RESUMO
The species Pinus taeda is largely used in intensive silviculture worldwide. This species has propagation through seeds, which requires determining seeds viability for their commercialization. The germination test recommended for this species usually requires up to 63 days to provide results on the quality of freshly harvested seeds, delaying commercialization and favoring contamination during the conduction of the test. The authors of this study aimed to establish the developmental stages of P. taeda seedlings to determine a criterion for interpreting the germination test with greater speed and efficiency to obtain results. The seeds were sown in transparent plastic boxes on two sheets of blotting paper and placed in a germinator at 22 °C with constant lighting. Five morphological stages of seedling development were defined with daily counts of the number of normal seedlings for each criterion, distribution in time, and the accumulated percentage of normal seedlings adjusted to time-to-event nonlinear regression. The new interpretation criterion proposed in this study is efficient, and P. taeda seedlings can be considered normal when cotyledon leaves differ by approximately 3 mm between the integument and hypocotyl, reducing the time to conduct the germination test by up to ten days compared to the criterion usually used in the routine analysis of seed laboratories.
Assuntos
Germinação/fisiologia , Pinus taeda/crescimento & desenvolvimentoRESUMO
Accurate forest inventory is of great economic importance to optimize the entire supply chain management in pulp and paper companies. The aim of this study was to estimate stand dominate and mean heights (HD and HM) and tree density (TD) of Pinus taeda plantations located in South Brazil using in-situ measurements, airborne Light Detection and Ranging (LiDAR) data and the non- k-nearest neighbor (k-NN) imputation. Forest inventory attributes and LiDAR derived metrics were calculated at 53 regular sample plots and we used imputation models to retrieve the forest attributes at plot and landscape-levels. The best LiDAR-derived metrics to predict HD, HM and TD were H99TH, HSD, SKE and HMIN. The Imputation model using the selected metrics was more effective for retrieving height than tree density. The model coefficients of determination (adj.R2) and a root mean squared difference (RMSD) for HD, HM and TD were 0.90, 0.94, 0.38m and 6.99, 5.70, 12.92%, respectively. Our results show that LiDAR and k-NN imputation can be used to predict stand heights with high accuracy in Pinus taeda. However, furthers studies need to be realized to improve the accuracy prediction of TD and to evaluate and compare the cost of acquisition and processing of LiDAR data against the conventional inventory procedures.
Assuntos
Modelos Estatísticos , Pinus taeda/crescimento & desenvolvimento , Tecnologia de Sensoriamento Remoto/métodos , Árvores/crescimento & desenvolvimento , Algoritmos , Brasil , Confiabilidade dos Dados , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Agricultura Florestal/métodosRESUMO
ABSTRACT Accurate forest inventory is of great economic importance to optimize the entire supply chain management in pulp and paper companies. The aim of this study was to estimate stand dominate and mean heights (HD and HM) and tree density (TD) of Pinus taeda plantations located in South Brazil using in-situ measurements, airborne Light Detection and Ranging (LiDAR) data and the non- k-nearest neighbor (k-NN) imputation. Forest inventory attributes and LiDAR derived metrics were calculated at 53 regular sample plots and we used imputation models to retrieve the forest attributes at plot and landscape-levels. The best LiDAR-derived metrics to predict HD, HM and TD were H99TH, HSD, SKE and HMIN. The Imputation model using the selected metrics was more effective for retrieving height than tree density. The model coefficients of determination (adj.R2) and a root mean squared difference (RMSD) for HD, HM and TD were 0.90, 0.94, 0.38m and 6.99, 5.70, 12.92%, respectively. Our results show that LiDAR and k-NN imputation can be used to predict stand heights with high accuracy in Pinus taeda. However, furthers studies need to be realized to improve the accuracy prediction of TD and to evaluate and compare the cost of acquisition and processing of LiDAR data against the conventional inventory procedures.
