Densidade da madeira de árvores em savanas do norte da Amazônia brasileira

Densidade da madeira (DM) é uma variável importante para estimativas de estoques de carbono arbóreo em ecossistemas terrestres. Este tema é pobremente investigado em áreas de savana da Amazônia brasileira. O objetivo deste estudo foi investigar a DM das oito principais espécies arbóreas que ocorrem na savana aberta de Roraima, a maior área de savana do norte do bioma Amazônia. Foram verificadas as variações na DM em função da espécie e dos diferentes diâmetros observados ao longo da dimensão vertical de 75 indivíduos amostrados em seis sítios de coleta. Foi utilizado o método direto para obtenção de peças de madeira do fuste e da copa. Os resultados indicaram discrepância significativa interespecífica, sendo Roupala montana Aubl. a espécie de maior DM média (0,674 g cm-3). Foi detectado que existe variação significativa da DM entre as peças do fuste e da copa, independente da espécie e do sítio de coleta. A densidade da madeira de peças da copa com diâmetro entre 5 e 10 cm pode ser utilizada como preditora da DM média do indivíduo arbóreo. Nós concluimos que a DM das oito espécies arbóreas investigadas possui variabilidade interespecífica, com discrepâncias entre a DM do fuste e das partes lenhosas da copa. As distinções aqui detectadas devem ser considerados como uma importante ferramenta para melhorar as estimativas de estoque de carbono em áreas de savanas na Amazônia

Occurrence of Indigenous Plant Species in a Middle-Elevation Melaleuca Plantation on O'ahu (Hawaiian Islands)

The occurrence of native species at a middle-elevation (265-290 m) site on the island of O'ahu is of interest because of the extremely disturbed character of the vegetation and paucity of native forest species in the vicinity and at these elevations generally. 'Ohi'a (Metrosideros polymorpha) and native shrubs are understory elements in a plantation of Melaleuca quinquenervia that was planted in the early 1930s. The relatively open character of the stand (light levels underneath the canopy 20-50% of incident radiation) may allow enough penetration of light to the subcanopy for native woody plants while excluding more light-demanding alien taxa. The variety of Metrosideros present is the smooth-leaved form (M polymorpha var. glaberrima) more prevalent in the later stages of succession. The findings presented here may be an example of a tree plantation acting to foster native species and promote forest regeneration, a phenomenon that has been reported in degraded lands elsewhere in the Tropics

Tree mold evidence of Loulu Palm (Pritchardia sp.) Forest on the Kona Coast, Hawai'i

Lava flows at Pu'uhonua o Honaunau National Historical Park on the island of Hawai'i contain tree molds identified as native loulu (Pritchardia sp.) palms on the basis of gross morphology and surface features and patternings. The vegetation is reconstructed as loulu forest with an admixture of dicot species, represented by branched molds. Occurrence of loulu forest at ∼1000 B.P. (calibrated radiocarbon dates on charcoal from beneath the flow) suggests that these palms persisted into the early period of Polynesian settlement on the Kona coast and that Pritchardia was an important component of precontact vegetation in this area

A Multidimensional Multiple-Choice Knapsack Model for Resource Allocation in a Construction Equipment Manufacturer Setting Using an Evolutionary Algorithm

Part 2: Knowledge Discovery and SharingInternational audienceThis paper presents an approach to production resource allocation. The approach is applied to a real-world problem within the construction equipment manufacturing industry. A multidimensional knapsack problem formulated; was the proposed model being based on an evolutionary algorithm using a three-dimensional binary-coded chromosome. Various tests were carried out to show the appropriateness of the solution. The experiment results suggest to be satisfactory from the manufacturing company perspective