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Bernard Thibaut - One of the best experts on this subject based on the ideXlab platform.
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The decreasing radial wood stiffness pattern of some tropical trees growing in the Primary Forest is reversed and increases when they are grown in a plantation
Annals of Forest Science, 2011Co-Authors: J. Paul Mclean, Tian Zhang, Sandrine Bardet, Jacques Beauchêne, Anne Thibaut, Bruno Clair, Bernard ThibautAbstract:Background This study examines the radial trend in wood stiffness of tropical rainForest trees. The objective was to determine if the type of growing environment (exposed plantation or dense Primary Forest) would have an effect on this radial trend.
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The decreasing radial wood stiffness pattern of some tropical trees growing in the Primary Forest is reversed and increases when they are grown in a plantation
Annals of Forest Science, 2011Co-Authors: John Paul Mc Lean, Tian Zhang, Sandrine Bardet, Jacques Beauchêne, Anne Thibaut, Bruno Clair, Bernard ThibautAbstract:Background : This study examines the radial trend in wood stiffness of tropical rainForest trees. The objective was to determine if the type of growing environment (exposed plantation or dense Primary Forest) would have an effect on this radial trend. Methods : The axial elastic modulus of wood samples, representing a pith to bark cross-section, of six trees from several French Guianese species (two of Eperua falcata, one of Eperua grandiflora, two of Carapa procera and one of Symphonia gloubulifera) was measured using a dynamic "forced vibration" method. Results : Primary Forest trees were observed to have a decrease in wood stiffness from pith to bark, whereas plantation trees, from the same genus or species, displayed a corresponding increase in wood stiffness. Juvenile wood stiffness appears to vary depending on the environment in which the tree had grown. Conclusion : We suggest that the growth strategy of Primary Forest trees is to produce wood resistant to selfbuckling so that the height of the canopy may be obtained with the maximum of efficiency. In contrast, the growth strategy of the trees growing in an exposed plantation is to produce low-stiffness wood, important to provide flexibility in wind. Further experiments to study the behaviour of more species, with more individuals per species, growing across a range of physical environments, are required.
Deborah Lawrence - One of the best experts on this subject based on the ideXlab platform.
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EROSION OF TREE DIVERSITY DURING 200 YEARS OF SHIFTING CULTIVATION IN BORNEAN RAIN Forest
Ecological Applications, 2004Co-Authors: Deborah LawrenceAbstract:The long-term effect of shifting cultivation on tree diversity was examined in West Kalimantan, Indonesia. Ten sites formed a gradient of cultivation history: seven secondary Forest fallows (9–12 years old) having experienced from one to 10 prior cycles of long-fallow shifting cultivation plus three adjacent Primary Forest stands. For trees >10 cm diameter at breast height (dbh), stand-level species density was >70% lower in secondary Forest recovering from the first cycle of shifting cultivation than in nearby Primary Forest. The species density of trees 5–10 cm dbh declined only 30%, and that of stems 1000 m away. The richness of seed rain also declined with distance ...
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The impact of shifting cultivation on a rainForest landscape in West Kalimantan: spatial and temporal dynamics
Landscape Ecology, 1998Co-Authors: Deborah Lawrence, David R. Peart, Mark LeightonAbstract:To assess the role of shifting cultivation in the loss of rainForests in Indonesia, we examined the spatial and temporal dynamics of traditional land-use north of Gunung Palung National Park in West Kalimantan. We analyzed the abundance, size, frequency, and stature (by tree size) of discrete management units (patches) as a function of land-use category and distance from the village. Data were gathered from point samples along six 1.5-km transects through the landscape surrounding the Dayak village of Kembera. Most land was managed for rice, with 5% in current production, 12% in wet-rice fallows (regenerating swamp Forest), and 62% in dry-rice fallows (regenerating upland Forest). The proportion of land in dry-rice increased with distance from the village; rubber gardens (17% of the total area), dominated close to the village. The size of rubber trees declined with distance, reflecting the recent establishment of rubber gardens far from the village. Fruit gardens accounted for only 4% of the area. From interviews in Kembera and three other villages, we estimated rates of Primary Forest clearing and documented changes in land-use. Most rice fields were cleared from secondary Forest fallows. However, 17% of dry-rice fields and 9% of wet-rice fields were cleared from Primary Forest in 1990, resulting in the loss of approximately 12 ha of Primary Forest per village. Almost all dry-rice fields cleared from Primary Forest were immediately converted to rubber gardens, as were 39% of all dry-rice fields cleared from fallows. The rate of Primary Forest conversion increased dramatically from 1990 to 1995, due not to soil degradation or population growth but rather to changes in the socio-economic and political environment faced by shifting cultivators. Although the loss of Primary Forest is appreciable under shifting cultivation, the impact is less than that of the major alternative land-uses in the region: timber extraction and oil palm plantations.
