As its name implies, the caucasian fir (Abies nordmanniana) is native to the Caucasus Mountains spanning Europe and Asia. This cold weather lover typically grows to about 15 m tall (and can reach 61 m), but much younger specimens are often grown and taken home as Christmas trees.
I. Appearance and Characteristics
Abies nordmanniana, the Nordmann fir or Caucasian fir, is a fir indigenous to the mountains south and east of the Black Sea, in Turkey, Georgia and the Russian Caucasus. It occurs at altitudes of 900–2,200 m on mountains with precipitation of over 1,000 mm.
The current distribution of the Nordmann fir is associated with the forest refugia that existed during the Ice Age at the eastern and southern Black Sea coast. In spite of the currently suitable climate, the species is not found in areas of the Eastern Greater Caucasus, which are separated from the Black Sea Coast by more than 400–500 km.
The species is named by Christian von Steven after his compatriot, the Finnish zoologist Alexander von Nordmann (1803–1866), who was the director of the Odessa Botanical Gardens.
It is a large evergreen coniferous tree growing to 55–61 m tall and with a trunk diameter of up to 2 m. In the Western Caucasus Reserve, some specimens have been reported to be 78 m (256 ft) and even 85 m (279 ft) tall, the tallest trees in the Caucasus, Anatolia, the Russian Federation and the continent of Europe.
The leaves are needle-like, flattened, 1.8–3.5 cm long and 2 mm wide by 0.5 mm thick, glossy dark green above, and with two blue-white bands of stomata below. The tip of the leaf is usually blunt, often slightly notched at the tip, but can be pointed, particularly on strong-growing shoots on young trees. The cones are 10–20 cm long and 4–5 cm broad, with about 150–200 scales, each scale with an exerted bract and two winged seeds; they disintegrate when mature to release the seeds.
II. How to Grow and Care
Sunlight
The caucasian fir does well in many different light conditions, from full sun to partial shade, although a minimum of four hours of sunlight a day is preferable. This tree enjoys direct sunlight unless temperatures are too high – this is because the caucasian fir prefers a cooler climate.
Ideally, avoid placing your caucasian fir in full shade because this could affect its rate of growth. Mature trees will cope with full shade a little better, and there are some variants that prefer this environment, but this is usually not recommended for optimal growth.
Temperature
Native to North and Central America, Europe and Asia, the caucasian fir prefers summer temperatures to be between 18 ℃ and 21 ℃. If temperatures rise and stay above 27 ℃ for too long, the tree will suffer. Conversely, if the temperature drops below -20 ℃ for an extended period in the winter, the tree may struggle to survive. The caucasian fir is best suited to mountain regions where it mostly grows in the wild, meaning that it can be a challenging tree to keep healthy in the Southern Hemisphere, unless it is at a high elevation.
Watering
Water more regularly in the summer, as the caucasian fir requires moist soil; this is particularly important in the first two years after planting. Though frequency will depend on your climate, a good rule of thumb is to water twice a week during the summer months. However, allow the top layer of soil to slightly dry out between waterings to ensure that your tree does not become waterlogged. Watering once a week during spring and fall should be sufficient, but be mindful of both your climate and the level of moisture in the soil. Cease watering when it rains and do not water in the winter.
Soil
The optimum soil for your caucasian fir would be a sand or loam soil that is well-draining, with a pH value of 6-6.5 (so slightly acidic). While the soil should stay moist and not dry out for long periods, try to avoid clay soil – this compacts easily and does not drain well, resulting in your caucasian fir becoming waterlogged.
Fertilizing
It is not always necessary to fertilize your caucasian fir – if your soil is rich in nutrients, you won’t need to fertilize your tree at all. Otherwise, apply a mulch to your caucasian fir in either the spring or early summer to aid your tree’s growth and help the soil to retain more moisture as the weather gets warmer. You may also choose to sprinkle a granular, slow-acting fertilizer on the soil under the foliage at the beginning of fall. Use sparingly and make sure that it does not come into contact with the trunk or foliage.
Planting Instructions
Depending on the variety, the caucasian fir can reach up to 100 m in height, with its foliage extending to around 10 m. The trunk can grow to a diameter of 4 m, so it is essential to give your trees enough space when planting – keep them about 20 m apart.
plant your caucasian fir in late fall or winter, once the tree is dormant. Choose a day when the ground is not too waterlogged or frozen and plant in an area that is sheltered from the wind, with fertile, well-draining soil.
Dig a hole that is slightly wider than the root ball and just deep enough to cover the roots, before filling the hole with soil and watering generously. If there is a risk of high winds, you may wish to stake your caucasian fir to reduce the risk of the tree getting blown over. Finally, spread a 8 cm thick layer of mulch around the base of the tree, around a 51 cm radius, to promote healthy growth. Leave a small gap of 8 to 13 cm around the trunk to allow for some water to evaporate.
Keep the soil quite moist for the first few weeks after planting to help your caucasian fir become established.
Pruning
The caucasian fir is a very low maintenance tree and requires little pruning. Other than for aesthetic purposes, the primary need for pruning is to remove dead, damaged, or diseased branches. The best time to prune is in late winter or early spring, just as the tree comes out of its dormant state – this can encourage new growth.
When pruning, focus on removing branches that are growing at a strange angle and rubbing against other branches, as this friction can become an entry point for disease. This is best done in a period of dry weather, but if this isn’t going to be possible for a while, it is best to deal with the problem a little sooner, regardless of the weather. Once you have removed problem branches, burn them instead of placing them in a compost bin, as this can spread potential diseases.
Propagation
The easiest and most common way of propagating the caucasian fir is with cuttings, either from softwood or hardwood. Take softwood cuttings in late spring and hardwood cuttings in late fall when the tree has entered dormancy. Though softwood cuttings do tend to root quicker than hardwood (3-4 weeks instead of 4-6 months), they are more tender and will need a lot more monitoring to ensure they do not dry out.
Transplanting
The perfect time to transplant caucasian fir is during late winter to early spring (S4-S5). This period is ideal as the plant is dormant, ensuring minimal transplant shock. Location wise, caucasian fir prefers well-drained, cool, shady conditions. If possible, mulch after transplanting to retain soil moisture.
III. Uses and Benefits
The Nordmann fir is one of the most important species grown for Christmas trees, being favored for its attractive foliage, with needles that are not sharp and do not drop readily when the tree dries out.
It is also a popular ornamental tree in parks and large gardens, and along with the cultivar ‘Golden Spreader’ has gained the Royal Horticultural Society’s Award of Garden Merit.
In Europe, the tree has also been used for reforestation as a way to mitigate expected forest decline caused by climate changes.
The wood is soft and white, and is used for general construction, paper,…
