There is a constant state of confusion surrounding walnut wood and walnut trees. Walnuts are almost always grafted, and there are various combinations out there depending on soil and scientific research. Juglans nigra or black walnut is a common rootstock for Juglans regia or English walnut. The word Claro walnut is commonly attached to a variety of woods because the word sells better than the actual wood. There is a geographic bias for Juglans hinsii or Hind’s walnut because this is the native Northern California walnut and is correctly called ‘Claro Walnut’. There is a native Southern Californis Walnut - Juglans californica and it also has the name Claro walnut. Although many black and English walnuts are called Claro, this is a mistake and should be avoided. The two native California walnuts are the real Claro.
Juglans hindsii no longer exists in natural large stands. You will find the occasional Claro walnut in a Berkeley backyard or stuck alone in a field. You might not know that these trees are a walnut because they often do not bear at all. The close proximity to cross pollination is missing. But if a branch should fall or a little pruning done, the chocolate color inner wood is a dead giveaway. The leaves are compound with five or more leaflets. The leaves are also odd pinnate with a single terminal leaflet. Leaflets are ¾” wide or greater, singly serrate, evenly toothed. Leaflets are uniform in size or middle ones largest.
John Doyen states, “The local walnut is justifiably celebrated for its excellent working characteristics and beautiful figure.. Natural stands extirpated, but readily available as a street tree and as rootstock in orchards.” My experience is limited but I have not seen Claro as a rootstock, and I have not seen Juglans hindsii as a street tree. I do believe they can be found. We once had to remove a medium size Juglans hindsii on the Albany El Cerrito border. It had a high percentage of sap wood and was difficult to turn, very fibrous and frustrating. Recently we had one claro walnut die on the UC Berkeley property and I offered to cut it down at no cost. This wood is a dream to turn and the figure is amazing. The heartwood seems to actually bleed into the sap wood and various shades of brown and green and off white make the wood very colorful. But the best aspect is the figure. It is outstanding wood.
Not everybody likes to turn walnut of any sort. It is a very dirty wood. Your skin and clothes will be a crusty mess with dark coloration. Tools and machinery will suffer as well. I try to make a habit of cleaning every thing thourougly right after finishing turning any walnut. However, the wood itself turms brilliantly and easi ly. Claro walnut has an excess of oils and sap so expect a shower when turning fresh off the tree wood. The wood dries slowly, again a factor of the oils in the wood. But it dries without major cracks or checking. The wood moves some but not a lot, actually it is fairly stable. Walnut wood lots often have twenty or thirty year old chunks that work just fine. I do not have to tell most of you how valuable this wood can be.