THE INFLUENCE OF COMPETITION IN THE GROWTH-CLIMATE RELATIONSHIP OF Pinus taeda: A CASE STUDY IN SOUTHERN BRAZIL

Understanding how climate affects tree growth is crucial for assessing climate change impacts on forests. Furthermore, trees in more competitive environments appear to respond to climate differently than trees in less competitive environments. An important tool for investigating the growth-environment relationships is tree ring dating. This study aimed to characterize the climatic factors that affect Pinus taeda growth in southern Brazil in two distinct stand types: open growth trees and competing trees. We hypothesized that competing trees present more vulnerable responses to climate variability than open growth trees. Thus, we used increment borers to access long-term growth through tree rings. Pearson’s correlation was applied to compare radial growth with monthly and annual climatic data. The chronologies generated for the two environments present similar year-to-year growth patterns. However, competing trees are more sensitive under limiting climate conditions than open growth trees. Water availability during the current spring/summer was the primary climate constraint for P. taeda growth in the region, followed by high temperatures during the summer, probably due to photosynthetic restrictions. The paper provides additional information on climatic factors that contribute to growth models and reports an important research field, considering planning forest management in the future

APPROXIMATION OF NUMERICAL INTEGRATION APPLIED TO Araucaria angustifólia STEM TAPER MODELS

AbstractAPPROXIMATION OF NUMERICAL INTEGRATION APPLIED TO Araucaria angustifólia STEM TAPER MODELSFunctions describing stem shape allow to determine dimension and volume class, with direct application in technical and economic activities in the forest. The aim of this study was to evaluate the accuracy of the Trapezoidal and Simpson 1/3 rules in the approximation of numerical integration applied to Kozak, Lee et al. and Sharma and Zhang models. The evaluated data were diameter and height of sixty Araucaria angustifolia (Bertol.) Kuntze individuals from a planted forest located in Caçador, State of Santa Catarina, Brazil. Analysis of results showed the high efficiency of the two volume and assortments determination methods compared to the exact value of the numerical integration. Kozak and Lee et al. models showed better results compared to Sharma and Zhang models. The first, when estimating volume of trunk with bark, applying the Trapezoidal rule, showed an error smaller than 10-4, through eight integration intervals, equidistant between sections with relative length equal to 20% of the total height. The Simpson 1/3 rule resulted in greater accuracy with an error smaller than 10-6, though with complex mathematical structure using six equidistant integration intervals.Keywords: Taper; stem profile; individual volume. ResumoAproximação da integral numérica de modelos de forma do tronco para Araucaria angustifólia. Funções que descrevem a forma do tronco de árvores permitem determinar classes de dimensão e volume com aplicação direta no planejamento das atividades técnicas e econômicas na floresta. Neste sentido o presente estudo avaliou a acurácia da regra dos Trapézios e de Simpson 1/3 na aproximação da integral numérica aplicada aos modelos de Kozak, Lee et al. e Sharma e Zhang. Os dados avaliados incluem diâmetros e alturas relativas de sessenta árvores de Araucaria angustifolia (Bertol.) Kuntze provenientes de plantios florestais situados em Caçador, SC. A análise dos resultados mostrou alta eficiência dos dois métodos de determinação do volume e dos sortimentos quando comparados com o valor exato da integral numérica. Os modelos de Kozak e Lee et al. obtiveram resultados superiores quando confrontados com Sharma e Zhang, sendo estes, quando estimado o volume do tronco com casca, aplicando a regra do Trapézio, mostrou um erro inferior a 10-4 mediante a oito intervalos de integração equidistantes entre secções de comprimento relativo igual a 20% da altura total. A regra de Simpson 1/3 propiciou maior acurácia com erro inferior a 10-6, mas com estrutura matemática complexa utilizando seis intervalos de integração equidistantes.Palavras-chave: Afilamento; perfil do fuste; volume individual.AbstractFunctions describing stem shape allow to determine dimension and volume class, with direct application in technical and economic activities in the forest. The aim of this study was to evaluate the accuracy of the Trapezoidal and Simpson 1/3 rules in the approximation of numerical integration applied to Kozak, Lee et al. and Sharma and Zhang models. The evaluated data were diameter and height of sixty Araucaria angustifolia (Bertol.) Kuntze individuals from a planted forest located in Caçador, State of Santa Catarina, Brazil. Analysis of results showed the high efficiency of the two volume and assortments determination methods compared to the exact value of the numerical integration. Kozak and Lee et al. models showed better results compared to Sharma and Zhang models. The first, when estimating volume of trunk with bark, applying the Trapezoidal rule, showed an error smaller than 10-4, through eight integration intervals, equidistant between sections with relative length equal to 20% of the total height. The Simpson 1/3 rule resulted in greater accuracy with an error smaller than 10-6, though with complex mathematical structure using six equidistant integration intervals.Keywords: Taper; stem profile; individual volume.

