ABSTRACT Background: We analyzed if C. lusitanica can be planted in a shelterwood system with P. taeda as the shelter stratum. The study was conducted in a 13-yr-old C. lusitanica stand under P. taeda canopy in Southern Brazil. Samples of these trees were measured in terms of diameter at breast height (DBH), total height, individual volume, and crown projection area. The species´ growing space efficiency (GSE) was also analyzed. A 10-meters distance criterion from P. taeda trees was applied to check their influence on C. lusitanica growth behavior through correlation. Results: The 36-yr-old P. taeda trees showed expressive means in the dendrometric variables, compatible with its age (mean DBH of 58 cm, total height 30 m, individual volume of 3.7 m³, and crown projection area of 128 m²). There was a statistically significant effect (p>0.05) of P. taeda cover on C. lusitanica diameter (mean of ~13 cm). Although not significant, an effect of P. taeda canopy was also observed on C. lusitanica height. The two species summed a basal area of 36.5 m² ha-1 and a crown projection area of 34,209.2 m² ha-1. A tendency of increasing GSE with increasing diameter was observed for both species. Conclusion: These results show that a shelterwood with C. lusitanica under P. taeda is possible, but further investigations with longer production cycles and with silvicultural treatments (i.e. thinnings and shelter removal) should be conducted for a better understanding of shelterwood systems with these species in southern Brazil in terms of growth performance and soil use sustainability.

ABSTRACT: Araucaria angustifolia (Bertol.) Kuntze is a native tree species of major importance in southern Brazil. It is a regional symbol due to its iconic shape and stature in the landscape; its wood was once economically important and its seeds are an important source of food for the fauna and are presently used in regional cuisine. Despite its importance and apparent abundance, the species is facing extinction mainly as a result of unregulated exploitation and deforestation. This study catalogued the remaining individuals in order to add to the body of knowledge available on A. angustifolia, a species that has become rare across its historic range. The circumference at breast height (1.30 m), the total height, and the tree volume were measured (3,529 araucarias). We catalogued trees with a large diameter measuring them in loco over three years involving a journey of more than 6,800 km. The volumes of these old trees are very large, ranging from 38.2 m3 to 106.6 m3. The largest A. angustifolia individual is located in the state of Santa Catarina and measures 3.25 m in diameter. The giant araucarias with > 2.00 m in diameter are rare and only 13 individuals could be found in southern Brazil; a priority action at the governmental level is to recognize and preserve these monumental trees and together with a need for a public policy of drawing up specific inventories of large trees.

RESUMO Aproximadamente 1,6 milhões de hectares são cultivados com Pinus no sul do Brasil, principalmente com Pinus taeda L. Mais de um terço dos povoamentos pertencem a produtores de toras independentes, cujos objetivos são maximizar os resultados econômicos. Neste estudo, um experimento de desbastes foi avaliado durante um período de produção de 30 anos. Os povoamentos avaliados foram submetidos a três diferentes intensidades de desbaste 'por copas', também denominado de 'pelo alto', mantendo uma testemunha não desbastada. Objetivou-se avaliar indicadores econômicos considerando taxas de desconto realistas e períodos de produção entre 16-30 anos. Para as circunstâncias estudadas, a liberação 'extrema' e precoce de competição de árvores podadas de P. taeda alcançou o melhor resultado econômico (valor esperado da terra = ~36.000 US$ ha-1, i = 3% ano-1). Povoamentos submetidos a desbastes por copas, independente da intensidade, produziram resultado econômico três vezes maior do que povoamentos sem desbastes e não podados. Embora a idade ótima de corte raso de acordo com a taxa interna de retorno (TIR) seja 18-22 anos para povoamentos desbastados ou não, a partir de uma perspectiva de longo prazo (valor esperado da terra) e para a atual relação preço-dimensão da tora, resultados ótimos econômicos indicam haver necessidade de prolongar os períodos de produção (24-26 anos) em comparação com a atual prática no sul do Brasil (15-20 anos).

ABSTRACT Approximately 1.6 million hectares of southern Brazil are cultivated with pines, and mainly with the loblolly pine (Pinus taeda L.). More than one third of the stands belong to independent log producers, whose aim is to maximize their economic results. In this study, a thinning experiment was evaluated over a production period of 30 years. The stands evaluated were submitted to three different crown thinning intensities, with an unthinned stand used as a control. The aim of the study was to evaluate economic criteria regarding realistic discount rates and production periods varying between 16-30 years. For the circumstances that were evaluated, 'extreme' and early release from competition of pruned loblolly pine trees lead to the best economic performance (land expectation value = ~36,000 US$ ha-1, i = 3% yr-1). Stands subjected to crown thinnings, independently of intensity, produced three times the economic output of unthinned and unpruned stands. Although the optimal harvest ages, according to the internal rate of return, are between 18-22 years for thinned and unthinned stands, from a long-term perspective (land expectation value) and for the current relationship between log price and size, the optimal economic performance requires that production periods are extended (to 24-26 years) from those currently practised in southern Brazil (15-20 years).

