Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Plantings with forest species have economical, social and environmental importance for Brazil, contributing to decrease the suppression of native forests. Implantation is a decisive step towards the success of a forestry enterprise and, among the precautions to be taken at this stage, stands out the control of weeds. However, the removal of these plants can eliminate food sources and shelter for natural predators of pest insects, favoring the prevalence of some species over others and causing environmental and economical damages. Considering that ants are potential bioindicators of these changes, this study aimed to evaluate the ant fauna in an initial planting of Eucalyptus grandis Hill ex Maiden, under different systems of weeds control. To this end, in March 2011, was installed a planting of E. grandis, spaced 3m x 2m, together the State Foundation of Agricultural Research in Santa Maria, RS. The Experimental design was the Entirely Randomized, with six treatments, being each having an area half a hectare, comprising: total chemical control of weeds in the line and interline planting, with glyphosate (T1); total chemical control of weeds, in the line planting, with glyphosate (T2); chemical control of monocots in the line and interline planting, with sethoxydim (T3); chemical control of dicots in the line and interline planting, with bentazone (T4); total chemical control of weeds in the range of one meter parallel to the line planting, with glyphosate, and one meter in the central part of the leading, without control (T5), e witness, without weed control (T6). The herbicides application was sequential, in total area, before planting and after transplant in the planting line. The survey was conducted from March 2011 to February 2012, using attractive baits, soil trap and Berlese funnel. Each method contained six repetitions per treatment, at each sampling date. Were collected 46,675 ants, belonging to seven subfamilies and 37 species. There was not statistical difference (ANOVA, p> = 0.05) between the total of ant specimens collected in the areas assessed. The T2 treatment presented the greatest observed richness of species (Sobs = 35), and sampling efficiency of 99.0%. The genera Camponotus and Pheidole were the richest in species number, with six each. Camponotus punctulatus, commonly found in antropized areas, it was demonstrated very frequent (mf) in the area of T3 treatment, and uncommon (mp) in T6. There was significant difference (ANOVA, p < 0.05) between mean values of observed richness per sample, with the lowest value found in T1 treatment (Sobs = 0.4), in Berlese funnel. In terms of vegetation, was verified similarity among the areas least altered, and between the areas most simplified. Ectatomma permagnum e Gnamptogenys sulcata, potential predators of pest insects, demonstrated higher occurrence frequency, respectively, in the areas of treatments T6 (51.4%) and T2 (41.7%). We conclude that the indirect effects of the herbicides affect more the composition of ant species than the ant species richness. / Plantios com espécies florestais possuem importância econômica e socioambiental para o Brasil, contribuindo para a diminuição da supressão das matas nativas. A implantação é uma etapa decisiva para o sucesso de um empreendimento florestal e, dentre os cuidados a serem tomados nessa fase, destaca-se o controle de plantas infestantes. Porém, a retirada dessas plantas pode eliminar fontes de alimento e abrigo para predadores naturais de insetos-praga, favorecendo a prevalência de algumas espécies em detrimento de outras e provocando prejuízos ambientais e econômicos. Haja vista que as formigas são potenciais bioindicadoras dessas alterações, este estudo objetivou avaliar a mirmecofauna em um plantio inicial de Eucalyptus grandis Hill ex Maiden, submetido a diferentes tipos de controle de plantas infestantes. Para tanto, em março de 2011, foi instalado um plantio de E. grandis, com espaçamento 3m x 2m, junto à Fundação Estadual de Pesquisa Agropecuária, em Santa Maria, RS. O Delineamento experimental arranjado foi Inteiramente Casualizado com seis tratamentos, sendo cada um com área de meio hectare, constituídos por: controle químico total de plantas infestantes, na linha e na entrelinha de plantio, com glifosato (T1); controle químico total de plantas infestantes, na linha de plantio, com glifosato (T2); controle químico de monocotiledôneas na linha e entrelinha de plantio, com setoxidim (T3); controle químico de dicotiledôneas na linha e entrelinha de plantio, com bentazona (T4); controle químico total de plantas infestantes em faixa de um metro paralela à linha de plantio, com glifosato, e de um metro na parte central da entrelinha, sem controle (T5); e testemunha, sem controle de plantas infestantes (T6). A aplicação dos herbicidas foi sequencial, em área total, antes do plantio e após o transplante na linha de plantio. O levantamento foi realizado de março de 2011 a fevereiro de 2012, utilizando-se isca atrativa, armadilha de solo e funil de Berlese. Cada método continha seis repetições por tratamento, em cada data de coleta. Foram coletadas 46.675 formigas, pertencentes a sete subfamílias e 37 espécies. Não houve diferença estatística (ANOVA, p>=0,05), entre o total de espécimes de formigas coletados nas áreas avaliadas. Na área do tratamento T2 verificou-se o maior número de espécies capturadas (Sobs = 35) e eficiência amostral de 99,0%. Os gêneros Pheidole e Camponotus foram os mais ricos em número de espécies, com seis cada um. Camponotus punctulatus, comum em áreas antropizadas, demonstrou-se muito frequente (mf) na área do tratamento T3, e pouco frequente (pf) em T6. Houve diferença significativa (ANOVA, p < 0,05) entre os valores médios de riqueza observada por amostra, sendo o menor valor foi encontrado na área do tratamento T1 (Sobs = 0,4), em funil de Berlese. Em termos de vegetação, verificou-se similaridade entre as áreas com estrutura florística menos alterada, e entre as áreas mais simplificadas. Ectatomma permagnum e Gnamptogenys sulcata, potenciais predadoras de insetospraga, demonstraram maior frequência de ocorrência, respectivamente, nas áreas dos tratamentos T6 (51,4%) e T2 (41,7%). Conclui-se que os efeitos indiretos da ação dos herbicidas afetam mais a composição local de espécies de formigas do que sua riqueza. Palavras-chave: Bioindicadores Ambientais. Entomologia Florestal. Formicidae. Matocompetição. Plantio Inicial