EFFECT OF SITE AND COMPETITION ON DIAMETER GROWTH OF Araucaria angustifolia

Although the historical interest in using the wood of Araucaria angustifolia, it is still little known concerning the factors that affect the growth. A broader understanding in this context might contribute to the development of appropriate management systems, thus increasing the productivity of plantations and, consequently, the interest in commercially using this species. The present study was based on monospecific populations established in different site conditions (Site Indices between 18-24) where individuals (n=654) were submitted to different competition levels. With the aid of multiple regression techniques, the factors that significantly affected the accumulated growth in diameter of the trees after 20 years of intervention were determined. For the set formed by all trees, 77% of the growth variation can be explained by three factors: site, the proportion of tree diameter at breast height (dbh) of the object tree for analysis in relation to the average dbh of the population before performing the clearings (Cdbh_before) and dominance status in relation to the neighboring trees (Call). The significance of the competition level before the clearing shows that late clearings have limited effects on tree growth. It is concluded that individuals are benefited for having a dominant position in relation to the neighboring trees, reaching diameters 50% larger at the end of the production cycle. Clearings that favour selected trees by removing direct competitors seem to be an interesting management strategy for the species.Keywords: Paraná-pine; Forest Management; Silviculture; Timber Production

ESTIMATIVAS VOLUMÉTRICAS EM PLANTIOS DE EUCALIPTO PARA DUAS MESORREGIÕES DO RIO GRANDE DO SUL

O volume de árvores é a variável de maior interesse florestal, sendo possível estima-la por várias técnicas, sendo a modelagem a mais usual. Portanto, o presente estudo teve como objetivo ajustar, validar e selecionar o melhor modelo volumétrico para árvores de Eucalyptus grandis W. Hill. ex Maiden de plantios em duas mesorregiões do estado do Rio Grande do Sul. Para isso, 791 árvores foram cubadas pelo método da Smalian e separadas em grupos de ajuste (≈74%) e validação (≈26%). Três modelos foram testados: (Husch) v = β0 × dapβ1 × εi; (Schumacher e Hall) v = β0 × dapβ1 × hβ2 × εi; (Schumacher e Hall modificado) v = β0 × dapβ1 × hβ2 × h100β3 × εi. Os modelos foram avaliados de acordo com os seguintes critérios: coeficiente de determinação ajustado (R² aj.), raiz quadrada do quadrado médio do erro em porcentagem (RMSE%) e análise gráfica dos resíduos em porcentagem (E%). De acordo com o teste χ2 à 5 % de probabilidade, não houve diferença significativa entre as estimativas volumétricas para as três equações com e sem casca quando confrontados com os volumes reais. O modelo de Schumacher e Hall modificado apresentou melhores resultados e tem maior destaque por utilizar a variável de altura dominante de Assmann (h100) que caracteriza o sítio florestal e com possibilidade de ampla utilização

