Parameterization of Mangrove Root Structure of Rhizophora stylosa in Coastal Hydrodynamic Model

Mangroves are able to attenuate tsunamis, storm surges, and waves. Their protective function against wave disasters is gaining increasing attention as a typical example of the green infrastructure/Eco-DRR (Ecosystem-based Disaster Risk Reduction) in coastal regions. Hydrodynamic models commonly employed additional friction or a drag forcing term to represent mangrove-induced energy dissipation for simplicity. The well-known Morison-type formula (Morison et al. 1950) has been considered appropriate to model vegetation-induced resistance in which the information of the geometric properties of mangroves, including the root system, is needed. However, idealized vegetation configurations mainly were applied in the existing numerical models, and only a few field observations provided the empirical parameterization of the complex mangrove root structures. In this study, we conducted field surveys on the Iriomote Island of Okinawa, Japan, and Tarawa, Kiribati. We measured the representative parameters for the geometric properties of mangroves, Rhizophora stylosa, and their root system. By analyzing the data, significant correlations for hydrodynamic modeling were found among the key parameters such as the trunk diameter at breast height (DBH), the tree height H, the height of prop roots, and the projected areas of the root system. We also discussed the correlation of these representative factors with the tree age. These empirical relationships are summarized for numerical modeling at the end.

Shift from Acquisitive to Conservative Root Resource Acquisition Strategy Associated with Increasing Tree Age: A Case Study of Fraxinus mandshurica

Tree age has an important effect on the form and function of fine roots. Previous studies have focused on the variations in root morphological and chemical traits among tree ages, while less attention has been given to the physiological traits, impeding a full understanding of the relationship between root resource acquisition strategy and tree age. Here, we measured root morphological (diameter, specific root length, specific root area and tissue density), chemical (nitrogen concentration) and physiological (respiration and exudation rate) traits of young, middle-aged and mature trees of Fraxinus mandshurica in a temperate secondary forest in northeastern China. Our overall aim was to determine how root traits and related resource acquisition strategy change with tree age. The results showed that from young to mature trees, root diameter gradually increased, but specific root length, specific root area, root nitrogen concentration, respiration and exudation rates all decreased, and the significant differences were mainly found between young and mature trees. Pearson’s correlation analysis revealed that the relationships of root respiration and exudation rates to root morphological and chemical traits depended on tree age and the specific traits examined, but these correlations were all significant except for root tissue density when the data were pooled across all tree age classes. Principal component analysis (PCA) showed that the conservative traits represented by root diameter, and the acquisitive traits such as root respiration and exudation rates and related morphological and chemical traits, occupied two ends of the first axis, respectively, while root tissue density occupied one end of the second axis, partially confirming the conceptual framework of “root economics space”. Standardized major axis (SMA) analysis of root exudation and respiration rates showed that young trees allocated more root carbon flux to the formation of root exudation, compared to middle-aged and mature trees. Our findings suggest that root resource acquisition strategy in F. mandshurica appears to shift from an absorptive to conservative strategy associated with increasing tree age, which may have substantial consequences for individual growth and interspecific competition, as well as belowground carbon allocation in ecosystems.

Shifting Precipitation Patterns Drive Growth Variability and Drought Resilience of European Atlas Cedar Plantations

Tree plantations have been proposed as suitable carbon sinks to mitigate climate change. Drought may reduce their carbon uptake, increasing their vulnerability to stress and affecting their growth recovery and resilience. We investigated the recent growth rates and responses to the climate and drought in eight Atlas cedar (Cedrus atlantica) plantations located along a wide climate gradient from wetter sites in south-eastern France and north Spain to dry sites in south-eastern Spain. The cedar growth increased in response to the elevated precipitation from the prior winter to the current summer, but the influence of winter precipitation on growth gained importance in the driest sites. The growth responsiveness to climate and drought peaked in those dry sites, but the growth resilience did not show a similar gradient. The Atlas cedar growth was driven by the total precipitation during the hydrological year and this association strengthened from the 1980s onwards, a pattern related to the winter North Atlantic Oscillation (NAO). High winter NAO indices and drier conditions were associated with lower growth. At the individual level, growth resilience was related to tree age, while growth recovery and year-to-year growth variability covaried. Plantations’ resilience to drought depends on both climate and tree-level features.