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Availability and extraction of Forest products in managed and Primary Forest around a Dayak village in West Kalimantan, Indonesia
Conservation Biology, 1995Co-Authors: Deborah Lawrence, Mark Leighton, David R. PeartAbstract:We examined the density and abundance of marketable products in managed Forest (rubber gardens, fruitgardens, and dry rice fallows) and in Primary Forest surrounding the Dayak village of Kembera near Gunung Palung National Park, West Kalimantan, Indonesia We calculated the proportion of trees that were marketable and usefulfor local consumption by counting and identifying trees in each managedForest type, and we documented extraction ofproducts through interviews. Villagers harvestedfour marketable tree products: tengkawang seeds (Shorea stenoptera), durian fruits (various Durio spp.), rubber (Hevea brasilien- sis), and timber, especially Bornean ironwood (Eusideroxylon zwageri). We inventoried trees at least 20 cm diameter at breast height (dbh) of marketed species from 0.4-ha plots in Primary Forest (n = 8) and from 0.1-ha plots in each managed Forest type (n = 10-1 1). With the exception of timber, the density of trees producing a marketable product was significantly higher in theForest type managedfor thatproduct than the density of the marketed species, or of similar wild species, in Primary Forest Total abundance (product of density and available area) of durian and tengkawang was greater in Primary Forest; however, villagers gathered these products only from managed Forest. We infer from this choice a greater efficiency of harvesting from trees in dense stands near the village. Historically, this choice resulted in deliberate development offruit gardens in preference or in addition to gathering from the more distant, Primary Forest Because of low product density in Primary Forest, extractive Forest reserves or buffer zones designed to encourage the pro- duction of fruits such as tengkawang or durian may not provide a sufficient incentive for the protection of Primary Forest around Kembera and other Dayak villages near Gunung Palung National Park.
Erick C M Fernandes - One of the best experts on this subject based on the ideXlab platform.
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termite insecta isoptera species composition in a Primary rain Forest and agroForests in central amazonia
Biotropica, 2009Co-Authors: Ilse L Ackerman, Reginaldo Constantino, Hugh G Gauch, Johannes Lehmann, Susan J Riha, Erick C M FernandesAbstract:Termites play important roles in organic matter decomposition, nutrient cycling, and soil structure in tropical rain Forests. When Forests are replaced by agriculture, termite species richness, abundance, and function often decline. We compared the termite assemblage of a Primary Forest site with that of a low plant diversity, palm-based agroForest (five plant species) and a high plant diversity, home-garden agroForest (10 plant species) using a rapid biodiversity assessment protocol. In comparing the Primary Forest termite species composition to previously published studies, we found soil feeders and the Apicotermitinae to be more dominant than previously reported in Amazonia. Thirty percent of the species belonged to the Apicotermitinae, and an unusually high percentage (57%) of species were soil feeders. Unexpectedly, the palm-based agroForest, despite its lower plant diversity, was closer to Primary Forest in termite species composition, rate of species accumulation, and proportions of species in taxonomic and functional classes than was the home-garden agroForest. This suggests that particular plant attributes may better determine the termite assemblage than plant diversity alone in these agroecosystems. Unlike other agroecosystems reported in the literature, Apicotermitinae and soil feeders were proportionally more abundant in these agroForests than in Primary Forest. The ability of agroForests to support populations of soil feeders has a potentially positive effect on soil fertility in these agroecosystems; insomuch as feeding guild is a proxy for function, these closed-canopy agroForests may be able to sustain the same termite-mediated functions as Primary Forest.
Chun-ming Yuan - One of the best experts on this subject based on the ideXlab platform.