MODELAGEM DO ESPAÇO DE CRESCIMENTO PARA ARAUCÁRIA

This study was developed in order to model the growing space for Araucaria angustifolia (Bertol.) Kuntze trees. A total of 869 Parana pine trees were sampled in three municipalities in southern Brazil, being 175 trees with free growing of competition in the municipalities of Canoinhas (SC state) and Lages (SC state), and 694 under influence of competition in natural forest in the municipalities of São Francisco de Paula (RS state) and Lages (SC state). In each tree was measured diameter at breast height, total height and crown rays following the directions of the cardinal points. The crown diameter was determined by doubling the value of the average radius of the crown. Three models were fitted and evaluated the fit statistics, accuracy and residual graphical analysis, according to the municipality and growth condition. When comparing the equations, covariance analysis indicated that there is no significant difference between the level and slope of the crown diameter equations of open growth trees and under competition in different places where data were sampled. A single equation was defined to estimate the crown diameter as a function of the diameter at breast height for this species.Este estudo foi desenvolvido com objetivo de modelar o espaço de crescimento para árvores de Araucaria angustifolia (Bertol.) Kuntze. Um total de 869 araucárias foram amostradas em três municípios no sul do Brasil, sendo 175 árvores com crescimento livre de competição nos municípios de Canoinhas-SC e Lages-SC, e 694 sob influência da competição em floresta natural nos municípios de São Francisco de Paula-RS e Lages-SC. Em cada árvore, foi medido o diâmetro a altura do peito, altura total e raios de copa seguindo as direções dos pontos cardeais. O diâmetro de copa foi determinado dobrando o valor do raio médio da copa. Três modelos foram ajustados e avaliados quanto ao ajuste, à precisão e à análise gráfica dos resíduos, segundo o município e a condição de crescimento. Na comparação das equações, a análise de covariância não indicou diferença significativa entre nível e inclinação das equações de diâmetro de copa de árvores livres e sob competição nos diferentes locais em que os dados foram amostrados. Uma única equação foi definida para estimar o diâmetro de copa em função do diâmetro a altura do peito para a espécie

INFLUÊNCIA DA POSIÇÃO SOCIAL NAS RELAÇÕES MORFOMÉTRICAS DE Araucaria angustifolia

http://dx.doi.org/10.5902/1980509821116The morphometric relations allow describing dimensions of trees without prior knowledge of the age, it help the forest planning and implementation of silvicultural treatments, especially when needs to make sustainable use of forests. For this purpose, the aim of this study was to model and comparising the morphometric relations araucaria trees in social position dominant, codominant and dominated in native forest remnant, located in Lages, SC. A total of 294 trees distributed in dbh classes were intentionally selected inside of forest. In each tree was measured dbh, total height, bole height, crown diameter by eight radius, as well as the classification of social position. Simple and multiple linear regression models were used to describe the relation h/d, the proportion of the crown and formal crown in function of diameter at breast height with simple transformation, quadratic, cubic, inverse and logarithmic form. The analysis of covariance with dummy variables were used to describe the social position and tested the parallelism and slope of regression indicating need or not of the use independent regressions. The results indicated that even with great variability in the shape and size of the crown due to growth and competition process, the morphometric relations of araucaria can be accurately estimated by regression models. The relation h/d, proportion of the crown and formal crown can be described by individual model for social position dominant, codominant and dominant, or alternatively a single model with the use of dummy variables that differentiate trees group dominated for the relation h/d and formal crown. The proportion of crown presented difference in dimensions of the trees, being necessary to use dummy variable for each social stratus or use the individual models.http://dx.doi.org/10.5902/1980509821116As relações morfométrias permitem descrever dimensões das árvores sem o prévio conhecimento da idade, auxilia no planejamento florestal e na execução de atividades silviculturais, principalmente quando se deseja tornar sustentável o uso das florestas. Com esse propósito, o objetivo do presente estudo foi modelar e comparar as relações morfométricas de árvores de araucária que crescem em posição social dominante, codominante e dominada em remanescente florestal nativo, localizado no município de Lages - SC. Um total de 294 árvores distribuídas em classes de DAP foi selecionado intencionalmente no interior da floresta. De cada árvore foi medido o DAP, altura total, altura do fuste, diâmetro de copa sob oito raios, bem como a classificação quanto à posição social. Modelos de regressão linear simples e múltipla foram empregados para descrever a relação h/d, proporção de copa e formal de copa em função do diâmetro a altura do peito na forma simples, quadrática, cúbica, inversa e logarítmica. A análise de covariância com variáveis dummy para descrever a posição social foram usadas para testar o paralelismo e inclinação das regressões indicando a necessidade ou não do emprego de regressões independentes. Os resultados indicaram que, mesmo com grande variabilidade na forma e dimensão das copas decorrente do processo de crescimento e de competição, as relações morfométricas de araucária podem ser estimadas com precisão por modelos de regressão. A relação h/d, proporção de copa e formal de copa pode ser descrita por modelo individual para posição social dominante, codominante e dominada, ou alternativamente por modelo único, com a utilização de variáveis dummy que diferenciam o estrato dominado no modelo de relação h/d e de formal de copa. Para a proporção de copa existe diferença de dimensões das árvores dos três estratos sociais, sendo necessário utilizar uma variável de classificação dummy para cada caso ou os modelos individuais