Assuntos
Árvores/crescimento & desenvolvimento , Modelos Estatísticos , Pinus taeda/crescimento & desenvolvimento , Tecnologia de Sensoriamento Remoto/métodos , Algoritmos , Brasil , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Agricultura Florestal/métodos , Confiabilidade dos DadosRESUMO
ABSTRACT Basal area (BA) is a good predictor of timber stand volume and forest growth. This study developed predictive models using field and airborne LiDAR (Light Detection and Ranging) data for estimation of basal area in Pinus taeda plantation in south Brazil. In the field, BA was collected from conventional forest inventory plots. Multiple linear regression models for predicting BA from LiDAR-derived metrics were developed and evaluated for predictive power and parsimony. The best model to predict BA from a family of six models was selected based on corrected Akaike Information Criterion (AICc) and assessed by the adjusted coefficient of determination (adj. R²) and root mean square error (RMSE). The best model revealed an adj. R²=0.93 and RMSE=7.74%. Leave one out cross-validation of the best regression model was also computed, and revealed an adj. R² and RMSE of 0.92 and 8.31%, respectively. This study showed that LiDAR-derived metrics can be used to predict BA in Pinus taeda plantations in south Brazil with high precision. We conclude that there is good potential to monitor growth in this type of plantations using airborne LiDAR. We hope that the promising results for BA modeling presented herein will stimulate to operate this technology in Brazil.
Assuntos
Florestas , Pinus taeda/crescimento & desenvolvimento , Clima Tropical , Brasil , Biomassa , Tecnologia de Sensoriamento Remoto , Modelos TeóricosRESUMO
Basal area (BA) is a good predictor of timber stand volume and forest growth. This study developed predictive models using field and airborne LiDAR (Light Detection and Ranging) data for estimation of basal area in Pinus taeda plantation in south Brazil. In the field, BA was collected from conventional forest inventory plots. Multiple linear regression models for predicting BA from LiDAR-derived metrics were developed and evaluated for predictive power and parsimony. The best model to predict BA from a family of six models was selected based on corrected Akaike Information Criterion (AICc) and assessed by the adjusted coefficient of determination (adj. R²) and root mean square error (RMSE). The best model revealed an adj. R²=0.93 and RMSE=7.74%. Leave one out cross-validation of the best regression model was also computed, and revealed an adj. R² and RMSE of 0.92 and 8.31%, respectively. This study showed that LiDAR-derived metrics can be used to predict BA in Pinus taeda plantations in south Brazil with high precision. We conclude that there is good potential to monitor growth in this type of plantations using airborne LiDAR. We hope that the promising results for BA modeling presented herein will stimulate to operate this technology in Brazil.
Assuntos
Florestas , Pinus taeda/crescimento & desenvolvimento , Biomassa , Brasil , Modelos Teóricos , Tecnologia de Sensoriamento Remoto , Clima TropicalRESUMO
This study aimed to evaluate the evolution of stem taper of trees in Pinus taeda stands using stem analysis data from 126 and 120 trees sampled from established stands in Paraná and Santa Catarina States, respectively. The integer and fractional power polynomial was fitted to estimate diameters inside bark along the stem and was used to construct taper curves by age class. The model identity test was applied to verify the change in stem form of trees. The evolution of natural and artificial form factors in the trees was also analyzed. The curves constructed from the fitted taper functions and form factors showed that the stems become more cylindrical with increasing age; the identity test indicated that, in general, the taper curves statistically differ between themselves. This showed that stratifying the data into age classes for fitting in taper functions can produce more accurate assortment estimates.(AU)
O objetivo desta pesquisa foi avaliar a evolução do afilamento dos fustes de árvores em povoamentos de Pinus taeda , utilizando dados de análise de tronco de 126 e 120 árvores amostradas, respectivamente, em plantios estabelecidos nos estados do Paraná e de Santa Catarina. O polinômio de potências inteiras e fracionárias foi ajustado para estimativa dos diâmetros sem casca ao longo do tronco e usado para construção de curvas de afilamento por classe de idade. O teste de identidade de modelos foi aplicado para verificar a mudança na forma do tronco das árvores. Foi analisada também, a evolução do fator de forma natural e artificial das árvores. As curvas construídas a partir das funções de afilamento ajustadas e os fatores de forma mostram que os troncos se tornam mais cilíndricos com o aumento da idade. O teste de identidade indicou que, em geral, as curvas de afilamento diferem estatisticamente entre si. Isso evidencia que a estratificação dos dados em classes de idades nos ajustes de funções de afilamento pode produzir estimativas mais acuradas do sortimento.(AU)
Assuntos
Pinus taeda/anatomia & histologia , Pinus taeda/crescimento & desenvolvimento , Agricultura FlorestalRESUMO
Urea fertilization decreases Pinus taeda L. growth in clay soils of subtropical areas. The negative effect of urea is related to changes in some hydraulic traits, similar to those observed in plants growing under drought. The aims of this work were (i) to determine whether different sources of nitrogen applied as fertilizers produce similar changes in growth and hydraulic traits to those observed by urea fertilization and (ii) to analyze the impact of those changes in plant drought tolerance. Plants fertilized with urea, nitrate [Formula: see text] or ammonium [Formula: see text] were grown well watered or with reduced water supply. Urea and [Formula: see text] fertilization reduced plant growth and increased root hydraulic conductance scaled by root dry weight (DW). [Formula: see text] fertilization did not reduce plant growth and increased shoot hydraulic conductance and stem hydraulic conductivity. We conclude that [Formula: see text] is the ion involved in the changes linked to the negative effect of urea fertilization on P. taeda growth. [Formula: see text] fertilization does not change drought susceptibility and it produces changes in shoot hydraulic traits, therefore plants avoid the depressive effect of fertilization. Urea and [Formula: see text] fertilizers induce changes in DW and root hydraulic conductance and consequently plants are less affected by drought.
