scholarly journals Divergent Hydraulic Strategies Explain the Interspecific Associations of Co-Occurring Trees in Forest–Steppe Ecotone

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 942 ◽  
Author(s):  
Jingyu Dai ◽  
Hongyan Liu ◽  
Chongyang Xu ◽  
Yang Qi ◽  
Xinrong Zhu ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Forest Dynamics ◽  
Physiological Mechanism ◽  
Forest Composition ◽  
Forest Plot ◽  
Forest Steppe ◽  
Interspecific Association ◽  
Early Stages ◽  
Interspecific Associations

Research Highlights: Answering how tree hydraulic strategies explain the interspecific associations of co-occurring trees in forest–steppe ecotone is an approach to link plant physiology to forest dynamics, and is helpful to predict forest composition and function changes with climate change. Background and Objectives: The forest–steppe ecotone—the driest edges of forest distribution—is continuously threatened by climate change. To predict the forest dynamics here, it is crucial to document the interspecific associations among existing trees and their potential physiological drivers. Materials and Methods: Forest–steppe ecotone is composed of forest and grassland patches in a mosaic pattern. We executed two years of complete quadrat surveys in a permanent forest plot in the ecotone in northern China, calculated the interspecific association among five main tree species and analyzed their hydraulic strategies, which are presented by combining leaf-specific hydraulic conductivity (Kl) and important thresholds on the stem-vulnerability curves. Results: No intensive competition was suggested among the co-occurring species, which can be explained by their divergent hydraulic strategies. The negative associations among Populus davidiana Dode and Betula platyphylla Suk., and P. davidiana and Betula dahurica Pall. can be explained as the result of their similar hydraulic strategies. Tilia mongolica Maxim. got a strong population development with its effective and safe hydraulic strategy. Generally, hydraulic-strategy differences can explain about 40% variations in interspecific association of species pairs. Oppositely, species sensitivity to early stages of drought is convergent in the forest. Conclusions: The divergent hydraulic strategies can partly explain the interspecific associations among tree species in forest–steppe ecotone and may be an important key for semiarid forests to keep stable. The convergent sensitivity to early stages of drought and the suckering regeneration strategy are also important for trees to survival. Our work revealing the physiological mechanism of forest compositions is a timely supplement to forest–steppe ecotone vegetation prediction.

scholarly journals Application of a computationally efficient method to approximate gap model results with a probabilistic approach

2014 ◽  
Vol 7 (1) ◽  
pp. 1535-1600
Author(s):  
M. Scherstjanoi ◽  
J. O. Kaplan ◽  
H. Lischke
Keyword(s):  
Climate Change ◽  
Efficient Method ◽  
Tree Species ◽  
Forest Dynamics ◽  
Probabilistic Approach ◽  
Age Distribution ◽  
Change Scenario ◽  
Model Parameters ◽  
Computationally Efficient ◽  
Tree Species Composition

Abstract. To be able to simulate climate change effects on forest dynamics over the whole of Switzerland, we adapted the second generation DGVM LPJ-GUESS to the Alpine environment. We modified model functions, tuned model parameters, and implemented new tree species to represent the potential natural vegetation of Alpine landscapes. Furthermore, we increased the computational efficiency of the model to enable area-covering simulations in a fine resolution (1 km) sufficient for the complex topography of the Alps, which resulted in more than 32 000 simulation grid cells. To this aim, we applied the recently developed method GAPPARD (Scherstjanoi et al., 2013) to LPJ-GUESS. GAPPARD derives mean output values from a combination of simulation runs without disturbances and a patch age distribution defined by the disturbance frequency. With this computationally efficient method, that increased the model's speed by approximately the factor 8, we were able to faster detect shortcomings of LPJ-GUESS functions and parameters. We used the adapted LPJ-GUESS together with GAPPARD to assess the influence of one climate change scenario on dynamics of tree species composition and biomass throughout the 21st century in Switzerland. To allow for comparison with the original model, we additionally simulated forest dynamics along a north-south-transect through Switzerland. The results from this transect confirmed the high value of the GAPPARD method despite some limitations towards extreme climatic events. It allowed for the first time to obtain area-wide, detailed high resolution LPJ-GUESS simulation results for a large part of the Alpine region.

scholarly journals Application of a computationally efficient method to approximate gap model results with a probabilistic approach

