Browsing by Autor "Pieter A. Zuidema"

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15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods
(Frontiers Media, 2015) Peter van der Sleen; Mart Vlam; Peter Groenendijk; Niels P. R. Anten; Frans Bongers; Sarayudh Bunyavejchewin; Peter Hietz; Thijs L. Pons; Pieter A. Zuidema
Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated (15)N abundance (δ(15)N) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of (15)N-depleted nitrate from the soil, following anthropogenic nitrogen deposition over the last decades. To find further evidence for altered nitrogen cycling in tropical forests, we measured long-term δ(15)N values in trees from Bolivia, Cameroon, and Thailand. We used two different sampling methods. In the first, wood samples were taken in a conventional way: from the pith to the bark across the stem of 28 large trees (the "radial" method). In the second, δ(15)N values were compared across a fixed diameter (the "fixed-diameter" method). We sampled 400 trees that differed widely in size, but measured δ(15)N in the stem around the same diameter (20 cm dbh) in all trees. As a result, the growth rings formed around this diameter differed in age and allowed a comparison of δ(15)N values over time with an explicit control for potential size-effects on δ(15)N values. We found a significant increase of tree-ring δ(15)N across the stem radius of large trees from Bolivia and Cameroon, but no change in tree-ring δ(15)N values over time was found in any of the study sites when controlling for tree size. This suggests that radial trends of δ(15)N values within trees reflect tree ontogeny (size development). However, for the trees from Cameroon and Thailand, a low statistical power in the fixed-diameter method prevents to conclude this with high certainty. For the trees from Bolivia, statistical power in the fixed-diameter method was high, showing that the temporal trend in tree-ring δ(15)N values in the radial method is primarily caused by tree ontogeny and unlikely by a change in nitrogen cycling. We therefore stress to account for tree size before tree-ring δ(15)N values can be properly interpreted.
A monocarpic tree species in a polycarpic world: how can Tachigali vasquezii maintain itself so successfully in a tropical rain forest community?
(Wiley, 2005) Lourens Poorter; Pieter A. Zuidema; Marielos Peña‐Claros; René Boot
Summary Although monocarpy is rare among long‐lived plant species that grow in stable habitats, one monocarpic species, Tachigali vasquezii , is extremely abundant in the rain forests of the Bolivian Amazon. We analyse how T. vasquezii is able to maintain itself successfully by comparing its life‐history traits with those of polycarpic tree species of the same community. We then evaluate the relative importance of such traits using population matrix models. Monocarpic species are expected to have a high fecundity. Seed production per basal area for T. vasquezii is indeed nearly twice that of an average polycarpic species, but this is not sufficient to maintain stable populations. Life‐history theory predicts that a monocarpic strategy is advantageous if juvenile survival rates are high compared with adult survival. Although seedlings of T. vasquezii have a lower mortality rate than polycarpic species, its sapling have higher mortality. We found that the success of T. vasquezii is due to its very high diameter growth rates in the larger size classes, which are four times higher than that of an average, co‐occurring polycarpic species. Fast diameter growth is enabled by investment in large, leafy crowns and by a low wood density. Applying this high diameter growth in a population model yielded a population growth rate close to that of polycarpic species. Life table response experiment analysis of Tachigali and polycarp models showed that higher growth compensated for the negative demographic effect of 100% adult mortality following reproduction. Rapid growth enables T. vasquezii to reach reproductive maturity in only 49 years, compared with 79 years for an average polycarpic species. It also reduces the risk of dying before reproducing, and 50% more seedlings survive to maturity for T. vasquezii compared with polycarpic species. The dramatic negative demographic consequences of one‐time flowering can therefore be completely balanced by taking a shorter time to reach maturity. Taking a time perspective, it appears that Tachigali vasquezii has an advanced, rather than a delayed, reproduction.
