There are 20 species of walnut trees (genus Juglans) -- six of which are native to the United States -- and more than 30 species of mahogany in the Rosaceae taxonomical family. Walnuts are deciduous -- meaning they lose their leaves in the cold season -- while mahogany trees are semi-evergreen and usually retain their leaves all year, depending on where they live.
Walnut Tree Description
Walnut trees grow between 40 and 80 feet tall and need particular conditions to thrive. Their soil must be at least 5 feet deep to maintain the health of their root systems and they must be spaced at least 30 feet apart, preferably more. Walnut shoots and blossoms are intolerant to frost and two different varieties must be planted together in order to produce overlapping bloom seasons, which will then fertilise the trees and produce fruit. While walnuts are monoecious -- having separate male and female flowers on the same tree -- the pollen sheds when the females on the same tree are not receptive. That means two different varieties of walnuts must be planted in proximity to fertilise each other.
Mahogany Tree Description
Mahogany trees are large, semi-evergreen trees that can grow as tall as 75 feet and as wide as 50 feet; however, they do not usually achieve heights and widths greater than 50 feet. The wood is resistant to strong winds if the tree is acclimated properly and it can grow well in full sun, partial sun or partial shade. Most mahoganies do well in almost any type of well-drained soil -- clay, loam, sand, alkaline or acidic -- and with little spacing from other trees. Because they do so well with limited spacing, mahoganies are often planted in car park islands or as street-side plantings. However, surface roots on many species are shallow and can buckle concrete if the tree is not located at least 6 feet from the street.
Mahogany and Walnut in Woodworking
Both walnut and mahogany are valued in woodworking for their aesthetic qualities and strength. Mahogany is often used as veneer and for carved wood pieces, though it can also be made into fine furniture. It is a strong, heavy wood that can be easily carved. It has an even texture, attractive finish, predominate grain pattern and open pores. Walnut is also used to make solid furniture and panelling. Walnut is stable, durable and has a good shock resistance as well.
Mahogany and Walnut As Hardwood Floors
Most hardwood flooring is constructed of oak, cherry, maple, pecan, white ash or hickory. However, several other hardwood species -- like walnut and mahogany -- are also used, often at a greater cost. Black walnut is used to make hardwood flooring, though it is softer and therefore less naturally resistant to dents and other damage than oak. Mahogany, on the other hand, is much harder than oak. On the Janka Hardness Test, Santos mahogany is second only to mesquite as the hardest type of wood usually used to make hardwood flooring.