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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dendroecologia de Cedrela fissilis vell. (Meliaceae) em um ecótono de florestas subtropicais montanas no Brasil

Rauber, Rita Cristina January 2010 (has links)
Cedrela fissilis é uma espécie arbórea decídua com uma ampla distribuição de ocorrência na América Latina. Ocorre desde a Argentina até o Panamá, na América Central. É uma espécie que pode habitar áreas baixas de florestas, ao nível do mar e pode ocorrer em altitudes de até 1000 metros. Conhecida popularmente como cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. Ela pertence a um dos gêneros de espécies mais importantes de todo o mundo para a produção de madeira, sendo por isso muito explorada. Estudos dendrocronológicos podem ajudar a entender quais fatores ambientais influenciam as taxas de crescimento da formação de lenho nas plantas. Bem como podem dar informações sobre a dinâmica de populações, o desenvolvimento e a produtividade dos ecossistemas. Devido à grande amplitude de ocorrência e a formação anual nas zonas de incremento no xilema secundário, C. fissilis é uma das espécies mais promissoras para estudos dessa natureza em regiões tropicais e subtropicais na América do Sul. / Cedrela fissilis a deciduous tree, is a species with a widespread distribution in Latin America. Occurring from Argentina to Panamá and Costa Rica in Central America. It can live in lowland forests from sea level up to 1000 m. Is popularly named as cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. It belongs to a world’s economically most important timber genus from the point of view of the excellence of its wood properties, which is the reason this species has been much exploited. Dendrochronological studies would help to understand the influence of environmental factors on its growth rate and wood formation, as well as to provide valuable information on the population dynamics and on the development and productivity of ecosystems. Due to its widespread distribution and the annual formation of increment zones in the secondary xylem Cedrela fissilis is one of the most promising tree species for dendroclimatological studies in tropical and subtropical South America.
2

Dendroecologia de Cedrela fissilis vell. (Meliaceae) em um ecótono de florestas subtropicais montanas no Brasil

Rauber, Rita Cristina January 2010 (has links)
Cedrela fissilis é uma espécie arbórea decídua com uma ampla distribuição de ocorrência na América Latina. Ocorre desde a Argentina até o Panamá, na América Central. É uma espécie que pode habitar áreas baixas de florestas, ao nível do mar e pode ocorrer em altitudes de até 1000 metros. Conhecida popularmente como cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. Ela pertence a um dos gêneros de espécies mais importantes de todo o mundo para a produção de madeira, sendo por isso muito explorada. Estudos dendrocronológicos podem ajudar a entender quais fatores ambientais influenciam as taxas de crescimento da formação de lenho nas plantas. Bem como podem dar informações sobre a dinâmica de populações, o desenvolvimento e a produtividade dos ecossistemas. Devido à grande amplitude de ocorrência e a formação anual nas zonas de incremento no xilema secundário, C. fissilis é uma das espécies mais promissoras para estudos dessa natureza em regiões tropicais e subtropicais na América do Sul. / Cedrela fissilis a deciduous tree, is a species with a widespread distribution in Latin America. Occurring from Argentina to Panamá and Costa Rica in Central America. It can live in lowland forests from sea level up to 1000 m. Is popularly named as cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. It belongs to a world’s economically most important timber genus from the point of view of the excellence of its wood properties, which is the reason this species has been much exploited. Dendrochronological studies would help to understand the influence of environmental factors on its growth rate and wood formation, as well as to provide valuable information on the population dynamics and on the development and productivity of ecosystems. Due to its widespread distribution and the annual formation of increment zones in the secondary xylem Cedrela fissilis is one of the most promising tree species for dendroclimatological studies in tropical and subtropical South America.
3

Dendroecologia de Cedrela fissilis vell. (Meliaceae) em um ecótono de florestas subtropicais montanas no Brasil