Assessing long-term changes in tropical forest dynamics: a first test using tree-ring analysis
(Springer Science+Business Media, 2010) Danaë M. A. Rozendaal; Claudia C. Soliz‐Gamboa; Pieter A. Zuidema
There is growing evidence that tree turnover in tropical forests has increased over the last decades in permanent sample plots. This phenomenon is generally attributed to the increase in atmospheric CO2, but other causes cannot be ruled out. A proper evaluation of historical shifts in tree turnover requires data over longer periods than used so far. Here, we propose two methods to use tree-ring data for detecting long-term changes in tree turnover. We apply these methods to two non-pioneer tree species in a Bolivian moist forest. First, we checked for temporal changes in the frequency of growth releases to determine whether this frequency has increased over time. Second, we calculated the degree of temporal autocorrelation—a measure that indicates temporal changes in growth rates that are likely related to canopy dynamics—and checked for changes in this parameter over time. In addition, we performed analyses that corrected for ontogenetic increases in the measures used by analyzing residuals from size–growth relations. No evidence for the occurrence of a large-scale disturbance was found as we did not observe synchronization in the occurrence of releases in time. For both species, we did not detect changes in autocorrelation or release frequency over the last 200–300 years. Only in one size category, we found increased release frequency over time, probably as a result of a remaining ontogenetic effect. In all, our analyses do not provide evidence for long-term changes in tree turnover in the study area. We discuss the suitability of the proposed methods.
Chemical differentiation of Bolivian Cedrela species as a tool to trace illegal timber trade
(Oxford University Press, 2018) Kathelyn Paredes-Villanueva; Edgard O. Espinoza; Jente Ottenburghs; Mark G. Sterken; Frans Bongers; Pieter A. Zuidema
Combating illegal timber trade requires the ability to identify species and verify geographic origin of timber. Forensic techniques that independently verify the declared species and geographic origin are needed, as current legality procedures are based on certificates and documents that can be falsified. Timber from the genus Cedrela is among the most economically valued tropical timbers worldwide. Three Cedrela species are included in the Appendix III of CITES: C. fissilis, C. odorata and C. angustifolia (listed as C. lilloi). Cedrela timber is currently traded with false origin declarations and under a different species name, but tools to verify this are lacking. We used Direct Analysis in Real Time Time-of-Flight Mass Spectrometry (DART-TOFMS) to chemically identify Cedrela species and sites of origin. Heartwood samples from six Cedrela species (the three CITES-listed species plus C. balansae, C. montana and C. saltensis) were collected at 11 sites throughout Bolivia. Mass spectra detected by DART-TOFMS comprised 1062 compounds; their relative intensities were analysed using Principal Component Analyses, Kernel Discriminant Analysis (KDA) and Random Forest analyses to check discrimination potential among species and sites. Species were identified with a mean discrimination error of 15–19 per cent, with substantial variation in discrimination accuracy among species. The lowest error was observed in C. fissilis (mean = 4.4 per cent). Site discrimination error was considerably higher: 43–54 per cent for C. fissilis and 42–48 per cent for C. odorata. These results provide good prospects to differentiate C. fissilis from other species, but at present there is no scope to do so for other tested species. Thus, discrimination is highly species specific. Our findings for tests of geographic origin suggest no potential to discriminate at the studied scale and for the studied species. Cross-checking results from different methods (KDA and Random Forest) reduced discrimination errors. In all, the DART-TOFMS technique allows independent verification of claimed identity of certain Cedrela species in timber trade.
