Lowland Tree Species Research Articles

Patterns in the genetic structure of 49 lowland rain forest tree species co‐distributed on opposite sides of the northern Andes

AbstractThe Andes are a major dispersal barrier for lowland rain forest plants and animals, yet hundreds of lowland tree species are distributed on both sides of the northern Andes, raising questions about how the Andes influenced their biogeographic histories and population genetic structure. To explore these questions, we generated standardized datasets of thousands of SNPs from paired populations of 49 tree species co‐distributed in rain forest tree communities located in Panama and Amazonian Ecuador and calculated genetic diversity (π) and absolute genetic divergence (dXY) within and between populations, respectively. We predicted (1) higher genetic diversity in the ancestral source region (east or west of the Andes) for each taxon and (2) correlation of genetic statistics with species attributes, including elevational range and life‐history strategy. We found that genetic diversity was higher in putative ancestral source regions, possibly reflecting founder events during colonization. We found little support for a relationship between genetic divergence and species attributes except that species with higher elevational range limits exhibited higher dXY, implying older divergence times. One possible explanation for this pattern is that dispersal through mountain passes declined in importance relative to dispersal via alternative lowland routes as the Andes experienced uplift. We found no difference in mean genetic diversity between populations in Central America and the Amazon. Overall, our results suggest that dispersal across the Andes has left enduring signatures in the genetic structure of widespread rain forest trees. We outline additional hypotheses to be tested with species‐specific case studies.

Spatial determinants of tree recruitment in mixed stands in southeastern Poland- silver fir's interaction with lowland tree species

Silver fir (Abies alba Mill.) is a typical mountain tree species, but it can also grow in lowlands below 300 m a.s.l., where it must coexist with a variety of competitors. Much less were studied in the northeastern part of its natural range, where annual precipitation varies between 500 and 600 mm, distinctly less than in the mountains. The general objective of this study was to investigate the regeneration process of silver fir in mixed lowland forests in regions with water shortage. The evaluation of spatial relationships between old, dominant and newly established trees was used to clarify the mechanisms of tree species coexistence. The study was conducted in managed and protected stands in Janów Forests in the southeastern part of Poland. We selected mature forest stands (oldest trees older than 100 years) representing three types of mixed stands in nature reserves, as well as in comparable managed forests. Data was collected on 500 m2 sample plots established randomly in each stand category (20 sample plots × 6 stands). Silver fir as the target tree showed statistically significant segregation from other species in 15 cases. Small silver fir trees were associated with large pines in two forest types and segregated form large firs in one. The spatial relationships between fir and black alder were negative. Black alder was the second species with the most statistically significant spatial relationships with other tree species (11 cases). Alders separated from large pines and large firs and from medium and small silver firs. Strong segregation of medium-sized hornbeam from the small class of silver fir was observed. Our study showed that silver fir natural regeneration and colonization of new areas at the northeastern limit of its range are limited by low seed rain density, interactions with other competing species, and local site conditions. Areas with moderately high water table are potentially suitable for fir regeneration, but black alder has a competitive advantage in wetter parts of forest stand. The major advantage of such sites is the absence of beech populations, which are an important competitor to fir in the central European mountains, but a likely equally important limitation would be the presence of hornbeam populations. Our results suggest that less intensive cuttings at carefully selected places are more conducive to fir regeneration than more intensive salvage cuttings.

Variations in the reproductive cycle of Bornean montane tree species along elevational gradients on ultrabasic and non‐ultrabasic soils

AbstractAlthough lowland tree species in the ever‐wet regions of Southeast Asia are characterized by the supra‐annual cycle of reproduction, the reproductive phenology of montane tree species remains poorly understood. In this study, we investigated the reproductive phenology of montane tree species using litter samples that were collected every 2 weeks from six rainforest sites, consisting of three elevations (1700, 2700, and 3100 m), on Mount Kinabalu, Borneo. At each elevation, one site was on infertile ultrabasic soil and one was on relatively fertile non‐ultrabasic soil. We used a composite sample from 10 or 20 litter traps per site and sorted it by species. Therefore, the obtained data captured reproductive phenology in the population of each species rather than in an individual tree. Ten‐year time series of flower and fruit litterfall were obtained for 30 and 39 tree species, respectively. Fourier analysis was used to identify the dominant cycle of each time series. The most abundant cycle across species was supra‐annual, followed by sub‐annual, and annual cycles. Many species at higher elevations showed supra‐annual cycles of flower litterfall, whereas species in the 1700 m sites often showed annual or sub‐annual cycles regardless of soil types. No systematic differences were found among sites for fruit litterfall. Mechanisms underlying these elevational patterns in reproductive cycle remain unclear but may include more severe El Niño droughts, lower primary productivity, lower soil fertility, and the absence of some sub‐annually or annually reproducing families at higher elevations.

