Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ...ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long‐term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground‐based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m3 of disturbed timber volume per year over the 70‐year study period. This value is likely a conservative estimate due to under‐reporting, especially of small‐scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m3/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long‐term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes.
Shifts in forest disturbance regimes may compromise the continuous provisioning of ecosystem services to society. Although forests in Europe are central to many policies, empirical data for understanding disturbance dynamics are lacking. We present a unique database of >170,000 ground‐based natural disturbance records in European forests from 1950 to 2019. Disturbances significantly increase over the study period, damaging on average 43.8 million m3 of timber volume per year. This is likely a conservative estimate due to under‐reporting. We estimated the magnitude of unreported damages to be between 8.6 and 18.3 million m3/year.
Beneficial effects of silicon (Si) on plants have primarily been studied in crop species under single stress. Moreover, nutrient acquisition-based responses to combination of biotic and abiotic ...stresses (a common situation in natural habitats) have rarely been reported, in particular in conjunction with soil amendments with Si. Pedunculate oak (
Quercus robur
L.), one of the ecologically and economically most important tree species in Europe, is facing a severe decline due to combined stresses, but also problems in assisted regeneration in nurseries. Here, we studied the effect of Si supply on the leaf nutriome, root traits and overall growth of 12-weeks-old oak seedlings exposed to abiotic stress low phosphorus (P) supply, biotic stress (
Phytophthora plurivora
root infection), and their combination. The application of Si had the strongest ameliorative effect on growth, root health and root phenome under the most severe stress conditions (i.e., combination of P deficiency and
P. plurivora
root infection), where it differentially affected the uptake and leaf accumulation in 11 out of 13 analysed nutrients. Silicon supply tended to reverse the pattern of change of some, but not all, leaf nutrients affected by stresses: P, boron (B) and magnesium (Mg) under P deficiency, and P, B and sulphur (S) under pathogen attack, but also nickel (Ni) and molybdenum (Mo) under all three stresses. Surprisingly, Si affected some nutrients that were not changed by a particular stress itself and decreased leaf Mg levels under all the stresses. On the other hand, pathogen attack increased leaf accumulation of Si. This exploratory work presents the complexity of nutrient crosstalk under three stresses, and opens more questions about genetic networks that control plant physiological responses. Practically, we show a potential of Si application to improve P status and root health in oak seedlings, particularly in nurseries.
Composition of Calocedrus decurrens and Cupressus arizonica essential oils (CDEO and CAEO, respectively), their antifeedant activity on spongy moth (Lymantria dispar) larvae, as well as their ...antimicrobial activity on three Phytophthora species were investigated. In leaves of these two conifers from the Cupressaceae family, monoterpenes strongly dominated (90.5 and 85.0%, respectively), but their terpene profiles were different. The dominant compound of CDEO was δ-3-carene (49.5%), followed by myrcene (9.4%), terpinolene (8.6%) and α-pinene (7.0%). In CAEO, the most dominant compounds were limonene (23.3%) and α-pinene (20.5%), followed by umbellulone (12.0%) and terpinen-4-ol (9.5%). CDEO showed a strong antifeedant activity, while leaf discs treated with CAEO had phagostimulatory effect on spongy moth larvae. CAEO had no significant effect on relative consumption and larval growth rate, while CDEO reduced consumption and stimulated growth at the lowest EO concentration (0.05%). Both EOs significantly affected the growth of colonies of the Phytophthora species tested. At concentrations of 0.5% and 1%, a 100% inhibition was observed in almost all experimental groups, with the exception of P. plurivora on 0.5% CDEO. At a concentration of 0.1% inhibition rate varied from 15% in P. ×cambivora treated with CDEO to 90% in P. quercina treated with CAEO. These findings indicate that these two EOs could be used to control tree pests.
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•δ-3-Carene dominated in Calocedrus decurrens essential oil (CDEO).•Limonene and α-pinene dominated in Cupressus arizonica essential oil (CAEO).•CDEO had an antifeedant and CAEO a phagostimulant effect on the spongy moth.•CDEO and CAEO inhibited the mycelial growth of Phytophthora species.