Climate is a stronger driver of tree and forest growth rates than soil and disturbance
(Wiley, 2010) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; Claudio Leaño; Juan Carlos Licona; Oscar Llanque; Vincent Vroomans; Pieter A. Zuidema
Summary 1. Essential resources such as water, nutrients and light vary over space and time and plant growth rates are expected to vary accordingly. We examined the effects of climate, soil and logging disturbances on diameter growth rates at the tree and stand level, using 165 1‐ha permanent sample plots distributed across Bolivian tropical lowland forests. 2. We predicted that growth rates would be higher in humid than in dry forests, higher in nutrient‐rich than nutrient‐poor forests and higher in logged than non‐logged forests. 3. Across the 165 plots we found positive basal area increases at the stand level, which agree with the generally reported biomass increases in tropical forests. 4. Multiple regression analysis demonstrated that climate variables, in particular water availability, were the strongest drivers of tree growth. More rainfall, a shorter and less intense dry period and higher temperatures led to higher tree growth rates. 5. Tree growth increased modestly with soil fertility and basal area growth was greatest at intermediate soil fertility. Surprisingly, tree growth showed little or no relationship with total soil nitrogen or plant available soil phosphorus. 6. Growth rates increased in logged plots just after logging, but this effect disappeared after 6 years. 7. Synthesis . Climate is the strongest driver of spatial variation in tree growth, and climate change may therefore have large consequences for forest productivity and carbon sequestration. The negative impact of decreased rainfall and increased rainfall seasonality on tree growth might be partly offset by the positive impact of increased temperature in these forests.
Commercial Logging of Timber Species Enhances Amazon (Brazil) Nut Populations: Insights from Bolivian Managed Forests
(Multidisciplinary Digital Publishing Institute, 2021) Marlene Soriano; Pieter A. Zuidema; Cristina Barber; G.M.J. Mohren; Nataly Ascarrunz; Juan Carlos Licona; Marielos Peña‐Claros
A typical case of multiple-use forest management (MFM) in Southwestern Amazon is the commercial harvesting of Amazon or Brazil nut (Bertholletia excelsa) seeds and of timber of other tree species. Although the Amazon nut is the most important non-timber forest product (NTFP) in the Amazon basin, the species is under serious threat due to deforestation and may also be affected by overharvesting. However, selective logging of other tree species coexisting with Bertholletia may positively affect Bertholletia populations, thus enabling a special case for MFM. For this research, we investigated the impact of the intensity of Amazon nut harvesting and timber logging on Bertholletia populations in the Bolivian Amazon. We used demographic data from 72 two-hectare transects located within 24 community-based household forests varying in the intensity of nut collection (0–100%) and timber logging (0–15% of logging-disturbed forest area). Simulated Bertholletia population size increased with logging intensity but decreased with Amazon nut harvesting intensity. Bertholletia populations were projected to grow at the average MFM harvesting scenario tested: 57.4% of nut harvesting, 5.3% of logging-disturbed area (λ100 = 1.011). Our simulations also revealed that up to 89% of Amazon nut seeds can be harvested while sustaining Bertholletia populations, under 15% of logging-disturbed area, and applying liana cutting. Modest levels of timber logging and application of liana cutting may compensate for the negative effect of Amazon nut collection on Bertholletia populations for the next century. Our study demonstrates that Amazon nut and timber production could be combined in a sustainable MFM scheme, thus increasing the economic value of managed tropical forests and its promotion to reduce the increasing pressure by deforestation.
Detecting evidence for CO2 fertilization from tree ring studies: The potential role of sampling biases
(Wiley, 2012) Roel Brienen; Emanuel Gloor; Pieter A. Zuidema
Tree ring analysis allows reconstructing historical growth rates over long periods. Several studies have reported an increasing trend in ring widths, often attributed to growth stimulation by increasing atmospheric CO 2 concentration. However, these trends may also have been caused by sampling biases. Here we describe two biases and evaluate their magnitude. (1) The slow ‐ grower survivorship bias is caused by differences in tree longevity of fast‐ and slow‐growing trees within a population. If fast‐growing trees live shorter, they are underrepresented in the ancient portion of the tree ring data set. As a result, reconstructed growth rates in the distant past are biased toward slower growth. (2) The big ‐ tree selection bias is caused by sampling only the biggest trees in a population. As a result, slow‐growing small trees are underrepresented in recent times as they did not reach the minimum sample diameter. We constructed stochastic models to simulate growth trajectories based on a hypothetical species with lifetime constant growth rates and on observed tree ring data from the tropical tree Cedrela odorata . Tree growth rates used as input in our models were kept constant over time. By mimicking a standard tree ring sampling approach and selecting only big living trees, we show that both biases lead to apparent increases in historical growth rates. Increases for the slow‐grower survivorship bias were relatively small and depended strongly on assumptions about tree mortality. The big‐tree selection bias resulted in strong historical increases, with a doubling in growth rates over recent decades. A literature review suggests that historical growth increases reported in many tree ring studies may have been partially due to the big‐tree sampling bias. We call for great caution in the interpretation of historical growth trends from tree ring analyses and recommend that such studies include individuals of all sizes.
