Expected adult lifespan in tropical trees: Long-term matrix demography in a large plot

Background: Documenting the entire lifetime of long-lived organisms requires splicing together short-term observations. Matrix demography provides a tool to calculate lifetime statistics, but large samples from juvenile to adult are needed, and few such studies have been done in tropical trees because high species diversity limits sample sizes. The 50-ha plot at Barro Colorado in Panama was designed to provide large samples, and with 30years of censuses, accurate population matrices can be constructed.Methods: In 31 abundant species, I divided all individuals≥1 cm dbh into 4 or 5 size class in each of seven censuses. Movements of stems between size classes over two censuses are termed transitions, and I constructed complete transition matrices for each species. From the matrices, I derived analytic solutions for lifetime demographic statistics. Expected adult lifespan from the sapling stage was the key statistic.Results: Expected adult lifespan from the sapling stage varied 100-fold over the 31 species, from 0.5 to 50 years,and maturation time varied from 19 to nearly 200 years. Species with the highest growth rates also had high death rates, and theoretical calculations of reproductive lifespan show that the fast-growing pioneer species have short expected adult lifespans relative to the average slow-growing, shade-tolerant species. Within the slowgrowth category, however, there was high variation in expected adult lifespan, and several shade-tolerant species under-performed the pioneers in terms of adult lifespan.Conclusions: Analytical solutions from population matrices allow theoretical analyses that integrate short-term growth records into lifespans of tropical trees. The analyses suggest that pioneer species must reproduce more successfully than shade-tolerant species to persist in the Barro Colorado forest. My next goal is to incorporate seed production and germination into lifetime matrix demography to test this hypothesis.

Soil Carbon Storage in Experimental Forest Plantations with Tropical Species

Forest ecosystems represent a third of the total organic carbon (TOC) stored in the soil. However, studies still need to be carried out to generate reliable information on its soil carbon storage potential in an experimental plantation. Therefore, the objective of this research was to determine the storage of total organic carbon (TOC) in the soil in two experimental forest plantations with tropical species, located in the state of Nayarit, México. The research was carried out in two experimental plantations with tropical species, located at the Santiago Ixcuintla Experimental Field (CESIX) and at the El Verdine?o Experimental Site (SEEV). The established species are Swietenia macrophylla King (mahogany), Cedrela odorata L. (cedar) and Tabebuia rosea Bertoil (pink trumpet-tree). In addition, data from dasometric variables were used in order to define if any of these variables had a similar variation to the soil TOC stock by species. The sampling was done under a randomized block experimental design in each experimental forest plantation (CESIX and SEEV). Nine composite samples were collected in the soil under the tree species at a depth of 0 - 30 cm, and 1.5 m distance from the tree. To determine the soil TOC, an elemental analyzer with a thermal conductivity detector Thermo Scientific (Flash 2000) was used. The results showed that TOC presented mean values of 103.60 and 219.98 t·ha-1 at a depth of 0 - 30 cm in CESIX and SEEV respectively. The highest TOC was obtained in soil under mahogany;142.95 t·ha-1 in CESIX and 284.41 t·ha-1 in SEEV. The analysis of the differences in TOC between the two plantations was highly significant. In the analysis of the species, it showed a statistically significant difference (p < 0.0001), defining that the soil under the mahogany, in general, presented the highest stock of TOC. Regarding the TOC in the soil plantation and the dasometric variables, none of the variables analyzed showed the same behavior in its variability.

Growth Traits and the Trade-Offs for Tree Species with Arbuscular Mycorrhizal Fungi in a Tropical Rain Forest Edge at Los Tuxtlas,Mexico

The effect of arbuscular mycorrhizal fungi on seedling growth across the rain forest-pasture edge has not received much attention. In a tropical rain forest in eastern Mexico, the seedlings of light demanding (Ficus insipida), nonsecondary light demanding (Lonchocarpus cruentus) and shade tolerant species (Nectandra ambigens, Coccoloba hondurensis) were grown and transplanted to a forest edge with three inoculation treatments (AM fungus spores and colonized roots, spores, and no inoculum). For all species, stem height, stem diameter, total dry weight, leaf area and net assimilation rate were higher in the pasture. Stem height, stem diameter and root/shoot were higher for L. cruentus, and leaf area ratio, specific leaf area and net assimilation rate were higher for F. insipida;the lowest values of almost all variables were recorded for N. ambigens. L. cruentus and C. hondurensis with mycorrhizae had the highest values for root/shoot and net assimilation rate, respectively. The lowest values of root/shoot and net assimilation rate were observed for nonlight-demanding species in the forest. There were clear trade-offs for the pioneer species between survival and growth, and in underground biomass allocation and assimilation for nonsecondary light demanding, but there was not for the shade-tolerant species.

