There is something of a debate when it comes to answering the question, what is the hardest wood in the world?
Most experts are of the opinion that the Australian Buloke, which is an ironwood tree, provides the hardest wood in the world, with a Janka hardness rating of 5,060 lbf.11 Others argue that Quebracho (which translates to ‘ax-breaker’ in Spanish) is the tree with the hardest wood in the world.
But what does ‘hardness’ related to wood actually refer to? While it’s easy to assume that hardness refers to strength, that is not entirely the truth.
The hardness makes up one measurement, of the many that exist, which establishes how much force it takes to destroy any given wood piece.
In the case of hardness measurement, hardness equals resistance to indentation. This, in simple terms means, hardness is measured by how much force is required to make a sizable mark in the wood.
So, what is the hardest wood in the world? The Janka test says Australian Buloke.
Related Reading: How Many Trees Are in the World?
What Is the Hardest Wood in the World? (Wood Hardness Scale)
For the purpose of measuring hardness, the Janka test and Janka wood hardness scale are used.
The test was created by Gabriel Janka and basically consists of a 0.44-inch steel ball with a small ‘belt’ placed around it. The ball is pressed into a piece of wood until it has made a dent up to the little belt (which is halfway).
The score from this Janka test is the amount of force required to get the ball into the wood.16
However, there are several factors that come into play to ensure the test is done properly. These include:
- A piece of wood containing exactly 12% moisture
- The wood thickness must be exactly 2 inches, as must be the width, while the length must be 6 inches
- When the test is done, the ball should be pressed into each side of the piece of wood, to ensure six scores at the end, then the average is taken from these scores
- The wood itself must be derived from the main tree trunk, as opposed to a branch
- There should be no knots in the wood
- The ball must be pressed into the wood at an average of 0.25 inches a minute1
These conditions are required for the Janka test, so that all types of wood are treated exactly the same.
What Is the Hardest Wood in the World? (Janka Wood Scale)
The Janka Wood Scale offers the pounds-force rating of different wood species including domestic and exotic wood.
The below Janka wood scale chart indicates the hardness of both domestic and exotic wood species, with high ratings meaning a higher level of hardness than low ratings.18 (The rating is given in pounds-force (lbf).5,7
The following list starts with some of the hardest woods that have been tested, and proceeds to the softest.
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Lignum Vitae | 4380 lbf |
| Snakewood25 | 3800 lbf |
| Red Coolibah Burl | 3730 lbf |
| Argentine Lignum Vitae (Image: Abarmot26) | 3710 lbf |
| Brazilian Ebony | 3692 lbf |
| African Blackwood | 3670 lbf |
| Figured Katalox | 3660 lbf |
| Katalox (Image: Abarmot26) | 3660 lbf |
| Brown Ebony | 3590 lbf |
| Mopani | 3390 lbf |
Argentine Lignum Vitae
Katalox
Macassar Ebony
Gaboon Ebony
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Mun Ebony | 3000 lbf |
| Cocobolo | 2960 lbf |
| Yellow Box Burl (Image: Ottre27) | 2920 lbf |
| Bloodwood | 2900 lbf |
| Osage Orange | 2760 lbf |
| Madagascar Rosewood | 2720 lbf |
| Granadillo | 2700 lbf |
| Olivewood (Image: Androstachys26) | 2690 lbf |
| Jatoba | 2690 lbf |
| Amazon Rosewood | 2620 lbf |
Yellow Box Burl
Olivewood
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Marblewood | 2532 lbf |
| Figured Purpleheart | 2520 lbf |
| Purpleheart (Image: Villanueva27)19 | 2520 lbf |
| Tulipwood (Image: Rob Hille27) | 2500 lbf |
| Brown Mallee Burl | 2490 lbf |
| Tamboti | 2480 lbf |
| East Indian Rosewood | 2440 lbf |
| Indian Ebony | 2430 lbf |
| Cochen Rosewood | 2430 lbf |
| Quilted Bubinga | 2410 lbf |
Purpleheart
Tulipwood Trunk
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Bubinga (Image: Rotational27) | 2410 lbf |
| Figured Bubinga | 2410 lbf |
