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New taxa in the Eriophyidae (Acari, Prostigmata) from forest trees in southern Brazil

FLECHTMANN, Carlos H. W.; QUEIROZ, Dalva L. De
Fonte: MAGNOLIA PRESS Publicador: MAGNOLIA PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.31%
Two new genera and five new species of Eriophyidae from forest trees in southern Brazil are described, namely: Juxtacolopodacus n. gen., Juxtacolopodacus phalakros n. sp. from Mollinedia clavigera Tul. (Monimiaceae); Procalacarus perporosus n. sp., from Randia armata (Sw.) (Rubiaceae); Scolotosus Flechtmann & Keifer, n. gen., Scolotosus centrolobii Flechtmann & Keifer, n. sp., from Centrolobium robustum Mart. (Leguminosae); Scolotosus hartfordi n. sp., from Centrolobium tomentosum Guill. (Leguminosae), and Metaculus tanythrix n. sp., from Dicksonia sellowiana Hook. (Dicksoniaceae).

Height-diameter relationships of tropical Atlantic moist forest trees in southeastern Brazil

Scaranello, Marcos Augusto da Silva; Alves, Luciana Ferreira; Vieira, Simone Aparecida; Camargo, Plinio Barbosa de; Joly, Carlos Alfredo; Martinelli, Luiz Antonio
Fonte: UNIV SÃO PAULO; PIRACICABA Publicador: UNIV SÃO PAULO; PIRACICABA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.36%
Site-specific height-diameter models may be used to improve biomass estimates for forest inventories where only diameter at breast height (DBH) measurements are available. In this study, we fit height-diameter models for vegetation types of a tropical Atlantic forest using field measurements of height across plots along an altitudinal gradient. To fit height-diameter models, we sampled trees by DBH class and measured tree height within 13 one-hectare permanent plots established at four altitude classes. To select the best model we tested the performance of 11 height-diameter models using the Akaike Information Criterion (AIC). The Weibull and Chapman-Richards height-diameter models performed better than other models, and regional site-specific models performed better than the general model. In addition, there is a slight variation of height-diameter relationships across the altitudinal gradient and an extensive difference in the stature between the Atlantic and Amazon forests. The results showed the effect of altitude on tree height estimates and emphasize the need for altitude-specific models that produce more accurate results than a general model that encompasses all altitudes. To improve biomass estimation, the development of regional height-diameter models that estimate tree height using a subset of randomly sampled trees presents an approach to supplement surveys where only diameter has been measured.; FAPESP; FAPESP [07/06821-5]; Thematic Project Functional Gradient [03/12595-7]; Thematic Project Functional Gradient; BIOTA/FAPESP; BIOTA/FAPESP

Análise dos padrões espaciais de árvores em quatro formações florestais do estado de São Paulo, através de análisses de segunda ordem, como a função K de Ripley.; Spatial pattern analysis of trees of four forest communities in southeastern Brazil, using Ripley’s K function.

Capretz, Robson Louiz
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/12/2004 PT
Relevância na Pesquisa
46.58%
O padrão espacial das árvores em uma floresta é influenciado por variáveis abióticas e bióticas. Entre as principais variáveis abióticas estão o relevo, a disponibilidade de luz, nutrientes e água, e a caracterização do solo. Entre as principais variáveis bióticas estão os processos dependentes da densidade, tais como a competição intraespecífica e interespecífica, a herbivoria, a ocorrência de doenças, a fenologia e dispersão de sementes. Desse modo, investigar o padrão espacial das árvores, segundo suas classes de tamanho, e segundo suas espécies mais abundantes, pode fornecer evidências sobre a estrutura da comunidade vegetal. A descrição do padrão espacial das árvores e das espécies mais abundantes em diferentes formações florestais foi realizada usando ferramentas estatésticas mais apropriadas para investigar mapas das árvores. A Função K de Ripley tem como principais vantagens a possibilidade de detectar o padrão espacial em diversas escalas de distâncias simultaneamente, e avaliar a dependência espacial entre grupos de árvores. Os padrões observados foram comparados com os modelos de Completa Aleatoriedade Espacial, para a função univariada, e de Completa Independência Espacial...

