油桐因樹似梧桐 、種子可榨油（稱桐油）而得名。樹高4～10米。小枝粗壯，無毛。單葉互生，心臟形或闊卵形，全緣，葉柄圓形，頂端與葉片連接處有2個紫色腺體。單性花，雌雄同株，間有異株，白色，基部有淡紅色斑紋。核果球形或扁球形，果皮光滑。中國產(chǎn)的另一種木油桐樹形高大，外果皮有3～4縱棱，并有許多皺紋。有時油桐是這兩種的泛指。 世界上種植的油桐有6種，以原產(chǎn)中國的三年桐和千年桐最為普遍。油桐屬大戟科，落葉喬木。三年桐學(xué)名油桐，長得快，結(jié)果早，產(chǎn)量高，盛果期可達(dá)20 年～30年。千年桐學(xué)名木油桐，因果皮有皺紋，又稱龜背桐，寓意長命百歲。千年桐比三年桐高大，有10多米，樹齡較長。油桐種子榨出的油叫桐油；木油桐種子榨出的油叫木油，質(zhì)量稍遜。
      
    油桐喜光 。喜溫暖 ，忌嚴(yán)寒 。冬季短暫的低溫(－8～－10℃)有利于油桐發(fā)育 ，但長期處在－10℃以下會引起凍害。適生于緩坡及向陽谷地，盆地及河床兩岸臺地。富含腐殖質(zhì)、土層深厚、排水良好、中性至微酸性沙質(zhì)壤土最適油桐生長。油桐栽培方式有桐農(nóng)間作、營造純林、零星種植和林桐間作等。
      
    桐油是重要工業(yè)用油，制造油漆和涂料，經(jīng)濟價值特高。桐油和木油色澤金黃或棕黃，都是優(yōu)良的干性油，有光澤，不能食用，具有不透水、不透氣、不傳電、抗酸堿、防腐蝕、耐冷熱等特點。


 

Tung Oil Tree

    Tung oil tree gets this name for it's similar with Chinese parasol tree and its seeds can be used to make oil. It height varies from 4 m to 10 m with thick and solid branches and no hair. Its flowers are in the same sex and white color commonly. Tung oil tree likes light, warmth and hates cold climate. Short time low temperature (above subzero 10) in winter will be helpful for its growing, while if the temperature reaches below subzero 10, it will be hurt. Slight slope and sunny valley, basin and shores of rivers are appropriate for its growing, which had better be full of humus, normal to acidic sandy loam, and have thick soil and good dewatering quality. It cultivating methods are trees and crops intercropping agriculture, only planting trees, planting sporadicly, forest and trees interplanting and so on. Tung oil it produces is an important industrial oil which can be used to make paint and coating and contains much high economic values.