| Santos Mahogany | 2400 lbf |
| Argentine Osage Orange | 2400 lbf |
| Spalted Tamarind (Image: Bishnu28) | 2318 lbf |
| Chakte Viga | 2250 lbf |
| Honduras Rosewood Burl | 2200 lbf |
| Honduras Rosewood | 2200 lbf |
| Chechen | 2200 lbf |
| Goncalo Alves | 2160 lbf |
Bubinga
Spalted Tamarind
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Leopardwood | 2150 lbf |
| Sucupira | 2140 lbf |
| Black Palm (Image: DEZALB28)12 | 2020 lbf |
| Bocote | 2010 lbf |
| Ziricote | 1970 lbf |
| Padauk | 1970 lbf |
| Bolivian Rosewood | 1960 lbf |
| Wenge | 1930 lbf |
| Red Palm | 1900 lbf |
| Yellowheart | 1978 lbf |
Black Palm
Padauk
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Jarrah Burl | 1860 lbf |
| Zebrawood (Image: Mnemosine27) | 1830 lbf |
| Figured Zebrawood | 1830 lbf |
| Hickory (Image: Internet Archive Book Images | NCSU Libraries29) | 1820 lbf |
| Afzelia Burl | 1810 lbf |
| Figured Camphor Bush | 1800 lbf |
| Camphor Bush Burl | 1800 lbf |
| Black & White Ebony | 1780 lbf |
| Merbau | 1712 lbf |
| Afrormosia | 1560 lbf |
Zebrawood
Hickory
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Honey Locust (Image: Josie Weiss33) | 1548 lbf |
| Canarywood | 1520 lbf |
| Sapele | 1500 lbf |
| Madrone Burl (Image: Internet Archive Book Images | NCSU Libraries29) | 1460 lbf |
| Rift Sawn Hard Maple | 1450 lbf |
| Spalted Maple | 1450 lbf |
| Hard Maple Burl | 1450 lbf |
| Bark Pocket Maple | 1450 lbf |
| Quarter Sawn Maple | 1450 lbf |
| Curly Hard Maple | 1450 lbf |
Honey Locust
Madrone Burl
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Hard Maple14 | 1450 lbf |
| Birdseye Maple | 1450 lbf |
| Quilted Sapele | 1439 lbf |
| Eucalyptus (Image: Kylie128) | 1400 lbf |
| Mayan Walnut (Image: Internet Archive Book Images | NCSU Libraries29) | 1400 lbf |
| English Brown Oak | 1360 lbf |
| Ebiara | 1350 lbf |
| White Oak | 1335 lbf |
| Quarter Sawn White Oak | 1335 lbf |
| Shedua | 1330 lbf |
Eucalyptus
Mayan Walnut
Swamp Ash
Birch
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Amboyna Burl | 1260 lbf |
| Spalted Oak | 1220 lbf |
| Quarter Sawn Red Oak | 1220 lbf |
| Curly Oak | 1220 lbf |
| Red Oak (Image: Internet Archive Book Images | NCSU Libraries29)21 | 1220 lbf |
| Nicaraguan Rosewood | 1210 lbf |
| Mirindiba | 1200 lbf |
| Masur Birch | 1200 lbf |
| Redheart | 1200 lbf |
| Acacia (Image: Herbert II Timtim (herbert11timtim)28) | 1180 lbf |
Spanish Cedar
Acacia
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Koa (Image: Scot Nelson29) | 1170 lbf |
| Thuya Burl | 1160 lbf |
| Figured Mango | 1100 lbf |
| African Mahogany | 1100 lbf |
| Teak | 1080 lbf |
| Curly Pyinma | 1055 lbf |
| Holly | 1020 lbf |
| Figured Walnut | 1010 lbf |
| Walnut | 1010 lbf |
| Peruvian Walnut | 960 lbf |
Koa
Thuya Burl
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Ambrosia Maple | 950 lbf |
| Curly Cherry | 950 lbf |
| Soft Maple | 950 lbf |
| Cherry Burl | 950 lbf |
| Curly Soft Maple | 950 lbf |
| Tornillo | 950 lbf |
| Cherry | 950 lbf |
| Anigre | 930 lbf |
| Lacewood | 891 lbf |
| Spalted Hackberry | 880 lbf |
Ambrosia Maple
Lacewood
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Western Maple (Image: Internet Archive Book Images | NCSU Libraries30) | 850 lbf |
| Black Ash17 | 850 lbf |
| Curly Western Maple | 850 lbf |
| Western Maple Burl | 850 lbf |
| Quilted Western Maple | 850 lbf |
| Genuine Mahogany (Image: jessicuak28) | 800 lbf |
| Spanish Cedar | 600 lbf |
| Mappa Burl | 540 lbf |
Western Maple
Genuine Mahogany
| Wood Species | Janka Hardness Rating (in pounds-force) |
| Poplar | 540 lbf |
| American Chestnut | 540 lbf |
| Butternut | 490 lbf |
| Guanacaste (Image: Alison Phillips32) | 470 lbf |
| Basswood Tree | 410 lbf |
| Aspen | 380 lbf |
| Buckeye Burl (Image: internet Archive Book Images | NCSU Libraries30) | 350 lbf2 |
Guanacaste
Buckeye Burl
Hardest Wood in the World
The below wood species are some of the hardest woods in the world:
Australian Buloke: 5,060 lbf
Australian Buloke is often reported as producing the hardest wood in the world, even though it must be considered that this ranking is based on only one data source.
