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The dynamics of species composition, stand structure and aboveground biomass were studied over a 4.3-yr period (December 2004 – April 2009) in a lowland dipterocarp forest of Samboja, East Kalimantan. This study was conducted in six permanent sample plots (100 m x 100 m each) distributed over an area of 26.5 ha of Samboja Research Forest. All woody plants = 10 cm dbh (diameter at 1.3 m aboveground) were identified. In December 2004, 2.143 trees were measured in the six plots, consisting of 39 families, 82 genera and 111 species. The condition in April 2009 (after 4.3 yr) was: 2,466 trees, 40 families, 86 genera and 123 species. Most species were found in both occasions. Fourteen new species were registered, which contributed to 9.8% of a net addition of the total number of species found in the six plots. Over the 4.3-yr period, there was also an increase of 15.1% in density, 12.9% in basal area, and 11.6% in aboveground biomass, respectively. The density increased from 357 to 411 trees per ha; the basal area increased from 20.09 to 22.67 m2 ha-1; and the aboveground biomass increased from 286.3 to 319.4 ton ha. The family Dipterocarpaceae was the richest in species (more than 20 species found in both occasions), followed by Euphorbiaceae, Burseraceae, Fabaceae, and Anacardiaceae (more than five species). Most genera (80%) contained just one species, but Shorea with 13 species was the richest. Four families (Dipterocarpaceae, Fabaceae, Myrtaceae and Lauraceae) contained more than 80% of the aboveground biomass in both occasions (75% of them from Dipterocarpaceae family). The increases in species richness and density did not cause any significant differences in the diversity index and diameter distribution. This condition suggested that forest vegetation of the study site maintains its diversity composition and structural features over the period of study.

O Pinheiro-manso tem sido uma das espécies mais utilizadas nas acções de arborização nos últimos anos, o que implica uma significativa alteração na estrutura da paisagem rural e uma nova perspectiva de gestão sustentável no médio e longo prazo de forma a preservar a sua multifuncionalidade. Os modelos de crescimento permitem a análise das implicações de diferentes estratégias de gestão de uma forma economicamente eficiente, sendo em reduzido número os que foram desenvolvidos para esta espécie, além de incidirem nas áreas consideradas de maior produtividade. Pretende-se desenvolver um modelo de crescimento espacial assente na recolha de dados dendrométricos em parcelas permanentes instaladas em duas áreas sob gestão distintas. A consideração das preferências do público para o recreio e para outras características, como a estética da paisagem, é um aspecto relevante no estabelecimento dos diferentes cenários de gestão. Pretende-se avaliar a disponibilidade em alterar a gestão dos povoamentos tendo em vista a melhoria da sua atractividade visual e identificar as acções que possibilitariam melhorar a potencialidade para o recreio; #### Pinus pinea L. has been one of the most used species in forestations in the last decades, which implies a significant alteration in the structure of the rural landscape and a new perspective on sustainable management that is in a way it preserves its multifuncionality. Growth models allow an analysis of different management strategies in order to attain an economical efficiency, but until now few models have been developed for this species and the ones that have been developed are for areas of high productivity. It is the aim of this work to develop a growth model based on dendrometric data, obtained in permanent plots in two public areas. Taking into account public preferences for recreation and other characteristics such as landscape aesthetics is a relevant aspect in the establishment of different management scenarios. One of the goals is to evaluate the will to change forest management in order to improve its visual attractivity and identify the actions that can improve recreation potentialities.

International audience; The spatial distribution of tillers within a pure grass stand and fluctuation over time result from an interaction between environmental factors and tiller population behaviour. Simulating the latter would provide a tool for ecological analysis. The population behaviour is composed of death, displacement and birth of tillers, the birth coming from clonal processes in perennial grasses. On each tiller, every time a new leaf becomes adult, its axillary bud can grow, according to an evaluation of the environment and of the neighbourhood. If the ratio of red to far-red light is low enough and if the level of available nitrogen is high enough, the bud is put in growth. Otherwise, it becomes dormant. After a gestation period, a new daughter tiller is born close to its mother. Other new tillers can be born farther from an existing tiller, after growth of dormant buds through the old sheaths. Most tillers die at vegetative stage, mainly when they are young and when they are dominated by the canopy. On this basis, an individual-based, discrete events and spatial simulator was built. The space is managed both by indices of cells and by continuous coordinates. Environmental conditions are given by external files. The tillering is mechanistic, according to the positions of the neighbouring tillers and to environmental data. The death is stochastic. Tillers are placed and move according to given rules. The simulator accurately reproduced the fine-scale spatial heterogeneity of the local tiller densities in a pure tall-fescue sward observed eight times throughout 2 years. In spite of necessary improvements, this modelling shows the determining part of plant processes in the observed heterogeneity and in its dynamics.