O eucalipto é um gênero amplamente cultivado no Brasil desde o início do século XX. É utilizado principalmente na produção de carvão e polpa, apesar da aptidão para produção de toras para serraria. Para as espécies cultivadas no Brasil, as técnicas de manejo para serraria foram pouco desenvolvidas e delas depende a introdução efetiva da madeira serrada de eucalipto no mercado. O presente estudo objetivou identificar as variáveis do manejo florestal do Eucalyptus urophylla que determinam, física e temporalmente, a formação de madeira limpa (clear) em árvores manejadas para serraria. O experimento foi implantado em julho de 2013 na Estação Experimental de Ciências Florestais de Itatinga (E.E.C.F.I/ESALQ/USP) e consistiu de 4 espaçamentos, sendo eles (3 x 1), (3 x 2), (3 x 3) e (6 x 1,5) m. Realizou-se o primeiro inventário em janeiro de 2015, aos 18 meses de idade, com medições de atributos das árvores e dos galhos. As parcelas foram subdivididas pela metade e, também em janeiro de 2015, aplicou-se a desrama artificial (poda) até os 2,5 m do tronco em uma de cada par de subparcelas. Daí em diante foram realizadas medições de cicatrizes e incremento secundário (dendrômetros) tomadas periodicamente até fevereiro de 2016, aos 31 meses de idade. Em junho de 2015 foi feita a primeira amostragem destrutiva de toras para medição de espessura da casca e em fevereiro de 2016 uma segunda leva de toras foi amostrada e submetida a análise em laboratório. Esta amostragem não incluiu o tratamento sem poda devido à ausência de desrama natural. Toretes foram gradualmente processados em torno mecânico para observação em plano tangencial da madeira formada após a desrama artificial. Nesta etapa também mediu-se a espessura da zona de oclusão e de madeira clear. A zona de oclusão é essencialmente composta pelo exsudado secretado para proteção periférica da cicatriz na casca. A área calculada do anel de oclusão está altamente correlacionada à área do anel da casca. Portanto, a espessura da casca determina a espessura do anel de oclusão e a formação de clear se inicia quando o xilema secundário sobrepõe o ponto mais externo no plano tangencial marcado pelo exsudado. / Eucalyptus is a genus widely grown in Brazil since the beginning of the 20th century, traditionally used to produce fuel and pulp despite its potential for sawlog production. The silvicultural techniques developed for eucalyptus short rotation woody crops in Brazil have neglected essential traits for high quality sawlog production, without which eucalyptus solid wood is not marketable. The aim of the present study was to identify the variables in silvicultural management of Eucalyptus urophylla limiting, physical and temporally, clear wood formation. The experiment was established in July 2013 at the Itatinga Experimental Station, College of Agriculture \"Luiz de Queiroz\" (ESALQ), University of São Paulo (USP), Brazil, consisting of spacing trials of (3 x 1), (3 x 2), (3 x 3) e (6 x 1,5) m. Measurements o trees and branches attributes were first taken in January 2015, when trees were 18 months old. The plots were split in half (subdivided) and one of the subplots was addressed for a pruning trial in which all live and dead branches were removed to 2,5 m, also in January 2015From then on, wound occlusion and secondary growth (band dendrometers) were periodically measured until February 2016, when the trees were 31 months old. Destructive samplings were firstly carried out in June 2015, for bark thickness determination, and secondly in February 2016. The latter did not include unpruned subplots, once the trees had not yet shed the branches. Logs were debarked and processed in mechanical lathe while measurements of clear wood and occlusion zone were taken in the tangential plane. High correlation between occlusion zone ring area and bark ring area has been found. The occlusion zone of Eucalyptus urophylla is mainly composed by the exudate released by trees during the bark wound closure process. Therefore, the bark thickness establishes the occlusion ring thickness and clear wood formation starts after the secondary xylem overlaps the most external point in the tangential plane marked by the exudate.