Schinopsis Brasiliensis: 4,800 Ibf
Schinopsis Brasiliensis belongs to the cashew family and is also known as Baraúna. This tree is harvested mainly for construction because its wood is so hard. Excessive harvesting has led to the tree becoming an endangered species.
Schinopsis Balansae: 4,570 Ibf
This hardwood tree is also well known as Argentina’s National Forest Tree after it was declared so in 1956.
It is also called the willow leaf red quebracho and its wood is mainly used for quebracho extract which consists of around sixty-three percent pure tannin.
Lignum Vitae (Tree of Life): 4,500 Ibf
Lignum Vitae is also known as the tree of life and is one of the hardest and heaviest woods on the planet.15 This tree is currently listed as endangered because of the over-extraction of resin.
Piptadenia Macrocarpa: 3,840 Ibf
This timber tree is often compared to a mimosa tree and is native to several South American countries.
The wood from this tree is very durable and hard and is often used for construction and marine purposes.
Snakewood: 3,800 Ibf
Snakewood wood is considered to be one of the heaviest commercial woods worldwide, as well as one of the hardest. It is popular for use in the manufacturing of violins and tools.
Brazilian Olivewood: 3,700 Ibf
Brazilian Olivewood has a deceptively delicate appearance, as it is very hard and durable. It is commonly used for interior decoration and upmarket furniture.
Brazilian Ebony: 3,692 Ibf
Like its counterpart, olivewood, Brazilian ebony wood is also heavy and hard. It is almost black in color with a grain that runs in straight lines.
Ebony wood in general is popular for use in instruments and furniture.
Brazilian Walnut: 3,684 Ibf
Brazilian walnut wood is known for being exceptionally durable and pest resistant. An example of this is the beach boardwalk in Coney Island, which was built using Brazilian walnut wood.
This boardwalk lasted for 25 years before replacements were required. However, this type of wood is tough to work with, because it is very dense and hard. It is a popular wood for flooring purposes.
African Pearwood: 3,680 Ibf
African pearwood wood is highly durable and easy to work with. It is commonly used for furniture and veneer purposes.
This tree is also listed as vulnerable because of ongoing exploitation.
Furthermore, the below table indicates some more details about the hardest hardwoods in the world:
| Hardwood Species | Scientific Name | Janka Hardness Rating (in pounds-force) |
| Cebil (Curupay) | Anadenanthera colubrina | 3630 lbf |
| Katalox / Wamara | Swartzia spp. | 3655 lbf |
| Black Ironwood20 | Krugiodendron ferreum | 3660 lbf |
| African Blackwood | Dalbergia melanoxylon | 3670 lbf |
| Camelthorn (Image: Sohadiszno31) | Vachellia erioloba | 3680 lbf |
| Verawood | Bulnesia arborea | 3710 lbf |
| Snakewood | Brosimum guianensis | 3800 lbf |
| Gidgee | Acacia cambagei | 4270 lbf |
| Lignum Vitae | Guaiacum officinale | 4390 lbf |
| Quebracho | Schinopsis spp. | 4570 lbf3 |
Camelthorn
Verawood
Related Reading: How Many Trees Are Planted Each Year?
