scholarly journals Causes of variation in leaf-level drought tolerance within an Amazonian forest

2016 ◽  
Vol 3 ◽  
pp. e004 ◽  
Author(s):  
Isabelle Maréchaux ◽  
Megan K. Bartlett ◽  
Philippe Gaucher ◽  
Lawren Sack ◽  
Jérôme Chave
Keyword(s):  
Drought Tolerance ◽  
Tree Species ◽  
Current Knowledge ◽  
Tree Size ◽  
Species Identity ◽  
Canopy Tree ◽  
Plant Trait ◽  
Leaf Osmotic Potential ◽  
Leaf Level ◽  
Successional Species

Amazonian tree communities have already been seriously impacted by extreme natural droughts, and intense droughts are predicted to increase in frequency. However, our current knowledge of Amazonian tree species’ responses to water stress remains limited, as plant trait databases include few drought tolerance traits, impeding the application and predictive power of models. Here we explored how leaf water potential at turgor loss point (πtlp), a determinant of leaf drought tolerance, varies with species life history, season, tree size and irradiance within a forest in French Guiana. First, we provided a further direct validation of a rapid method of πtlp determination based on osmometer measurements of leaf osmotic potential at full hydration for five Amazonian tree species. Next, we analysed a dataset of 131 πtlp values for a range of species, seasons, size (including saplings), and leaf exposure. We found that early-successional species had less drought-tolerant leaves than late-successional species. Species identity was the major driver of πtlp variation, whereas season, canopy tree size and leaf exposure explained little variation. Shifts in πtlp from saplings to canopy trees varied across species, and sapling leaf drought tolerance was a moderate predictor of canopy tree leaf drought tolerance. Given its low within-species variability, we propose that πtlp is a robust trait, and is useful as one index of species’ drought tolerance. We also suggest that measuring this trait would considerably advance our knowledge on leaf drought tolerance in hyperdiverse communities and would thus likely shed light on the resilience of such vulnerable species-rich ecosystem. 

Tracing recent carbon from photosynthesis to stem and soil respiration in an experimental tropical rainforest in response to drought

2020 ◽  
Author(s):  
Johannes Ingrisch ◽  
Kathiravan Meeran ◽  
Angelika Kübert ◽  
Nemiah Ladd ◽  
Joost van Haren ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Tree Species ◽  
Large Scale ◽  
Tropical Rainforest ◽  
Water Cycle ◽  
Tree Size ◽  
Species Identity ◽  
Stem Respiration ◽  
Plant Soil ◽  
C Cycle

<p>Tropical rainforests play a major role in the terrestrial carbon (C) cycle. However, to date little is known about the mechanisms and processes controlling C fluxes in tropical forests. Within the C cycle of a forest, trees allocate a substantial amount of photoassimilates belowground, and fuel respiration by stems, roots and microorganisms. This link between assimilation and respiration represents a significant pathway by which assimilated C is quickly returned to the atmosphere. However, the nature of this coupling, including the speed of above- to below-ground C allocation and the proportion of rapidly metabolized assimilates is yet unknown for mature tropical rainforest systems. Furthermore, the role of tree species and size and the relative roles of canopy versus understory plants are still unresolved.</p><p>Drought spells can exert a major control on the C balance of tropical forest ecosystems by altering C uptake, the partitioning of C and the dynamics of C allocation and belowground utilization. As such responses are difficult to measure in tropical rainforest, the consequences of drought for the dynamics of recent C in stem and soil respiration in this biome remain unclear.</p><p>To assess and quantify these processes, we made use of the Tropical Rain Forest at the Biosphere 2 research complex in Arizona, US. This infrastructure provides unique opportunities to study drought effects on the C dynamics in a controlled environment. We simulated a drought spell for eight weeks and continuously measured stem and soil CO<sub>2</sub> fluxes using isotope laser spectroscopy before and during the drought as well as during the subsequent rewetting period. Our study is part of a large-scale experiment that aims to disentangle C- and water-cycle processes underpinning ecosystem responses to drought from a molecular to an ecosystem-scale level, with particular focus on plant-soil and plant-atmosphere interfaces.</p><p>We performed two canopy-scale <sup>13</sup>CO<sub>2</sub> pulse labeling campaigns under ambient environmental conditions and towards the end of the experimental drought. We traced the allocation dynamics of recently assimilated C to soil respiration and to stem respiration of dominant tree species. First results show that the allocation of assimilates from the canopy to soil-respired CO<sub>2</sub> took several days and was affected by tree size and species identity. Under drought, tracer efflux from stems and soils was  slowed down, with strong species-specific differences. Our results will allow novel insights into the combined effects of tree size, species identity and drought on the allocation dynamics and respiratory utilization of photoassimilates in tropical rainforest.</p>

scholarly journals Soil carbon and nutrient stocks under Scots pine plantations in comparison to European beech forests: a paired-plot study across forests with different management history and precipitation regimes