Contribution of plant anatomy to forensic investigation: Tree bark morphology

Plant science has been more and more utilized in forensic investigation, although its full potential is still to be reached. Plant macroremains are a powerful tool to link a body or other evidence back to a primary crime scene as they can provide detailed information about its previous ecological and geographic location. However, plant macroremains are often poorly preserved and difficult to identify, as diagnostic elements are seldom present within the assemblage occurring on the scene. Plant fragments most likely to be found are those exposed to the environment and resistant to degradation. The bark of woody plants meets these requirements but the possibility of its identification at species level from small fragments is not known.Starting from a real homicide case, where bark splinters were found on the victim, we aimed to assess the forensic potential of bark identification from small fragments like those likely to occur on a crime scene. Two identification keys were prepared for 16 common lowland tree species from Northern Italy; one key used all the available anatomical traits, the second only those from the outer bark. The second key was not able to discriminate some couples of species unambiguously, but could identify the bark fragments of the homicide as Robinia pseudoacacia, as confirmed from direct comparison with a reference sample. Bark fragments deserve to be included into the macroremains to be analyzed during an investigation, but small samples could easily lack diagnostic traits, and the building of a reference collection should be encouraged.

Carbon dioxide absorption and physiological characteristics of selected tropical lowland tree species for revegetation

Biological diversity can make a significant contribution to reducing greenhouse gases in the atmosphere. Trees form an essential part of the functioning of the terrestrial biosphere, especially in the carbon cycle. Yet, tree photosynthesis is far less studied than crop photosynthesis. This research aims to assess CO2 absorption-related physiological characteristics of selected tropical lowland trees that are curated in Cibinong Science Center-Botanical Garden (CSC-BG) Indonesia for revegetation prospecting. CO2 absorption, stomatal conductance, and transpiration were measured using an infrared gas analyzer photosynthesis system. Meanwhile, leaf chlorophyll content was estimated using a SPAD chlorophyll-meter. CO2 absorption rate ranged from 3.42 to 20 μmol m−2 s−1. The highest rate was observed in Teijsmanniodendron bogoriense followed by Tectona grandis (19.67 μmol m−2 s−1). The rate of transpiration ranged from 4.7 μmol m−2 s−1 to 7.82 μmol m−2 s−1. Diospyros discolor was the highest, followed by T. grandis (7.65 μmol m−2 s−1). CO2 absorption and rate of transpiration were positively correlated to stomatal conductance. In contrast, the CO2 absorption and chlorophyll content were very weakly correlated. The stomatal conductance ranged from 0.14 to 0.54 μmol m−2 s−1, with that of T. grandis was the highest, followed by Erythrina crista-galli (0.53 μmol m−2 s−1), whereas the chlorophyll content ranged from 31 up to 78.43 SPAD.

EBONY (Diospyros celebica Bakh) CONSERVATION

Eboni (Diospyroscelebica Bakh.) is aspeciesof Diospyros.It isone of the endemic species that distributesonly in Wallacea geographicalregion. Ebony is lowland tree species found in both rain forest and monsoon forest in Sulawesi with various soils types including in Alluvial, Latosols, Mediterranean, and Litosols. In its natural habitat this species associateswitharen (Arengapinnata), rattan and other palm trees.Ebony iswell known as an outstanding tree speciesthat producesdurable, fancy wood withcolorful mixed red and brownish yellow. Because of its superior quality and luxury, ebony has been utilized for high class furniture and house interior. Before trade banning ebony was an important species exported mainly to Japan.High demand in both domestic and foreign markets has lead the overcutting of the ebony and put the extinction of this species. To date, only few ebony treesremaining in Sulawesi natural forest. This species is having struggle of natural regeneration. The data showed that the potential ebony trees in term of IVI decreased dramatically from 92% to 23% during 1970 to 1990. At this moment, it is hard to find the ebony trees in the conservation areas, only a few ebony at poles levels can be found in those areas. Therefore, it is important to conserve the ebony through in situ replanting programs.Before Forest Concession was handed over to private parties in the 70s, the potential of value approached 92% and after management until the 90s, IVI droppedto less than 23%.At present the existence of ebony trees in some ex-processing is only in the pillars form and in the conservation area they can still be found at poles with small diameter. In the future, ebony conservation could be implemented through.