We examined essential oils (EOs) of Chamaecyparis lawsoniana and Thuja plicata (Cupressaceae), their antifeedant activity on Lymanthria dispar larvae and their antimicrobial activity. Studies of EOs ...showed that these two conifer species differed both in content of terpene classes and the major compounds. Total monoterpenes strongly dominated in T. plicata (96.4%), while C. lawsoniana was rich in both mono- and sesquiterpenes (40.8% and 30.3%, respectively) as well as in diterpenes (19.1%). The most dominant compounds of C. lawsoniana EO were: limonene (16.7%), oplopanonyl acetate (14.5%), beyerene (10.1%), and 13-epi-dolabradiene (6.7%). The dominant compound of T. plicata EOs was α-thujone (76.9%), followed by relatively small amounts of β- thujone (5.3%), sabinene (4.5%) and terpinene-4-ol (3.2%). The difference in EO compositions of the conifers was reflected on Lymantria dispar larvae performance. Larvae fed on the leaf discs treated by C. lawsoniana EO had a slight phagostimulatory effect at lower concentration shown by higher relative rate of food consumption and relative growth rate than the larvae in the control group. Contrastingly, leaf discs treated with EO of T. plicata EO had an antifeedant effect and lower relative consumption rate (RCR) and relative growth rate RGR than the larvae in the control group. Both tested EOs influenced substantially the colony growth of the subjected Phytophthora plurivora and P. quercina. Namely, 100% inhibitory effect was recorded at concentration of 0.1% in the case of C. lawsoniana EO, whereas of T. plicata colonies did not grow at 0.5% concentration. The implications of these findings and possibility of using the tested EOs in further experiments in vitro and in vivo are discussed.
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•Antifeedant and antimicrobial activity of the Cupressaceae species essential oils were tested.•Diterpenes and sesquiterpenes are dominant classes in C. lawsoniana essential oil.•Monoterpenes are dominant class in T. plicata essential oil.•Both essential oils had stronger antimicrobial than larval antifeedant activity.
Well-balanced nutrition is important for the successful cultivation of healthy plants. In this paper, we demonstrate a nondestructive optical method that can sense a deficiency of certain nutrients. ...The setup was tested on hydroponically grown Ocimum basilicum. The plants were subjected to nutrient deficiency by the exclusion of one of the essential elements (Fe, Mg, P, N) from the hydroponic solution. A control group of plants, fed by the balanced hydroponic solution, was also grown under the same conditions. The proposed method tracks and records the optical transmittance of the plants' leaves. All groups exhibit clearly defined day-night Circadian rhythms. When compared to the control group, the treated plants exhibited modified circadian rhythms of the optical transmission, suggesting an early indicator of the plants' stress. The condition of the plants under test was also assessed by the more common (destructive) methods such as: measurements of the determination of the photosynthetic pigment content, dray weight determination and the efficiency of PSII. Several biological parameters were observed, calculated and compared to the graphs of optical transmission dependence in real time. Presented results have demonstrated a significant potential of the proposed optical method for the early detection of plants' stress in hydroponic cultivation.
The degradation of riparian ecosystems occurring throughout the past decades has motivated efforts aimed at the restoration of these ecosystems. The success of active revegetation approaches to ...restoration requires appropriate selection of reproductive material, which in turn requires knowledge of seed traits and germination. Alnus glutinosa (L.) Gaertn. (common alder) is a key riparian tree widely used in restoration projects, and has recently been classified as comprising three species: A. glutinosa; A. lusitanica Vít, Douda, & Mandák; and A. rohlenae Vít, Douda, & Mandák. To help guide restoration species selection, we assessed differences among populations of these species by (1) investigating seed weight, morphology, and germination success from a large population set and (2) modeling germination success in each species in relation to morphological traits and environmental conditions. Seeds were collected from 12 populations encompassing the latitudinal extremes of the species complex, and were then characterized and germinated. Ploidy levels and species were distinguished using cytometric analysis. Site‐level climatic data and seed morphology data were used to model germination success for each species. All seed traits differed between populations and one morphological‐trait (seed weight‐to‐area ratio) differed significantly between the three species. Germination modeling showed that the southwestern species, A. lusitanica, responded positively to high temperature extremes, suggesting tolerance to the climate changes projected for southern Europe. Populations of A. lusitanica located at the latitudinal rear edge of common alder's distribution appear to show establishment‐facilitating adaptations, and therefore may contribute to ecological restoration efforts under a range of environmental conditions.
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.
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