The below table indicates the comparison of wood hardness when choosing wood for flooring purposes:
| Very Hard Wood | Hard Wood | Moderately Hard Wood | Soft Wood |
| Spotted Gum | Brushbox | Messmate | Radiata Pine |
| Red Ironbark | Tallowwood | Mountain Ash | Araucaria |
| Gray Ironbark | Stringybark | Tasmanian Oak | Kauri |
| Blackbutt | River Red Gum | Victorian Ash | White Baltic |
| New England Blackbutt | Rose Gum | Shining Gum | Western Yellow Pine |
| Forest Red Gum | Sydney Blue Gum | Manna Gum | Rimu |
| Turpentine | Southern Blue Gum | Myrtle | Teak4 |
| White Mahogany | Jarrah | Blackwood | |
| Gympie Messmate | Karri | Cypress | |
| Gray Box | Marri | American White Oak | |
| Wandoo | Kwila | European Oak | |
| Brazilian Cherry | Northern Box | European Ash | |
| Jatoba | Kempas | Maple Sugar | |
| Hevea |
The option that comes in as the average choice around the world when choosing hardwood for flooring, is red oak wood.
The other options include the following:
When it comes to ‘good’ Janka ratings, a ranking of 1,000 lbs or more is considered to be acceptable. But it must also be considered that even though a certain type of wood may have a very high Janka score, it is not a guarantee that the wood won’t warp or wear.
Speaking of warping and wearing, and denting, the below wood is rated as the softest wood on the Janka wood hardness scale:
| Wood | Scientific Name | Janka Hardness Rating | Common Uses |
| Western Red Cedar | Thuja plicata | 350 lbf | Western Red Cedar is commonly used for musical instruments such as guitars, but because it is so soft, it is not easy to keep it from denting during construction. |
| Black Cottonwood (Image: Patrick Alexander30) and Quaking Aspen | Populus tremuloides / P. trichocarpa | 350 lbf | These two types of wood have similar Janka scores and are both soft and easily dented or damaged. Black cottonwood is used for paper while quaking aspen is used for lumber. |
| Atlantic White Cedar | Chamaecyparis thyoides | 350 lbf | While Atlantic white cedar wood is soft, it has excellent resistance against decay and moisture. It is often used for shingles and in boat construction. |
| Yellow Buckeye (Image: Internet Archive Book Images | NCSU Libraries30) | Aesculus octandra | 350 lbf | This softwood is popular for use in guitar manufacturing and other high-end wood products. It is also used for lumber. |
| Subalpine Fir | Abies lasiocarpa | 350 lbf | Subalpine fir wood is the softest of all fir woods, except for European silver fir. This soft wood is used for pulp, veneer, and lumber. |
| Wood | Scientific Name | Janka Hardness Rating | Common Uses |
| Northern White Cedar23 | Thuja occidentalis | 350 lbf | Northern white cedar wood is considered one of the softest cedars and is used for various products including pails, poles, fencing, logs, and more. |
| European Silver Fir | Abies alba | 320 lbf | This is the softest wood of all fir woods and makes for lightweight timber that can be used for pulp, plywood, and lightweight furniture. |
| Balsam Poplar | Populus balsamifera | 300 lbf | Being one of the lightest woods, balsam poplar wood is commonly used for crates, veneer, and pulp. |
| Paulownia | Paulownia spp. | 260 lbf | Paulownia is a type of softwood that truly stands on its own merit. Even though it is a very soft and light wood, it is also strong and fire, water, and pest-resistant. Paulownia wood can be used for making instruments, in construction, and for plywood. |
| Balsa | Ochroma pyramidale | 90 lbf | Balsa is officially both the lightest and the softest wood on the wood market today. It is often used for insulation and recreational purposes such as model vehicles and planes. |
Black Cottonwood
Yellow Buckeye
When looking at all of the wood ratings, it must also be considered that while the Janka scale is still the go-to scale for wood hardness measuring worldwide, it might no longer be relevant to some industries, including the wood flooring industry.6
For this reason, many flooring companies and associates prefer to use the new table as indicated above, which groups wood into Very Hard, Hard, Moderate Hard, and Soft categories.
The reasons debated for the Janka scale being outdated for the flooring industry are as follows:
- Wood is used in a different way when it comes to flooring. For instance, most modern floors require more than one type of material, which means the Janka rating no longer applies.
- Studies into tree regrowth have shown that the Janka scale’s information may be too out of date for some industries to use. This is because the existing scores are based on primeval wood data.
- The Janka score also doesn’t provide the complete picture when it comes to ranking the hardness of a particular wood. For instance, while it is good to know the hardness of the wood related to dent resistance, it is essential to measure the stability and lifespan of the wood, as well as the wood’s ability to recover after being damaged.6
Strongest Types of Wood
The strongest types of wood include the following factors that influence its strength:
- Increased microfibril angle may cause lesser elasticity.
