Forest fire risk has increased globally during the previous decades. The Mediterranean region is traditionally the most at risk in Europe, but continental countries like Serbia have experienced ...significant economic and ecological losses due to forest fires. To prevent damage to forests and infrastructure, alongside other societal losses, it is necessary to create an effective protection system against fire, which minimizes the harmful effects. Forest fire probability mapping, as one of the basic tools in risk management, allows the allocation of resources for fire suppression, within a fire season, from zones with a lower risk to those under higher threat. Logistic regression (LR) has been used as a standard procedure in forest fire probability mapping, but in the last decade, machine learning methods such as fandom forest (RF) have become more frequent. The main goals in this study were to (i) determine the main explanatory variables for forest fire occurrence for both models, LR and RF, and (ii) map the probability of forest fire occurrence in Eastern Serbia based on LR and RF. The most important variable was drought code, followed by different anthropogenic features depending on the type of the model. The RF models demonstrated better overall predictive ability than LR models. The map produced may increase firefighting efficiency due to the early detection of forest fire and enable resources to be allocated in the eastern part of Serbia, which covers more than one-third of the country’s area.
Oak lace bug – Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae) is a North American species that has been introduced to Europe and Asia, where it became a serious oak pest. As little is known ...about its behavior, we conducted a study in which we tested the preference and performance of the oak lace bug for different oak species and the influence of powdery mildew and CO2 on the behavior of the oak lace bug. Four of the most represented oak species in Serbia (Hungarian, pedunculate, sessile, and Turkey oak) were used for testing the preference and performance of the oak lace bug, and the influence of oak powdery mildew on the behavior of the oak lace bug. The influence of CO2 on the behavior of the oak lace bug was tested on pedunculate oak. The results of this study have shown that there are differences in preference and performance of the oak lace bug between the analyzed oak species; there are significant differences in the oak lace bug host preference in the laboratory and in field conditions; Hungarian oak is most threatened by the oak lace bug, as the oak lace bug performs best on this species and preferers this species in field conditions; the oak powdery mildew and oak lace bug are in an antagonistic relationship; and that the changes in the leaves caused by the expected increase in CO2 concentration in the future will probably not influence the feeding behavior of the oak lace bug adults.
In recent years, forest fires have become an important issue in Central Europe. To model the probability of the occurrence of forest fires in the Lower Silesian Voivodeship of Poland, historical fire ...data and several types of predictors were collected or generated, including topographic, vegetation, climatic, and anthropogenic features. The main objectives of this study were to determine the importance of the predictors of forest fire occurrence and to map the probability of forest fire occurrence. The H2O driverless artificial intelligence (DAI) cloud platform was used to model forest fire probability. The gradient boosted machine (GBM) and random forest (RF) methods were applied to assess the probability of forest fire occurrence. Evaluation the importance of the variables was performed using the H2O platform permutation method. The most important variables were the presence of coniferous forest and the distance to agricultural land according to the GBM and RF methods, respectively. Model validation was conducted using receiver operating characteristic (ROC) analysis. The areas under the curve (AUCs) of the ROC plots from the GBM and RF models were 83.3% and 81.3%, respectively. Based on the results obtained, the GBM model can be recommended for the mapping of forest fire occurrence in the study area.
Atmospheric carbon dioxide (CO2) has increased substantially since the industrial revolution began, and physiological responses to elevated atmospheric CO2 concentrations reportedly alter the ...biometry and wood structure of trees. Additionally, soil nutrient availability may play an important role in regulating these responses. Therefore, in this study, we grew 288 two-year-old saplings of sessile oak (Quercus petraea (Matt.) Liebl.) in lamellar glass domes for three years to evaluate the effects of CO2 concentrations and nutrient supply on above- and belowground biomass, wood density, and wood structure. Elevated CO2 increased above- and belowground biomass by 44.3% and 46.9%, respectively. However, under elevated CO2 treatment, sapling wood density was markedly lower (approximately 1.7%), and notably wider growth rings-and larger, more efficient conduits leading to increased hydraulic conductance-were observed. Moreover, despite the vessels being larger in saplings under elevated CO2, the vessels were significantly fewer (p = 0.023). No direct effects of nutrient supply were observed on biomass growth, wood density, or wood structure, except for a notable decrease in specific leaf area. These results suggest that, although fewer and larger conduits may render the xylem more vulnerable to embolism formation under drought conditions, the high growth rate in sessile oak saplings under elevated CO2 is supported by an efficient vascular system and may increase biomass production in this tree species. Nevertheless, the decreased mechanical strength, indicated by low density and xylem vulnerability to drought, may lead to earlier mortality, offsetting the positive effects of elevated CO2 levels in the future.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
With the process of urbanization, cities are expanding, while forests are declining. Many conditions in the urban habitats are modified compared to those in the rural ones, so the organisms present ...reactions to these changes. To determine to what extent the habitat type influences insects, we tested the differences in the pedunculate oak (Quercus robur L.) leaf-mining insect community between urban and rural habitats in Serbia. Lower species richness, abundance, and diversity were determined on trees in the urban environment. Due to the differences in the habitat types, many of the species disappeared, while most of the remaining species declined. The seasonal dynamics of species richness, abundance, and diversity differed between the habitat types. Both rural and urban populations started with low values in May. Subsequently, rural populations gained higher species richness, abundance, and diversity. As about 60% of the leaf miners’ species present in the rural habitats survive on the trees in urban areas, those trees are of great importance as a species reservoir. This is why we need to preserve and strive to improve the condition of urban areas where the pedunculate oak is present.
