Agroforestree Database

Local names:
 Dutch (Amerikaanse Populier), English (necklace poplar,Caroline poplar,cottonwood,eastern poplar,plains cottonwood,eastern cottonwood), French (peuplier noir d'Amérique,peuplier de Virginie), German (ostamerikanische Pappel,Texaspappel,Rosenkranzpappel),

Populus deltoides is a medium-sized to large tree, 20-30 (max. 50) m tall, 100 cm dbh; bark greyish-green and smooth at first, later blackish and furrowed; trunk short and massive in the open, often divided into a few large, wide-spreading limbs near the ground to form a broad, irregular-shaped, open crown. In the forest, the trunk is long, straight, with a small, rounded crown; root system usually shallow, wide spreading, may be deep in deep soils. It is one of the fastest growing trees, often planted where fast growth is the main requirement.

Leaves broadly deltoid, 8-15 cm long and nearly as broad, glabrous on both sides, short-acuminate, dentate, with incurved glandular or callous-tipped teeth; bases truncate to subcordate, with 2-3 basal glands; petiole strongly flattened laterally. 

Bracts of catkins fringed or fimbriate, the divisions narrow; staminate aments 7.5-12.5 cm long, thick; stamens about 60 or more; anthers red; pistillate aments green and slender; ovaries glabrous; stigmas 3 or 4. 

Mature seed catkins 15-25 cm long; stalk hairless; capsules ovoid, 6-10 mm long, glabrous, green, splitting into 3-4 parts when mature; peduncle 3-10 mm long; seeds cottony.

The generic name is the classical Latin name for poplars, possibly from ‘paipallo’ (vibrate or shake) or originating in ancient times when the poplar was called ‘arbor populi’ (the tree of the people), because in Rome it was used to decorate public places. The specific name means ‘triangular’, referring to the shape of the leaves, from the Greek letter delta and ‘oides’ (resembling).

Ecology

P. deltoides tolerates frost, heavy soil, sand, slope, and waterlogging. Because of its intolerance to competition and the absence of suitable seedbeds under existing stands, it does not usually succeed itself. It is estimated to range in forest life zones from warm temperate dry to moist through cold temperate dry to moist.

Native range
Canada, United States of America

Tree management

Annual productivity in P. deltoides ranges from 3 to 22 t/ha. Fast-growing trees in Sweden, harvested young, have given biomass yields of 14-28 t/ha. The maximum possible production of fast-growing P. deltoides, with optimum fertilization and moisture, is 44 t/ha in the Netherlands, but normal production levels are closer to 6 t/ha.

Seeds are microbiotic. However, with proper drying and cold storage in sealed containers, their viability can be maintained for several years. Seed storage behaviour is orthodox; 50-70% germination following 2 years of hermetic air-dry storage at 2-5 deg. C; 21% viability lost after 6 years of hermetic storage at -20 deg. C with 6-10% mc; 24-100% viability lost after 10 years hermetic storage at -18 deg. C with 8.4-13.5% mc.

P. deltoides tolerates frost, heavy soil, sand, slope, and waterlogging. Because of its intolerance to competition and the absence of suitable seedbeds under existing stands, it does not usually succeed itself. It is estimated to range in forest life zones from warm temperate dry to moist through cold temperate dry to moist.

Natural seed regeneration can be obtained on moist sites with exacting site preparation. Seed should not be covered or pressed into the soil of the seedbed. Young seedlings are very susceptible to drying out, and the seedbed must be kept water saturated for germination and at least 1 month thereafter. Plant about 300 seeds per 100 sq cm by broadcasting, and 30 seeds per 100 sq cm by drilling. About 4 weeks after germination, beds should be thinned to 20 plants per 100 sq cm. Nursery beds are often fumigated with methyl bromide to help control damping off. Finely divided sphagnum moss is a good medium for culturing P. deltoides seedlings in the greenhouse.

P. deltoides has been used extensively as a fodder species for sheep, goats and other livestock.

Wood is used for fuel.

Fibre:  A good fibre and pulp is obtainable from P. deltoides. 

Timber:  The timber is used principally for lumber, veneer, pulpwood and excelsior.

Shade or shelter:  In India during the summer months it works as a windbreak and saves the crop from scorching winds. It is popularly used as a shelterbelt species. 

Tannin/dyestuff:  Salicylic acid, derivable from this species, is now synthesized. In its technical form, it is used as a coupling agent in dye intermediates, in the foundry industry as a curing agent in the production of shell moulding compounds, as an agent for retarding the vulcanization process in rubber, as a preservative for glues and leather goods, and in alkyl and alkyd resins and latex paints.

Medicine:  The bark is used to treat rheumatism, gout and scurvy and infections of the chest, kidneys and stomach; the buds are used as a vulnerary and pectoral. In Europe, the fresh flowers are steeped in cold water to purify blood. Used as a cancer remedy by native Americans, who also used the buds in many ways, for example, stewed in bear fat for earache, bronchitis or cough, or cooked in tallow to make an ointment for eczema, myalgia and sores, or in poultices for hip or lung pain, colds and respiratory problems. Rotten leaves are a herbal bath for general body pain; chewed root is applied as a haemostat. Bark is for heart ailments, sprains and strains, and the root for backache, female ailments such as metrorrhagia and weakness.

Ornamental:  Widely used in the USA and Canada for amenity plantings

Trees planted in and around the edges of fields are regularly ploughed and planted with agricultural crops and hence develop vigorous roots, attain great height and diameter, and produce a high quantity of timber.

Soil improver:  P. deltoides produces a large quantity of leaves. The nitrogen contribution to the soil could be as much as 43 kg in 3 years and 102 kg in 11 years. Improvements in soil structure and chemical properties under P. deltoides are also possible. 

Intercropping:  Soya beans, sugarcane, wheat, maize, potatoes, mustard, lentils, fodder crops and aromatic herbs such as lemon grass are all commonly intercropped with P. deltoides.