- Extractives from heartwood may add several substances that make wood stronger.
- In addition to these substances, heartwood extractives are also known to add other substances that would increase the density of the wood without making a noticeable difference in the strength.
- Some types of wood always have defects that will affect its overall strength.7
World’s Strongest Wood
The world’s strongest wood is ranked in order of how popular the wood is for building and construction applications:
- Australian Buloke
- Schinopsis Brasiliensis
- Brazilian Ebony
- Schinopsis Balansae13
- Lignum Vitae8
The Strongest Tree in the World
Looking at the above information, it might be surprising to learn that the strongest tree in the world is considered to be the Giant Sequoia.
A giant sequoia named General Sherman has a height of 274.9 feet and a girth of 79 feet.
This makes it the biggest tree in the world.
What Is the Hardest Wood in the World? Most Durable Wood
The giant sequoia redwood is known for having some of the most durable wood in the world. Wood from this tree is often used for outdoor furniture and decking because of its exceptional weather resistance.
Sequoia is also the most expensive wood in the world when calculated by cubic meters.
Other woods that deserve the distinction of most durable wood is:
- Black Cherry Wood
- White Oak Wood
- Cypress Wood
- Red Mulberry Wood
- Black Locust Wood
- Southern Yellow Pine Wood
- Black Walnut Wood
- Eastern Red Cedar Wood9
What Is the Hardest Wood in the World?
When compiling a comprehensive answer to the question, what is the hardest wood in the world, it is important to list the hardest wood to split.
Hardest Wood To Split
The hardest wood to split includes the following:
- Eucalyptus24
- Ash
- London Plane
- Elm
- Hornbeam
What Is the Hardest Wood in the World?
Also, when it comes to answering the question, of what is the hardest wood in the word, the wood hardness for woodworking must also be considered.
Woodworking Wood Hardness Chart
When looking at a woodworking wood hardness chart, the most important information is the pressure to mar (in pounds), which indicates the hardness of the face of the wood (excluding the sides and edges).
The below chart is useful when deciding what wood to use for a project:
Hard Maple
Yellow Birch
| Species of Wood | Pressure To Mar (in pounds) |
| Hackberry | 880 |
| Gum | 850 |
| Elm (Image: daizuoxin31) | 830 |
| Sycamore | 770 |
| Alder | 590 |
| Yellow Poplar | 540 |
| Cottonwood22 | 430 |
| Basswood | 410 |
| Aspen | 35010 |
Elm
Aspen
It is clear that the different types of wood that are ranked as the hardest woods in the world, all have their own characteristics to consider.
What Does Janka Hardness Refer To?
Janka hardness refers to the Janka hardness test developed by researcher Gabriel Janka. The Janka test measures the force used to dig a 0.44 steel ball into a piece of wood.
Janka hardness tests are often required to determine the suitability of wood for flooring.
Is the Australian Buloke the Hardest Wood Around the World?
Australian Buloke wood is the hardest commercially available wood in the world.
The Australian Buloke Tree grows to heights of 66 feet and its life span is around 15 years.
As the name suggests, the tree is native to Australia.
What Is the Carbon Footprint of Timber?
Timber is wood that has been specially prepared for furniture manufacturing and construction. Timber also has a carbon footprint which is explained as: Every dry ton of timber captures around 1.8 tons of CO2 from the atmosphere.
The CO2 remains locked in the wood which assists in offsetting harmful emissions. It is estimated that building timber cities could cut around 100 billion tons of carbon dioxide from the atmosphere by 2100.
However, the transportation of timber does release GHG emissions because of vehicle fossil fuels.
How Much Weight Can Plywood Hold?
The weight-bearing capacity of plywood is dependent on the thickness of the plywood, in other words, the thicker the sheet of plywood, the stronger the sheet of plywood.
For instance, a 12-inch by 36-inch sheet of plywood that is 1/4 inch thick will support only 5 pounds. However, a 12-inch by 36-inch sheet of plywood that is 3/4 inches thick will support up to 50 pounds.
Knowing the answer to the question, what is the hardest wood in the world, might come in handy one day, but at the very least, it’s very cool to understand how trees are ranked by their Janka score and what that means.