2014 ◽  
Vol 7 (4) ◽  
pp. 1543-1571 ◽  
Author(s):  
M. Scherstjanoi ◽  
J. O. Kaplan ◽  
H. Lischke
Keyword(s):  
Climate Change ◽  
Efficient Method ◽  
Tree Species ◽  
Forest Dynamics ◽  
Probabilistic Approach ◽  
Age Distribution ◽  
Model Parameters ◽  
Gap Model ◽  
Computationally Efficient ◽  
Dynamic Global Vegetation Model

Abstract. To be able to simulate climate change effects on forest dynamics over the whole of Switzerland, we adapted the second-generation DGVM (dynamic global vegetation model) LPJ-GUESS (Lund–Potsdam–Jena General Ecosystem Simulator) to the Alpine environment. We modified model functions, tuned model parameters, and implemented new tree species to represent the potential natural vegetation of Alpine landscapes. Furthermore, we increased the computational efficiency of the model to enable area-covering simulations in a fine resolution (1 km) sufficient for the complex topography of the Alps, which resulted in more than 32 000 simulation grid cells. To this aim, we applied the recently developed method GAPPARD (approximating GAP model results with a Probabilistic Approach to account for stand Replacing Disturbances) (Scherstjanoi et al., 2013) to LPJ-GUESS. GAPPARD derives mean output values from a combination of simulation runs without disturbances and a patch age distribution defined by the disturbance frequency. With this computationally efficient method, which increased the model's speed by approximately the factor 8, we were able to faster detect the shortcomings of LPJ-GUESS functions and parameters. We used the adapted LPJ-GUESS together with GAPPARD to assess the influence of one climate change scenario on dynamics of tree species composition and biomass throughout the 21st century in Switzerland. To allow for comparison with the original model, we additionally simulated forest dynamics along a north–south transect through Switzerland. The results from this transect confirmed the high value of the GAPPARD method despite some limitations towards extreme climatic events. It allowed for the first time to obtain area-wide, detailed high-resolution LPJ-GUESS simulation results for a large part of the Alpine region.

scholarly journals The cost of risk management and multifunctionality in forestry: a simulation approach for a case study area in Southeast Germany

2021 ◽  
Author(s):  
Stefan Friedrich ◽  
Torben Hilmers ◽  
Claudia Chreptun ◽  
Elizabeth Gosling ◽  
Isabelle Jarisch ◽  
...  
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Tree Species ◽  
Species Selection ◽  
Forest Composition ◽  
Future Research ◽  
Adaptation Measures ◽  
Financial Return ◽  
The Cost

AbstractForest management faces growing uncertainty concerning environmental conditions and demand for ecosystem services. To help forest managers consider uncertainty, we applied a robust and multi-criteria approach to select the optimal composition of a forest enterprise from 12 stand types. In our simulation, the forest enterprise strives for either financial return or a multi-criteria forest management considering financial return, carbon storage and forest ecosystem stability. To quantify the influence of climate change on these decision criteria, we used the concept of analogous climate zones. Our results provide recommendations for long-term strategies for tree species selection in a Southeast German forest enterprise. The results show that considering both uncertainty and multifunctionality in forest management led to more diversified forest compositions. However, robust and multi-criteria optimisation required the forest enterprise to pay a premium in terms of lower income. Financial returns decreased when forest composition accounted for uncertainty or multiple objectives. We also found that adaptation measures could only partly financially compensate the effects of climate change. As the study is limited to two tree species, including additional tree species, variants of mixing proportions and further silvicultural strategies in the optimisation appears a promising avenue for future research.

scholarly journals A 40-year Evaluation of Drivers of African Rainforest Change

2021 ◽  
Author(s):  
Colin Chapman ◽  
Carmen Galán-Acedo ◽  
Jan F. Gogarten ◽  
Rong Hou ◽  
Michael J. Lawes ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Forest Dynamics ◽  
Stand Structure ◽  
Life History Strategies ◽  
Forest Composition ◽  
Maximum Temperature ◽  
Individual Species ◽  
Tree Community ◽  
Foraging Preferences

