Abies homolepis var. homolepis

Pinaceae Abies homolepis var. homolepis Siebold & Zucc.

Etymology
Abies refers to ‘to rise’; indicating large trees.
homolepis refers to ‘similar scales’; indicating its bracts and scales have similar lengths.

Colloquial Name
Nikko fir

Description
These trees grow between 35 and 40 meters tall, with a trunk diameter of up to 1.5 meters. The trunk is straight and column-like, supporting a broad pyramidal crown that becomes flat-topped in older trees. The bark on young trees is smooth and has thin, papery flakes with a grayish color and pinkish tones, while older trees develop rough, dark gray-brown bark that breaks into plates.

The main branches are long and spread out horizontally, while smaller branches either spread outward or angle slightly upward. The twigs are sturdy and firm, with a glossy light yellowish-brown color. They have distinct ridges and deep grooves between the leaves and are smooth, with no visible hairs. The scars left by fallen leaves are circular or oval.

The buds that produce new growth are shaped like small cones, measuring 3 to 5 millimeters long and 2 to 4 millimeters wide. They are sticky with resin, and their protective scales are triangular, reddish brown, and have a noticeable central ridge. These scales remain on the tree for several years. The needles grow in a spiral pattern along the branches. On shaded branches, they may be arranged in two rows, while on cone-bearing shoots, they curve upward or backward, often forming a V-shape. They range from 1 to 3.5 centimeters long and 2 to 3.5 millimeters wide, with a slight twist or curve at the base. Their shape is long and narrow, flattened, and they have deep grooves on the glossy green upper surface. The underside has two pale white bands. The tips can be blunt or slightly notched. Stomata, which help control gas exchange, are arranged in two wide bands separated by a central ridge on the lower surface.

Pollen cones grow in clusters along the branches and hang downward. They are yellow and packed closely together. The seed cones are upright and often appear in groups. They are attached by short, scaly stalks about half a centimeter long. The cones are oblong and cylindrical, measuring 7 to 10 centimeters long and 2.5 to 3.5 centimeters wide. When young, they have a striking violet-blue color and gradually darken as they mature. Their tip is rounded rather than pointed. Once the seeds are released, the central cone axis remains on the tree as a narrow, blackish-brown cone-shaped structure.

The cone scales, which protect the seeds, are broad and fan-shaped, measuring 1.5 to 2 centimeters long and 2.5 to 3 centimeters wide at the middle of the cone. Their surface is smooth but has fine hairs and is often covered in sticky resin. The upper edges are slightly curved inward, and the base is attached by a small stalk. The bracts, which are small structures between the cone scales, are rectangular and about 1 centimeter long. They remain hidden within the cone.

The seeds are wedge-shaped, about 6 by 4 millimeters, and light brown. Each seed has a broad, wing-like extension to help with wind dispersal. The wings are also wedge-shaped, measuring about 10 by 8 millimeters, and have a yellowish-brown color.

Subordinate Taxa
There exist 2 subordinate taxa for Abies homolepis:

Distribution

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TDWG Codes
3, 38, JAP, JAP-HN, JAP-SH

Habitat
The natural habitats for Abies homolepis var. homolepis are temperate forests. It is naturally found at an elevation of at least 2000 up to 2000 metres. Other conifers associated with Abies homolepis var. homolepis are:

USDA Hardiness zone – 4
Abies homolepis var. homolepis is hardy to USDA Zone 4 (Bannister & Neuner, 2001), meaning its frost tolerance lies somewhere in the range of -34.4C (-30F) to 28.9C (-20F).

Species Continuity
The population trend for Abies homolepis var. homolepis is decreasing. There are no known threats for Abies homolepis var. homolepis.

IUCN Category – NT
According to the IUCN Red List, Abies homolepis var. homolepis has been assigned the status of NT(Near Threatened). This means that according to the Red List criteria, this species is not threatened, but is close to having this status.

Superordinate Taxa
The nearest superordinate taxon for Abies homolepis is Subsect. Homolepides. The coordinate taxa for Abies homolepis are therefore:

Abies homolepis var. homolepis is further placed under Abietoideae. Abies homolepis var. homolepis is also placed under Pinaceae.

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