Comparison of stem taper models for the four tropical tree species in Mount Makiling, Philippines

This study was conducted to evaluate the performance of six stem taper models on four tropical tree species, namely Celtis luzonica(Magabuyo),Diplodiscus paniculatus(Balobo), Parashorea malaanonan(Bagtikan), and Swietenia macrophylla(Mahogany) in Mount Makiling Forest Reserve(MMFR), Philippines using fit statistics and lack-of-fit statistics. Four statistical criteria were used in this study, including the standard error of estimate(SEE),coefficient of determination(R^2), mean bias( E),and absolute mean difference(AMD). For the lack-offit statistics, SEE, E and AMD were determined in different relative height classes. The results indicated that the Kozak02 stem taper model offered the best fit for the four tropical species in most statistics. The Kozak02 model also consistently provided the best performance in the lack-of-fit statistics with the best SEE, E and AMD in most of the relative height classes. These stem taper equations could help forest managers and researchers better estimate the diameter of the outside bark with any given height,merchantable stem volumes and total stem volumes of standing trees belonging to the four species of thetropical forest in MMFR.

Synergistic effects of tropical cyclones on forest ecosystems:a global synthesis

Tropical cyclones are large-scale strong wind disturbance events that occur frequently in tropical and subtropical coastal regions and often bring catastrophic physical destruction to ecosystems and economic disruption to societies along their paths. Major tropical cyclones can infrequently move into the midaltitudes and inland areas. Ecologically, tropical cyclones have profound impacts on diversity, structure, succession and function of forest ecosystems. The ecological effects are both dramatic and subtle. The dramatic effects can be visible, noticeable and to some extent predictable over the short-term and relatively well documented in the literature. However, the subtle effects are often invisible, complex and at smaller scale relatively unpredictable in the long-term. Many factors, meteorologic, topographic and biologic, simultaneously interact to influence the complexity of patterns of damage and dynamics of recovery. I present a global synthesis on the effects of tropical cyclones on forest ecosystems and the complexity of forest responses, with particular attention on the response to large hurricanes in the neotropics and the temperate North America, and strong typhoons on the subtropical and temperate forests in the East and Southeast Asia. Four major aspects provide on organizational framework for this synthesis：（1） consistent damage patterns,（2） factors that influence response patterns and predict damage risks,（3） complexity of forest responses and recovery, and（4） the long-term effects. This review reveals highly variable and complex effects of tropical cyclones on forest ecosystems. A deep understanding of the synergistic effects of tropical cyclones is essential for effective forest management and biodiversity conservation.

Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon

Background： Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods： We used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. We tested two predictions. First, within a given topographic habitat, species specializing on that habitat （＇residents＇） should outperform species that are specialists of other habitats （＇foreigners＇）. Second, across different topographic habitats, species should perform best in the habitat on which they specialize （＇home＇） compared to other habitats （＇away＇）. Species＇ performance was estimated using growth and mortality rates. Results： In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions＂ We reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees _〉1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval.

Genetic Variation in Tropical Tree Species and Plantations: A Review

The global efforts to restore tropical forests and their productive and ecological functions through plantation forestry largely depend on the available genetic variation in the tree species used to establish the plantations. However, there is limited information on the levels and trends of the genetic variation and variability of different plantation tree species in the tropics. Therefore, this study reviews several marker-based studies that have investigated genetic variation. Most of the top economic species like Eucalyptus tereticornis and Mansonia altissima are attributed to low levels of genetic diversity, while others like Pinus caribaea and Swietenia macrophylla still exhibit high expected heterozygosity across different populations. However, the levels of genetic diversity assessed may depend on the markers used. Microsatellites, i.e., simple sequence repeats (SSRs), mostly give higher estimates when compared to other polymerase chain reaction-based markers. Other factors that typically contribute to the directional pattern of genetic variation in tropical tree species and populations include their distribution, density, seed dispersal, succession, and reproduction. Also, anthropogenic impacts like logging and fragmentation have contributed to the vast genetic base reduction of many tropical species and populations. Having adequate genetic variation within the plantation populations is significant in improving their fitness, resilience, fecundity, productivity, and other ecological functions. It also provides a basis for tree improvement and breeding in plantation forests. Although clonal forestry is becoming widespread and considered highly productive, it is attributed to specific economic, technical, and ecological risks, such as the increased spread of pests and diseases. Therefore, further discussions and recommendations to maximise genetic diversity in tropical (clonal) plantations are provided.