CROWN MORPHOMETRY FOR TWO VALUABLE TIMBER SPECIES FROM MIOMBO WOODLAND IN MOZAMBIQUE

Pterocarpus angolensis DC and Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema are two hardwood species found in Miombo woodland. Crown size, being closely related to the photosynthetic capacity of a tree, is an important parameter in studies of the growth of individual trees. In this sense, the present study aimed to study the morphometric relationships of P. angolensis and B. madagascariensis as a resource to describe the morphometric features of these species. Data were sampled in 60 rectangular plots of 20 x 50 m, systematically distributed within the forest. In each plot, the diameter at breast height (DBH), height (h), crown insertion point (cih) and four crown radii of all trees with DBH ≥ 10 cm were measured. Results indicated that crown diameter and crown length of P. angolensis grow as DBH and height increase, the larger the crown, the greater the trees dimensions; as for B. madagascariensis, crown features have shown low correlation when considering DBH. It was concluded that crown features influence on tree growth and are important measures of description and planning of silvicultural activities to be performed in natural forests. The results are of interest to forest managers since they make decisions about silvicultural operations. Keywords: crown dimensions; prediction models; umbila; pau-ferro; forest management.ABSTRACT: Pterocarpus angolensis DC and Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema are two hardwood species found in Miombo woodland. Crown size, being closely related to the photosynthetic capacity of a tree, is an important parameter in studies of the growth of individual trees. In this sense, the present study aimed to study the morphometric relationships of P. angolensis and B. madagascariensis as a resource to describe the morphometric features of these species. Data were sampled in 60 rectangular plots of 20 x 50 m, systematically distributed within the forest. In each plot, the diameter at breast height (DBH), height (h), crown insertion point (cih) and four crown radii of all trees with DBH ≥ 10 cm were measured. Results indicated that crown diameter and crown length of P. angolensis grow as DBH and height increase, the larger the crown, the greater the trees dimensions; as for B. madagascariensis, crown features have shown low correlation when considering DBH. It was concluded that crown features influence on tree growth and are important measures of description and planning of silvicultural activities to be performed in natural forests. The results are of interest to forest managers since they make decisions about silvicultural operations. Keywords: crown dimensions; prediction models; umbila; pau-ferro; forest management.   Morfometria da copa para duas espécies madeireiras comerciais da floresta de Miombo em Moçambique   RESUMO: Pterocarpus angolensis DC e Bobgunnia madagascariensis (Desv.) J. H. Kirkbr. & Wiersema são duas espécies de madeira de lei encontradas na floresta de Miombo. O tamanho da copa, está intimamente relacionado à capacidade fotossintética de uma árvore, e é um parâmetro importante nos estudos do crescimento de árvores individuais. Nesse sentido, o presente estudo teve como objetivo estudar as relações morfométricas de P. angolensis e B. madagascariensis como recurso para descrever as características morfométricas dessas espécies. Os dados foram obtidos em 60 parcelas retangulares de 20 x 50 m, distribuídas sistematicamente na floresta. Em cada parcela, foram medidos o diâmetro à altura do peito (DAP), altura (h), altura de inserção da copa (hic) e quatro raios da copa de todas as árvores com DAP ≥ 10 cm. Os resultados indicaram que o diâmetro e o comprimento da copa de P. angolensis crescem com o aumento do DAP e da altura; quanto maior a copa, maior dimensão das árvores, enquanto que para B. madagascariensis, as características da copa mostraram baixa correlação ao considerar o DAP. Concluiu-se que as características da copa influenciaram no crescimento das árvores e são importantes medidas de descrição e planejamento das atividades silviculturais a serem realizadas na floresta. Estes resultados são de interesse dos manejadores florestais, pois são eles que tomam decisões sobre as operações silviculturais. Palavras-chave: dimensões da copa; modelos preditivos; umbila; pau-ferro; manejo florestal