Rauber, Rita Cristina January 2010 (has links)
Cedrela fissilis é uma espécie arbórea decídua com uma ampla distribuição de ocorrência na América Latina. Ocorre desde a Argentina até o Panamá, na América Central. É uma espécie que pode habitar áreas baixas de florestas, ao nível do mar e pode ocorrer em altitudes de até 1000 metros. Conhecida popularmente como cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. Ela pertence a um dos gêneros de espécies mais importantes de todo o mundo para a produção de madeira, sendo por isso muito explorada. Estudos dendrocronológicos podem ajudar a entender quais fatores ambientais influenciam as taxas de crescimento da formação de lenho nas plantas. Bem como podem dar informações sobre a dinâmica de populações, o desenvolvimento e a produtividade dos ecossistemas. Devido à grande amplitude de ocorrência e a formação anual nas zonas de incremento no xilema secundário, C. fissilis é uma das espécies mais promissoras para estudos dessa natureza em regiões tropicais e subtropicais na América do Sul. / Cedrela fissilis a deciduous tree, is a species with a widespread distribution in Latin America. Occurring from Argentina to Panamá and Costa Rica in Central America. It can live in lowland forests from sea level up to 1000 m. Is popularly named as cedro, cedro branco, cedro rosado, cedro missioneiro, cedro vermelho. It belongs to a world’s economically most important timber genus from the point of view of the excellence of its wood properties, which is the reason this species has been much exploited. Dendrochronological studies would help to understand the influence of environmental factors on its growth rate and wood formation, as well as to provide valuable information on the population dynamics and on the development and productivity of ecosystems. Due to its widespread distribution and the annual formation of increment zones in the secondary xylem Cedrela fissilis is one of the most promising tree species for dendroclimatological studies in tropical and subtropical South America.
4

ANALYSIS OF ANNUAL GROWTH PATTERNS OF MILLETTIA STUHLMANNII, IN MOZAMBIQUE

Remane, Ivan Abdul Dula 01 August 2013 (has links)
The tropical hardwood forests of Mozambique are among its most important natural resources. Long-term sustainable management of these resources will require proper forest management, which depends on understanding the growth rates and the life history of important commercial species as well as the impacts of natural forces (e.g., climate variability) and human management. This study analyzes radial growth rate dynamics and climate-growth relationships of Millettia stuhlmannii and examines its dendrochronological potential. This tree locally known as Panga-panga or Jambirre is one of the most important timber species in Mozambique. Ranked as a first class commercial timber in Mozambique, it is frequently harvested in an unsustainable way and sustainable management of the species is urgently needed for the continued utilization of this resource. Five different methods demonstrate that the semi-ring porous tree rings of M. stuhlmannii are annual: (1) Ring structure and anatomy; (2) Successful cross-dating within and between trees; (3) Ring counting in trees with known age (young trees collected from an experimental "plantation") (4) Cambial wounding and (5) Correlation between ring width and climate data. Through these methods, M. stuhlmannii trees showed distinct reaction to pinning, adding one annual ring after one year. Cross dating of annual ring width growth was successful within and among selected M. stuhlmannii trees, which indicates that this species forms annual rings and that growth responds to an external climate variability. M. stuhlmannii annual growth ring boundaries were characterized by alternating patterns of parenchyma and fibre vessels and marginal parenchyma. Precipitation during previous December (r= 0.30; p<0.05), current February (r=0.30; p<0.05) and the entire rainy season (NDJFM; r=0.43, p<0.01) over a long period (1900-1996) showed a significant influence on Panga-panga tree ring growth. Declining rainfall has caused a growth increment decrease since 1940. The results of this study show that the mean annual increment of M. stuhlmannii is 0.51 cm/year and it takes about 75 years for an average M. stuhlmannii tree to reach the minimum lawful cutting diameter of 40 cm DBH (diameter at breast height). Temporal differences in movement through increasing diameter classes are large among and within classes. The median time necessary for trees to grow into the next diameter class was not statistically significant (Kruskal-Wallis chi-squared = 9.568, p>0.001). The relationship between stem diameter and percentage of heartwood is significantly high (R2 = 0.9701, p < 0.0001) and results suggest that from 33cm diameters on, the HW% remain stable. Partial correlation coefficients show that significant effects on growth to minimum cutting diameter occur while stems move through the 20-30 cm DBH class. This indicates the specific sizes at which silviculture treatments have to be started in order to maximize the productivity of this species. Correlation analyses revealed that heartwood width (HW) is positively correlated with total stem diameter (TSD), cambial Age (Ac), number of rings in heartwood (HWR), heartwood area (HWA), Total stem diameter area (TSDA) and Mean annual increment (MAI). This study suggests that further studies to improve diameter growth rate models as well as volume increment models need to be carried out. Strong correlation with precipitation during the rainy season suggests that this species is potentially useful for future climate reconstruction studies in Mozambique.

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