Assuntos
Secas , Fertilizantes/análise , Pinus taeda/fisiologia , Água/metabolismo , Compostos de Amônio/metabolismo , Argentina , Nitratos/metabolismo , Pinus taeda/crescimento & desenvolvimento , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Ureia/análiseRESUMO
Plants of Pinus taeda L. from each of four families were fertilized with nitrogen (N), phosphorus (P) or N + P at planting. The H family had the highest growth in dry mass while the L family had the lowest growth. Measurements of plant hydraulic architecture traits were performed during the first year after planting. Stomatal conductance (gs), water potential at predawn (Ψpredawn) and at midday (Ψmidday), branch hydraulic conductivity (ks and kl) and shoot hydraulic conductance (K) were measured. One year after planting, dry weight partitioning of all aboveground organs was performed. Phosphorus fertilization increased growth in all four families, while N fertilization had a negative effect on growth. L family plants were more negatively affected than H family plants. This negative effect was not due to limitations in N or P uptake because plants from all the families and treatments had the same N and P concentration in the needles. Phosphorus fertilization changed some hydraulic parameters, but those changes did not affect growth. However, the negative effect of N can be explained by changes in hydraulic traits. L family plants had a high leaf dry weight per branch, which was increased by N fertilization. This change occurred together with a decrease in shoot conductance. Therefore, the reduction in gs was not enough to avoid the drop in Ψmidday. Consequently, stomatal closure and the deficient water status of the needles resulted in a reduction in growth. In H family plants, the increase in the number of needles per branch due to N fertilization was counteracted by a reduction in gs and also by a reduction in tracheid lumen size and length. Because of these two changes, Ψmidday did not drop and water availability in the needles was adequate for sustained growth. In conclusion, fertilization affects the hydraulic architecture of plants, and different families develop different strategies. Some of the hydraulic changes can explain the negative effect of N fertilization on growth.
Assuntos
Nitrogênio/farmacologia , Fósforo/farmacologia , Pinus taeda/fisiologia , Argentina , Biomassa , Fertilizantes/efeitos adversos , Variação Genética , Umidade , Nitrogênio/metabolismo , Fósforo/metabolismo , Fotossíntese/efeitos dos fármacos , Fotossíntese/fisiologia , Pinus taeda/efeitos dos fármacos , Pinus taeda/genética , Pinus taeda/crescimento & desenvolvimento , Componentes Aéreos da Planta/efeitos dos fármacos , Componentes Aéreos da Planta/genética , Componentes Aéreos da Planta/crescimento & desenvolvimento , Componentes Aéreos da Planta/fisiologia , Transpiração Vegetal/efeitos dos fármacos , Transpiração Vegetal/fisiologia , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Temperatura , Árvores , Água/fisiologiaRESUMO
Uma questão que tem sido discutida é o papel das monoculturas florestais exóticas na manutenção da fauna nativa e vários estudos têm mostrado que a remoção de propágulos é menor nesses ambientes. O presente trabalho comparou a taxa de remoção de propágulos (pinhão, amendoim, milho) entre áreas de Floresta Nativa (FN), Reflorestamentos de Pinus taeda L. (RP), de Eucalyptus saligna Sm. (RE) e Araucaria angustifolia (Bertol) Kuntze (RA). Na FN, todos os propágulos foram removidos e não houve diferença significativa na remoção de pinhão entre a FN e o RA. A remoção de propágulos nessas áreas diferiu da remoção no RP e RE. No RP, houve alta remoção de amendoim, enquanto que o RE apresentou os menores valores de remoção dos três propágulos. As baixas taxas de remoção nos reflorestamentos de pinus e eucalipto refletem a menor exploração desses habitas pela fauna, o que pode estar relacionado com um subosque pouco estruturado.