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Marco Diers ◽  
Robert Weigel ◽  
Heike Culmsee ◽  
Christoph Leuschner
Keyword(s):  
Scots Pine ◽  
Tree Species ◽  
European Beech ◽  
Organic Layer ◽  
Species Identity ◽  
Data Set ◽  
Nutrient Pools ◽  
Total N ◽  
Precipitation Regimes ◽  
Pine Stands

Abstract Background Organic carbon stored in forest soils (SOC) represents an important element of the global C cycle. It is thought that the C storage capacity of the stable pool can be enhanced by increasing forest productivity, but empirical evidence in support of this assumption from forests differing in tree species and productivity, while stocking on similar substrate, is scarce. Methods We determined the stocks of SOC and macro-nutrients (nitrogen, phosphorus, calcium, potassium and magnesium) in nine paired European beech/Scots pine stands on similar Pleistocene sandy substrates across a precipitation gradient (560–820 mm∙yr− 1) in northern Germany and explored the influence of tree species, forest history, climate, and soil pH on SOC and nutrient pools. Results While the organic layer stored on average about 80% more C under pine than beech, the pools of SOC and total N in the total profile (organic layer plus mineral soil measured to 60 cm and extrapolated to 100 cm) were greater under pine by about 40% and 20%, respectively. This contrasts with a higher annual production of foliar litter and a much higher fine root biomass in beech stands, indicating that soil C sequestration is unrelated to the production of leaf litter and fine roots in these stands on Pleistocene sandy soils. The pools of available P and basic cations tended to be higher under beech. Neither precipitation nor temperature influenced the SOC pool, whereas tree species was a key driver. An extended data set (which included additional pine stands established more recently on former agricultural soil) revealed that, besides tree species identity, forest continuity is an important factor determining the SOC and nutrient pools of these stands. Conclusion We conclude that tree species identity can exert a considerable influence on the stocks of SOC and macronutrients, which may be unrelated to productivity but closely linked to species-specific forest management histories, thus masking weaker climate and soil chemistry effects on pool sizes.

scholarly journals Effect of tree species identity and related habitat parameters on understorey bryophytes – interrelationships between bryophyte, soil and tree factors in a 50-year-old experimental forest

2021 ◽  
Author(s):  
Kaja Rola ◽  
Vítězslav Plášek ◽  
Katarzyna Rożek ◽  
Szymon Zubek
Keyword(s):  
Species Richness ◽  
Tree Species ◽  
Forest Floor ◽  
Vascular Plant ◽  
Soil Parameters ◽  
Species Identity ◽  
Habitat Factors ◽  
Positive Correlations ◽  
Old Trees ◽  
Habitat Parameters

Abstract Aim Overstorey tree species influence both soil properties and microclimate conditions in the forest floor, which in turn can induce changes in ground bryophyte communities. The aim of the study was to investigate the effect of tree species identity and the most important habitat factors influencing understorey bryophytes. Methods We assessed the effect of 14 tree species and related habitat parameters, including soil parameters, vascular plant presence and light intensity on bryophytes in monospecific plots covered by nearly fifty-year-old trees in the Siemianice Experimental Forest (Poland). Results The canopy tree species determined bryophyte species richness and cover. The strongest differences were observed between plots with deciduous and coniferous trees. Soils with a more acidic pH and lower content of macronutrients supported larger bryophyte coverage. We also found a positive correlations between vascular plants and availability of light as well as bryophyte species richness. Conclusion Tree species identity and differences in habitat conditions in the forest floor lead to changes of ground bryophyte richness, cover and species composition. Consequently, the changes in the dominant tree species in the stand may result in significant repercussions on ground bryophyte communities. We indicated that the introduction of alien tree species, i.e. Quercus rubra, has an adverse effect on bryophyte communities and suggested that the selection of tree species that contribute to the community consistent with the potential natural vegetation is highly beneficial for maintaining ground bryophyte biodiversity.

scholarly journals Diurnal and seasonal carbon balance of four tropical tree species differing in successional status

