Burls (or Burrs in Europe) are growths that form on trees. These growths contain a gnarled twisted grain pattern that can also have what are referred to as "eyes". They are by far some of the most interesting woods visually. Burling is possible on all trees, but some are extremely rare. Some may say that certain species of trees will not burl, but I think that is simply a rule that's waiting to be broken.
I did not include dyed burls on this page. Please see Dyed Woods for a listing of those.
Eucalyptus Viridis
Eucalyptus Sp.
Brown Mallee Burl
New Mallee Burl
Native to Australia
Native to Australia
Olea Europaea
Eucalyptus Microcarpa
Olive Burl
Grey Box Burl
Native to Europe
Native to Australia
Cotinus Obovatus
Dalbergia Retusa
Chittum Burl (American Smoke Tree Root burl)
Mexican Cocobolo Burl
Found in limestone fields in Alabama, Dynamite is often needed to excavate the root burls. Due to the excavation process, This is one of the Rarest of North American Burls and one of the most expensive.