Frequently Asked Questions About What Is the Hardest Wood in the World
What Is the Hardest Wood in the World?
The hardest wood in the world is considered by many experts to be the Australian Buloke. This wood has a Janka hardness rating of 5,060 lbf and is native to the Australian continent.
What Is the Strongest Wood?
The strongest wood is listed as follows (for building purposes):
- Oak tree wood
- Ash tree wood
- Hickory tree wood
- Ebony tree wood
- Cherry tree wood
- Lignus Vitae wood
- Schinopsis balansae wood
- Brazilian ebony wood
- Schinopsis brasiliensis wood
- Australian buloke wood
What Is the Hardest Wood?
The hardest wood in the world includes the following:
- Quebracho Wood: 4,570 lbf
- Lignum Vitae Wood: 4,390 lbf
- Gidgee Wood: 4,270 lbf
- Snakewood Wood: 3,800 lbf
- Australian Buloke Wood: 3,370 lbf
- Verawood Wood: 3,710 lbf
- Camelthorn Wood: 3,680 lbf
- African Blackwood Wood: 3,680 lbf
- Gray Ironbark Wood: 3,680 lbf
- Black Ironwood Wood: 3,660 lbf
- Curupay Wood: 3,360 lbf
- Ipe Wood: 3,510 lbf
- Cumaru Wood: 3,330 lbf
- Desert Ironwood Wood: 3,260 lbf
- Bulletwood Wood: 3,130 lbf
What Are the Grades of Marine Plywood?
Marine plywood is the strongest type of plywood and comes in the following grades:
- A-A
- A-B
- B-B
- Medium Density Overlay
- High-Density Overlay
Is It Possible To Get Free Tree Removal in Exchange for Wood?
It is possible to get free tree removal in exchange for wood, by considering the following:
- How hard is it to reach the location of the tree? If the tree is in a difficult-to-reach location, a tree removal company may not want to remove it free of charge.
- What is the tree species? If the tree is a valuable species, a tree removal company may be convinced to remove it for free in exchange for the wood.
- How big is the tree? Bigger trees take longer to remove, and the tree removal company may want to evaluate whether it is worth their time to remove them.
- Will the local utility company remove the tree for free or for wood?
- Will home insurance cover the cost of a potential accident during tree removal?
Read More About What Is the Hardest Wood in the World
Willow Tree Guide: All 19 Species & How Its Bark Changed Science
Summer Chocolate Mimosa Tree: 5 Odd Differences vs Pink Mimosa Tree
Cherry Tree Guide: 12 Colors, Species, How to Plant (Best Way to Buy)
Oak Tree Guide: 7 Types, Colors, Leaves, Identification (How to Buy, Plant)
Red Oak Tree: Leaves (Northern vs Texas vs White Oak vs Southern vs Cali)
Cashew Tree Guide by a Tree Expert: How to Grow, Uses, Nuts (Warning)
Ash Tree Guide: All 12 Species, Colors, Types, Identification (& Disease)
References
1Nosowitz, D. (2022, February 23). What’s the Hardest Wood in the World? Atlas Obscura. Retrieved December 21, 2022, from <https://www.atlasobscura.com/articles/whats-the-hardest-wood-in-the-world>
2Bell Forest Products. (2022.). Janka Hardness chart for Exotic Wood and Domestic Wood. Bell Forest Products. Retrieved December 21, 2022, from <https://www.bellforestproducts.com/info/janka-hardness/>
3Meier, E., & Bootle, K. R. (2022). Top Ten Hardest Woods. The Wood Database. Retrieved December 21, 2022, from <https://www.wood-database.com/top-ten-hardest-woods/>
4Parameshwaran, M. (2020, April 14). What Is A Janka Rating? | ASH. Australian Sustainable Hardwoods. Retrieved December 21, 2022, from <https://ash.com.au/blog/what-is-a-janka-rating/>