Complexidade da acumulação de elementos químicos por árvores nativas da Mata Atlântica; Complexity of the accumulation of chemical elements by native trees of the Atlantic Forest

Araújo, André Luis Lima de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 08/06/2009 PT
Relevância na Pesquisa
46.45%
Plantas acumulam elementos químicos devido aos mais variados fatores como atendimento às necessidades estruturais e fisiológicas e características ambientais. Em estudos de biomonitoração, é comum a seleção de uma espécie para a avaliação da qualidade ambiental. A bioacumulação de vários elementos químicos já foi demonstrada para as espécies arbóreas mais abundantes da Mata Atlântica na parcela permanente do Parque Estadual Carlos Botelho (PECB), uma das áreas mais preservadas da Mata Atlântica. Contudo, dado o elevado nível de alteração ambiental e a alta biodiversidade do bioma, torna-se necessário avaliar os padrões de bioacumulação em outras regiões da Mata Atlântica. Uma das areas mais significativas da Mata Atlântica para o Estado de São Paulo é o Parque Estadual da Serra do Mar (PESM), com exemplos de áreas bem preservadas e outras sob grande pressão antrópica. O núcleo Picinguaba é um dos núcleos mais conservados do parque que alcança a zona costeira. Por outro lado, o núcleo Itutinga-Pilões tem sido constantemente impactado por atividades humanas. Por exemplo, há muitos relatos sobre os efeitos da poluição na vegetação próxima aos centros urbanos e complexos industriais de São Paulo e Cubatão. Assumindo-se a hipótese de que a proximidade das unidades de conservação com o oceano e grandes centros urbanos pode influenciar a absorção de elementos químicos por plantas...

Dendrocronologia, fenologia, atividade cambial e qualidade do lenho de árvores de Cedrela odorata L., Cedrela fissilis Vell. e Schizolobium parahyba var. amazonicum Hub. ex Ducke, no estado do Acre, Brasil; Dendrochronology, phenology and cambium activity and quality of the wood trees of Cedrela odorata L., Cedrela fissilis Vell. and Schizolobium parahyba var. amazonicum Hub. ex Ducke, in Acre state, Brazil

Lobão, Moisés Silveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/05/2011 PT
Relevância na Pesquisa
46.51%
O estado do Acre possui uma vocação eminentemente florestal, devido a alta abundância natural de espécies madeireiras em um ecossistema caracterizado pela biodiversidade de espécies tropicais. Pesquisas em dendrocronologia nessa região tropical indicam que 35-50% das espécies arbóreas formam anéis de crescimento. Neste sentido, a dendrocronologia, método baseado na análise de anéis de crescimento anuais no lenho, torna-se importante ferramenta, fornecendo dados de longos períodos de crescimento e estimativas acuradas da idade das árvores, para o entendimento da dinâmica da floresta e desenvolvimento de sistemas de manejo florestal sustentados. Portanto, o objetivo dessa pesquisa foi o de estudar três espécies arbóreas de ocorrência natural no Acre, verificar a influência da quantidade total e distribuição sazonal de pluviosidade, temperatura e evapotranspiração, e os aspectos fenológicos apresentados por cada espécie, no seu crescimento em diâmetro e na qualidade do lenho produzido. O estudo foi realizado em três diferentes sítios, sendo que na Reserva Experimental Catuaba, havia três diferentes microsítios: floresta primária, borda de floresta e pastagem. Avaliou-se mensalmente o incremento em circunferência do tronco das árvores com dendrômetros e a fenologia com observações visuais das árvores das espécies selecionadas. Foram retiradas amostras de lenho no DAP do tronco para as avaliações dendrocronológicas...