Intraspecific DNA Barcoding and Variation Analysis for Citri Reticulatae Pericarpium of Citrus reticulata “Chachi”

Citri Reticulatae Pericarpium, the desiccative mature peel of Citrus reticulata Blanco or its cultivated varieties, is a national geographical indicated product that has the concomitant function of both medicine and foodstuff. The primary source of Citri Reticulatae Pericarpium is Citrus reticulata “Chachi,” called “Guang chenpi,” while it differs in variety, propagation, grafting rootstock, and tree age, and the hereditary stability of its biological information between intraspecific plants is worthy of our attention. Homologous analysis result of 4 DNA barcodings in the ribosome or the chloroplast showed that the homology of them (ITS2, rbcl, matK, and psbA-trnH) of 22 samples was 100.00%, 99.97%, 99.99%, and 99.81%, respectively, which indicated that 4 DNA barcodes maintained a high degree of genetic stability in Citrus reticulata “Chachi.” Also, ITS2 was considered to identify Citrus reticulata “Chachi” from other varieties because it presented not only low variability within a certain taxon but also a high level of interspecies variability. Simultaneously, variant site detection of Citrus reticulata “Chachi” was analyzed by comparing with the reference Citrus reticulata genome, and 2652697 SNP sites and 533906 InDel sites were detected from whole-genome resequencing data of 22 samples, providing the data resources and theoretical foundation for the future study about the relevant molecular makers of “Guang chenpi.”

CLIMATE REGULATING ECOSYTEM SERVICES OF THE FOREST LANDSCAPE IN THE UKRAINIAN CARPATHIANS

Ecosystems provide multiple services for humans. Among them, a group of supporting and regulating ecosystem services is often less recognized by people as benefit and has been less studied by researchers. Amid various manifestations of climate change, more attention has been paid to particular subset of this group of services called climate regulating. Despite these there still few quantitative studies in this field. Trying to fill this research gap we conducted a study aimed at exploration of relation between climate regulating ecosystem services and their spatial determinants in the forest landscape within Ukrainian Carpathians. For that we chose the territory within Rakhiv and Tsiachiv districts in Transcarpathian region which represents all diversity of forest mountain ecosystems. For this study we used information on land surface temperature (LST) extracted from Landsat 8 thermal band for summer season of 2015. In order to account for vertical thermal gradient in mountains the LST data underwent normalization and in further analysis a dependent variable we employed normalized LST (nLST). Set of independent variables included geomorphometric indicators (altitude, slope, aspect, TPI) and data on forest cover (disturbance, density, dominant species, and disturbance in the neighborhood). For key study area of Velykyi watershed of 4059 ha we additionally used data on forest biomass and tree age. In general, all forest ecosystems in present research have been divided into three distinct classes – “natural”, “disturbed” and “other” forests. Using boosted regression trees method we built three statistical models for each of the forest classes called “global” models. Also we developed 12 “local” models that showed the link between nLST and analyzed independent variables within each altitudinal bioclimatic zone with considering also forest class. Three separate statistical models have been built for each of the forest classes for key study area. Our results suggest that both maximum and mean values of nLST within particular altitudinal bioclimatic zone are the lowest in “natural” forests and the highest in “disturbed” ones.. The statistical model performance based on the variance explained indicator ranged from 32 to 74 %, whilst for models for key study area it was between 77 and 89 %. The set of influential variables for different forest classes varied substantially, but the most often they included aspect, forest density and elevation despite of normalization applied before. In models created for class “disturbed” forests between 19 and 35 % of all explained variance has been contributed by variable indicating time of disturbance. In “local” models for class “natural” forests we revealed gradual decrease of influence of the geomorphometric indicators (elevation, slope, and TPI) when move from warmer to cooler altitudinal zones while for topographic aspect and forest density the trends were just the opposite. In case of key study area a wood stock and tree age variables along with elevation and aspect were amongst the most influential ones. We can conclude that depending on the state of naturalness of forest ecosystems they have different climate regulating potential which might be severely depleted by human and natural disturbances. Keywords: forest landscape, ecosystem services, remote sensing, climate regulation, climate change, Landsat satellite images, Ukrainian Carpathians.

Assessing effects of drought on tree mortality and productivity in European forests across two decades: a conceptual framework and preliminary results

Forests are currently experiencing an unprecedented period of progressively drier growing conditions around the globe, which is threatening many forest ecosystem functions. Trees as long-living organisms are able to withstand drought periods. Our understanding on critical drought severity resulting in substantial decline in net primary productivity and/or eventually tree mortality is underdeveloped. A wide range of remote sensing products and ground observations, including information on productivity, tree vitality, climate, and soil moisture with high temporal and spatial resolution are now available. Linking these data sources could improve our understanding of the complex relationship between forest growth and drought. We introduce here a conceptual framework using satellite remotely sensed net primary productivity (MOD17A3 and MODIS EURO), ground observations of tree mortality (ICP level I survey data), soil moisture anomaly (Copernicus European Drought Observatory), and spatially-downscaled daily climate data for entire Europe. This unique analysis will enable us to test the influence of biotic and abiotic covariates such as tree age, stand history, and drought legacy using historic droughts for model development. This conceptual framework, as evident from the preliminary results shown here, can help anticipating the effects of future droughts and optimize global climate models considering drought effects.

