Black Walnut

Juglans nigra

by John Brouwer

Black walnut is considered the matriarch of the North American Juglaniceae family which includes butternut, the hickories, and pecan. This is the tree that produces the round hard shelled nuts which are so hard to crack and whose nutmeats take forever to extract, even with good nutcrackers and picks.

We are in the northern range of the black walnut. The tallest Canadian walnut reaches 100 feet in Halton county – 2 counties to the east. We can see three old walnuts in the cornfield just across Westmount road. Their off-spring can be found in the environmental reserve and along Fischer-Hallman. We have two twenty-something year old walnuts in the co-op. One is between the playground and unit 7 – the other is just behind units 8 & 9. Three saplings have been planted among the sugar maple seedlings between block 2 and Pine Ridge road.

Walnuts have been widely planted as nut trees, ornamentals, and timber trees. In open spaces the side branches are very strong, spreading high and wide to provide shade over large areas. Walnut leaves are fern-like composed of 17 - 20 leaflets so the shade is dappled. The large strong branches provide an excellent habitat for children. The related butternut in the conservation area adjacent to the picnic shelter over-looking the dam provides an immense shady area with a panoramic view of the lake – an excellent location, by the way, for those who have to plan summer family gatherings.

In some park areas, walnuts are considered messy, as the baseball-size husks around the nuts become a lawn nuisance in the fall. I haven't seen this to be a problem here; instead I have experienced some difficulty in collecting nuts for seed as squirrels tend to get to them earlier and are more adept at getting to the higher branches. Two years ago in the tree nursery I had carefully planted two rows of walnuts, only to find two weeks later that all I had were two lines of neatly spaced holes. Any further planting will include laying down wire mesh to protect the seeds.

A walnuts has a deep tap root, allowing it to readily withstand droughts as roots can penetrate to below the water table. Having a tap root means that saplings are difficult to transplant so most have to be seeded in place or transplanted as seedlings.

All the Juglandiceae family are unique in producing their own herbicide. Juglone, a chemical in the leaves, husks, and roots, stunts and kills other nearby plants giving walnuts the ability to kill off the competition providing them with an edge in competing for sunshine in the forest canopy. This is a problem for the landscapers among us who have been thinking about extending the community center flower garden into the pie-shaped parcel across the ramp. The walnut will win!

Walnuts were a staple in the diet of the indigenous peoples. They were eaten fresh, boiled, baked, made into soups, or dried and made into flour. Walnuts are rich in protein, fat, phosphorous, iron, and vitamin E. Walnut husks provided a dark brown dye – a characteristic, which can be confirmed by anyone who has husked the nuts using bare hands. The roots produce a black dye.

Settlers used walnut for fence posts and shingles since the heartwood, like cedar, is rot resistant. As a hardwood it was used for water wheels for grist and sawmills, charcoal for gun powder, and railway ties to transport people and goods. Later walnut was finally recognized as one of the best cabinet woods and became used in the alters, pillars, and paneling in19th century churches and cathedrals. The early and mid-20th century wars created huge demands for walnut rifle stocks and airplane propellers. Through the middle of the century the deep chocolate brown colour of walnut was a prized component of furniture. As stocks decreased and timber prices soared, almost all remaining walnut is sliced into veneers less than .5 mm in thickness. Be careful re-finishing and sanding that walnut desktop!

At up to $7,000 for a specimen tree, the value of walnut timber has spawned a new criminal – the tree rustler, who, using sophisticated techniques - even helicopters, swoops in to poach trees from private woodlots. The trees across the road may be safe because, as part of an old homestead it is likely that their trunks contain nails, fence wire and staples, bullets, and maybe even horseshoes. At more than $50,000 a blade, veneer mills shy away from homestead trees that likely contain stuff that would destroy veneer blades. This reality has led to a new protection strategy for tree-huggers.

As noted earlier, the Carolinian hardwoods, including walnut, have become valuable furniture woods. We certainly have no reason to be cutting rainforests to provide north American flooring and furniture. It is much better to manage our Carolinian forests to provide a sustainable harvest to meet local needs and provide unique products reflecting our own heritage. The best time to plant a walnut is twenty years ago. The second best time is now.

PS Be sure to spend some time this spring enjoying the unique flower displays (trilliums plus) in the old growth woodlots along the Fischer-Hallman bike trail.

March 2008