Abstract Background: Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of longitudinal data on forest change and changes in drivers.Methodology: We quantify changes in tree abundance, diversity, and stand structure along transects first enumerated in 1978 and resampled 2019 in Kibale National Park, Uganda. We tested five predictions. First, based on the purported role of seed dispersal and herbivory and our quantification of changes in the abundance of frugivores and herbivores, we tested two predictions of how faunal change could have influenced forest composition. Second, based on an evaluation of life history strategies, we tested two predictions concerning how the forest could have changed following disturbance that happened prior to written history. Finally, based on a 50-year climate record, we test the possible influence of climate change on forest dynamics. Results: More trees were present on the assessed transects in 2019 (508) than in 1978 (436), species richness remained similar, but diversity declined as the number of dominant species increased. Rainfall increased by only 3 mm over the 50 years but this effect was not significant. Annual average monthly maximum temperature increased significantly by 2.2°C over 50 years. The abundance of frugivorous and folivorous primates and elephants increased over the 50 years of monitoring. The predictions that as the abundance of seed dispersing frugivores increases the abundance of their preferred fruiting tree species would increases and that as the abundance of folivorous would cause a decline in their preferred species were both not supported. Since Kibale was disturbed prior to historical records, we predicted that light-demanding species would decrease in abundance, while shade-tolerant species would increase - this was supported. Finally, while temperature increased over the 50 years, we found no means to predict a priori how individual species would respond.Conclusions: Our study revealed subtle changes in the tree community over 40 years, sizable increases in primate numbers, a substantial increase in the elephant population and an increase in local temperature. Yet, a clear picture of what set of interactions impact the change in the tree community remains elusive. Our data on tree life-history strategies and frugivore/herbivore foraging preferences suggest that trees species are under opposing pressures.

Understanding and predicting species- and elevation-dependent dynamics in East Asian temperate forests

2020 ◽  
Author(s):  
Moonil Kim ◽  
Nick Strigul ◽  
Elena Rovenskaya ◽  
Florian Kraxner ◽  
Woo-Kyun Lee
Keyword(s):  
Climate Change ◽  
Tree Species ◽  
Forest Dynamics ◽  
Tree Age ◽  
Mountain Forest ◽  
High Mountain ◽  
Increment Core ◽  
Impact Of Climate Change ◽  
Wide Range ◽  
The Impact

<p>The velocity and impact of climate change on forest appear to be site, environment, and tree species-specific. The primary objective of this research is to assess the changes in productivity of major temperate tree species in South Korea using terrestrial inventory and satellite remote sensing data. The area covered by each tree species was further categorized into either lowland forest (LLF) or high mountain forest (HMF) and investigated. We used the repeated Korean national forest inventory (NFI) data to calculate a stand-level annual increment (SAI). We then compared the SAI, a ground-based productivity measure, to MODIS net primary productivity (NPP) as a measure of productivity based on satellite imagery. In addition, the growth index of each increment core, which eliminated the effect of tree age on radial growth, was derived as an indicator of the variation of productivity by tree species over the past four decades. Based on these steps, we understand the species- and elevation-dependent dynamics. The secondary objective is to predict the forest dynamics under climate change using the Perfect Plasticity Approximation with Simple Biogeochemistry (PPA-SiBGC) model. The PPA-SiBGC is an analytically tractable model of forest dynamics, defined in terms of parameters for individual trees, including allometry, growth, and mortality. We estimated these parameters for the major species by using NFI and increment core data. We predicted forest dynamics using the following time-series metrics: Net ecosystem exchange, aboveground biomass, belowground biomass, C, N, soil respiration, and relative abundance. We then focus on comparing the impact of climate change on LLF and HMF. The results of our study can be used to develop climate-smart forest management strategies to ensure that both LLF and HMF continue to be resilient and continue to provide a wide range of ecosystem services in the Eastern Asian region.</p>

scholarly journals Biodiversity and climate change: consequences for upper tree line in Slovakia

2016 ◽  
Vol 62 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Jozef Minďaš ◽  
Jana Škvareninová
Keyword(s):  
Climate Change ◽  
Species Diversity ◽  
Tree Species ◽  
Forest Plot ◽  
Climate Change Scenarios ◽  
Tree Line ◽  
Tree Species Diversity ◽  
Gap Model ◽  
Ecological Data ◽  
Model Calculations

Abstract Study of the effects of climate change on upper tree limit has mainly focused on the diversity of tree species as a result of the ability of species to tolerate temperature and moisture changes as well as some effects of disturbance regime changes. The tree species diversity changes due to climate change has been analysed via gap model and biodiversity indices. Gap models are individually based on simulations of establishment, growth, and mortality of each tree on the forest plot. Input ecological data for model calculations have been taken from the permanent research plots located in primeval forests in mountainous regions in Slovakia. The results of regional scenarios of the climatic change for the territory of Slovakia have been used, from which the values according to the CGCM3.1 (global) model, KNMI and MPI (regional) models. Model results for conditions of the climate change scenarios suggest a shift of the upper forest limit to the region of the present subalpine zone, in supramontane zone. The most significant tree species diversity changes have been identified for the upper tree line and current belt of dwarf pine (Pinus mugo) occurrence. Hill’s index of biodiversity in the upper forest line increased by 30 – 35% for horizon of 2050, resp. by 45 – 50% modeled for the horizon of 2075. Calculated values of Shannon’s index show an even higher increase due to climate change. For horizon 2050 is a roughly of three fold increase and horizon for 2075 by almost fivefold increase in the value of the index. Results from the gap model indicate the increase of tree species diversity 2 – 2,5 times.