Exploring the Effects of Thinning on Cunninghamia lanceolata Lamb. Carbon Allocation in Southwestern China Using a Process-Based Model

We investigated the effects of thinning intensity on the carbon allocation of Cunninghamia lanceolata Lamb. Hook by analyzing the stand growth and carbon content of a plantation under three thinning intensities (I: 70%; II: 50%; III: 30%) and with no thinning treatment. Using the carbon balance framework of the CROwn BASe (CROBAS) model and multi-source inventory data, we calibrated the parameters of the CROBAS-C. lanceolata (CROBAS-CL) model to simulate the carbon content in the plantation. We validated the CROBAS-CL model by comparing the predicted stand diameter at breast height (DBH) and stand height (H) with the measured values. Finally, the predicted stand carbon was compared with the soil carbon to assess the dynamics and allocation of ecosystem carbon content. Overall, our findings suggest that the predicted stand carbon of CROBAS-CL satisfies the statistical test requirements: the deviation of height and DBH predicted by the CROBAS-CL model from the measured height and DBH are less than 0.087 m and 0.165 cm, respectively. These results confirm that the model is useful for a dynamic prediction of stand carbon in C. lanceolata plantations. Based on the results of the proposed model, we determine that Thinning III (30% thinning intensity) is beneficial for the growth of C. lanceolata plantations and improving soil carbon sequestration. Additionally, the simulated carbon storage of an individual tree in the C. lanceolata plantation gradually increased with the tree age. Our study provides a strong reference for the efficient operation and management of C. lanceolata plantations in southwestern China.

Modelling Maximum Stem Basal Area Growth Rates of Individual Trees of Eucalyptus pilularis Smith

The growth rate of a tree at any time relates to its size and the level of competition exerted by its neighbors for the resources it needs for growth. This work describes the development of a model to predict the maximum growth rate in stem basal area of Eucalyptus pilularis Smith trees in native and plantation forests of subtropical eastern Australia. It shows maximum growth rates increasing with size until the tree reaches a stem diameter at breast height of 27 cm. Thereafter, maximum growth rates decline progressively as the tree grows larger. Physiological reasons that might describe this growth pattern are discussed. The maxima are shown to be independent of tree age, stand stocking density or average tree size, and the productive capacity of the site on which the forest is growing. Study Implications The maximum possible growth rate in stem diameter of a Eucalyptus pilularis tree growing in subtropical eastern Australia is found to depend only on tree size, not its age nor the productive capacity of the site on which it is growing. It increases until stem diameter reaches a certain size and decreases progressively thereafter as the tree continues to grow. There are interesting physiological reasons that may explain this pattern of growth.

Quantification of the Ecological Value of Railroad Development Areas Using Logistic Regression Analysis

According to the national railway network construction plan, Investment in railways has increased due to the need for environmentally friendly transportation, and the rail network is expanding throughout South Korea. Railway projects should be evaluated using strategic environmental impact assessments. In the “Guidelines for the Construction of Environment-friendly Railways,” seven priority headings that must be considered for railway projects are described. This guide notes that qualitative evaluation must be conducted during the survey process to reasonably predict impacts on the environment. However, quantitative evaluation with specific indicator values may also be necessary. In this study, independence analysis and logistic regression analysis were used to quantitatively evaluate railway environmental and ecological indicators. The results were used to develop a regression model reflecting seven indicators; biodiversity class, ecosystem type, vegetation conservation class, tree age class, ecological naturalness, presence of river ecosystems, and fragmented patch size. The fitness regression model showed 90.3% classification accuracy and the receiver operating curve (ROC) model fit was 88.6%. An environmental quality assessment map was prepared by classifying areas of environmental quality according to five grades. This is the first model for environmental and ecological evaluation of railway projects. Evaluation using the map showed that the railroad passes through areas with lower protection values compared to the results obtained using the national environmental evaluation map. Kappa analysis showed a low level of agreement between the two maps (kappa coefficient = 0.212). The results of this study can be applied to railway development project sites and may help to identify the best sites for the development of an environmentally friendly railway system.