2008 ◽  
Vol 68 (4) ◽  
pp. 781-793 ◽  
Author(s):  
GM. Souza ◽  
RV. Ribeiro ◽  
AM. Sato ◽  
MS. Oliveira
Keyword(s):  
Functional Groups ◽  
Tree Species ◽  
Carbon Balance ◽  
Dark Respiration ◽  
Tropical Tree ◽  
Pioneer Species ◽  
Wet Season ◽  
Gross Photosynthesis ◽  
Tropical Tree Species ◽  
Successional Species

This study addressed some questions about how a suitable leaf carbon balance can be attained for different functional groups of tropical tree species under contrasting forest light environments. The study was carried out in a fragment of semi-deciduous seasonal forest in Narandiba county, São Paulo Estate, Brazil. 10-month-old seedlings of four tropical tree species, Bauhinia forficata Link (Caesalpinioideae) and Guazuma ulmifolia Lam. (Sterculiaceae) as light-demanding pioneer species, and Hymenaea courbaril L. (Caesalpinioideae) and Esenbeckia leiocarpa Engl. (Rutaceae) as late successional species, were grown under gap and understorey conditions. Diurnal courses of net photosynthesis (Pn) and transpiration were recorded with an open system portable infrared gas analyzer in two different seasons. Dark respiration and photorespiration were also evaluated in the same leaves used for Pn measurements after dark adaptation. Our results showed that diurnal-integrated dark respiration (Rdi) of late successional species were similar to pioneer species. On the other hand, photorespiration rates were often higher in pioneer than in late successional species in the gap. However, the relative contribution of these parameters to leaf carbon balance was similar in all species in both environmental conditions. Considering diurnal-integrated values, gross photosynthesis (Pgi) was dramatically higher in gap than in understorey, regardless of species. In both evaluated months, there were no differences among species of different functional groups under shade conditions. The same was observed in May (dry season) under gap conditions. In such light environment, pioneers were distinguished from late successional species in November (wet season), showing that ecophysiological performance can have a straightforward relation to seasonality.

scholarly journals The effect of rootstock on the tree size of apricot cultivars

2004 ◽  
Vol 10 (3) ◽  
Author(s):  
Szalay L. ◽  
Molnár B. P.
Keyword(s):  
Drought Tolerance ◽  
Tree Size ◽  
Soil Conditions ◽  
Cultivation System ◽  
Cultivation Method ◽  
Ecological Conditions ◽  
Production Site ◽  
Crown Volume ◽  
Wild Apricot ◽  
Old Trees

The apricot is propagated on several kinds of rootstocks in Hungary. The main aspects of selecting rootstocks are as follows: adaptability to environmental circumstances, primarily soil conditions, ensuring the tree size that complies with the cultivation method, and compatibility with the grafted cultivar. At advanced, intensive orchards rootstocks ensuring smaller tree size are privileged. For the establishment of the appropriate cultivation system, it is important to be aware of the expected growing vigour and tree size of certain cultivar­rootstock combinations when the orchard is designed. In the course of our experiment the size of 15-year-old trees of 4 apricot cultivars were examined on several rootstocks at an orchard in Siófok. On the basis of the data measured for each cultivar-rootstock combination, it can be stated that trees on wild apricot (P. armeniaca) rootstocks are the largest in size. Trees on prune (P. domestica) rootstock have 10-15% smaller crown volume than the previous combination. Trees on bullace (P. insititia) rootstock have the smallest tree size and their crown volume is 30-50% smaller than that of the trees on P. armeniaca rootstock. Thus, the application of prune and bullace rootstocks is beneficial at intensive apricot orchards as the size of trees can be reduced by their usage. However, their compatibility with the cultivars and their adaptability to the ecological conditions of the production site have to be tested before applying them widely. In the course of our research incompatibility was not experienced for any of the cultivar-rootstock combinations examined. Nevertheless, the drought tolerance of the rootstocks examined showed significant differences. Trees on P. domestica or P. insititia rootstock requires more water than those on P. armeniaca rootstock, therefore, they have to be irrigated.

scholarly journals Plant, fungal, bacterial, and nitrogen interactions in the litter layer of a native Patagonian forest

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4754 ◽  
Author(s):  
Lucía Vivanco ◽  
Nicolás Rascovan ◽  
Amy T. Austin
Keyword(s):  
Bacterial Community ◽  
Litter Decomposition ◽  
Plant Species ◽  
Tree Species ◽  
Microbial Interactions ◽  
N Addition ◽  
Litter Layer ◽  
Species Identity ◽  
Single Tree ◽  
Stimulation Of