Growth response of three plantation species of the tropics exposed to elevated CO_2 levels

The response of forest trees, the largest carbon sinks on the earth, to continuing rise in atmospheric carbon levels is unknown. Re- ports state that increasing levels of atmospheric CO2 will stimulate pho- tosynthesis and productivity in most ecosystems. However, the duration and magnitude of this stimulation, particularly in the tropics, remains a question. To investigate the effects of CO2 fertilization on plant growth, seedlings of three common plantation species, Casuarina equisetifolia, Ailanthus excelsa and Tectona grandis were grown in closed chambers enriched with CO2. After 180 days of treatment, morphological traits of seedling height, biomass of root and shoot and root-shoot allometric co-efficient were measured. The activity of carbonic anhydrase and con- tents of chlorophylls, total carbohydrates and soluble proteins were de- termined. In Tectona grandis, significant effects of CO2 supply were found on chlorophylls, root-shoot allometric ratio and seedling quality index. Ailanthus excelsa showed significant effect on only the shoot characteristics on exposure to elevated CO2 but the root characteristics and concentrations of chlorophylls were not significantly different. Ca- suarina equisetifolia also showed significant effects on exposure to ele- vated CO2 in terms of shoot characteristics and concentrations of chlo- rophylls. Total sugars, the major photosynthates, did not show any sig- nificant variation to elevated CO2 in any of the three species. Carbonic anhydrase, the key enzyme responsible for transfer of CO2 into the tis- sues significantly increased in all three species. Overall, all the variables responded to elevated CO2, reflecting the positive effects of one parame- ter of climate change conditions on seedling quality. A positive response of these three plantation species to elevated CO2 content is a good indi- cation for their future existence in potentially changed climatic eonditions.

The responses of carbon-and nitrogen-acquiring enzymes to nitrogen and phosphorus additions in two plantations in southern China

In tropical plantations,nutrients such as nitrogen(N)or phosphorus(P)are often applied as management practices.However,the effects of such nutrient additions on topsoil C-and N-acquiring enzymes activities are unclear.In this study,the impacts of fertilization onβ-1,4-glucosidase(BG),β-D-cellobiosidase(CBH),β-1,4-xylosidase(BX),β-1,4-N-acetyl-glucosaminidase(NAG),and leucine amino peptidase(LAP)enzymes activities from topsoil and litter layer of two tropical plantations(Acacia auriculiformis and Eucalyptus urophylla)were measured.The results showed that N addition had neutral impact on topsoil enzymes,while significantly elevating the activities of BG,CBH,BX,and NAG in the litter layer.P fertilization had no impacts except for an elevation of NAG in litter sample.There was no interactions found between N and P additions on these enzyme activities.The clearer impacts of N over P fertilization were unexpected because that the study site receives a high rate of atmospheric N deposition,and has low soil P availability.The impact of P fertilization on hydrolytic enzyme activities may be less important compared with that of N.

Antinecrotic and Antiapoptotic Effects of Different Concentrations of Copaiferalangsdorffii Essential Oil in Macrophages and Lymphocytes of Mice

Purpose： to evaluate the in vitro influence of Copaiferalangsdorffii essential oil on the antinecrotic activity in macrophages, and on the antiapoptotic activity in macrophages and lymphocytes of Swiss mice. Methods： lymphocytes and macrophages were obtained from ten 60-day-old male mice weighing 42-45 g, and then cultured in 24-well plates. Cells were treated with concentrations of 2%, 5%, 10% and 20% of oil from Copaiferalangsdorffii before or after induction of apoptosis with ultraviolet light. We used positive and negative controls. Hoechst staining was performed, and then images of cells under fluorescence microscope were captured and digitalized. We used Image J_1.46o to quantify the fluorescence intensity/brightness of condensation of the chromatin ofapoptotic cells. We used one-way ANOVA with Bonferroni＇s and Tukey＇s multiple comparison tests. Results are expressed as the means of relative densities after adjustment and 95% confidence intervals; P 〈 0.05 was considered statistically significant. Results： oil from Copaiferalangsdorffii at different concentrations has decreased necrosis and apoptosis of both lymphocytes and macrophages from mice, when compared to C＋ （all P 〈 0.05）. Discussion： Copaiferalangsdorffii is typically Brazilian and found in the Amazon region, with anti-inflammatory, antioxidant and antineoplastic effects due to its oil compounds, such as xyloglucans and kaurenoic acid. Its potential therapeutical usage was demonstrated in a national study. The present study showed that its oil has significant in vitro antiapoptotic and antinecrotic activity and it should be tested experimentally in vivo.

