Characterization of four pioneering species from a tropical forest in the Pindorama Biological Reserve, Sao Paulo State, Brazil based on soil and Phytosociological attibutes

摘要

This work had the objective to characterize populations of pioneering tree species of the Biological Reserve of Pindorama, SP, Brazil, based on the physical and chemical attributes of the soil. For this, 65 parcels of 400 m~2 had been demarcated in two toposequences located in remainders of a Seasonal Semi-deciduous Forest. In each parcel the degree of infestation of weed species was evaluated. Inside of each parcel was drafted a subunit of 10 x 10 m (100 m~2), where the physical and chemical attributes of the soil had been evaluated, the altitude, the basal area, the height, the number of individuals of the trees species with diameter at breast height (DAP) equal or superior than 5 cm .The species diversity was calculated with the Index of Shannon(H') and with the Index of Equability of Pielou (J) of the trees species community of each top sequence. It was also calculated the Similarity Index of Jaccard (ISJ) between the two remainders. The characterization was made by sampling parcels considering pioneering species that presented six or more individuals in at least one of the remainders evaluated: Aloysia virgata Ruiz & Pav. A. L. Juss., Acacia polyphylla DC, Croton floribundus Spreng and Casearia Sylvestris Sw. The hierarchic grouping analysisby the Ward method made possible a division of the physical and chemical attributes of the ground in five groups of parcels. For each group the average values of each characteristic had been determined, as well as recalculated the index of diversity ofspecies and equability of the tree species that allowed a characterization of the pioneering species for groups. The evaluated species were responsive to different soils and phytosociological attributes. Croton floribundus occurred in sandy soil parcelsand with lower fertility, Acacia polyphylla and Aloysia virgata occurred in soils of higher altitudes. The soils with higher clay percentage and of natural good fertility had greater infestation of weeds such as lianas, bamboo and other grassy and lowerdiversity of tree species. The infestation of the parcels by weeds affected the basal area and height of the evaluated species. In these parcels it was observed that the pioneering species had reduced basal area and height.