Effects of irrigation on diameter growth and vertical resin duct production in Pinus sylvestris L.
Also, most coniferous tree species produce resin ducts as a reaction to environmental stress (Gartner, 2007; Schweingruber, 2007).
Tree vole nests were identified based on the presence of fecal pellets, resin ducts, debarked twigs, or fresh cuttings (Benson and Borell 1931; Clifton 1960; Maser 1966).
Tree voles in the Sitka Spruce Zone (Franklin and Dyrness 1973) of northwest Oregon feed primarily on Western Hemlock and Sitka Spruce, and the resin ducts in their nests differ from resin ducts in nests of tree voles that feed on Douglas-fir.
Instead, Mitchell is looking for evidence of their presence: rice-sized scat and resin ducts of fir needles, the rodent's primary food.
The evidence itself appears unremarkable: vole feces and the husk of fir needles known as resin ducts - the part of the needle left after a vole has devoured it, like a banana's peel, said McKenzie Ranger District wildlife biologist Shane Kamrath.
Weigand, who studied conifer resin ducts
, traumatic gum formation in Prunus, and the properties of commercially obtained resins, strongly promoted the resorption concept in a series of publications and claimed that wherever resinous material is found, cells had been reabsorbed (Frank, 1868; Tschirch & Stock, 1933).
Ground below the nest was searched for the presence of resin ducts
and nest material.
The wide sapwood is pale yellow and the heartwood ranges from deep yellow to reddish-brown; brown lines in the cut wood are caused by resin ducts
. Mature trees yield a honey-colored wood uniform in texture and are non-resinous.