Açıl Ahmet, MSc

In terms of engineering standards, the dimensions of hydraulic structures such as culverts on forest roads should have the capability to drain the expected maximum discharge for a 50-year return period during their lifespan (i.e., 20 years). In Turkey, Talbot’s formula, as empirical method, has commonly been used in determining the required cross-sectional area (CSA) of the structures. However, in practice, forest road engineers in Turkey do not pay enough attention to their construction with required dimensions calculated by Talbot’s formula. In the present study, the Hydrological Engineering Centre – River Analysis System (HEC-RAS) model was used to evaluate the dimensions of installed structures in terms of their ability to drain maximum discharges, with the aim of determining the required dimensions for those that could not meet this requirement. To this purpose, the 6+000 km forest road No. 410 in Acısu Forest Enterprise, Gerede Forest Directorate (Bolu, Turkey) was selected as the study area. In total, 15 small watersheds crossed by the forest road were delineated, with only six of them having cross-drainage structures. The HEC-RAS model geometry was generated by manual unmanned aerial vehicle (UAV) flights at altitudes of 5–15 m, providing very high spatial resolution (<1 cm). The maximum discharges of the watersheds were estimated for the HEC-RAS model using the Rational, Kürsteiner, and Soil Conservation Service-Curve Number (SCS-CN) methods. Maximum discharges of 0.18–6.03 were found for the Rational method, 0.45–4.46 for the Kürsteiner method, and 0.25–7.97 for the SCS-CN method. According to the HEC-RAS hydraulic model CSA simulations, most of the installed culvert CSAs calculated by Talbot’s formula were found to be incapable of draining maximum discharges. The study concluded that the HEC-RAS model can provide accurate and reliable results for determining the dimensions of such structures for forest roads.

Natural and human-induced disturbances are major drivers of the decline and loss of vulnerable species worldwide. Among these, fires are particularly disruptive as they can devastate entire ecosystems. Assessing the likelihood and severity of such disturbances on plant communities is crucial for the management and conservation of biodiversity. This study aims to analyze fire susceptibility using the Maximum Entropy (MaxEnt) model to evaluate the potential impacts of fires on the biodiversity of a lowland forest in Azerbaijan. The research was conducted as part of the project on the evaluation of Red Book species in Azerbaijan based on IUCN categories and criteria. In this study, 21 rare plant species found in the Samur-Yalama National Park (SYNP) were assessed for fire susceptibility, as they have been significantly affected by fires in recent years. The fire susceptibility analysis included 12 driving factors, categorized into topographic, vegetation, and climatic factors, and identified 564 wildfire incidents. Model performance was evaluated using the AUC value, which was 0.855, indicating good model accuracy. Fire susceptibility was classified into three categories: low, moderate, and high. According to the results, 12,642 hectares (60.82%) of the SYNP area fall under low susceptibility, 5532 hectares (26.62%) under moderate susceptibility, and 2611 hectares (12.56%) under high susceptibility. Rare plant species in SYNP were evaluated based on their fire susceptibility. It was found that Alcea kusariensis (Iljin ex Grossh.) Iljin, Anacamptis morio subsp. picta (Loisel.) Jacquet & Scappat., Equisetum hyemale L., Orchis purpurea Huds., Pinus brutia var. eldarica (Medw.) Silba, Platanus orientalis L., Punica granatum L., and Quercus castaneifolia C.A.Mey are located in areas classified as having high susceptibility.