Picea engelmannii

Picea engelmannii

The Engelmann spruce or  white spruce, mountain spruce, silver spruce (Picea engelmannii Parry ex Engelm., 1863) is an arboreal species belonging to the Pinaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Pinophyta division,
Class Pinopsida,
Pinales Order,
Pinaceae family,
Genus Picea,
P. engelmannii species
The terms are synonyms:
– Abies engelmannii (Engelm.) Engelm.;
– Abies engelmannii var. glauca R.Sm.;
– Picea engelmannii Parry;
– Picea engelmannii f. argentea Beissn.;
– Picea engelmannii f. engelmannii;
– Picea engelmannii f. glauca (R.Sm.) Beissn.;
– Picea engelmannii f. microphylla Hesse;
– Picea engelmannii f. microphylla Hesse ex Beissn.;
– Picea engelmannii f. pendula Schelle;
– Picea engelmannii var. mexicana R.J.Taylor & T.F.Patt.;
– Picea engelmannii var. typica Goodman.

Etymology –
The term picea is the Latin name of the wild pine in Virgil and Pliny.
The specific epithet engelmanni was assigned by W.E.Parry in honor of the German-American botanist George Engelmann, who shortly after managed to publish the description of the new species before him.

Geographic Distribution and Habitat –
Picea engelmannii is a conifer native to North America, where it is present in an area that includes: British Columbia and Alberta, in Canada, Arizona, Idaho, Texas, Utah, Montana, Nevada, New Mexico, California, Wyoming, Washington, Oregon and Colorado in the United States of America and Chihuahua and Nuevo León in Mexico.
Its habitat is that of a cold and humid climate, with annual rainfall of no less than 600 mm, characterized by long, snowy winters and cool summers. It grows up to an altitude of 3700 m, with the upper limit gradually rising from north to south, preferring both calcareous and non-calcareous soils.
In this area it forms extensive pure or mixed forests with Abies lasiocarpa, Pseudotsuga menziesii, Larix occidentalis, Picea laxa and species of the genus Pinus. The subpopulations of Mexico are confined to the highest elevations, on the northern slopes of steep slopes.
At the lowest altitude, it is a riparian tree with associates such as Abies grandis, Pseudotsuga menziesii, Larix occidentalis, Populus balsamifera subsp. trichocarpa and Populus tremuloides. It may be that its ability to grow at these low elevations is due to cold air drainage, as it is typically only found at these sites in narrow valleys near high mountains.

Description –
The Picea engelmannii is a tree that can reach 40-45 in height with a single straight trunk that can reach 1-1.5 m. in circumference, with a narrow, conical, or columnar crown, especially in individuals growing on the northern slopes at high altitudes.
The bark is initially smooth, reddish-brown in color, then over time becomes gray with light brown spots, rough and grooved.
The branches of the first order are short and slender, developed horizontally, with the terminal part facing upwards, the lower ones more hanging. The branches of the second order, also short, are drooping.
The shoots are initially solid, then drooping, first greenish-yellow, then yellowish-brown, grooved; when young they have a fine hair.
The leaves are needle-like, with a glaucous green color, up to 3 cm long, linear, straight or slightly curved, with acute tips that do not prick; these have stomata on both sides (two narrow bands with 2-3 lines on the upper one, 2 bands of 4-6 lines on the lower one).
The vegetative buds are ovoid-conical, 5-6 mm long, resinous at the tip; they have triangular, obtuse, red-brown pearls, dormant for years.
The male cones are yellowish, produced in the axillary position and 1-1.5 cm long.
The female cones are sessile, ovoid-cylindrical in shape, initially erect, then drooping when ripe, 3-6 cm long and 2-2,5 cm broad, initially of green color tinged with red, then reddish-brown or yellowish-brown . Macrosporophylls are thin and flexible, with a smooth or finely striated abaxial surface. The bracts are largely ovate, with a cusp, 3-6 mm long, totally hidden. The yellowish brown seeds are ovoid and 2-3 mm long.

Cultivation –
Picea engelmannii is a plant of economic importance due to its wood, being light and quite resistant.
It is generally exploited for papermaking and construction.
This conifer is native primarily in the Rocky Mountains and eastern slopes of the Cascade range, from central British Columbia to southern Oregon in the Cascades and commonly in Montana, Idaho and Colorado, and more sparsely to Arizona and New Mexico in the Sky Islands; in addition, there are also two isolated populations in northern Mexico.
For its growth it prefers areas at high altitudes, where in many areas it reaches the limit of the arboreal vegetation, but at lower altitudes it occupies canyons with fresh waters.
Both water uptake and root-stored water appear to be critical to the survival of saplings of this conifer that are exposed above the snowpack in late winter to early spring.
Transpiration is greatly reduced in small saplings while they are covered in snow. For exposed trees, soil water availability can be critical in late winter when transpiration increases.
Increased transpiration rates in response to snow loss, together with low water reserves in the sapwood, and a prolonged period of soil freezing in windswept areas, may prevent this spruce from regenerating in open areas both above than below the treeline. Cuticular damage from windblown ice is probably most important at the tree line, but damage from desiccation is probably most important at lower elevations.
Despite wind damage, the species tends to grow taller than others at the tree line. It is shade tolerant therefore somewhat reliant on fire to outrun competitors, although its thin bark and shallow roots also make it vulnerable to fire.
It is also susceptible to avalanches.
From the pedological point of view it has a wide adaptability, managing to grow both in calcareous and non-calcareous soils.
The plant reproduces by seed.

Customs and Traditions –
Picea engelmannii is a plant which, in addition to the wood, was already known by the Native Americans who obtained various medicines from the resin and the foliage.
This conifer is of great economic importance for the exploitation of its wood; although it is gnarled and of not very high quality, it is used more and more frequently in construction, for the manufacture of musical instruments, such as violins and pianos, while its use as mining timber, sleepers for railway lines and telephone poles, is in sharp decline . Currently, most of the timber obtained is used in the paper industry, particularly in western Canada. As an ornamental species it is not very common, and there are few cultivars on the market, also because the use of spruces as Christmas trees is not widespread in North America.
Also, as it is odorless and has little resin, it has been used for food containers such as barrels.
Ecologically, although older Picea engelmannii forests are not very useful to animals for forage, they are after fires, which allow many other plants to grow. The streams shaded by this conifer are exploited by trout. Additionally, aphids produce galls that hang from the tree and look similar to cones when dried.
As regards its state of conservation, being one of the most common conifers, and with a very vast range, in the North American continent, it is classified as a minimum risk species in the IUCN Red List.

Method of Preparation –
Picea engelmannii is a plant that was used by Native Americans as a source of medicines obtained from resin and foliage.
The current use is above all for its timber while, to a small extent, as an ornamental plant or Christmas tree.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
https://inaturalist-open-data.s3.amazonaws.com/photos/216893557/original.jpg

Attention: The pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not in any way represent a medical prescription; we therefore decline all responsibility for their use for curative, aesthetic or food purposes.