Comparação de métodos não-destrutivos de cubagem de árvores em pé visando à determinação da biomassa; Comparison of non-destructive methods of wood volume determination of standing trees for biomass determination

Nicoletti, Marcos Felipe
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/10/2011 PT
Relevância na Pesquisa
46.35%
As florestas são vistas como excelentes acumuladoras de biomassa e carbono da atmosfera, contribuindo para a redução do efeito estufa. Para ter conhecimento da biomassa acumulada nas árvores é necessário realizar determinadas técnicas para levantar o volume de madeira dos povoamentos. Desta forma, objetiva-se neste trabalho estudar a qualidade das medidas de cubagem da árvore em pé através de dendrômetros ópticos de medição do tronco visando à determinação da biomassa de árvores sem amostragem destrutiva. O trabalho foi desenvolvido na Estação Experimental de Itatinga/SP que pertence a Universidade de São Paulo (ESALQ-USP). Foram amostradas 175 árvores em três parcelas de Eucalyptus grandis. O diâmetro do fuste das árvores em pé foi mensurado com os dendrômetros (Criterion 400 e RC3H) em distâncias de 0,1; 0,4; 0,7; 1,0; 1,3; 2,0 m e a partir deste de metro em metro ao longo do tronco até os 8 m de altura. Após a cubagem em pé foi derrubada a árvore e seccionada para pesagem do tronco, sendo que o diâmetro foi obtido com auxílio de suta e da trena nas mesmas posições em que se realizou a cubagem não destrutiva. De posse dos diâmetros foram calculados o volume por secção e por árvore individual através da fórmula de Smalian para posterior comparação dos métodos. Depois de seccionado o tronco...

Phenology of Atlantic rain forest trees: A comparative study

Morellato, L. Patricia C.; Talora, Daniela C.; Takahasi, Adriana; Bencke, Cinara C.; Romera, Eliane C.; Zipparro, Valescka B.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 811-823
ENG
Relevância na Pesquisa
56.54%
This paper describes the phenology of leaf, flower, and fruit phenology in the Atlantic rain forests of southeastern Brazil. For 17 months, we observed the phenological patterns of trees from two Atlantic forest types at four sites: premontane forest (Sites I and IV; the typical Atlantic rain forest) and coastal plain forest (Sites II and III). All sites experience a nonseasonal, tropical wet climate, characterized by an annual rainfall usually > 2000 mm and lacking a dry season. We tested for the occurrence (or absence) of seasonal phenological patterns within each site and compared the patterns detected among the four different forest sites using circular statistics. The expected weakly seasonal phenological patterns were not observed for these forests. Flowering and leaf flush patterns of Atlantic rain forest trees were significantly seasonal, concentrated at the beginning of the wettest season, and were significantly correlated with day length and temperature. These results stress the influence that seasonal variation in day length has on ever-wet forest tree phenology. Fruiting phenologies were aseasonal in all four forests. Flowering patterns did not differ significantly among three of the four forest sites analyzed, suggesting the occurrence of a general flowering pattern for Atlantic rain forest trees.

Seasonal variation in leaf traits between congeneric savanna and forest trees in Central Brazil: Implications for forest expansion into savanna

Rossatto, Davi Rodrigo; Hoffmann, William Arthur; de Carvalho Ramos Silva, Lucas; Haridasan, Mundayatan; Sternberg, Leonel S.L.; Franco, Augusto César
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1139-1150
ENG
Relevância na Pesquisa
46.64%
The ecology of forest and savanna trees species will largely determine the structure and dynamics of the forest-savanna boundaries, but little is known about the constraints to leaf trait variation imposed by selective forces and evolutionary history during the process of savanna invasion by forest species. We compared seasonal patterns in leaf traits related to leaf structure, carbon assimilation, water, and nutrient relations in 10 congeneric species pairs, each containing one savanna species and one forest species. All individuals were growing in dystrophic oxisols in a fire-protected savanna of Central Brazil. We tested the hypothesis that forest species would be more constrained by seasonal drought and nutrient-poor soils than their savanna congeners. We also hypothesized that habitat, rather than phylogeny, would explain more of the interspecific variance in leaf traits of the studied species. We found that throughout the year forest trees had higher specific leaf area (SLA) but lower integrated water use efficiency than savanna trees. Forest and savanna species maintained similar values of predawn and midday leaf water potential along the year. Lower values were measured in the dry season. However, this was achieved by a stronger regulation of stomatal conductance and of CO2 assimilation on an area basis (A area) in forest trees...