Does climate change alter the nutrient trends of Cedrela fissilis Vell.trees in the southern Brazilian Amazon?

Background The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin.An eco-nutritional approach using X-ray fluorescence micro-analysis(μXRF)is proposed to verify the long-and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell.Methods Fourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner.Profiles of ring width,wood density,and concentrations of aluminum(Al),phosphorus(P),sulfur(S),calcium(Ca),potassium(K),manganese(Mn),iron(Fe)and strontium(Sr)together with Al/Ca,Ca/Mn,K/Ca,Sr/Ca and Mn/S ratios were constructed and correlated with precipitation,temperature,the difference between precipitation and potential evapotranspiration(P-PET)and standardized precipitation-evapotranspiration index(SPEI).Results During dry years,C.fissilis showed narrower,less dense rings,lower Al,P,S and Ca,and higher K and Fe concentrations(the opposite was found in wet years).Ring width decreased(together with Al,P,S,K,Ca,Mn,Fe,Sr,Al/Ca,K/Ca and Sr/Ca)and wood density increased(together with Ca/Mn and Mn/S),which was associated with an increase in evapotranspiration and temperature over time,mainly since 1990.Cedrela fissilis showed a tendency to increase its capacity for resistance,and a recovery and resilience in growth over time associated with responses in Al,Ca,P and S.However,it showed a risk in the capacity for recovery of the pre-drought density values,associated with unsatisfactory responses in Al,Ca,K,Fe and P.Conclusions This study is the first attempt to analyze tree-ring nutritional evidences of C.fissilis trees to climate sensitivity and resilience to drought,based on long-term data from seasonal moist tropical forests of the Amazon.Our data suggested that C.fissilis is undergoing alterations in the concentration,use and redistribution of nutrients associated with increasing wood density and decreasing growth over time,due to the increase of drought frequency in the southern Amazon.

Growth and phenotypic plasticity of two tropical tree species under low light availability

Aims Screening tree species in tropical rainforest according to their shade tolerance is important to efficiently manage the native trees of economic significance in secondary forest enrichment regimes.The objective of this study was to determine the whole-plant light compensation point(WPLCP)and compare the phenotypic plasticity in relation to growth and carbon allocation of Cariniana legalis and Gallesia integrifolia seedlings under low light availability.Methods Seedlings were cultivated for 77 days under conditions of five photosynthetically active radiation(PAR)(0.02,1.1,2.3,4.5 and 5.9 mol photons m^(−2)day^(−1))in three replicates.Growth and carbon allocation variables were determined.Important Findings Growth rates of C.legalis were higher and lower than those of G.integrifolia under 1.1 and 5.9 mol photons m^(−2)day^(−1),respectively.The WPLCP differed significantly between the two species.In accordance with the criteria of the shade tolerance classification for these two tropical tree species,our results showed that C.legalis had lower WPLCP and phenotypic plasticity in terms of higher growth rates and greater shade tolerance than G.integrifolia.From a practical point of view,we demonstrated that the differential linkage between growth and changing PAR between the two species can become a useful tool for comparing and selecting tree species in forest enrichment projects.

The Growth and Species-by-site Interaction of 18 Central American Multipurpose Tree Species Grown at 15 Tropical Sites World-wide

From a world-wide plant introduction trial series utilising 25 central American species planted at over 100 sites in nearly 60 countries, eighteen species planted at 15 sites in the tropics were chosen for further study of the factors determining site productivity and site by species interactions. The species were Acacia pennatula, Acacia farnesiana, Albizia guachapele, Ateleia herbert-smithii, Caesalpinia coriaria, Caesalpinia eriostachys, Caesalpinia velutina, Enterolobium cyclocarpum, Gliricidia sepi...