Acacia dealbata

Acacia dealbata Link (syn: Acacia affinis Sweet; Acacia dealbata subsp. dealbata ; Acacia decurrens var. dealbata (Link) Muller; Acacia decurrens var. dealbata (Link) Maiden; Acacia derwentii Siebert & Voss; Acacia puberula Dehnh.; Racosperma dealbatum (Link) Pedley);
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SE. Australia: New South Wales, Tasmania, Victoria; Introduced into: Albania, Amsterdam-St.Paul Is, Argentina Northeast, Assam, Azores, Brazil South, California, Canary Is., Cape Provinces, Chile Central, Chile South, China South-Central, China Southeast, Costa Rica, Desventurados Is., East Himalaya, Easter Is., Ecuador, Ethiopia, France, Free State, Guatemala, Haiti, India, Italy, Jamaica, Juan Fernández Is., KwaZulu-Natal, Lesotho, Madagascar, Madeira, Mauritius, Mozambique, Nepal, New Zealand North, New Zealand South, Norfolk Is., Northern Provinces, Palestine, Portugal, Romania, Réunion, Sardegna, South Australia, Spain, Sri Lanka, Swaziland, Taiwan, Tanzania, Transcaucasus, Uganda, Uruguay, West Himalaya, Yugoslavia, Zaïre, Zimbabwe as per POWO;

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tree for id, mm1 27012012: tall tree, binsar wildlife sanctuary near almora

saw these tall trees almost all the way down to haldwani which is where the mountains turn into plains

the bright yellow flowers were just beginning to bloom last week

wondering if this tree can be identified

may be Acacia decurrens

Many thanks … for reviewing it and … for taking the trouble to id it.
It is possible that this is Acacia decurrens but this is a Australian tree. The hills were covered with it all the way down to Haldwani. It appears to have spread like wildfire.

Three species which have been introduced in India are quite confusing, with differences as below as per Lucid Central:
Silver wattle (Acacia dealbata subsp. dealbata) may be confused with several other native wattles (Acacia spp.) including black wattle (Acacia mearnsii), Sydney green wattle (Acacia decurrens), green wattle (Acacia irrorata), northern silver wattle (Acacia leucoclada), Bodalla silver wattle (Acacia silvestris), dwarf silver wattle (Acacia nanodealbata), Cootamundra wattle (Acacia baileyana) and Karri wattle (Acacia pentadenia). These species can be distinguished by the following differences:

silver wattle (Acacia dealbata subsp. dealbata) has young branches and foliage tips that are finely hairy and whitish-green or whitish-yellow in colour (i.e. pruinose). Its silvery-grey leaves have numerous (10-30) pairs of hairy branchlets (i.e. pinnae). These leaves are shortly stalked (i.e. petiolate) and there is usually a small raised structure (i.e. gland) near the top of this leaf stalk (i.e. petiole). There are also similar glands at the junction of the each of the pairs of branchlets (i.e. jugary glands). The leaflets are relatively small (1.5-6 mm long) and usually quite elongated in shape. Its flowers are yellow or golden yellow and borne in small globular clusters, which are arranged into larger elongated compound clusters (i.e. racemes or panicles). The pods are relatively large (20-115 mm long and 6-14 mm wide).
black wattle (Acacia mearnsii) has young branches and foliage tips that are finely hairy and yellow or greenish-yellow in colour (i.e. not pruinose). Its dark green leaves have numerous (7-31) pairs of hairy branchlets (i.e. pinnae). These leaves are shortly stalked (i.e. petiolate) and there is usually a small raised structure (i.e. gland) near the top of this leaf stalk (i.e. petiole). There are also similar glands at the junction of the each of the pairs of branchlets (i.e. jugary glands), and also between some or all pairs of branchlets (i.e. interjugary glands). The leaflets are quite small (1-3.5 mm long) and usually not particularly elongated in shape. Its flowers are pale yellow or cream-coloured and borne in small globular clusters, which are arranged into larger elongated compound clusters (i.e. racemes or panicles). The pods are relatively large (30-150 mm long and 4-8 mm wide).
Sydney green wattle (Acacia decurrens) has young branches with conspicuous flanges and foliage tips that are mostly hairless and yellowish in colour (i.e. not pruinose). Its dark green leaves have several to numerous (3-13) pairs of hairless branchlets (i.e. pinnae). These leaves are shortly stalked (i.e. petiolate) and there is usually a small raised structure (i.e. gland) near the top of this leaf stalk (i.e. petiole). There are also similar glands at the junction of the each of the pairs of branchlets (i.e. jugary glands). The leaflets are quite large (5-15 mm long) and very narrow. Its flowers are yellow or golden yellow and borne in small globular clusters, which are arranged into larger elongated compound clusters (i.e. racemes or panicles). The pods are relatively large (20-105 mm long and 4-9 mm wide).