Plant–microbial interactions in the litter layer represent one of the most relevant interactions for biogeochemical cycling as litter decomposition is a key first step in carbon and nitrogen turnover. However, our understanding of these interactions in the litter layer remains elusive. In an old-growth mixed Nothofagus forest in Patagonia, we studied the effects of single tree species identity and the mixture of three tree species on the fungal and bacterial composition in the litter layer. We also evaluated the effects of nitrogen (N) addition on these plant–microbial interactions. In addition, we compared the magnitude of stimulation of litter decomposition due to home field advantage (HFA, decomposition occurs more rapidly when litter is placed beneath the plant species from which it had been derived than beneath a different plant species) and N addition that we previously demonstrated in this same forest, and used microbial information to interpret these results. Tree species identity had a strong and significant effect on the composition of fungal communities but not on the bacterial community of the litter layer. The microbial composition of the litter layer under the tree species mixture show an averaged contribution of each single tree species. N addition did not erase the plant species footprint on the fungal community, and neither altered the bacterial community. N addition stimulated litter decomposition as much as HFA for certain tree species, but the mechanisms behind N and HFA stimulation may have differed. Our results suggest that stimulation of decomposition from N addition might have occurred due to increased microbial activity without large changes in microbial community composition, while HFA may have resulted principally from plant species’ effects on the litter fungal community. Together, our results suggest that plant–microbial interactions can be an unconsidered driver of litter decomposition in temperate forests.

Shooting the messenger: Identifying the mycorrhizal species transferring carbon between neighboring trees

2021 ◽  
Author(s):  
Stav Livne- Luzon ◽  
Rotem Cahanovitc ◽  
Tamir Klein
Keyword(s):  
Tree Species ◽  
Resource Sharing ◽  
Pinus Halepensis ◽  
Stable Isotope Probing ◽  
Root Tips ◽  
Species Identity ◽  
Mycorrhizal Networks ◽  
Carbon Transfer ◽  
Root Tissues ◽  
Control Resource

<p>EMF play an important role in forests around the globe, by improving tree nutrition and water supply, as well as connecting different tree species through common mycorrhizal networks (CMN's). However, the extent to which EMF control resource sharing within these networks has not yet been thoroughly addressed. We constructed a simple network of tree-fungus-tree and monitored carbon flow from a <sup>13</sup>CO<sub>2</sub> labeled donor tree to the final recipient.  DNA Stable Isotope Probing (DNA-SIP) of ectomycorrhizal root tips was used to identify the main fungal symbionts involved in carbon transfer among trees. We used pairs of inter and intra-specie Pinus halepensis and Quercus calliprinos saplings, and examined the carbon dynamics for 40 days within the leaf, stem and root tissues. The peak of <sup>13</sup>C in the roots of the donor trees was around day 4 post labeling, while the recipient roots peaked at day 9 with observed differences between pairs. The intrinsic tree carbon pool, and not the tree species identity, was the main factor governing carbon transfer between trees. Finally, we were able to identify the main fungal symbionts enriched with <sup>13</sup>C. Our results add the "missing piece of the puzzle" by linking specific mycorrhizal species to carbon transfer within CMN's.</p>

Tree Size and Species, Stand Volume, and Tract Size: Effects on Southern Harvesting Costs

1989 ◽  
Vol 13 (3) ◽  
pp. 145-152 ◽  
Author(s):  
Frederick W. Cubbage ◽  
W. Dale Greene ◽  
John P. Lyon
Keyword(s):  
Tree Species ◽  
Size Effects ◽  
Timber Harvesting ◽  
Tree Size ◽  
Labor Costs ◽  
Production Rates ◽  
Stand Volume ◽  
Factors Affecting ◽  
Harvesting Costs ◽  
Significant Factors

Abstract Timber harvesting production rates and equipment and labor costs were used to estimate average logging costs for a variety of tract volumes and sizes, stand structures, and tree species. Average costs were estimated for conventional logging systems typical in the South. Regression analysiswas used to identify significant factors affecting the costs for each system. Highly mechanized systems were generally cheapest for harvesting southern pines, but were not much cheaper for harvesting hardwoods. Hardwoods were substantially more expensive to harvest, as were tracts of lessthan 250 cords in total volume. South. J. Appl. For. 13(3):145-152.

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