RESUMO Espécies do gênero Eucalyptus, manejadas com o objetivo de produzir madeira para serraria em plantios de rápido crescimento, demonstram um grande potencial para substituir madeiras nativas nobres. Para que madeira de alta qualidade seja obtida, povoamentos precisam ser necessariamente podados. O objetivo do estudo é analisar o desenvolvimento dos galhos presentes no momento da primeira e segunda podas e quantificar a biomassa obtida com a remoção dos mesmos. Dois povoamentos de Eucalyptus grandis foram selecionados (idades 18 e 36 meses) para a avaliação das podas de 0 a 3 m e de 3 a 6 m. O diâmetro e comprimento médios foram 18 mm e 2,1 m no povoamento mais jovem e 21 mm e 2,3 m no mais velho. A relação entre o diâmetro e o comprimento dos galhos pode ser expressa em um modelo linear (R²=0,8). Nos dois povoamentos uma maior proporção de galhos já estava morta. O peso seco em estufa da biomassa produzida pela poda dos galhos foi 2,2 ton.ha-1 na primeira intervenção e 1,2 ton.ha-1 na segunda. Os resultados demonstraram que o desenvolvimento dos galhos em plantações de eucalipto estabelecidas com espaçamentos amplos e desbastadas estão de acordo com o objetivo de se produzir madeira de alta qualidade. A poda, entretanto, precisa iniciar antes dos 18 meses para evitar galhos mortos. O peso seco da biomassa de galhos produzida nas duas intervenções é insuficiente para permitir sua utilização comercial.

ABSTRACT Species of the genus Eucalyptus managed for sawlogs in fast-growing plantations show high potential for substitution for valuable native hardwoods. To obtain high quality wood, technical pruning is necessary. The objective of the study is to analyse the development of the branches for the first and second pruning lifts and to quantify the biomass of the pruned branches. For the study two stands of Eucalyptus grandis were selected (age 18 and 36 months) for evaluating a pruning lift from 0 to 3 m and 3 to 6 m. The average branch diameter and length were 18 mm and 2.1 m in the younger stand and 21 mm and 2.3 m in the older one. The relation between branch diameter and branch length could be expressed in a linear model (R² = 0.8). In both stands a higher proportion of branches were already dead. The oven-dry biomass of the pruned branches was 2.2 ton.ha-1 in the first pruning lift and 1.2 ton.ha-1 in the second. The results showed that branch development in wide spaced and early thinned eucalypt plantations is in line with the objective of high quality wood production. Pruning should take place before 18 month to avoid dead branches. The oven-dry branch biomass cut in the two pruning lifts shows a low volume making a commercial utilization difficult.

RESUMO Cryptomeria japonica é originária da região temperada do Japão onde é conhecida como 'sugi'. No Brasil, o plantio da espécie é recomendado em regiões altas e frias do sul do país, onde possui boa adaptação às condições edafoclimáticas. O objetivo do trabalho foi avaliar as correlações entre variáveis meteorológicas e o crescimento de um povoamento de Cryptomeria japonica com 25 anos de idade. Para tal, foram coletados discos transversais de 30 diferentes árvores, compreendendo toda a amplitude de variação diamétrica. Após secos e lixados, os discos tiveram seus anéis anuais de crescimento medidos e correlacionados com dados meteorológicos, utilizando ferramentas de análise dendrocronológica. As séries de crescimento apresentaram uma intercorrelação de 0,668. O crescimento radial da espécie foi influenciado positivamente pela temperatura mínima do mês de setembro e pela temperatura média do mês de maio. Não houve correlação significativa do crescimento com a precipitação, embora tenham sido verificados picos de crescimento em anos mais chuvosos.

ABSTRACT Cryptomeria japonica is indigenous to the temperate region of Japan, where it is known as 'sugi'. In Brazil, the plantation of this species is recommended for the highlands and cold regions in the southern, where it is well adapted to the edaphoclimatic conditions. The aim of the study was to evaluate the correlation between meteorological variables and growth of a 25 years old Cryptomeria japonica stand. Cross-sectional discs from 30 different trees were collected, within all diametric classes. After dried and sanded, annual rings were measured and correlated with meteorological data by dendrochronological analysis tools. The growth series showed an intercorrelation of 0.668. The radial growth of the species was positively influenced by the minimum temperature of September and by the medium temperature of May. There was no correlation between growth and precipitation, although peaks of growth were observed in years with high precipitation.