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Regeneration pattern of Primary Forest species across Forest-field gradients in the subtropical Mountains of Southwestern China
Journal of plant research, 2010Co-Authors: Wen-yao Liu, Cindy Q. Tang, Jun-wen Chen, Chun-ming YuanAbstract:Evergreen broad-leaved Forest is now gradually degraded and fragmented, and there is an increase in the amount of habitat edges as a result of long-term human activity. However, the role of edges in the regeneration of Primary Forest species is poorly understood. After 20 years of the edge creation, we analyzed Primary Forest species distribution and abundance, and changes in floristic composition, vegetation structure across Forest-field gradients in Ailao Mountain, SW China. Our results revealed that there was a higher abundance and richness of Primary species, late secondary species and thorny lianas at the distances 0–50 m than at the distances more than 50 m from the edge into the Forest exterior. At the distances >50 m, no individuals of dominant canopy trees Lithocarpus xylocarpus, Castanopsis wattii, and L. jingdongensis were found, whereas the abundance of early pioneer shrub species and herbaceous cover was significantly greater. The richness of Primary species showed a decrease with increasing distances from the Forest edge to the exterior, particularly of medium-seeded Primary species showing a drastic decrease. Moreover, no large-seeded Primary species occurred at the distances >60 m. This study indicates that the Forest edge as a buffer zone may be in favor of Primary species regeneration. A dense shrub and herb layer, and seed dispersal may be the major factors limiting the Forest regeneration farther from the Forest edge. Therefore, to facilitate Forest recovery processes, management should give priority to the protection of buffer zones of this Forest edge.
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Species composition, diversity, and abundance of lianas in different secondary and Primary Forests in a subtropical mountainous area, SW China
Ecological Research, 2009Co-Authors: Chun-ming Yuan, Cindy Q. Tang, Xiao-shuang LiAbstract:The species composition, diversity, and abundance of lianas were studied in four secondary Forests (a 100-year-old Forest, a middle-aged Forest, and two younger secondary Forests), and compared with an undisturbed Primary Forest in the Ailao Mountains of subtropical SW China. The results showed that the species composition of lianas differed greatly from the secondary Forests to the Primary Forest, which exhibit early and late-successional species. The abundance of lianas was relatively higher in the two younger and middle-aged secondary Forests than in the old-growth secondary and Primary Forests. However, liana species richness was very limited in the four secondary Forests as compared to the Primary Forest. Root climbers mainly grew in the Primary Forest, whereas tendril and hook climbers predominated in the four secondary Forests, while stem twiners were common in both. The majority of lianas recorded in this study reproduced by animal dispersal, and there was no variation in dispersal modes across the five Forest types. A step-wise regression showed that the abundance of small lianas (dbh
Sandrine Bardet - One of the best experts on this subject based on the ideXlab platform.
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The decreasing radial wood stiffness pattern of some tropical trees growing in the Primary Forest is reversed and increases when they are grown in a plantation
Annals of Forest Science, 2011Co-Authors: J. Paul Mclean, Tian Zhang, Sandrine Bardet, Jacques Beauchêne, Anne Thibaut, Bruno Clair, Bernard ThibautAbstract:Background This study examines the radial trend in wood stiffness of tropical rainForest trees. The objective was to determine if the type of growing environment (exposed plantation or dense Primary Forest) would have an effect on this radial trend.
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The decreasing radial wood stiffness pattern of some tropical trees growing in the Primary Forest is reversed and increases when they are grown in a plantation
Annals of Forest Science, 2011Co-Authors: John Paul Mc Lean, Tian Zhang, Sandrine Bardet, Jacques Beauchêne, Anne Thibaut, Bruno Clair, Bernard ThibautAbstract:Background : This study examines the radial trend in wood stiffness of tropical rainForest trees. The objective was to determine if the type of growing environment (exposed plantation or dense Primary Forest) would have an effect on this radial trend. Methods : The axial elastic modulus of wood samples, representing a pith to bark cross-section, of six trees from several French Guianese species (two of Eperua falcata, one of Eperua grandiflora, two of Carapa procera and one of Symphonia gloubulifera) was measured using a dynamic "forced vibration" method. Results : Primary Forest trees were observed to have a decrease in wood stiffness from pith to bark, whereas plantation trees, from the same genus or species, displayed a corresponding increase in wood stiffness. Juvenile wood stiffness appears to vary depending on the environment in which the tree had grown. Conclusion : We suggest that the growth strategy of Primary Forest trees is to produce wood resistant to selfbuckling so that the height of the canopy may be obtained with the maximum of efficiency. In contrast, the growth strategy of the trees growing in an exposed plantation is to produce low-stiffness wood, important to provide flexibility in wind. Further experiments to study the behaviour of more species, with more individuals per species, growing across a range of physical environments, are required.