5Superior Hardwood Flooring. (2022). Janka Hardness Scale – Superior Flooring. Superior Hardwood Flooring. Retrieved December 21, 2022, from <https://www.superiorflooring.ca/janka-hardness-scale/>
6Christofix Woodworking. (2022). What Is Janka Rating And Is It Still Relevant? Solved. Christofix Woodworking. Retrieved December 21, 2022, from <https://www.christofix.com/what-is-janka-rating/#what-is-the-purpose-of-the-janka-scale>
7Meier, E. (2022). World’s Strongest Woods. The Wood Database. Retrieved December 21, 2022, from <https://www.wood-database.com/worlds-strongest-woods/>
8Dane, K. (2021, September 24). Ranking The 10 Strongest Woods to Build With. Inspired Homes. Retrieved December 21, 2022, from <https://inspiredhomes.uk.com/ranking-the-10-strongest-woods-to-build-with/>
9Saxton, T. (2021, May 28). Your Guide to the Most Durable Wood Species for Outdoor Use. Rise. Retrieved December 21, 2022, from <https://www.buildwithrise.com/stories/durable-outdoor-wood-guide>
10Tiny Timbers. (2022). Janka Hardness & Density Rating Scale. Tiny Timbers. Retrieved December 21, 2022, from <https://tinytimbers.com/resources/janka/>
11Australian Government’s National Environmental Science Program. (2022). Restoring Buloke Woodland Structure. Threatened Species Recovery Hub. Retrieved December 22, 2022, from <https://www.nespthreatenedspecies.edu.au/media/vwrbhuno/1-2-2-restoring-buloke-woodland-structure-guide-factsheet_v9.pdf>
12Doubrava, N., Blake, J. H., Munnerlyn, C., & Williamson, J. (2021, September 10). PALM DISEASES & NUTRITIONAL PROBLEMS. Clemson Cooperative Extension Home and Garden Information Center. Retrieved December 23, 2022, from <https://hgic.clemson.edu/factsheet/palm-diseases-nutritional-problems/>
13Emanuele, E., Šket, P., Causin, V., Zanetti, M., & Tondi, G. (2021, December 16). Development of Quebracho (Schinopsis balansae) Tannin-Based Thermoset Resins. National Library of Medicine. Retrieved December 23, 2022, from <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8706668/>
14Godman, R. M., Yawney, H. W., & Tubbs, C. H. (2022). Sugar Maple. USDA Forest Service. Retrieved December 23, 2022, from <https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/acer/saccharum.htm>
15Government of The Bahamas. (2022). The Lignum Vitae – National Tree of The Bahamas. The Government of The Bahamas. Retrieved December 23, 2022, from <https://www.bahamas.gov.bs/wps/portal/public/about%20the%20bahamas/national%20symbols/the%20lignum%20vitae%20-%20national%20tree%20of%20the%20bahamas/!ut/p/b1/vZLJkqJAGISfxQegKaDYjigIFBQgiwoXQ0CQTUBwgacfey6zREz3HKan_lNFfFkZmfWTEbkno8vxXuTHsWgvx_r9HnEHBqhYkqCAVRZwQA8cU3J4jbYp9gWEHwAQ_J0e_OFIn-p35N4PWFNucb42H4bKJsqxKeTpycoWES5lLnCxowPuRJlxasCmu2A0YRWnZ8UQ6CKmfZxdN6ziRX1kFBAdJxw1ru_0vdExTh06yObR8MCKrYAhV9aasTpHW8bSqu4OldpXG4eXcmWSS_5Mn-XIqjMENuKYGIpcDeMlaVV0aOPJHA8ECnkKhddEZ5lrZyV9eiyoMWwBbNq9IDj9Q5vxY7F4ZYo-jG3QnwDvtX8HPujV0trmRIYvjP_pHX8LgE4ByfWoDRAsivTJPYAHr5w6fa5mt5xdbMlLC4NhBhWFxqDcWUGNvVSlfFMBQA6eOOjsMV7qfonQMPpOunWDpSRRz_r0_N3Qpn3xZbiiOCNggQfgVxuqrC28muJ9R2JpoNrU_zZk_mulqmODL0_4y9LAzb__Q0RGRdy8PZLmDbwJIkexvABFgQMQCjy5rQPhGef4KTs3Yw0J5GjZlclPcLe5sm07WDsUnTmC8xgxtYppqdeXTYFcJVi5kGjpThwEjovTO21kS0K5xrfZrAFH937LbLWt5ZroNDRG0K3hXqqjx_auJXdBjE-MmVPDeRP7nh1WHFvC0_VyUVXXFTisq2j9zFZ96226BkxCgpw0y9mnHe3UGVXBZDPYP3p4wqMYP9QxtfJedJu-9NGuaaTkph9PXVg5t8Qo2iTKDNNeZWGLDqV0Ie6zNhN3jZB36tYWqgXZNUFw75RM3s8_RlosvgHYDn1d/dl4/d5/L2dBISEvZ0FBIS9nQSEh/>
16Green, D. W., Begel, M., & Nelson, W. (2006). Janka Hardness Using Nonstandard Specimens. Forest Service US Department of Agriculture. Retrieved December 23, 2022, from <https://www.fs.usda.gov/research/treesearch/23824>