scholarly journals A 40-year evaluation of drivers of African rainforest change

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Colin A. Chapman ◽  
Carmen Galán-Acedo ◽  
Jan F. Gogarten ◽  
Rong Hou ◽  
Michael J. Lawes ◽  
...  
Keyword(s):  
Climate Change ◽  
Life History ◽  
Forest Dynamics ◽  
Stand Structure ◽  
Life History Strategies ◽  
Forest Composition ◽  
Maximum Temperature ◽  
Individual Species ◽  
Tree Community ◽  
Foraging Preferences

Abstract Background Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of long-term data on forest change and changes in drivers. Methodology We quantify changes in tree abundance, diversity, and stand structure along transects first enumerated in 1978 and resampled 2019 in Kibale National Park, Uganda. We tested five predictions. First, based on the purported role of seed dispersal and herbivory and our quantification of changes in the abundance of frugivores and herbivores, we tested two predictions of how faunal change could have influenced forest composition. Second, based on an evaluation of life history strategies, we tested two predictions concerning how the forest could have changed following disturbance that happened prior to written history. Finally, based on a 50-year climate record, we evaluate the possible influence of climate change on forest dynamics. Results More trees were present on the assessed transects in 2019 (508) than in 1978 (436), species richness remained similar, but diversity declined as the number of dominant species increased. Rainfall increased by only 3 mm over the 50 years but this had not significant effect on forest changes measured here. Annual average monthly maximum temperature increased significantly by 1.05 °C over 50 years. The abundance of frugivorous and folivorous primates and elephants increased over the 50 years of monitoring. Neither the prediction that an increase in abundance of seed dispersing frugivores increases the abundance of their preferred fruiting tree species, nor that as an increase in folivore abundance causes a decline in their preferred species were supported. As predicted, light-demanding species decreased in abundance while shade-tolerant species increased as expected from Kibale being disturbed prior to historical records. Finally, while temperature increased over the 50 years, we found no means to predict a priori how individual species would respond. Conclusions Our study revealed subtle changes in the tree community over 40 years, sizable increases in primate numbers, a substantial increase in the elephant population and an increase in local temperature. Yet, a clear picture of what set of interactions impact the change in the tree community remains elusive. Our data on tree life-history strategies and frugivore/herbivore foraging preferences suggest that trees species are under opposing pressures.

scholarly journals Tropical tree growth sensitivity to climate is driven by species intrinsic growth rate and leaf traits

2021 ◽  
Author(s):  
David Bauman ◽  
Claire Fortunel ◽  
Lucas A. Cernusak ◽  
Lisa P. Bentley ◽  
Sean M. McMahon ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Tree Species ◽  
Forest Dynamics ◽  
Species Traits ◽  
Growth Responses ◽  
Growth Data ◽  
Short Term ◽  
Evaporative Demand

A better understanding of how climate affects growth in tree species is essential for improved predictions of forest dynamics under climate change. Long-term climate averages (mean climate) and short-term deviations from these averages (anomalies) both influence tree growth, but the rarity of long-term data integrating climatic gradients with tree censuses has so far limited our understanding of their respective role, especially in tropical systems. Here, we combined 49 years of growth data for 509 tree species across 23 tropical rainforest plots along a climatic gradient to examine how tree growth responds to both climate means and anomalies, and how species functional traits mediate these tree growth responses to climate. We showed that short-term, anomalous increases in atmospheric evaporative demand and solar radiation consistently reduced tree growth. Drier forests and fast-growing species were more sensitive to water stress anomalies. In addition, species traits related to water use and photosynthesis partly explained differences in growth sensitivity to both long-term and short-term climate variations. Our study demonstrates that both climate means and anomalies shape tree growth in tropical forests, and that species traits can be leveraged to understand these demographic responses to climate change, offering a promising way forward to forecast tropical forest dynamics under different climate trajectories.

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