Ciência Florestal (Mar 2014)

CHANGES IN HORIZONTAL STRUCTURE, IN THE PERIOD 2002-2008, IN A MIXED RAIN FOREST IN CENTRAL SOUTHERN PARANA STATE, BRAZIL

  • Alex Roberto Sawczuk,
  • Afonso Figueiredo Filho,
  • Andrea Nogueira Dias,
  • Luciano Farinha Watzlawick,
  • Thiago Floriani Stepka

DOI
https://doi.org/10.5902/1980509813332
Journal volume & issue
Vol. 24, no. 1
pp. 149 – 160

Abstract

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http://dx.doi.org/10.5902/1980509813332Changes in the horizontal structure of a fragment of Mixed Rain Forest, located at Irati National Forest, in Parana state, were evaluated by measurements performed during the years 2002, 2005 and 2008. The study area has 25 ha, divided into 25 permanent sample plots of 1 ha (100 m x 100 m) each. All trees with diameter at 1,30 m above the ground equal or higher 10 cm were measured and identified. Density, dominance, frequency, importance value and cover value were analyzed and, to understand better the phytosociological estimators and successional stage of the forest, the species were classified into ecophysiologicalgroups: pioneers, early secondary, late secondary and undetermined. There was a decrease of 2.3% in thenumber of individuals per hectare, with 581 recorded in 2002 and 567 individuals/ha in 2008. Currently,Ilex paraguariensis was the species with the greatest number of individuals, representing 9.4% of the total.The dominance (basal area) changed from 28.6 in 2002 to 30.2 m²/ha in 2008, i.e., there was an increaseof 5.1% in the period, and currently Araucaria angustifolia has been the species that dominates the forestwith 25.9%. The frequency pointed to an uneven distribution of species in the forest, with rates of 47,4%in 2002 and 46,3% in 2008. Araucaria angustifolia was the dominant species and the most ecologicallyimportant one in the period with 35.2 (11.7%) of the total absolute importance value in 2008. According tothe phytosociological estimators and ecophysiological groups the forest still has a growing stock, due to theincrement in trees with bigger diameters from species such as Araucaria angustifolia and Ocotea porosa,and is in advanced stage of ecological succession, with the majority of species and individuals belongingto the early and late secondary, and every year it becomes more mature with the ingress of new species andshade tolerant individuals.

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