Características funcionais de folhas de sol e sombra de espécies arbóreas em uma mata de galeria no Distrito Federal, Brasil; Leaf functional traits in sun and shade leaves of gallery forest trees in Distrito Federal, Brazil

Rossatto, Davi Rodrigo; Takahashi, Frederico Scherr Caldeira; Silva, Lucas de Carvalho Ramos; Franco, Augusto César
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
46.36%
As matas de galeria são formações florestais que ocupam cerca de 10% da área dos cerrados e representam 1/3 da diversidade de espécies arbóreas ali encontradas. Estudos recentes têm demonstrado a importância dessas florestas em regiões do Brasil central, mas pouco se sabe sobre a fisiologia e plasticidade de espécies de mata de galeria em relação a variantes ambientais, como a irradiação solar. No presente estudo, foram comparados in situ aspectos fisiológicos e nutricionais de folhas de sol e sombra, em dez espécies arbóreas comumente encontradas em matas de galeria. Folhas de sol apresentaram maiores valores de assimilação de CO2 em base de área (Aarea), condutância estomática (gs), rendimento quântico do fotossistema II (ΦFSII) e uma maior fração de centros de reação abertos (qL), enquanto folhas de sombra apresentaram uma maior área foliar específi ca. Diferenças não foram encontradas para potencial hídrico foliar, assimilação de CO2 em base de massa e para a concentração foliar de macronutrientes. Dos atributos foliares analisados, a abertura estomática e o rendimento quântico do fotossistema II foram os principais fatores atuantes na Aarea em folhas de sol, enquanto em folhas de sombra apenas ΦFSII foi influente. As diferenças encontradas demonstram que...

Developing Post-Fire Eucalyptus globulus Stand Damage and Tree Mortality Models for Enhanced Forest Planning in Portugal

Marques, Susete; Garcia-Gonzalo, Jordi; Borges, José G.; Botequim, Brigite; Oliveira, Manuela; Tomé, José; Tomé, Margarida
Fonte: The Finnish Society of Forest Science · The Finnish Forest Research Institute Publicador: The Finnish Society of Forest Science · The Finnish Forest Research Institute
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
46.48%
Forest and fire management planning activities are carried out mostly independently of each other. This paper discusses research aiming at the development of methods and tools that can be used for enhanced integration of forest and fire management planning activities. Specifically, fire damage models were developed for Eucalyptus globulus Labill stands in Portugal. Models are based on easily measurable forest characteristics so that forest managers may predict post-fire mortality based on forest structure. For this purpose, biometric data and fire-damage descriptors from 2005/2006 National Forest Inventory plots and other sample plots within 2006, 2007 and 2008 fire areas were used. A three-step modelling strategy based on logistic regression methods was used. In the first step, a model was developed to predict whether mortality occurs after a wildfire in a eucalypt stand. In the second step the degree of damage caused by wildfires in stands where mortality occurs is quantified (i.e. percentage of mortality). In the third step this mortality is distributed among trees. Data from over 85 plots and 1648 trees were used for modeling purposes. The damage models show that relative damage increases with stand basal area. Tree level mortality models indicate that trees with high diameters...

Use of tree hollows by a Mediterranean forest carnivore

Carvalho, Filipe; Carfvalho, Rafael; Mira, António; Beja, Pedro
Fonte: Forest Ecology and Management Publicador: Forest Ecology and Management
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.53%
Although tree hollows seem to be key structures for a wide range of forest mammals, their importance for Mediterranean forest carnivores remain poorly understood. Here we address this issue, by analysing daily resting site use by 21 radio-collared common genets. Tree hollows were used far more frequently during the wet season (October–April; 73.1% of daily locations) than in the dry season (May–September; 47.6%). Nests and underground dens were the second and third most frequently used resting sites, respectively, in both wet (17.5% and 9.4%) and dry (34.1% and 18.3%) seasons. Each individual reused a large percentage of its resting sites (65.7%). Some resting sites (17.3%) were used by more than one individual, but simultaneous sharing was exceedingly rare (0.56% of daily locations). Hollow use probability during the wet season varied little in relation to environmental variables, though there was a tendency to be higher away from riparian habitats (>50 m) and to be lower in sites with very high shrub cover (>80%). Environmental influences were responsible for more variability in the dry season, when hollow usage was highest in hot days, in days with precipitation, far from riparian habitats, close to sources of human disturbance...

Hybrid zones as a tool for identifying adaptive genetic variation in outbreeding forest trees: lessons from wild annual sunflowers (Helianthus spp.)

