FLOR\ucdSTICA E ESTRUTURA DO COMPONENTE ARB 3REO E AN\uc1LISE AMBIENTAL DE UM FRAGMENTO DE FLORESTA OMBR\ud3FILA MISTA ALTO-MONTANA NO MUNIC\ucdPIO DE PAINEL, SC

Abstract

The highland Araucaria Forest is a little-studied forest formation, occurring in altitudes above 1,000 m. The objectives of this study were to understand the structural and floristic patterns of the tree component of a remaining of this forest in the southern plateau region of Santa Catarina State and to determine the environmental variables that influence these patterns. The tree component survey and the environmental data collection were conducted in 50 plots of 200 m2. Within these plots, all living trees with circumference at breast height (CBH) 65 15,7 cm were measured (CBH and height) and identified. In each plot, environmental variables related to soils physical and chemical traits, topography and canopy cover were collected. Phytosociological parameters and the diameter structure (whole tree community and tree populations with the importance value above 5 %) were calculated. The floristic-structural similarities among plots were analyzed by NMDS (Nonmetric Multidimensional Scaling) and vectors of environmental variables (p < 0.05) were plotted a posteriori. A total of 50 tree species were identified, distributed in 33 genera and 20 families. The species with the highest VI were Araucaria angustifolia (Bertol.) Kuntze (17.32 %), Myrceugenia euosma (O. Berg) D. Legrand (15.24 %) and Acca sellowiana (O. Berg) Burret (7.84 % ). The diameter structure of the whole community and of the study populations (except Dicksonia sellowiana Hook.) showed a distribution close to the "inverted J". The NMDS analysis showed a higher percentage of clay in the plots with the highest density of Acca sellowiana and lowest percentage in the plots with high density of Dicksonia sellowiana, Inga lentiscifolia Benth. and Ocotea pulchella Mart. Plots with higher declivity had a higher density of Drimys brasiliensis Miers and those of lower declivity, higher elevation and greater canopy closure, had a higher occurrence of Drimys angustifolia Miers, Prunus myrtifolia (L.) Urb, Calyptranthes concinna DC. and Myrceugenia oxysepala (Burret) D. Legrand & Kausel.A Floresta Ombr\uf3fila Mista Alto-Montana \ue9 uma forma\ue7\ue3o pouco estudada que ocorre em altitudes acima de 1.000 m. Os objetivos deste estudo foram conhecer os padr\uf5es flor\uedsticos e estruturais do componente arb\uf3reo de um fragmento desta floresta na regi\ue3o do Planalto Sul Catarinense e determinar as vari\ue1veis ambientais que influenciam esses padr\uf5es. O levantamento da composi\ue7\ue3o flor\uedstica e estrutural e a coleta das vari\ue1veis ambientais foram conduzidos em 50 parcelas de 200 m2. Nelas, todos os indiv\uedduos arb\uf3reos com CAP (circunfer\ueancia medida a altura do peito) 65 15,7 cm foram medidos (CAP e altura) e identificados. Foram coletadas, em cada parcela, vari\ue1veis ambientais relacionadas \ue0s caracter\uedsticas qu\uedmicas e f\uedsicas dos solos, topogr\ue1ficas e de cobertura do dossel. Foram calculados os par\ue2metros fitossociol\uf3gicos e a estrutura diam\ue9trica da comunidade e das popula\ue7\uf5es com valor de import\ue2ncia (VI) acima de 5 %. A similaridade flor\uedstico-estrutural entre as parcelas foi analisada pela NMDS (Nonmetric Multidimensional Scaling) e os vetores das vari\ue1veis ambientais significativas (p < 0,05) foram plotados a posteriori. Foram identificadas 50 esp\ue9cies arb\uf3reas distribu\ueddas em 33 g\ueaneros e 20 fam\uedlias bot\ue2nicas. As esp\ue9cies com maior VI foram: Araucaria angustifolia (Bertol.) Kuntze (17,32 %), Myrceugenia euosma (O.Berg) D.Legrand (15,24 %) e Acca sellowiana (O.Berg) Burret (7,84 %). A estrutura diam\ue9trica de toda a comunidade e das popula\ue7\uf5es estudadas (exceto Dicksonia sellowiana Hook.) teve distribui\ue7\ue3o pr\uf3xima ao "J invertido". A an\ue1lise NMDS demonstrou maior porcentagem de argila nas parcelas com maior densidade de Araucaria angustifolia e menor porcentagem, nas parcelas com maior densidade de Dicksonia sellowiana, Inga lentiscifolia Benth. e Ocotea pulchella Mart. As parcelas de maior declividade tiveram maior densidade de Drimys brasiliensis Miers e aquelas de menor declividade, maior cota e maior cobertura do dossel, tiveram maior ocorr\ueancia de Drimys angustifolia Miers, Prunus myrtifolia (L.) Urb., Calyptranthes concinna DC. e Myrceugenia oxysepala (Burret) D.Legrand & Kausel