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Unformatted text preview: Pine wood: transverse section radial section tangential section Growth Rings The cambium layers in woody secondary growth plants of temperate biomes have seasonal dormancy. Growth is most active in spring and tapers in summer, ceasing in fall. Spring (or early) wood typically has larger vessels that are more porous and fewer, smaller rays. Summer (or late) wood is comprised of denser, smaller cells with thicker walls. The first cells of the next seasons spring wood form are produced next to the smallest summer wood cells of the previous year. Annual growth rings are the result of the alternating pattern of spring and summer wood. Vessel size in spring and summer wood Section of Bristlecone Pine Wood 4240 4210 BC...
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- Fall '09