Lexer, Christian; Heinze, Berthold; Alia, Ricardo; Rieseberg, Loren H.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/2004 EN
Relevância na Pesquisa
46.51%
The identification and study of adaptively important genes in forest trees represents a formidable challenge because of their long generation spans. In annual or perennial herbs, formal genetic studies can be employed to identify the quantitative trait loci (QTLs) and/or candidate genes that underlie important traits, and the segregating populations can be transplanted into natural populations to measure the strength and direction of selection. However, the application of these methods to forest trees is difficult, because the creation of appropriate genetic material is extremely time-consuming in long-lived, woody plants, and lifetime fitness estimates are difficult or impossible to obtain. Although QTL mapping should in principle be feasible in wild intraspecific populations (as an alternative to artificial crosses), this approach is less likely to be successful in trees because LD (linkage disequilibrium) will decay quickly in large outbreeding plant populations. Within the present paper, we discuss a modified approach based on natural hybrid zones. We describe the use of wild annual sunflowers (Helianthus spp.) as a model for exploring the hybrid zone approach. Transplanted experimental hybrids allowed us to assess the adaptive value of individual chromosomal blocks in nature...

Long-distance gene flow and adaptation of forest trees to rapid climate change

Kremer, Antoine; Ronce, Ophélie; Robledo-Arnuncio, Juan J; Guillaume, Frédéric; Bohrer, Gil; Nathan, Ran; Bridle, Jon R; Gomulkiewicz, Richard; Klein, Etienne K; Ritland, Kermit; Kuparinen, Anna; Gerber, Sophie; Schueler, Silvio
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Publicado em /04/2012 EN
Relevância na Pesquisa
46.4%
Forest trees are the dominant species in many parts of the world and predicting how they might respond to climate change is a vital global concern. Trees are capable of long-distance gene flow, which can promote adaptive evolution in novel environments by increasing genetic variation for fitness. It is unclear, however, if this can compensate for maladaptive effects of gene flow and for the long-generation times of trees. We critically review data on the extent of long-distance gene flow and summarise theory that allows us to predict evolutionary responses of trees to climate change. Estimates of long-distance gene flow based both on direct observations and on genetic methods provide evidence that genes can move over spatial scales larger than habitat shifts predicted under climate change within one generation. Both theoretical and empirical data suggest that the positive effects of gene flow on adaptation may dominate in many instances. The balance of positive to negative consequences of gene flow may, however, differ for leading edge, core and rear sections of forest distributions. We propose future experimental and theoretical research that would better integrate dispersal biology with evolutionary quantitative genetics and improve predictions of tree responses to climate change.

Impacts of Population Structure and Analytical Models in Genome-Wide Association Studies of Complex Traits in Forest Trees: A Case Study in Eucalyptus globulus

Cappa, Eduardo P.; El-Kassaby, Yousry A.; Garcia, Martín N.; Acuña, Cintia; Borralho, Nuno M. G.; Grattapaglia, Dario; Marcucci Poltri, Susana N.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 25/11/2013 EN
Relevância na Pesquisa
46.31%
The promise of association genetics to identify genes or genomic regions controlling complex traits has generated a flurry of interest. Such phenotype-genotype associations could be useful to accelerate tree breeding cycles, increase precision and selection intensity for late expressing, low heritability traits. However, the prospects of association genetics in highly heterozygous undomesticated forest trees can be severely impacted by the presence of cryptic population and pedigree structure. To investigate how to better account for this, we compared the GLM and five combinations of the Unified Mixed Model (UMM) on data of a low-density genome-wide association study for growth and wood property traits carried out in a Eucalyptus globulus population (n = 303) with 7,680 Diversity Array Technology (DArT) markers. Model comparisons were based on the degree of deviation from the uniform distribution and estimates of the mean square differences between the observed and expected p-values of all significant marker-trait associations detected. Our analysis revealed the presence of population and family structure. There was not a single best model for all traits. Striking differences in detection power and accuracy were observed among the different models especially when population structure was not accounted for. The UMM method was the best and produced superior results when compared to GLM for all traits. Following stringent correction for false discoveries...