Log processor heads have become increasingly used in New Zealand (NZ) forest harvesting operations to increase productivity and improve worker safety. Information regarding the measurement accuracy and productivity of new model processor heads is limited. As a result, log quality control (QC) is carried out on logs that have been merchandised by a processor head. This task can have a high risk for injury from man – machine interaction. A trend between studies was that older model Waratah’s did not have sufficient measurement accuracy to alleviate the requirement for log QC. In this study, a Waratah HTH 625c processor head operating in NZ was analysed for measurement accuracy and productivity. Measurement accuracy was considered by measuring logs for length, diameter and branch size. A comparison of two methods of processing was also considered to determine measurement accuracy, productivity and production efficiency for the way logs are delimbed and merchandised. Once gathered, the data was then analysed to identify significant effects, trends and relationships between variables. Length measurements were highly accurate but diameter measurements were under- estimated. It was also evident that although there was absolute accuracy, there was a high variability in measurements with underestimating and overestimating. Branch size was also found to have a significant impact in reducing length measurement accuracy and productivity. Single pass processing has significantly higher production efficiency than two pass processing, although single pass processing had a higher length error associated with it. The Waratah HTH 625c processor head has better measurement accuracy than older model Waratah’s. However, logs are still cut out-of-spec which will require a log QC to identify. As measurement technology is further improved in processor heads, and improvements to NZ’s plantation resource (improved form and smaller branching) are realised at harvest age, measurement accuracy and productivity of log processor heads will further improve.

O eucalipto é um gênero amplamente cultivado no Brasil desde o início do século XX. É utilizado principalmente na produção de carvão e polpa, apesar da aptidão para produção de toras para serraria. Para as espécies cultivadas no Brasil, as técnicas de manejo para serraria foram pouco desenvolvidas e delas depende a introdução efetiva da madeira serrada de eucalipto no mercado. O presente estudo objetivou identificar as variáveis do manejo florestal do Eucalyptus urophylla que determinam, física e temporalmente, a formação de madeira limpa (clear) em árvores manejadas para serraria. O experimento foi implantado em julho de 2013 na Estação Experimental de Ciências Florestais de Itatinga (E.E.C.F.I/ESALQ/USP) e consistiu de 4 espaçamentos, sendo eles (3 x 1), (3 x 2), (3 x 3) e (6 x 1,5) m. Realizou-se o primeiro inventário em janeiro de 2015, aos 18 meses de idade, com medições de atributos das árvores e dos galhos. As parcelas foram subdivididas pela metade e, também em janeiro de 2015, aplicou-se a desrama artificial (poda) até os 2,5 m do tronco em uma de cada par de subparcelas. Daí em diante foram realizadas medições de cicatrizes e incremento secundário (dendrômetros) tomadas periodicamente até fevereiro de 2016, aos 31 meses de idade. Em junho de 2015 foi feita a primeira amostragem destrutiva de toras para medição de espessura da casca e em fevereiro de 2016 uma segunda leva de toras foi amostrada e submetida a análise em laboratório. Esta amostragem não incluiu o tratamento sem poda devido à ausência de desrama natural. Toretes foram gradualmente processados em torno mecânico para observação em plano tangencial da madeira formada após a desrama artificial. Nesta etapa também mediu-se a espessura da zona de oclusão e de madeira clear. A zona de oclusão é essencialmente composta pelo exsudado secretado para proteção periférica da cicatriz na casca. A área calculada do anel de oclusão está altamente correlacionada à área do anel da casca. Portanto, a espessura da casca determina a espessura do anel de oclusão e a formação de clear se inicia quando o xilema secundário sobrepõe o ponto mais externo no plano tangencial marcado pelo exsudado. / Eucalyptus is a genus widely grown in Brazil since the beginning of the 20th century, traditionally used to produce fuel and pulp despite its potential for sawlog production. The silvicultural techniques developed for eucalyptus short rotation woody crops in Brazil have neglected essential traits for high quality sawlog production, without which eucalyptus solid wood is not marketable. The aim of the present study was to identify the variables in silvicultural management of Eucalyptus urophylla limiting, physical and temporally, clear wood formation. The experiment was established in July 2013 at the Itatinga Experimental Station, College of Agriculture \"Luiz de Queiroz\" (ESALQ), University of São Paulo (USP), Brazil, consisting of spacing trials of (3 x 1), (3 x 2), (3 x 3) e (6 x 1,5) m. Measurements o trees and branches attributes were first taken in January 2015, when trees were 18 months old. The plots were split in half (subdivided) and one of the subplots was addressed for a pruning trial in which all live and dead branches were removed to 2,5 m, also in January 2015From then on, wound occlusion and secondary growth (band dendrometers) were periodically measured until February 2016, when the trees were 31 months old. Destructive samplings were firstly carried out in June 2015, for bark thickness determination, and secondly in February 2016. The latter did not include unpruned subplots, once the trees had not yet shed the branches. Logs were debarked and processed in mechanical lathe while measurements of clear wood and occlusion zone were taken in the tangential plane. High correlation between occlusion zone ring area and bark ring area has been found. The occlusion zone of Eucalyptus urophylla is mainly composed by the exudate released by trees during the bark wound closure process. Therefore, the bark thickness establishes the occlusion ring thickness and clear wood formation starts after the secondary xylem overlaps the most external point in the tangential plane marked by the exudate.