A Comparison of Sap Flow Measurements and Potometry in Two Tropical Lowland Tree Species with Contrasting Wood Properties

We evaluated the performance of the Heat Dissipation Technique (HDT) to measure sap flow in whole trees by comparison with potometric water uptake. Two tropical lowland species, Ochroma lagopus (balsa), a pioneer species with light wood and Hyeronima alchorneoides (pilón), a late-successional species with hard wood were examined. Diurnal courses of sap flow measured with the HDT showed good agreement with potometry. At the low sap flow rates (below 1 Kg h(-1)) occurring during nocturnal recharge HDT consistently underestimated sap flow rates. This resulted in the failure of the current version of the HDT to measure nocturnal water uptake, an important component of the water budget of at least one of the two species examined.

Phylogeography of Neotropical trees

Special issue editorial. Freely available on the publisher's website - access full text via the Official URL link.

Climate change impacts on tree ranges: model intercomparison facilitates understanding and quantification of uncertainty

Model-based projections of shifts in tree species range due to climate change are becoming an important decision support tool for forest management. However, poorly evaluated sources of uncertainty require more scrutiny before relying heavily on models for decision-making. We evaluated uncertainty arising from differences in model formulations of tree response to climate change based on a rigorous intercomparison of projections of tree distributions in France. We compared eight models ranging from niche-based to process-based models. On average, models project large range contractions of temperate tree species in lowlands due to climate change. There was substantial disagreement between models for temperate broadleaf deciduous tree species, but differences in the capacity of models to account for rising CO(2) impacts explained much of the disagreement. There was good quantitative agreement among models concerning the range contractions for Scots pine. For the dominant Mediterranean tree species, Holm oak, all models foresee substantial range expansion.

Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes

Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 × 10 −5 SI) than adjacent to floodplain or lowland tree species (17 × 10 −5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species’ flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species’ flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation.

Ecophysiological characteristics of Taiwan alder (Alnus formosana) seedlings adapted to the subtropical region.

We investigated several ecophysiological characteristics of seedlings of a low-elevation (100-200 m) and a high-elevation (2000-2400 m) population of Taiwan alder (Alnus formosana Makino) from subtropical Taiwan. Both populations had a wide optimal temperature range for photosynthesis, and there was little difference in the optimal temperature range for photosynthesis between populations. Photosynthetic rate (P(N)) was near maximal from 20 to 35 degrees C when seedlings of both the low-elevation and the high-elevation populations were acclimated at a day/night temperature of 30/23 degrees C. When seedlings were acclimated at a day/night temperature of 20/10 degrees C, P(N) was near maximal over the range 15-35 degrees C in the low-elevation population and 15-30 degrees C in the high-elevation population. Compared with nine other tree species native to Taiwan, Taiwan alder had a high P(N) and stomatal conductance (g(s)) under well-watered conditions. Reflecting its higher transpiration rate, Taiwan alder had a significantly greater leaf-air temperature difference than camphor (Cinnamomum camphora (L.) J. Presl), a co-occurring lowland tree species with leaves similar in shape and size to those of Taiwan alder. Despite higher g(s), high root and shoot hydraulic conductances enabled Taiwan alder to maintain higher leaf water potentials than camphor under well-watered conditions. We conclude that both photosynthetic characteristics and water relations are important factors enabling Taiwan alder to adapt to a wide temperature range, thereby ensuring its success at both high and low elevations in subtropical Taiwan.

A modelling analysis of the genetic variation of phenology between tree populations

Summary 1 The phenology of temperate woody plants is commonly assumed to be locally adapted to climate. 2 However, the high gene flow expected in forest tree species, the high between year variance of thermal conditions at a given place and the high plasticity of phenology regarding temperature, lead us to hypothesize that genetic variation of phenology between populations is likely to be insignificant for many lowland tree species. 3 Using phenological models, we investigated variation in the timing of flowering between locations for four European clonal trees and between different populations of a further five species. 4 Models were also used to study the responses of the different populations to climate change by simulating transfers of each population to different locations. 5 While clinal variations can be observed in the phenological response to temperature between populations, only one species (Corylus avellana) showed significantly different responses between populations and even then only one of three populations could be separated from the others. 6 Hypothetical transfers show that the differences observed between populations depend on the thermal conditions at the location of transfer, and that these differences are less marked in warmer conditions. 7 Our results indicate that local adaptation will probably not be a serious constraint in predicting the phenological responses of temperate lowland tree species to global warming.