Forest Trees in Human Modified Landscapes: Ecological and Genetic Drivers of Recruitment Failure in Dysoxylum malabaricum (Meliaceae)

Ismail, Sascha A.; Ghazoul, Jaboury; Ravikanth, Gudasalamani; Kushalappa, Cheppudira G.; Uma Shaanker, Ramanan; Kettle, Chris J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 18/02/2014 EN
Relevância na Pesquisa
46.55%
Tropical agro-forest landscapes are global priority areas for biodiversity conservation. Little is known about the ability of these landscapes to sustain large late successional forest trees upon which much forest biodiversity depends. These landscapes are subject to fragmentation and additional habitat degradation which may limit tree recruitment and thus compromise numerous ecosystem services including carbon storage and timber production. Dysoxylum malabaricum is a large canopy tree species in the Meliaceae, a family including many important tropical timber trees. This species is found in highly fragmented forest patches within a complex agro-forest landscape of the Western Ghats biodiversity hot spot, South India. In this paper we combined a molecular assessment of inbreeding with ecological and demographic data to explore the multiple threats to recruitment of this tree species. An evaluation of inbreeding, using eleven microsatellite loci in 297 nursery-reared seedlings collected form low and high density forest patches embedded in an agro-forest matrix, shows that mating between related individuals in low density patches leads to reduced seedling performance. By quantifying habitat degradation and tree recruitment within these forest patches we show that increasing canopy openness and the increased abundance of pioneer tree species lead to a general decline in the suitability of forest patches for the recruitment of D. malabaricum. We conclude that elevated inbreeding due to reduced adult tree density coupled with increased degradation of forest patches...

Seeing the fruit for the trees in Borneo

Kettle, C.; Ghazoul, J.; Ashton, P.; Cannon, C.; Chong, L.; Diway, B.; Fariday, E.; Harrison, R.; Hector, A.; Hollingsworth, P.; Koh, L.; Koo, E.; Kitayama, K.; Kartawinata, K.; Marshall, A.; Maycock, C.; Nanami, S.; Paoli, G.; Potts, M.; Samsoedin, I.; e
Fonte: Wiley-Blackwell Publishing Publicador: Wiley-Blackwell Publishing
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
46.52%
The recent mass fruiting of forest trees in Borneo is an urgent wakeup call: existing policy instruments, financial mechanisms, and forestry infrastructure are inadequate to take full advantage of these infrequent opportunities for forest restoration and conservation. Tropical forest restoration can provide substantial benefits for biodiversity conservation, climate change mitigation, and poverty alleviation. Yet the unpredictability of the synchronized flowering and consequent mass fruiting of many forest trees in Borneo presents a distinctive set of challenges for forest restoration. Significant financing and a considerable coordinated effort are required to prepare for future mass fruiting events if we are to capitalize on opportunities for ecological restoration. The continued high rate of forest clearance in this region and the rarity of mass fruiting events suggest that there may be few remaining opportunities to prevent widespread species extinctions. In this article we propose a facilitatory policy framework for forest restoration in Borneo to stimulate action in advance of the next mass fruiting of forest trees.; Chris J. Kettle ... Lian Pin Koh ... et al

Wood specific gravity of trees and forest types in the southern Peruvian Amazon

WOODCOCK,Deborah W.
Fonte: Instituto Nacional de Pesquisas da Amazônia Publicador: Instituto Nacional de Pesquisas da Amazônia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2000 EN
Relevância na Pesquisa
46.54%
Estimates of terrestrial biomass depend critically on reliable information about the specific gravity of the wood of forest trees. The study reported on here was carried out in the southern Peruvian Amazon and involved collection of wood samples from trees (70 spp.) in intact forest stands. Results demonstrate the high degree of variability in specific gravity (ovendry weight/green volume) in trees at single locations. Three forest types (swamp, high terrace forest with alluvial soil, and sandy-soil forest) had values close to the average reported for tropical forest woods (.69). Two early successional forest types, which make up as much as 12% of the total vegetated area in this part of the Amazon, had values significantly lower (.40). An increase in specific gravity with increasing age of the tree, which has been reported in some spe cies of tropical-forest woods, is seen in a positive relationship between specific gravity and di ameter for a species prevalent in one plot. Increases in specific gravity with tree and forest age may be significant in estimating changes in carbon stores over time.