Diameter Growth of Juvenile Trees after Gap Formation in a Bolivian Rain Forest: Responses are Strongly Species‐specific and Size‐dependent
(Wiley, 2011) Claudia C. Soliz‐Gamboa; Anne Sandbrink; Pieter A. Zuidema
ABSTRACT We evaluated growth responses to gap formation for juvenile individuals of three canopy rain forest species: Peltogyne cf. heterophylla, Clarisia racemosa and Cedrelinga catenaeformis . Gaps were formed during selective logging operations 7 yr before sampling in a Bolivian rain forest. We collected wood samples for tree‐ring analyses at different distances to the stump (<10, 10–40 and >40 m) and from trees with different diameters (5–30 cm diameter at breast height [dbh]). Tree‐rings width was measured in at least two radii and converted to average diameter growth. Changes in 7‐yr median diameter growth before and after selective logging were analyzed. Diameter growth rates significantly increased by 0.7–0.8 mm/yr after gap formation for P. heterophylla and C. catenaeformis , but not for C. racemosa . We applied a multiple regression analysis to explain variation in growth responses of P. heterophylla and C. catenaeformis by distance to logging gap and tree size. For P. heterophylla we found that growth increase occurring close to logging gaps was strongest for large juvenile trees (20–25 cm dbh) and almost absent in small juveniles. For C. catenaeformis , variation in growth responses was not related to tree size or distance to gaps. Our results show that growth responses to gap formation strongly differ across species and tree sizes. This finding calls for caution in the interpretation of growth releases in tree‐ring series, as gap formation does not necessarily invoke growth responses and if such growth responses occur, their strength is species‐ and size specific.
Does biomass growth increase in the largest trees? Flaws, fallacies and alternative analyses
(Wiley, 2016) Douglas Sheil; Chris S. Eastaugh; Mart Vlam; Pieter A. Zuidema; Peter Groenendijk; Peter van der Sleen; Alex Jay; Jerome K. Vanclay
Summary The long‐standing view that biomass growth in trees typically follows a rise‐and‐fall unimodal pattern has been challenged by studies concluding that biomass growth increases with size even among the largest stems in both closed forests and in open competition‐free environments. We highlight challenges and pitfalls that influence such interpretations. The ability to observe and calibrate biomass change in large stems requires adequate data regarding these specific stems. Data checking and control procedures can bias estimates of biomass growth and generate false increases with stem size. It is important to distinguish aggregate and individual‐level trends: a failure to do so results in flawed interpretations. Our assessment of biomass growth in 706 tropical forest stems indicates that individual biomass growth patterns often plateau for extended periods, with no significant difference in the number of stems indicating positive and negative trends in all but one of the 14 species. Nonetheless, when comparing aggregate growth during the most recent five years, 13 out of our 14 species indicate that biomass growth increases with size even among the largest sizes. Thus, individual and aggregate patterns of biomass growth with size are distinct. Claims concerning general biomass growth patterns for large trees remain unconvincing. We suggest how future studies can improve our knowledge of growth patterns in and among large trees. A lay summary is available for this article.
