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›› 1964, Vol. 9 ›› Issue (1): 32-44.

• 论文及研究报告 • Previous Articles     Next Articles

A METHOD OF ECOLOGICAL STUDY OF POPLARS GROWING AS SCATTERED TREES ON THE LEVELLAND

Yang Hanxi,Song Zhaoshu,Fang Qi,Li Yiquan,Deng Mingquan   

  1. Institute of Forest Science, Academy of Forest Science
  • Received:1900-01-01 Revised:1900-01-01 Online:1965-10-01 Published:1965-10-01

Abstract: Methods of soil and vegetation survey generally used for forest trees in mountainous areas are considered inapplicable to poplars growing as scattered trees on the levelland. In the present paper, therefore, a method catering for this purpose together with the result of its application to poplar sheltabelts in East Honan is presented. In soil survey, besides detailed profile descriptions, field determinations of important soil properties, including water permeability, volume weight, moisture content, texture, ground water table and composition, thickness and depth of clay layer, pH value, available N and available P have been obtained. All the data are later annalysed and interpreted from two rather different but complementary approaches. On the first hand, by the calculation of correlation coefficient, correlation between height growth of Populus pyramidalis and ground water tables is found to be significant (r=0.458 P<0.05), and correlation between height growth of this species and volume weight of soil at root-concentrating horizon highly significant (r=0.804 P<0.01). But correlation coefficient between height growth of the same species and all other studied soil properties fall below the significant leyel generally adapted i.e. 5% level. Secondly, on the comparative study of field determinations of soil properties and height measurements of this species, ground water tables with reference to tree heights are divided into 3 classes, soil textures 4 classes, pH values (at root-concentrating horizon) 3 classes, and volume weights 3 classes respectively. In vegetation survey, qualitative investigations are carried out following the ZurichMontpellier School's procedures with but a few modifications, and total estimation, sociability, aspect, life form, root system and plant height are recorded. Also, point quadrat method is employed to collect quantitative data such as cover and frequency. Populetum pyramidalise association is classified into two subassociation:P. Pyr. Imperata cylindrica subassociation and P. Pyr. Imperata cylindrica var. major subassociation respectively. The latter is further classified into Lactuca variant and typical variant. To the above-mentioned plant community units and their respective differential species, a weighted mean of the class value with respect to each soil property is calculated separately. On this basis their indicating values to the growth of the tree are interpreted. Meanwhile, quantitative criteria of soil properties and a list of plant indicators (including individual species and community units) for the choice of planting sites of Populus pyramidalis in the studied area are given. Lastly, merits and demerits of the present method are discussed.