Forest, Trees, and Woodlands in Africa : An Action Plan for World Bank Engagement

Bromhead, Marjory-Anne
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Economic & Sector Work :: Other Environmental Study; Economic & Sector Work
ENGLISH; EN_US
Relevância na Pesquisa
46.56%
The purpose of this paper is to outline an approach for Bank engagement in forests, trees, and woodlands on farms in Sub-Saharan Africa for the coming five years. The paper takes the framework of the Africa development strategy, which has two main pillars: supporting employment and competitiveness, and building resilience and reducing vulnerability; and one underlying foundation: strengthening capacity and governance. It is consistent with the pillars of the bank forest strategy from 2002, which highlight the contribution of forests to economic development, poverty reduction, and protection of global public goods. Several other World Bank corporate strategies are also relevant for the implementation of this action plan. The primary messages of this paper are linked: enhanced forest, tree and woodland management can play a key role in achieving the goals of the Africa Strategy. Employment generation, improving competitiveness as well as building resilience and reducing vulnerability are the overall objectives of the World Bank's forest engagement in Sub-Saharan Africa; and in many countries the most effective approaches will be outside the traditional forestry institutions and will involve working through operations and reforms supported through other sectors.

Effects of an intense ice storm on the structure of a northern hardwood forest

Rhoads, Anne; Hamburg, Steven; Fahey, Timothy; Siccama, Thomas; Hane, Elizabeth; Battles, John; Cogbill, Charles; Randall, Jesse; Wilson, Geoff
Fonte: National Research Council Canada: Canadian Journal of Forest Research Publicador: National Research Council Canada: Canadian Journal of Forest Research
Tipo: Artigo de Revista Científica Formato: 39576 bytes; application/pdf
EN_US
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46.52%
A major ice storm in January 1998 provided an opportunity to study the effects of a rare, intense disturbance on the structure of the northern hardwood forest canopy. Canopy damage was assessed using visual damage classes within watersheds of different ages at the Hubbard Brook Experimental Forest (HBEF) and changes in leaf area index in two of these watersheds. Ice thickness was measured, and ice loads of trees were estimated using regression equations. In the 60- to 120-year-old forests (mean basal area 26 m2•ha–1), damage was greatest in trees >30 cm diameter at breast height and at elevations above 600 m. Of the dominant tree species, beech (Fagus grandifolia Ehrh.) was the most damaged, sugar maple (Acer saccharum Marsh.) was the most resistant, and yellow birch (Betula alleghaniensis Britt.) was intermediate. Trees with advanced beech bark disease experienced heavier ice damage. Little damage occurred in the 14-year-old forest, while the 24- to 28-year-old forest experienced intense damage. In the young stands of this forest, damage was greatest between 600 and 750 m, in trees on steep slopes and near streams, and among pin cherry (Prunus pensylvanica L.). Recovery of the canopy was tracked over three growing seasons, and root growth was monitored 1 year after the storm. Because of the high density of advance regeneration from beech bark disease and root sprouting potential in ice-damaged beech...

Nitrogen and phosphorus resorption in a neotropical rain forest of a nutrient-rich soil

Martínez-Sánchez,José Luis
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2005 EN
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In tropical forests with nutrient-rich soil tree’s nutrient resorption from senesced leaves has not always been observed to be low. Perhaps this lack of consistence is partly owing to the nutrient resorption methods used. The aim of the study was to analyse N and P resorption proficiency from tropical rain forest trees in a nutrient-rich soil. It was hypothesised that trees would exhibit low nutrient resorption in a nutrient-rich soil. The soil concentrations of total N and extractable P, among other physical and chemical characteristics, were analysed in 30 samples in the soil surface (10 cm) of three undisturbed forest plots at ‘Estación de Biología Los Tuxtlas’ on the east coast of Mexico (18°34’ - 18°36’ N, 95°04’ - 95°09’ W). N and P resorption proficiency were determined from senescing leaves in 11 dominant tree species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid. Soil was rich in total N (0.50%, n = 30) and extractable P (4.11 µg g-1, n = 30). As expected, trees showed incomplete N (1.13%, n = 11) and P (0.11%, n = 11) resorption. With a more accurate method of nutrient resorption assessment...