Driving factors of forest growth: a reply to Ferry et al. (2012)
(Wiley, 2012) Marisol Toledo; Lourens Poorter; Marielos Peña‐Claros; Alfredo Alarcón; Julio Balcázar; Claudio Leaño; Juan Carlos Licona; Oscar Llanque; Vincent Vroomans; Pieter A. Zuidema
Summary 1. In a recent paper, we analysed the effects of climate, soil and logging disturbance on tree and forest growth (Toledo et al. 2011a). We took advantage of one of the largest data sets in the Neotropics, consisting of 165 1‐ha plots and over 62 000 trees distributed over an area of c. 160 000 km 2 , across large environmental gradients in lowland Bolivia. The main findings were that climate was the strongest driver of spatial variation in tree growth, whereas soils had only a modest effect on growth and that the effect of logging disappeared after a few years. 2. Ferry et al. (2012) suggest that we underestimated the disturbance effects on growth because of a supposedly wrong coding of Time After Logging (TAL) for unlogged plots. Although we have good biological reasons why we coded TAL like we did, we checked Ferry et al. ’s suggestions for recoding and found no differences in variables that significantly explained tree and forest growth. We agree, however, that for future research, it is important to go beyond simple descriptors such as time after logging and basal area logged, to better describe the variation in logging impact found in areas under forest management. 3. Ferry et al. claim that we did not define basal area growth properly. We believe this is a semantic issue, as we clearly defined basal area growth as the net change in basal area. This net basal area change in Bolivian forests is indeed relatively high compared to other studies, which may be attributed to the higher soil fertility and biogeographic differences in species composition and their traits. 4. Synthesis . Many apparent discrepancies in the ecological literature arise because tropical forest ecologists tend to see the world from the perspective of their ‘own’ forest (despite clear biogeographic differences) and try to capture the same ecological processes using different variables and measurement protocols. To advance our understanding and go beyond single‐case studies, we need to assemble large databases, quantify forest dynamics and disturbances in similar ways, be aware of differences among forests and analyse environmental dose–response curves.
Economically important species dominate aboveground carbon storage in forests of southwestern Amazonia
(Resilience Alliance, 2017) N. Galia Selaya; Pieter A. Zuidema; Christopher Baraloto; Vincent Antoine Vos; Roel Brienen; Nigel C. A. Pitman; Foster Brown; Amy E. Duchelle; Alejandro Araujo‐Murakami; Luis A. Oliveira Carillo
Selaya, N. G., P. A. Zuidema, C. Baraloto, V. A. Vos, R. J. W. Brienen, N. Pitman, F. Brown, A. E. Duchelle, A. Araujo-Murakami, L. A. Oliveira Carillo, G. H. Vasquez Colomo, S. Meo Chupinagua, H. Fuentes Nay, and S. Perz. 2017. Economically important species dominate aboveground carbon storage in forests of southwestern Amazonia. Ecology and Society 22(2):40. https://doi.org/10.5751/ES-09297-220240
Evaluating the annual nature of juvenile rings in Bolivian tropical rainforest trees
(Springer Science+Business Media, 2010) Claudia C. Soliz‐Gamboa; Danaë M. A. Rozendaal; Gregório Ceccantini; Verônica Angyalossy; Klaas van der Borg; Pieter A. Zuidema
Genetic differences among Cedrela odorata sites in Bolivia provide limited potential for fine-scale timber tracing
(Springer Science+Business Media, 2019) Kathelyn Paredes-Villanueva; G.A. de Groot; Ivo Laros; J. Bovenschen; Frans Bongers; Pieter A. Zuidema
Long-term growth patterns of juvenile trees from a Bolivian tropical moist forest: shifting investments in diameter growth and height growth
(Cambridge University Press, 2015) Danaë M. A. Rozendaal; Heinjo J. During; Frank J. Sterck; Daan Asscheman; Jeroen Wiegeraad; Pieter A. Zuidema
Abstract: Juvenile tropical trees grow from the shaded understorey to the high-light conditions of the canopy, but actual height growth trajectories towards the canopy remain unknown. Although height growth is the determining factor for reaching the canopy, investment in diameter growth is needed to sustain mechanical stability. We quantified variation in long-term juvenile tree growth patterns in diameter and height within three Bolivian moist forest species, and evaluated whether diameter growth and height growth were related. We reconstructed lifetime growth in diameter and height for 21–27 juvenile trees per species by measuring tree rings at various heights in the stem. Growth in diameter and height strongly varied among and within tree species. The light-demanding species Cedrelinga cateniformis needed just 6–19 y to reach a height of 3 m, while the more shade-tolerant species Clarisia racemosa and Peltogyne cf. heterophylla needed 8–39 y and 13–43 y, respectively. Diameter growth and height growth were not, or just weakly, positively related, and trees of the same height displayed a wide range in stem diameter. Our results indicate that trees of all three species shifted investment in diameter growth and height growth over time, most likely in response to variation in light levels.
