Reemplazos electronicos online dating builddating
PROMAB, Casilla 107, Riberalta, Beni, Bolivia, ( Internet: or c/o/ Plant Ecology Group, Department of Biology, Utrecht University, PO Box 80084, 3508 TB Utrecht, the Netherlands ( R. Many studies use light requirement for successful regeneration as a basis to classify species into functional groups (e.g, Clark & Clark 1992; Poorter 1998; Peña-Claros 2001). Gispen, ingevolge het besluit van het College voor Promoties in het openbaar te verdedigen op donderdag 20 october 2005 des ochtends te uur door Roel Jacobus Wilhelmus Brienen Geboren op 21 augustus 1974 te Heerlen, Nederland Promotor: Co-promotor: Prof. To test whether species do specialise for niches along a disturbance or light gradient, information is required on abundance, spatial distribution and performance of tree species in relation to light conditions and other site conditions (e.g. Over the last decades a large number of permanent sample plots has been established and monitored in tropical forests, providing necessary data on tree abundance, distribution and performance (Condit 1995). Dynamics play a central role in many theories, and disturbances that cause these dynamics are considered crucial for species maintenance in tropical rain forests (Sheil & Burslem 2003; Baker et al. As they create spatial and temporal variation in environmental conditions (mainly light), disturbances provide different niches for which species may specialize ('niche differentiation', Denslow 1980). In particular, it is important to understand how trees respond to canopy openings (gaps) in the forest caused by tree falls, and to what extent they depend on gaps to reach the canopy. Contents Chapter 1 General Introduction 9 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Relating tree growth to rainfall in Bolivian rain forests: a test for six species using tree ring analysis 19 with P. Zuidema; Oecologia 2005 Lifetime growth patterns and ages of Bolivian rainforest trees obtained by tree ring analysis 35 with P. Zuidema; Journal of Ecology, accepted Autocorrelated growth of tropical forest trees: unraveling patterns and quantifying consequences 53 with P. These theories and hypotheses in general explain species coexistence by interspecific differences in growth conditions for which species specialize (Grubb 1977; Ricklefs 1977).Non-pioneer species do not need high light for germination and are able to survive prolonged periods in the dark forest understorey, growing at low rates.The differences between those two major groups are well known, but the majority of tropical rainforest tree species belong to the non-pioneer group (Swaine & Whitmore 1988).In recent years there has been a major debate about the ages of tropical trees.
Direct methods estimate or determine tree ages by radiocarbon dating (Stuiver & Becker 1986) or by counting of annual tree rings (Worbes et al. Indirect methods use projections of short-term growth data to estimate the ages of trees at particular size (for an overview of methods see: Martinez-Ramos & Alvarez-Buylla 1998; Baker 2003).Some methods are more suitable than others for application to tropical trees.Radiocarbon dating (a direct method) is very costly and can therefore not be used on a large scale.So far, these classifications have mainly been based on seedling performance (survival: Augspurger 1984, growth: Popma & Bongers 1988; Poorter 1998) or sapling performance (Poorter & Werger 1999), on the occurrence of saplings or larger trees under different natural light conditions (Clark & Clark 1992; Poorter & Arets 2003), or on maximum diameter growth of trees (Clark & Clark 1999).Classifications resulting from such studies are not consistent, and differences between species are less clear for large trees (Zagt & Werger 1997), which seem to share the same characteristics (Hubbel & Foster 1990; Clark & Clark 1992; Lieberman et al. One of the most important criteria that has been put forward in these classifications is whether a species requires a gap for successful regeneration (Clark & Clark 1992).
This is long compared to the periods covered by most studies on tree growth in permanent sample plots, which typically lasted for General introduction Tropical forest tree ages Comparisons of tree ages among tree species in tropical forests tell us something about the variation in life history and may be useful to classify species.