SITE INDEX CURVES FOR CLONAL STANDS OF Eucalyptus saligna Smith FOR THE CENTRAL DEPRESSION AND SOUTHEASTERN MOUNTAIN RANGE, RIO GRANDE DO SUL

This work was an attempt to study the growth in dominant height of Eucalyptus saligna Smith clones, to build site index curves and to compare them with curves built for stands of the same species originated from seeds. The dominant height growth trends analysis indicated the necessity of constructing three monomorfic site index curves systems according to clone and soil type. The comparison with the site index curves obtained from stands of the same species originated from seeds available for the same locality indicated that they could not be used for the clones studied.Este trabalho foi desenvolvido com o objetivo de estudar o crescimento em altura dominante de clones de Eucalyptus saligna Smith e construir curvas de \uedndice de s\uedtio fazendo uma compara\ue7\ue3o com curvas constru\ueddas para povoamentos da mesma esp\ue9cie originados de mudas por sementes. A an\ue1lise das tend\ueancias de crescimento em altura dominante indicaram a necessidade de se construir tr\ueas sistemas de curvas de \uedndices de s\uedtio monom\uf3rficas em fun\ue7\ue3o do clone e do tipo de solo. A compara\ue7\ue3o com as curvas de \uedndice de s\uedtio existentes no mesmo local de estudo, para povoamentos de Eucalyptus saligna originados de mudas por sementes indicou que elas, de maneira geral, n\ue3o poderiam ser utilizadas para os clones estudados

INFLUENCE OF SPACING ON SELF-THINNING OF A MONOCLONAL STAND OF Eucalyptus saligna Smith

No presente trabalho foi estudado o efeito do espa\ue7amento inicial sobre a rela\ue7\ue3o entre a densidade de \ue1rvores por hectare e o di\ue2metro m\ue9dio em povoamentos monoclonais de Eucalyptus saligna Smith. Os dados foram obtidos em povoamentos de densidade completa e altamente estocados, monitorados anualmente em parcelas permanentes at\ue9 os 18 anos. Para isto, foram testados os modelos de densidade de \ue1rvores por hectare pelo di\ue2metro m\ue9dio, indicado o modelo de autodesbaste de Tang como o mais preciso, para gerar as estimativas dos valores de densidade, apresentando um coeficiente de determina\ue7\ue3o ajustado de 0,85, erro padr\ue3o da estimativa baixo igual a 0,1026, coeficiente de varia\ue7\ue3o igual a 1,39 %, uma tend\ueancia m\uednima igual a -0,0534 e efici\ueancia elevada igual a 0,3903. O autodesbaste ocorre numa dimens\ue3o de di\ue2metro m\ue9dio diretamente proporcional \ue0 densidade inicial de \ue1rvores por hectare do plantio. Quanto maior o espa\ue7amento inicial, maior \ue9 o di\ue2metro m\ue9dio no momento do in\uedcio do autodesbaste na popula\ue7\ue3o. O coeficiente angular da equa\ue7\ue3o de densidade pelo di\ue2metro foi igual a 1,0124, divergente do valor indicado para esp\ue9cies florestais na lei de autodesbaste.In the present study the effect of initial spacing on relationship between the density of trees per hectare and the average diameter in monoclonal stands of Eucalyptus saligna were investigated. The data used were collected from full stocked stands and highly stored annually, monitored until 18 years old using permanent plots. For that, the density model of trees per hectare by diameter was tested and the self-thinning model of Tang was indicated as the most accurate one and provided great performance statistics, with a coefficient of determination equal to 0.85, lower standard error equal to 0.1026, low coefficient of variation equal to 1.39%, a minimal tendency equal to -0.0534 and high-efficiency equal to 0.3903. The self-thinning occurs in a diameter directly proportional to the initial density of trees per hectare of plantation. As great is the initial spacing greater is the mean diameter in the moment of initiation of self-thinning of the population. The slope of the equation of density and diameter was equal to 1.0124 diverging from the value indicated for forest species in the law of self-thinning