The responses of shoot growth of Eucalyptus species to concentration and frequency of exposure to nitrogen oxides
Murray, F., Monk, R. and Walker, C.D. (1994) The responses of shoot growth of Eucalyptus species to concentration and frequency of exposure to nitrogen oxides. Forest Ecology and Management, 64 (1). pp. 83-95.
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To manage forests in areas with high concentrations of nitrogen oxides in the air, it is important to know the concentrations and frequencies of exposure which produce responses in trees. Four Eucalyptus species (E. microcorys F. Muell., E. globulus Labill., E. pilularis Smith and E. marginata Don ex Smith) were exposed to a range of nitrogen oxides concentrations (<5, 25, 50, 91 and 187 nl 1−1) at fixed frequency (2 h day−1, three times per week), and to fixed concentration (about 100 nl l−1), but variable frequency (never, once only, once per month, once per week and three times per week) for 169 days. The responses of growth to these treatments were determined using open-top chambers with plants grown directly in the soil.
Generally, increasing frequency or concentration of nitrogen oxide fumigations had effects of similar magnitude. The effects of nitrogen oxides on growth were consistent with bivariant response models having constants which varied between species. Eucalyptus microcorys grew taller and heavier with increasing exposure, with a significant response in the ascending and plateau regions of the curve. Eucalyptus globulus and E. pilularis grew taller and heavier at low exposures but this effect reversed at higher exposures. The response encompassed the ascending, plateau and descending regions of the curve. The height and weight of E. marginata were not statistically significantly affected by nitrogen oxides fumigation, although the response curve suggested a similar response, but with smaller ascending and narrower plateau regions of the curve than the other species.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Biological and Environmental Sciences|
|Copyright:||© 1994 Elsevier B.V.|
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