "botanical": "Fraxinus americana",
   "in_catalog": false,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "white-ash",
   "name": "White Ash",
   "botanical": "Fraxinus americana",
   "in_catalog": false,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  },
  {
   "species": "white-ash",
   "name": "White Ash",
   "botanical": "Fraxinus americana",
   "in_catalog": false,
   "factor": 6,
   "used": false,
   "kind": "table",
   "source": "friends",
   "source_name": "The Friends of the Wildflower Garden, Minneapolis, Tree Age Calculation, 2015",
   "url": "https://friendsofeloisebutler.org/pages/photosubpages/photoinfopages/treeagecalculator.html"
  },
  {
   "species": "white-ash",
   "name": "White Ash",
   "botanical": "Fraxinus americana",
   "in_catalog": false,
   "factor": 1.4,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "white-oak",
   "name": "White Oak",
   "botanical": "Quercus alba",
   "in_catalog": true,
   "factor": 5,
   "used": true,
   "kind": "chart",
   "source": "purdue",
   "source_name": "Purdue Extension, Lindsey Purcell, How Old Is My Tree?, Purdue Landscape Report, 2018",
   "url": "https://purduelandscapereport.org/article/how-old-is-my-tree/"
  },
  {
   "species": "white-spruce",
   "name": "White Spruce",
   "botanical": "Picea glauca",
   "in_catalog": false,
   "factor": 4.07,
   "used": false,
   "kind": "rate",
   "source": "urban",
   "source_name": "The Morton Arboretum, Estimated Age of Urban Trees by Species and Diameter (DBH), the State of Indiana's copy of 2015",
   "url": "https://content.govdelivery.com/attachments/INSTATE/2015/01/12/file_attachments/355000/TMAestimatetreeDBH_Age.pdf"
  },
  {
   "species": "willow-oak",
   "name": "Willow Oak",
   "botanical": "Quercus phellos",
   "in_catalog": true,
   "factor": 3.53,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "winged-elm",
   "name": "Winged Elm",
   "botanical": "Ulmus alata",
   "in_catalog": true,
   "factor": 4.44,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "yellow-birch",
   "name": "Yellow Birch",
   "botanical": "Betula alleghaniensis",
   "in_catalog": true,
   "factor": 6.67,
   "used": false,
   "kind": "rate",
   "source": "silvics",
   "source_name": "USDA Forest Service, Silvics of North America, Volume 2, Hardwoods, Agriculture Handbook 654, 1990",
   "url": "https://research.fs.usda.gov/download/treesearch/1548.pdf"
  },
  {
   "species": "yellow-buckeye",
   "name": "Yellow Buckeye",
   "botanical": "Aesculus flava",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "mdc",
   "source_name": "Missouri Department of Conservation, How Old is That Tree?, the Internet Archive's copy of 2016-03-15",
   "url": "https://web.archive.org/web/20160315233350/http://mdc.mo.gov/your-property/your-trees-and-woods/backyard-tree-care/how-old-tree"
  },
  {
   "species": "yellow-buckeye",
   "name": "Yellow Buckeye",
   "botanical": "Aesculus flava",
   "in_catalog": true,
   "factor": 5,
   "used": false,
   "kind": "table",
   "source": "allegheny",
   "source_name": "Allegheny County Parks, Latodami Nature Center, How to Age a Living Tree, 2016, updated 2021",
   "url": "https://www.alleghenycounty.us/files/assets/county/v/1/parks/north-park/latodami/how-to-age-a-living-tree.pdf"
  }
 ]
}