DENSITY MANAGEMENT DIAGRAM FOR Eucalyptus grandis W. Hill. ex Maiden STANDS CONTROLLED BY DOMINANT HEIGHT

Density management diagram for eucalyptus stands controlled by dominant height. The present study aimed to elaborate Density Management Diagrams (DMD) for Eucalyptus grandis W. Hill. ex Maiden stands including the dominant height. Data were obtained from permanent plots installed in the Centro Oriental Riograndense region and the Porto Alegre Metropolitan area, both located in the state of Rio Grande do Sul. The models to describe the relationships between average volume, number of trees per hectare, mean diameter, and dominant height were assessed by the statistical criteria of coefficient of determination (R²), standard error of the estimate in percentage (Syx%), and graphical analysis of residuals. The developed DMD allows for a better control of stocks in the management of stands due to the strong relationship of dominant height with stand development site and forest yield.Keywords: Growth, Site index, Forest regulation, Yield

Influence of social position and number of radius in estimate of area in araucaria crown

O objetivo do presente estudo foi avaliar a precisão e a acurácia na estimativa da área de projeção horizontal da copa de araucária em diferentes posições sociais. Foram amostradas 294 árvores na floresta e classificadas, conforme a sua posição sociológica, em dominante, codominante e dominada. Em cada árvore foram medidos o diâmetro à altura do peito, a altura total e oito raios de copa seguindo a direção dos pontos cardeais. A área de projeção horizontal da copa foi calculada pela média dos respectivos números de raios avaliados na copa (métodos): oito, quatro e dois. As diferenças estatísticas entre os métodos foram verificadas por análise de variância com arranjo fatorial, considerando dois fatores, os métodos de área de copa e a posição social ocupada pelas árvores. Os resultados indicaram que, apesar de não haver diferença significativa entre as médias de área de projeção da copa quando medido oito e quatro raios, a análise gráfica evidenciou tendência de superestimativa da área quando calculada com quatro e dois raios em copas irregulares, frequentemente encontradas nas árvores codominantes e dominadas. Ademais, em copas simétricas, a determinação da área de projeção horizontal da copa com quatro raios pode ser empregada sem perda de acurácia. AbstractInfluence of social position and number of radius in estimate of area in araucaria crown. The aim of this study was to evaluate precision and accuracy in estimating horizontal projection crown area of trees of Araucaria Angustifolia in different social positions. We sampled 294 trees in the forest and classified them according to their position in sociological position as dominant, codominant and dominated. In each tree it was measured the diameter at breast height, total height and eight crown radius following the cardinal points direction. The horizontal projection area of the crown was calculated by the average of the respective radius numbers evaluated in the crown (methods): eight, four and two. Statistical differences between among methods were verified by variance analysis with factorial arrangement, considering two factors, methods of crown area and the social position occupied by trees. The results indicated that although there was no significant difference between the mean area of crown projection when measured eight and four radius, the graphical analysis revealed tendency to overestimate the area  calculated with four and two radius in irregular crown, often identified in codominant and dominated trees. Furthermore, in relation to symmetrical crowns, determining the area of horizontal projection crown with four radius can be used without loss of accuracy.Keywords: Crown diameter; horizontal crown surface; social