17Gucker, C. L. (2005). Fire Effects Information System (FEIS). US Forest Service. Retrieved December 23, 2022, from <https://www.fs.usda.gov/database/feis/plants/tree/franig/all.html>
18Kasseney, B. D., Deng, T., & Mo, J. (2011, June). Effect of Wood Hardness and Secondary Compounds on Feeding Preference of Odontotermes formosanus (Isoptera: Termitidae). PubMed.Gov. Retrieved December 23, 2022, from <https://pubmed.ncbi.nlm.nih.gov/21735905/>
19Mahr, S. (2022). Purple Heart, Tradescantia pallida. Wisconsin Horticulture Division of Extension. Retrieved December 23, 2022, from <https://hort.extension.wisc.edu/articles/purple-heart-tradescantia-pallida/>
20Mayer, W. (2022, September 9). Intro to Trees of Indiana: Ironwood. Purdue University. Retrieved December 23, 2022, from <https://ag.purdue.edu/news/department/forestry-and-natural-resources/2022/09/intro-to-trees-of-indiana-ironwood.html>
21NC State University. (2022). Quercus rubra. NC State Extension. Retrieved December 23, 2022, from <https://plants.ces.ncsu.edu/plants/quercus-rubra/>
22Science.Gov Alliance. (2022). Sample records for eastern cottonwood trees. Science.Gov. Retrieved December 23, 2022, from <https://www.science.gov/topicpages/e/eastern+cottonwood+trees>
23USDA, NRCS, & National Plant Data Center & the Biota of North America Program. (2022). NORTHERN WHITECEDAR. US Department of Agriculture. Retrieved December 23, 2022, from <https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_thoc2.pdf>
24US Department of Interior. (2022). Eucalyptus Trees. National Park Service. Retrieved December 23, 2022, from <https://www.nps.gov/places/eucalyptus-trees.htm>
25US Fish and Wildlife Service. (2022). Snakewood. US Fish and Wildlife Service. Retrieved December 23, 2022, from <https://www.fws.gov/species/snakewood-rauvolfia-serpentina>
26Argentine Lignum Vitae by Abarmot, Katalox by Abarmot, Macassar Ebony by B. Ratunde, Gaboon Ebony by Disputantum, and Olivewood by Androstachys, retrieved from <https://commons.wikimedia.org/wiki/Main_Page>
27Yellow Box Burl by Ottre, Purpleheart by Villanueva, Tulipwood Trunk by Rob Hille, Bubinga by Rotational, Zebrawood by Mnemosine <https://commons.wikimedia.org/wiki/Main_Page>
28Spalted Tamarind by Bishnu Sarangi (sarangib), Black Palm by DEZALB, Eucalyptus by kylie1, Birch by Petra (Pezibear), Acacia by Herbert II Timtim (herbert11timtim), and Genuine Mahogany by jessicuak <https://pixabay.com>
29Koa by Scot Nelson, Hickory by Internet Archive Book Images | NCSU Libraries, Madrone Burl by Internet Archive Book Images | NCSU Libraries, Mayan Walnut by Internet Archive Book Images | NCSU Libraries, Red Oak by Internet Archive Book Images | NCSU Libraries, retrieved from <https://www.flickr.com/>
30Western Maple by Internet Archive Book Images | NCSU Libraries, Yellow Buckeye by Internet Archive Book Images | NCSU Libraries, Buckeye Burl by Internet Archive Book Images | NCSU Libraries, and Black Cottonwood by Patrick Alexander, retrieved from <https://www.flickr.com/>
31Camelthorn by Sohadiszno, Hard Maple Wood Texture by Ultramarinfoto, Elm by daizuoxin, Aspenwood by Ninjuna, and Yellow Birch NNehring, <https://www.canva.com/>
32Guanacaste by Alison Phillips and Swamp Ash by Minnecologies, retrieved from <https://commons.wikimedia.org/wiki/Main_Page>
33Photo by Josie Weiss via <https://unsplash.com/photos/P86I5vNtRv4?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText>