Development of Roots and Shoots of Certain Deciduous Tree Seedlings in Different Forest Sites

摘要: This investigation deals with the activities of 5 species deciduous forest-tree seedlings. Each was grown in 3 habitats, including one which it naturally occurs. The study includes development both roots and tops during first years; measurements factors. environment; physiological responses plants terms transpiration, photosynthesis, growth. From I927 to I929, this work conducted oak-hickory forest fringing Missouri River at Peru, southeastern Nebraska. great amount labor involved excavation root systems trees has been principal deterrent such investigations. In mature trees, European workers have accomplished more than Americans. America, however, initial habit extensively studied. Nobbe experimented conifers Germany as early I875. He discovered striking differences various under similar conditions (cf. Jost, '07). During 50 years following Nobbe's work, isolated investigations, especially Russia, laid foundations for studies tree published since I925. An excellent resume investigators is given by Bfisgen MUnch ('29). Toumey ('28, '29), a result his extensive experiments Connecticut, concludes that American depends upon most cases not essentially modified external conditions. Pulling ('i8), working far north, found vary degree flexibility they exhibit change environmental Haasis ('2I), Arizona, soil type greatly modifies form Pinus ponderosa scopulorum. Wahlenberg ('29), Montana, investigated possibility modifying western yellow pine seed beds fertilizing different depths. Studies Fraxinus lanceolata, Acer negundo, A. saccharinumn, Gleditsia americana were made eastern Nebraska (Clements, Weaver, Hanson, '29). These period degrees competition. system each