Estabelecimento inicial de espécies florestais nativas indicadas para recuperação de ambientes fluviais na Bacia do Itajaí/SC sob diferentes espaçamentos e condições pedológicas

Abstract

The riparian forests constitute diverse and dynamics ecosystems which have a great habitat complexity. These were intensively degraded along river streams in the Itajai basin. This work aims at give support to development of recovering models in riparian environments by means of native species planting under different spacements and pedological conditions. In order to do this, it was installed three different spacement treatments: lxl m, lxl,5 m and, 1x2 m in areas over Neossolo Fhivico (RU - semi-hydromorphic soil) and Cambissolo Hdplico (CX - non-hydromorphic soil) located at the margins of Itajai-acu river in Apizina municipality, besides these, another area located over Depésito Psamo-Pelitico (DPP — hydromotphic soil) at Itajai municipality. The nine selected species were: Alchornea glandulosa, Annona cacans, Cabralea canjerana, Citharexylum myrianthum, Cupania vemalis, Inga marginata, Posoqueria Iatzfolia, Rollinia sericea, and Schinus terebinthifolius. The planting in RU and CX areas were conducted in April of 2006 and in DPP area in October 2006. The silvicultural treatments (clearing) were conducted according to grass cover growing in each area. In order to evaluate the growing of planted seedlings, it was surveyed at each trimester the basal diameter, height, length of the crown and total stem length data, as well as the mortality number. It was calculated the mortality rate and the trimester increment for each species and the data were compared according to pedological conditions and spacement treatment by using ANOVA and Qui-square tests. The RU and DPP areas showed the better pedological conditions for species development during the analyzed period. The species that showed major increment were: Citharexjylum myrianthum, Annona cacans, and Alchomea glandulosa followed by Schinus terebinthifolius, Inga marginata, and Rollinia sericea. The species that showed little increment were: Posoqueria Iatifolia, Cupania vemalis, and Cabralea canjerana. In CX area the species increment were smaller, only Schinus terebinthifolius and Inga marginata have showed a relative major increment, therefore with a minor increment than those verified in the other two areas. It must be emphasized that the major increments were registered afier the beginning of spring and only Schinus terebinthifolius and Inga marginata have showed a relative major increment, therefore with a minor increment than those verified in the other two areas. It must be emphasized that the major increments were registered afier the beginning of spring and only between the summer and fall period the plant’s crown begin to be formed in the RU and DPP areas. This observation suggests that the better planting time is at the spring/summer period, because it reduces the costs involved in silvicultural treatments. The mortality rates varied according to pedological conditions and year seasons and the major rates were registered in C. canjerana (65% and 44.59% - CX and RU areas, respectively), P. Iatifolia (57.7% - RU area) and A. glandulosa (52% - CX area). Regarding to plating spacement, the applied treatments do not influenced the increment and mortality rates during the analyzed period. The humidity, determined by geomorphic features of each area, as well as the competitive effect of invasive exotic and native grass appears to influence in the plant development.