Tree poplar

Phytodegradation Soils, groundwater, landfill leachate, land application of wastewater Herbicides (atrazine, alachlor) Aromatics (BTEX) Chlorinated aliphatics (TCE) Nutrients (NO, NH4+, PO3) Ammunition wastes (TNT, RDX) Phreatophyte trees (poplar, willow, cottonwood, aspen) Grasses (rye, Bermuda, sorghum, fescue) Legumes (clover, alfalfa, cowpeas)... 

Mature phreatophyte trees (poplar, willow, cottonwood, aspen, ash, alder, eucalyptus, mesquite, bald cypress, birch, and river cedar) typically can transpire 3700 to 6167 m3 (3 to 5 acre-ft) of water per year. This is equivalent to about 2 to 3.8m3 (600 to 1000 gal) of water per tree per year for a mature species planted at a density of 600 trees per hectare (1500 trees per acre). Transpiration rates in the first two years would be somewhat less, about 0.75 m3 per tree per year (200 gal per tree per year), and hardwood trees would transpire about half the water of a phreatophyte. Two meters of water per year is a practical maximum for transpiration in a system with complete canopy coverage (a theoretical maximum would be 4 m/yr based on the solar energy supplied at latitude 40°N on a clear day). 

Groundwater. One approach to minimizing the environmental impact of excess nitrogen in groundwater migrating into rivers and aquifers is to intercept the water with rapidly growing trees, such as poplars, that will use the contaminant as a fertilizer. 

Sahcyl alcohol [90-01-7] (saligenin, o-hydroxybenzyl alcohol) crystallizes from water in the form of needles or white rhombic crystals. It occurs in nature as the bitter glycoside, saUcin [138-52-3] which is isolated from the bark of Salix helix S. pentandra S. praecos some other species of willow trees, and the bark of a number of species of poplar trees such as Folpulus balsamifera P. candicans and P. nigra. 

No drugs have been a more faithful companion to man throughout his history than salicylates, the forebears of aspirin. About 3,500 years ago the Ebers Papyrus recommended the application of a decoction of leaves of myrtle to the abdomen and back to get rid of rheumatic pains. Hippocrates championed the juices of the poplar tree and willow bark to treat fever and labor pains. These plants and trees are abimdant in compounds derived from salicylic acid, which gets its name from them (in Latin salix is a willow tree). For thousands of years on all continents they have helped to... 

Burken JG, JL Schnoor (1997) Uptake and metabolism of atrazine by poplar trees. Environ Sci Technol 31 1399-1406. 

Taghavi S, T Barac, B Greenberg, B Borremans, J Vangronsveld, D van der Lelie (2005) Horizontal gene transfer to endogenous endophytic bacteria from poplar trees improves phytoremediation of toluene. Appl Environ Microbiol 71 8500-8505. 

Thompson PL, LA Ramer, JL Schnoor (1998) Uptake and transformation of TNT by hybrid poplar trees. Environ Sci Technol 32 975-980. 

Widdowson MA, S Shearer, RK Andersen, IT Novak (2005) Remediation of polycyclic aromatic hydrocarbon compounds in groundwater using poplar trees. Environ Sci Technol 39 1598-1605. 

Orchard BJ, WJ Doucette, JK Chard, B Bugbee (2000) Uptake of trichloroethylene by hybrid poplar trees grown hydroponically in flow-through plant growth chambers. Environ Toxicol Chem 19 895-903. 

Most of the TCE that is taken up by the poplars is expected to volatilize slowly to the atmosphere. A portion will be metabolized by the leaves and woody tissue of the trees. 

From the 323 MTBE treatment profiles, eight projects were identified where MTBE was treated using phytoremediation. These projects used various approaches, including hybrid poplar trees, Monterey pine, oak, eucalyptus, and engineered wetlands. 

Preston, G.M. and McBride, R.A., Assessing the use of poplar tree systems as a landfill evapotranspira-tion barrier with the SHAW model, Waste Management and Research, 22 (4), 291-305, 2004. 

Most wood can be classified into two broad categories, hardwood and softwood, terms that distinguish between the nature of the trees rather than between the properties in wood. The term hardwood, for example, refers to the wood of deciduous, broad-leaved trees such as birch, oak, and poplar, from the temperate and tropical regions of the world. Softwood, on the other hand, is used to refer to the wood of coniferous trees, needleleaved, evergreen trees such as fir, hemlock, and pine, which grow mainly in temperate and cold regions (see Table 71). The terms hardwood and... 

However, some plants can accumulate more than 0.1% of Pb, Co, Cr, and more than 1% of Mn, Ni and Zn in the shoots. These accumulator plants are called hyperaccumulators. To date, there are approximately 400 known metal hyperaccumulator plants in the world (Baker and Walker, 1989). Thlaspi caerulescens, Alyssum murale, A. lesbiacum, A. tenium are Zn and Cd hyperaccumulators. Brassica juncea, a high-biomass plant, can accumulate Pb, Cr(III), Cd, Cu, Ni, Zn, Sr, B and Se. Thlaspi caerulescens accumulates Ni. Hybrid poplar trees are reported to phytoremediate Cd and As contaminated soils. A Chinese brake fem, Pteris vittata, is an As hyperaccumulator (Ma et al., 2001). 

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