A question that has been discussed is the role that reforestations with exotic species in native fauna and several studies have shown that removal of propagules is lower in these environments. This study compared the removal rate of propagules (araucaria seeds, peanuts, corn) from areas of native forest (FN), reforestations of Pinus taeda L. (RP), Eucalyptus saligna Sm. (RE) and Araucaria angustifolia (Bertol) Kuntze (RA). In FN all propagules were removed. There was no difference in the removal of araucaria seeds between FN and RA, and removal rate in both areas differ from the removal rate in the RP and RE. In RP there was high removal of peanuts, while the RE showed the lowest value of removal of the three propagules. The low removal rates in reforestation of pine and eucalyptus reflect the decreased exploitation of these habitats for wildlife, which may be related to a poorly structured understory.
Assuntos
Florestas , Eucalyptus , Pinus taeda/crescimento & desenvolvimentoRESUMO
A substituição das florestas naturais por plantios florestais comerciais, pode ser tão prejudicial quanto a agricultura ou a ocupação urbana. Porém, estudos sobre regeneração natural nessas áreas, apresentam resultados no desenvolvimento de espécies nativas no sub-bosque, sugerindo um processo sucessional favorável à recuperação da biodiversidade e também uma alternativa para a restauração. Este estudo teve como objetivo comparar parâmetros bióticos e abióticos entre fragmento de floresta secundária nativa e reflorestamento com Pinus taeda. O trabalho foi realizado no Parque Ecológico da Klabin, Fazenda Monte Alegre, Telêmaco Borba, Paraná. Foram avaliados dados bióticos (altura total, diâmetro à altura do peito (DAP - 1,30 m do solo) e área basal (AB), das espécies arbóreas com DAP ≥ 2,5 cm) e dados abióticos ( pH e compactação do solo, cobertura de herbáceas, cobertura de dossel, espessura da serapilheira, temperatura e umidade relativa do ar). A maioria dos parâmetros diferiu entre o reflorestamento de pinus e a floresta secundária, como pH e compactação do solo, cobertura do dossel, presença de herbáceas e também a estrutura de tamanho da vegetação (diâmetro e altura). Observou-se também, uma baixa regeneração no reflorestamento, evidenciada pela diferença na área basal. No entanto, houve regeneração no reflorestamento de pinus, e isso sugere que, com o tempo, poderá haver um incremento na regeneração da vegetação nativa, aumentando a riqueza de espécies e a complexidade estrutural da vegetação.
The substitution of natural forests for commercial forest plantations can be as damaging as farming or urban occupation. However, studies on natural regeneration in these areas show results in the development of native species in the understory, suggesting a successional process in favor of restoring biodiversity as well as an alternative forrestoration. This work aimed at comparing biotic and abiotic parameters between native secondary forest fragments and Pinus taeda reforestation. The study sites are located at Klabin Ecological Park, Monte Alegre Farm, Telêmaco Borba, Paraná. The following biotic data were evaluated: total height, diameter at breast height (DBH - 1.30 m above the ground) and basal area (BA), in tree species with DBH ≥ 2.5 cm. The following abiotic data were also evaluated: pH, soil compaction, herb cover, canopy cover, litter thickness, air temperature, and relative humidity. Most parameters differed between pine reforestation and secondary forest, such as pH and soil compaction, canopy cover, herb presence and the size structure of vegetation (diameter and height). It was also observed a low regeneration in reforestation, evidenced by the difference in the basal area. However, there was regeneration in pine reforestation, suggesting that, over time, there will be an increase in the regeneration of the native vegetation, increasing the wealth of species and the structural complexity of the vegetation.