class; araucaria forest.The aim of this study was to evaluate precision and accuracy in estimating horizontal projection crown area of trees of Araucaria Angustifolia in different social positions. We sampled 294 trees in the forest and classified them according to their position in sociological position as dominant, codominant and dominated. In each tree it was measured the diameter at breast height, total height and eight crown radius following the cardinal points direction. The horizontal projection area of the crown was calculated by the average of the respective radius numbers evaluated in the crown (methods): eight, four and two. Statistical differences between among methods were verified by variance analysis with factorial arrangement, considering two factors, methods of crown area and the social position occupied by trees. The results indicated that although there was no significant difference between the mean area of crown projection when measured eight and four radius, the graphical analysis revealed tendency to overestimate the area  calculated with four and two radius in irregular crown, often identified in codominant and dominated trees. Furthermore, in relation to symmetrical crowns, determining the area of horizontal projection crown with four radius can be used without loss of accuracy

Diametric increment modeling of Pinus taeda in function of the crown variables and competition index

The objective was to generate a periodic annual basal area increment (IPAG) model for Pinus taeda valid for stands located in Rio Grande do Sul and Paraná. Temporary plots were installed in stands of Cambará do Sul and Ponta Grossa, where the tree larger diameter was considered dominant in the sample. All tree diameters at breast height and total height were measured. The dominant trees was also measured the crown diameter, crown insertion height and crown length to calculate h/d ratio, crown proportion, crown formal, coverage ratio and crown/trunk diameter ratio. An increment core was obtained from each dominant tree to calculate the IPAG the last five years. The model was built by stepwise method in the statistical package SAS® and validated by regression constraints. The variables initial diameter, crown diameter, degree of slenderness, and competition index based on the total and relative basal area were selected. The model showed high determination coefficient and low standard error of the estimate. The statistical analysis showed no difference between actual and estimated curves, showing the developed model may be used in both analyzed sites and similar sites.Objetivou-se gerar um modelo de incremento periódico em área basal (IPAG) para Pinus taeda válido para povoamentos localizados no Rio Grande do Sul e Paraná. Foram instaladas parcelas temporárias em povoamentos de Cambará do Sul (RS) e Ponta Grossa (PR), em que a árvore de maior diâmetro foi considerada dominante na parcela. De todas as árvores, foi medido o diâmetro à altura do peito e altura total, e das dominantes foi medido também o diâmetro de copa, altura de inserção da copa e comprimento de copa, para o cálculo do grau de esbeltez, proporção de copa, formal de copa, índice de abrangência e saliência. Foi retirado um rolo de incremento de todas as árvores dominantes, para o cálculo do IPAG dos últimos cinco anos. O modelo foi construído pelo método stepwise, no pacote estatístico SAS® e validado pelas condicionantes da regressão. Foram selecionadas as variáveis diâmetro inicial, diâmetro de copa, grau de esbeltez e índice de competição baseado na área basal total e relativa. O modelo apresentou alto coeficiente de determinação e baixo erro padrão da estimativa, e a análise estatística não demonstrou diferença entre as curvas reais e estimada, evidenciando o uso do modelo em ambos os locais analisados e em locais semelhantes a eles