No evidence for consistent long‐term growth stimulation of 13 tropical tree species: results from tree‐ring analysis
(Wiley, 2015) Peter Groenendijk; Peter van der Sleen; Mart Vlam; Sarayudh Bunyavejchewin; Frans Bongers; Pieter A. Zuidema
The important role of tropical forests in the global carbon cycle makes it imperative to assess changes in their carbon dynamics for accurate projections of future climate-vegetation feedbacks. Forest monitoring studies conducted over the past decades have found evidence for both increasing and decreasing growth rates of tropical forest trees. The limited duration of these studies restrained analyses to decadal scales, and it is still unclear whether growth changes occurred over longer time scales, as would be expected if CO2 -fertilization stimulated tree growth. Furthermore, studies have so far dealt with changes in biomass gain at forest-stand level, but insights into species-specific growth changes - that ultimately determine community-level responses - are lacking. Here, we analyse species-specific growth changes on a centennial scale, using growth data from tree-ring analysis for 13 tree species (~1300 trees), from three sites distributed across the tropics. We used an established (regional curve standardization) and a new (size-class isolation) growth-trend detection method and explicitly assessed the influence of biases on the trend detection. In addition, we assessed whether aggregated trends were present within and across study sites. We found evidence for decreasing growth rates over time for 8-10 species, whereas increases were noted for two species and one showed no trend. Additionally, we found evidence for weak aggregated growth decreases at the site in Thailand and when analysing all sites simultaneously. The observed growth reductions suggest deteriorating growth conditions, perhaps due to warming. However, other causes cannot be excluded, such as recovery from large-scale disturbances or changing forest dynamics. Our findings contrast growth patterns that would be expected if elevated CO2 would stimulate tree growth. These results suggest that commonly assumed growth increases of tropical forests may not occur, which could lead to erroneous predictions of carbon dynamics of tropical forest under climate change.
No growth stimulation of tropical trees by 150 years of CO2 fertilization but water-use efficiency increased
(Nature Portfolio, 2014) Peter van der Sleen; Peter Groenendijk; Mart Vlam; Niels P. R. Anten; Arnoud Boom; Frans Bongers; Thijs L. Pons; Gideon Terburg; Pieter A. Zuidema
Sustaining conservation values in selectively logged tropical forests: the attained and the attainable
(Wiley, 2012) Francis E. Putz; Pieter A. Zuidema; T.J. Synnott; Marielos Peña‐Claros; Michelle A. Pinard; Douglas Sheil; Jerome K. Vanclay; Plínio Sist; Sylvie Gourlet‐Fleury; Bronson W. Griscom
Abstract Most tropical forests outside protected areas have been or will be selectively logged so it is essential to maximize the conservation values of partially harvested areas. Here we examine the extent to which these forests sustain timber production, retain species, and conserve carbon stocks. We then describe some improvements in tropical forestry and how their implementation can be promoted. A simple meta‐analysis based on >100 publications revealed substantial variability but that: timber yields decline by about 46% after the first harvest but are subsequently sustained at that level; 76% of carbon is retained in once‐logged forests; and, 85–100% of species of mammals, birds, invertebrates, and plants remain after logging. Timber stocks will not regain primary‐forest levels within current harvest cycles, but yields increase if collateral damage is reduced and silvicultural treatments are applied. Given that selectively logged forests retain substantial biodiversity, carbon, and timber stocks, this “middle way” between deforestation and total protection deserves more attention from researchers, conservation organizations, and policy‐makers. Improvements in forest management are now likely if synergies are enhanced among initiatives to retain forest carbon stocks (REDD+), assure the legality of forest products, certify responsible management, and devolve control over forests to empowered local communities.