When monitoring the state of health of
trees, unusual symptoms were discovered within a
plantation in Bosnia and Herzegovina. These symptoms included the appearance of necrosis and cankers in the ...basal parts of the trees, followed by the formation of fruiting bodies, however, none of these symptoms were found in the crowns. After sampling and isolation of the necrotic parts from the stem base, pathogen
was isolated and identified from the characteristics of pure cultures, morphology of the fruiting bodies, and from multilocus sequencing. In field conditions, juvenile
trees were inoculated with two
.
isolates obtained from the necrotic tissues of both juvenile
and mature
trees. In both isolates, 12 months post inoculation, the lengths and widths of the necroses were significantly larger compared to the control. Necroses of significantly larger lengths, widths and surfaces were found again in both tested isolates 24 months post inoculation. In the case of the
isolate, the lengths of the necroses at both the stem base and at breast height increased by 1.6 times, whereas the
isolate increased in size by up to 1.7 and 1.8 times, respectively. Trees inoculated without a previous bark wound showed no symptoms, similar to the control trees. Scanning electron microscopy and X-ray micro-computed tomography imaging revealed that
hyphae penetrated from the cankers to the woody outermost annual growth ring and that hyphae were present mostly in the large earlywood vessels and rarely in the axial parenchyma cells. Hyphae also spread radially through the pits in vessels. The infected trees responded with the formation of tyloses in the vessels to prevent a rapid fungal spread through the axial vascular transport pathway. The ability of
to cause necroses in juvenile ash trees was demonstrated for the first time during this study. It poses a serious threat to planted forests and natural regenerations of
especially if
is considered as a possible inoculum reservoir for future infections. This pathogen should be integrated within future ash resistance or breeding programs.
Temperature and food quality are the most important environmental factors determining the performance of herbivorous insects. The objective of our study was to evaluate the responses of the spongy ...moth (formerly known as the gypsy moth)
L. (Lepidoptera: Erebidae) to simultaneous variation in these two factors. From hatching to the fourth instar, larvae were exposed to three temperatures (19 °C, 23 °C, and 28 °C) and fed four artificial diets that differed in protein (P) and carbohydrate (C) content. Within each temperature regime, the effects of the nutrient content (P+C) and ratio (P:C) on development duration, larval mass, growth rate, and activities of digestive proteases, carbohydrases, and lipase were examined. It was found that temperature and food quality had a significant effect on the fitness-related traits and digestive physiology of the larvae. The greatest mass and highest growth rate were obtained at 28 °C on a high-protein low-carbohydrate diet. A homeostatic increase in activity was observed for total protease, trypsin, and amylase in response to low substrate levels in the diet. A significant modulation of overall enzyme activities in response to 28 °C was detected only with a low diet quality. A decrease in the nutrient content and P:C ratio only affected the coordination of enzyme activities at 28 °C, as indicated by the significantly altered correlation matrices. Multiple linear regression analysis showed that variation in fitness traits in response to different rearing conditions could be explained by variation in digestion. Our results contribute to the understanding of the role of digestive enzymes in post-ingestive nutrient balancing.
Forest fires are becoming a serious concern in Central European countries such as Austria (AT) and the Czech Republic (CZ). Mapping fire ignition probabilities across countries can be a useful tool ...for fire risk mitigation. This study was conducted to: (i) evaluate the contribution of the variables obtained from open-source datasets (i.e., MODIS, OpenStreetMap, and WorldClim) for modeling fire ignition probability at the country level; and (ii) investigate how well the Random Forest (RF) method performs from one country to another. The importance of the predictors was evaluated using the Gini impurity method, and RF was evaluated using the ROC-AUC and confusion matrix. The most important variables were the topographic wetness index in the AT model and slope in the CZ model. The AUC values in the validation sets were 0.848 (AT model) and 0.717 (CZ model). When the respective models were applied to the entire dataset, they achieved 82.5% (AT model) and 66.4% (CZ model) accuracy. Cross-comparison revealed that the CZ model may be successfully applied to the AT dataset (AUC = 0.808, Acc = 82.5%), while the AT model showed poor explanatory power when applied to the CZ dataset (AUC = 0.582, Acc = 13.6%). Our study provides insights into the effect of the accuracy and completeness of open-source data on the reliability of national-level forest fire probability assessment.
Interactions between plants, insects and pathogens are complex and not sufficiently understood in the context of climate change. In this study, the impact of a root pathogen on a leaf-eating insect ...hosted by a tree species at elevated CO2 concentration is reported for the first time. The combined and isolated effects of CO2 and infection by the root pathogen Phytophthora plurivora on English oak (Quercus robur) seedlings were used to assess growth rates of plants and of gypsy moth (Lymantria dispar) larvae. For this purpose, two Q. robur provenances (Belgrade and Sombor) were used. At ambient CO2 concentration, the relative growth rates of larvae consuming leaves of plants infected by P. plurivora was higher than those consuming non-infected plants. However, at elevated CO2 concentration (1000 ppm) higher relative growth rates were detected in the larvae consuming the leaves of non-infected plants. At ambient CO2 concentration, lower growth rates were recorded in L. dispar larvae hosted in Q. robur from Belgrade in comparison to larvae hosted in Q. robur from Sombor. However, at elevated CO2 concentration, similar growth rates irrespective of the provenance were observed. Defoliation by the gypsy moth did not influence the growth of plants while P. plurivora infection significantly reduced tree height in seedlings from Belgrade. The results confirm that a rise of CO2 concentration in the atmosphere modifies the existing interactions between P. plurivora, Q. robur, and L. dispar. Moreover, the influence of the tree provenances on both herbivore and plant performance at elevated CO2 concentrations suggests a potential for increasing forest resilience through breeding.
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