''Juglans hindsii'', commonly called the Northern California black walnut and Hinds's black walnut, is a species of walnut tree native to the western United States (California and Oregon). Jepson Herbarium (2013): ''Juglans hindsii''
/ref> It is commonly called claro walnut by the lumber industry and woodworkers, and is the subject of some confusion over its being the root stock for English walnut orchard stock.

Distribution

The historical range of ''Juglans hindsii'' is from the

San Joaquin Valley The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven ...

and

Sacramento Valley , photo =Sacramento Riverfront.jpg , photo_caption= Sacramento , map_image=Map california central valley.jpg , map_caption= The Central Valley of California , location = California, United States , coordinates = , boundaries = Sierra Nevada (ea ...

to the Inner Northern

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. ...

and

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area G ...

, in

Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...

. A 2020

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

assessment has extended this range: north to Oregon and south to Southern California, in areas of similar habitat type. The northernmost pre-colonial ''Juglans hindsii'' tree was located in Douglas County, Oregon before it was blown over in November 2017. A ring count determined the tree predated the arrival of settlers by approximately 100 years. The Native Plant Society of Oregon has also documented multiple trees of pre-colonial age in Oregon's Rogue Valley. The tree grows in

riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...

woodlands, either in mono-species stands, or mixed with California oak species (''

Quercus An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ...

'' spp.) and Fremont cottonwood (''Populus fremontii'') trees. ;Conservation ''Juglans hindsii'' was formerly assessed as Seriously Endangered on the California Native Plant Society Rare Plant Inventory. In a 2019 revision, the species was upgraded to common. It is threatened by hybridization with orchard trees, urbanization, and habitat conversion to agriculture.

Description

''Juglans hindsii'' is a large tree that grows up to tall in open settings, and may reach over tall in closed canopy settings. This species normally has a single erect trunk, commonly without branches in the lower half of the tree, and a crown that can be wider than the tree is tall. Trunks may reach in diameter near the base of the tree. The leaf is approximately long, with 13–21 leaflets per leaf, each 2-5" long, with dentate margins. Unlike the Southern California walnut, the vein angles bear tufts of hair. The nut has a smooth, brown, thick shell, that contains a small edible nutmeat.

Allergenicity

Hind's Walnut (Juglans hindsii) is a severe allergen. Pollination: Occurs in following seasons depending on latitude and elevation: Spring.

Uses

Cultivation

''Juglans hindsii'' has been commercially important as a

rootstock A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to a ...

for orchard stock of ''Juglans regia'' (English walnut) trees all over the world. It is also used as a parent to the fast-growing Luther Burbank hybrid rootstock, commonly called "Paradox" (''Juglans hindsii'' x ''Juglans regia''). ;Ornamental tree The Northern California walnut is cultivated by specialty California native plant nurseries. It is used as an

ornamental tree Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

in traditional and

wildlife garden A wildlife garden (or wild garden) is an environment created by a gardener that serves as a sustainable haven for surrounding wildlife. Wildlife gardens contain a variety of habitats that cater to native and local plants, birds, amphibians, ...

s, and for

habitat garden A wildlife garden (or wild garden) is an environment created by a gardener that serves as a sustainable haven for surrounding wildlife. Wildlife gardens contain a variety of habitats that cater to native and local plants, birds, amphibians, rep ...

natural landscaping Natural landscaping, also called native gardening, is the use of native plants and adapted species, including trees, shrubs, groundcover, and grasses which are local to the geographic area of the garden. Benefits Maintenance Natural land ...

projects, and climate compatible drought tolerant gardens. The tree is also planted in

habitat restoration Restoration ecology is the scientific study supporting the practice of ecological restoration, which is the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human interrupt ...

projects.

Pests

''Juglans hindsii'' is infested by ''

Rhagoletis juglandis ''Rhagoletis juglandis'', also known as the walnut husk fly, is a species of tephritid or fruit fly in the family Tephritidae. It is closely related to the walnut husk maggot '' Rhagoletis suavis'' (Loew, 1862). This species of fly belongs to the ...

'', commonly known as the walnut husk fly, which lays its eggs in the husks of walnut fruit. ''R. juglandis'' infests other varieties of walnut trees as well, such as ''

Juglans regia ''Juglans regia'', the Persian walnut, English walnut, Carpathian walnut, Madeira walnut, or especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himala ...

'' (the English or Persian walnut), ''Juglans rupestris'' (a species of walnut indigenous to Arizona and Texas), and ''Juglans hindsii'' (the California black walnut).

Lumber

The wood of ''Juglans hindsii'' is commonly called claro walnut by the lumber industry and woodworkers. It is highly figured with a rich brown color and striking grain patterns, especially in the crotch areas, where large limbs meet the trunk. It is used in small quantities to make fine furniture and gun stocks, and sold as slabs to make large natural-top tables because of its durability, good working properties, and swirling iridescent figure. Some confusion exists about the nature of claro walnut because ''Juglans hindsii'' is commonly used as the rootstock of orchard trees. The section below the original graft is claro walnut wood, while the section above is the lighter-colored English walnut. Some woodworkers take advantage of this by making the color change a feature of their work.

Taxonomy

The current classification of the plant is as a distinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

. Some botanists and the 1993 edition of " The Jepson Manual" had classified it as ''Juglans californica'' subsp. ''hindsii'', a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all specie ...

of ''Juglans californica'' (Southern California black walnut).Calflora: "''Juglans californica'' var. ''hindsii'' is not an active name in the Calflora species table."
. accessed 10.1.2013

References

*"Some preliminary observations on the California black walnut (''Juglans californica'')" — Anderson, E. N.; ''Fremontia: A Journal of the California Native Plant Society''. January 2002.

External links

* *
Jepson Flora Project: ''Juglans hindsii''

Calflora Database: Juglans hindsii'' (Northern California black walnut)

Virginia Tech tree ID: Hind's black walnut (''Juglans hindsii'')

''Juglans hindsii'' — U.C. Photo gallery
{{Taxonbar, from=Q291739 hindsii Trees of the Southwestern United States Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Natural history of the Central Valley (California) Trees of Mediterranean climate Edible nuts and seeds Plants used in Native American cuisine Pre-Columbian California cuisine Garden plants of North America Drought-tolerant trees Ornamental trees Plants described in 1909