The pace of life for forest trees
(American Association for the Advancement of Science, 2024) Lalasia Bialic‐Murphy; Robert M. McElderry; Adriane Esquivel‐Muelbert; Johan van den Hoogen; Pieter A. Zuidema; Oliver L. Phillips; Edmar Almeida de Oliveira; Patricia Álvarez-Loayza; Esteban Álvarez‐Dávila; Luciana F. Alves
Tree growth and longevity trade-offs fundamentally shape the terrestrial carbon balance. Yet, we lack a unified understanding of how such trade-offs vary across the world's forests. By mapping life history traits for a wide range of species across the Americas, we reveal considerable variation in life expectancies from 10 centimeters in diameter (ranging from 1.3 to 3195 years) and show that the pace of life for trees can be accurately classified into four demographic functional types. We found emergent patterns in the strength of trade-offs between growth and longevity across a temperature gradient. Furthermore, we show that the diversity of life history traits varies predictably across forest biomes, giving rise to a positive relationship between trait diversity and productivity. Our pan-latitudinal assessment provides new insights into the demographic mechanisms that govern the carbon turnover rate across forest biomes.
Time-dependent effects of climate and drought on tree growth in a Neotropical dry forest: Short-term tolerance vs. long-term sensitivity
(Elsevier BV, 2014) Hooz A. Mendivelso; J. Julio Camarero; Emília Gutiérrez; Pieter A. Zuidema
Trayectorias de crecimiento radial de especies maderables, yesquero blanco (Cariniana ianeirensis) y serebó (Schizolobium parahyba) en un bosque subhúmedo de la provincia Guarayos (Santa Cruz - Bolivia)
(2015) Alejandra Romero-Seas; Marisol Toledo; Pieter A. Zuidema
Dendrochronology allows to study variations in the growth of the trees. The following research questions were addressed: The growth trajectories of yesquero blanco (Cariniana ianeirensis Kunth) and serebo (Schizolobium parahyba Vell S. F. Blake) species that belong to different ecological guilds? And how these changes in trajectories is due to precipitation or are a consequence of their local adaptative strategies. Objectives were 1) to asses if rings are formed annually in the stem of yesquero blanco and serebo and 2) to evaluate changes in the growth trajectories of these species. We collected 207 samples of cores and disks from La Chonta (Prov. Guarayos) and the privately farm Don Humberto (Prov. Sara). We applied standard dendrochronological method. The annual ring formation in yesquero blanco was shown with a positive correlation between the average width of the ring and the annual precipitation (r = 0,73; p = 0,003). In serebo there was no synchronized growth, but we found proof for the formation of annual growth rings with samples. The majority of individuals of yesquero blanco achieved 25 dbh (diameter at breast height) in the first 40 years, although some of them only reached 65 cm dbh in 130 years. On the other hand, the majority of serebo trees achieved 10 cm dbh in the first three years and 30 cm dbh at the age of 12 years. Radial growth trajectories, considering that these are species of different ecological guilds showed different growth patterns for each species as well as for individuals of the same species.