Pamphlets on Forestry, Volume 4

abundant acidity activity aggregate amount appear areas average bark base basin bast fibers become bog plants branches cambium canals Castanopsis cells closely compared complete conifers contain covered crystals cutting deposits depressions diameter distribution drained effect evidence extending fact factors favorable foliar ray forest formation glacial growth important increase June lake lateral layers leaves less lower marked material mature Michigan middle natural nearly normal noted observations occur origin parenchyma peat period pine Pinus pith plants plates present produced Quercus reduction region relation resin ring River roots rows Salix sapwood scattered shoot shown shrubs side societies soil species sphagnum stem structure substratum surface swamp TABLE tamarack temperature thick throughout tissue trees trunk tyloses undrained usually vegetation vessels walls whorl wood xylem young zone