Thesis (MScFor)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Site Index is used extensively in modern commercial forestry both as an indicator of current and future site potential, but also as a means of site comparison. The concept is deeply embedded into current forest planning processes, and without it empirical growth and yield modelling would not function in its present form. Most commercial forestry companies in South Africa currently spend hundreds of thousands of Rand annually collecting growth stock data via inventory, but spend little or no money on the default compartment data (specifically Site Index) which is used to estimate over 90% of the product volumes in their long term plans. A need exists to construct reliable methods to determine Site Index for sites which have not been physically measured (the socalled "default", or indirect Site Index). Most previous attempts to model Site Index have used multiple linear regression as the model, alternative methods have been explored in this thesis: Regression tree analysis, random forest analysis, hybrid or model trees, multiple linear regression, and multiple linear regression using regression trees to identify the variables. Regression tree analysis proves to be ideally suited to this type of data, and a generic model with only three site variables was able to capture 49.44 % of the variation in Site Index. Further localisation of the model could prove to be commercially useful. One of the key assumptions associated with Site Index, that it is unaffected by initial planting density, was tested using linear mixed effects modelling. The results show that there may well be role played by initial stocking in some species (notably E. dunnii and E. nitens), and that further work may be warranted. It was also shown that early measurement of dominant height results in poor estimates of Site Index, which will have a direct impact on inventory policies and on data to be included in Site Index modelling studies. This thesis is divided into six chapters: Chapter 1 contains a description of the concept of Site Index and it's origins, as well as, how the concept is used within the current forest planning processes. Chapter 2 contains an analysis on the influence of initial planted density on the estimate of Site Index. Chapter 3 explores the question of whether the age at which dominant height is measured has any effect on the quality of Site Index estimates. Chapter 4 looks at various modelling methodologies and compares the resultant models. Chapter 5 contains conclusions and recommendations for further study, and finally Chapter 6 discusses how any new Site Index model will effect the current planning protocol. / AFRIKAANSE OPSOMMING: Hedendaagse kommersiële bosbou gebruik groeiplek indeks (Site Index) as 'n aanduiding van huidige en toekomstige groeiplek moontlikhede, asook 'n metode om groeiplekke te vergelyk. Hierdie beginsel is diep gewortel in bestaande beplanningsprosesse en daarsonder kan empiriese groeien opbrengsmodelle nie in hul huidige vorm funksioneer nie. SuidAfrikaanse bosboumaatskappye bestee jaarliks groot bedrae geld aan die versameling van groeivoorraad data deur middel van opnames, maar weinig of geen geld word aangewend vir die insameling van ongemete vak data (veral groeiplek indeks) nie. Ongemete vak data word gebuik om meer as 90% van die produksie volume te beraam in langtermyn beplaning. 'n Behoefte bestaan om betroubare metodes te ontwikkel om groeiplek indeks te bereken vir groeiplekke wat nog nie opgemeet is nie. Die meeste vorige pogings om groeiplek indeks te beraam het meervoudige linêre regressie as model gebruik. Alternatiewe metodes is ondersoek; naamlik regressieboom analise, ewekansige woud analise, hibriedeof modelbome, meervoudige linêre regressie en meervoudige linêre regressie waarin die veranderlike faktore bepaal is deur regressiebome. Regressieboom analise blyk geskik te wees vir hierdie tipe data en 'n veralgemeende model met slegs drie groeiplek veranderlikes dek 49.44 % van die variasie in groeiplek indeks. Verdere lokalisering van die model kan dus van kommersiële waarde wees. 'n Sleutel aanname is gemaak dat aanvanklike plantdigtheid nie 'n invloed op groeiplek indeks het nie. Hierdie aanname is getoets deur linêre gemengde uitwerkings modelle. Die toetsuitslag dui op 'n moontlikheid dat plantdigtheid wel 'n invloed het op sommige spesies (vernaamlik E. dunnii en E. nitens) en verdere navorsing kan daarom geregverdig word. Dit is ook bewys dat metings van jonger bome vir dominante hoogtes gee aanleiding tot swak beramings van groeiplek indekse. Gevolglik sal hierdie toestsuitslag groeivoorraad opname beleid, asook die data wat vir groeiplek indeks modellering gebruik word, beïnvloed. Hierdie tesis word in ses hoofstukke onderverdeel. Hoofstuk een bevat 'n beskrywing van die beginsel van groeiplek indeks, die oorsprong daarvan, asook hoe die beginsel tans in huidige bosbou beplannings prosesse toegepas word. Hoofstuk twee bestaan uit ń ontleding van die invloed van aanvanklike plantdigtheid op die beraming van groeplek indeks. In hoofstuk drie word ondersoek wat die moontlike invloed is van die ouderdom waarop metings vir dominante hoogte geneem word, op die kwaliteit van groeplek indeks beramings het. Hoofstuk vier verken verskeie modelle metodologieë en vergelyk die uitslaggewende modelle. Hoofstuk vyf bevat gevolgtrekkings en voorstelle vir verdere studies. Afsluitend, is hoofstuk ses ń bespreking van hoe enige nuwe groeiplek indeks modelle die huidige beplannings protokol kan beïnvloed.