Flooding effects in seedlings of Cytharexyllum myrianthum Cham. and Genipa americana L.: responses of two neotropical lowland tree species

Six-month-old seedlings of Cytharexyllum myrianthum and Genipa americana, two common tree species in different flood-prone areas in Brazil, were flooded for up to 90 days to compare their survival and growth responses under these conditions. Seedlings of both species were found to be relatively tolerant to flooding but growth responses changed according to treatment and plant species. Growth of G. americana was reduced by flooding, showing a decrease in root and leaf dry mass, root/shoot ratio and height, without showing any adaptive morphological changes. On the other hand, growth of C. myrianthum seedlings was stimulated under flooding conditions, showing an increase in root dry mass, root/shoot ratio, height, stem diameter and some morphological changes in roots and stems, i.e., development of new roots and stem base hypertrophy. These results could be regarded as an experimental corroboration of the field observations, showing that these species could be indicated for restoration programs of some Neotropical wetlands.

Growth rates and mortality patterns of tropical lowland tree species and the relation to forest structure in Amazonian Ecuador

ABSTRACTGrowth in diameter and the relationship between age and size are analysed for 22 tree species in Amazonian Ecuador using growth simulation by a stochastic technique that projects the diameter-age relationships of a species. Maximum diameter growth rates varied from 1.2 mm y–1 (Grias neuberthii) to 20.0 mm y–1 (Cecropia sciadophylla). Minimum growth rates ranged from almost zero in Neea divaricata to 2.4 mm y–1 in Mollia lepidota. Median growth rates ranged between c. 0.5 mm y–1 (Grias neuberthii, Neea divaricata) and 11.6 mm y–1 (Cecropia sciadophylla). The maximum simulated life-span spent between a DBH of 10 cm and the largest DBH of a species varied from 54 y (Cecropia sciadophylla) to 529 y (Neea divaricata). Fast growing species and species that potentially can grow old showed a convex survivorship curve, whereas slower growing species and species that do not grow very old showed sigmoid, linear and convex survivorship curves. The species were grouped according to their DBH-height relationship and according to their maximum age, maximum growth rate, and maximum DBH. The groups probably reflect different light requirements. A negative correlation was found between maximum age and mortality rate. Growth rates vary within species, thus the largest tree is not necessarily the oldest.

Dynamics of Nothofagus-dominated rainforest on mainland Australia and lowland Tasmania

Cool temperate rainforest in Australia is commonly dominated by Nothofagus species. In Victoria and Tasmania, Nothofagus cunninghamii dominates old rainforest on optimal sites and is able to regenerate continuously. Size structure analysis of the major lowland tree species in this forest suggest that no major changes in species composition or dominance are occurring. This contrasts with the status of Nothofagus in lowland rainforest in New Zealand and rainforest below about 1000 m a.s.l. in south-central Chile. N. cunninghamii is a relatively light-demanding species, and is maintaining its dominance by seedling regeneration in canopy gaps created by the death of old individuals. The dynamics of the cool temperate rainforest in northern New South Wales are more complex. These forests are dominated by Nothofagus moorei, and size structure analysis indicates that persistence of this species within the rainforest is dependent on vegetative regeneration. On some sites this rainforest is being actively invaded by warm temperate and sub-tropical elements from lower altitudes. In these areas N. moorei in unable to regenerate beneath the canopy.

Waterlogging Tolerance of Lowland Tree Species of the South¹

Abstract Many tree species in the South are adapted to periodic and/or prolonged soil waterlogging. However, artificial disturbances of natural water regimes sometimes cause flooding to occur at abnormal times or the flood water to be deeper and waterlogging longer in duration than is normal. As a consequence, it is difficult for forest managers to predict how a species will respond to such disturbances or to decide how to manage an area where the water regime has been significantly altered. This paper discusses some factors which influence the waterlogging tolerance of tree species, compiles several classification systems, indicates the pertinent literature, and offers a new relative waterlogging-tolerance rating for southern lowland tree species.