•Thinning affects ecohydrological processes under different biophysical conditions, silvicultural systems, and time scales.•Throughfall, net precipitation, soil moisture and tree-level water use ...increase after thinning by 1.19, 1.14 and 1.56 relative to the control, respectively.•Stemflow and stand transpiration decrease after thinning by 0.42 and 0.6 relative to the control, respectively.•Thinning enhances runoff and groundwater recharge and mitigates the effects of drought through increasing Water Use Efficiency.•Thinning intensity of about 50% of the stand density is determined as the threshold at or over which hydrological processes are significantly affected.•The duration of thinning effect can be set between 2.6 and 4.3 (throughfall) and 3.1–8.6 years (soil moisture and transpiration).
Forest thinning can significantly affect hydrological processes. However, these effects largely vary with forest types, climate, thinning intensity, and hydrological variables of interest. Understanding these effects and their variations can significantly support thinning treatments' design and selection to ensure desired hydrological benefits. In this global-level review paper, we report the first comprehensive meta-analysis on the effects of thinning on major hydrological processes with an emphasis on rainfall partitioning, soil moisture and evapotranspiration processes. The synthesized and reviewed studies encompass different biophysical conditions (climate and forest ecosystems), silvicultural systems, and time scales (from weeks to decades) across continents. The results showed a significant increase in net precipitation, soil moisture and tree-level water use after thinning (the effect sizes are 1.19, 1.14 and 1.56 relative to the value of the control, respectively), while decreases in stemflow and transpiration (the effect sizes of 0.42 and 0.6 relative to the value of the control, respectively). Thinning intensity of about 50% of the stand density is determined as the threshold at or over which hydrological processes are significantly affected. The duration of thinning effect can be set between 2.6 and 4.3 (throughfall) and 3.1–8.6 years (soil moisture and transpiration), asking for repeated thinning in order to effectively sustain these effects. These global averages can serve as benchmarks for assessment and comparisons, but the effects of thinning depend on local biophysical conditions and thinning treatments. The literature review on the rest of the studied hydrological variables suggests that thinning generally enhance runoff to increase water yield and groundwater recharge. Thinning can also have a positive or limited role in water use efficiency (WUE), but it mitigates the effects of drought through increasing WUE. Moderate adverse effects on water quality can be prevented by adequate forest managements to prevent soil degradation. Nevertheless, more researches at relatively less studied regions are needed to support a more robust analysis of these reviewed hydrological variables. The management implications of the synthesized and reviewed results are suggested and discussed within the context of climate change.
Evapotranspiration (ET) is a major hydrologic process to assess water budgets in terrestrial ecosystems. Since measurement of ET may involve labor intensive field technics in large areas, estimation ...is preferred in most cases. The FAO Penman-Monteith (PM FAO-56) is a widely recognized reference evapotranspiration (ET
o
) method for potential evapotranspiration calculations. The method requires a detailed and comprehensive meteorological data set; however, some empirical methods and models have attempted to calculate ET with less data. In this study, Makkink (ET_Mak), Hargreaves–Samani (ET_Har), Thornthwaite (ET_Thor), Blaney–Criddle (ET_BC), and Penman (ET_PM) were tested against the PM FAO-56. Penman method has achieved the highest accuracy among the empirical methods. In addition, the potential of artificial neural networks (ANN), support vector machines (SVM), random forest (RF), and multiple linear regression (MLR) for estimating ET
o
were investigated in a semi-arid Central Anatolian Region of Turkey. The results obtained with the ANN (based on multi-layer perceptron) and SVM models performed better than other tested data-driven models and empirical methods. These models could be used most effectively at elevation range of 850–1000 m. According to our results MLP, SVM, and Penman methods provided good performances in semi-arid regions in agricultural planning and water resources management studies. Furthermore, we concluded that integrating maximum temperature may result in improved accuracy in ET model simulations in semi-arid regions.
Research directions from the 27th conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems (2015) reflect knowledge advancements about (i) Mechanistic bases of tree ...responses to multiple climate and pollution stressors, in particular the interaction of ozone (O3) with nitrogen (N) deposition and drought; (ii) Linking genetic control with physiological whole-tree activity; (iii) Epigenetic responses to climate change and air pollution; (iv) Embedding individual tree performance into the multi-factorial stand-level interaction network; (v) Interactions of biogenic and anthropogenic volatile compounds (molecular, functional and ecological bases); (vi) Estimating the potential for carbon/pollution mitigation and cost effectiveness of urban and peri-urban forests; (vii) Selection of trees adapted to the urban environment; (viii) Trophic, competitive and host/parasite relationships under changing pollution and climate; (ix) Atmosphere–biosphere–pedosphere interactions as affected by anthropospheric changes; (x) Statistical analyses for epidemiological investigations; (xi) Use of monitoring for the validation of models; (xii) Holistic view for linking the climate, carbon, N and O3 modelling; (xiii) Inclusion of multiple environmental stresses (biotic and abiotic) in critical load determinations; (xiv) Ecological impacts of N deposition in the under-investigated areas; (xv) Empirical models for mechanistic effects at the local scale; (xvi) Broad-scale N and sulphur deposition input and their effects on forest ecosystem services; (xvii) Measurements of dry deposition of N; (xviii) Assessment of evapotranspiration; (xix) Remote sensing assessment of hydrological parameters; and (xx) Forest management for maximizing water provision and overall forest ecosystem services. Ground-level O3 is still the phytotoxic air pollutant of major concern to forest health. Specific issues about O3 are: (xxi) Developing dose–response relationships and stomatal O3 flux parameterizations for risk assessment, especially, in under-investigated regions; (xxii) Defining biologically based O3 standards for protection thresholds and critical levels; (xxiii) Use of free-air exposure facilities; (xxiv) Assessing O3 impacts on forest ecosystem services.
•Research directions from the biennial IUFRO RG conference.•Focus on ozone, nitrogen deposition and climate change.•Linking genetic control with physiological activity recommended.•Multi-factorial stand-level investigations recommended.•Bridging research, monitoring and modelling recommended.
Multi-factorial studies are a key to investigate the complex interactions between climate, pollution and forests (from genes to the planet).
•Forest managers see the need for climate-smart forestry (CSF) but require greater guidance.•CSF that focusses on regional level adapting to local culture and conditions is needed.•Considering ...small-scale forest owners and ownership types should be included in CSF development.•Structural and financial support will be important from both the state and knowledge brokers.
Climate change impacts are an increasing threat to forests and current approaches to management. In 2020, Climate-smart Forestry (CSF) definition and set of indicators was published. This study further developed this work by testing the definition and indicators through a forest manager survey across fifteen member European countries. The survey covered topic areas of demographics, climate change impacts, definition and indicators assessment, as well as knowledge and communication. Overall, forest managers considered the threat of climate change to their forests as high or critical and 62% found the CSF definition clear and concise; however, the minority suggested greater simplification or nuance. Indicators were viewed as comprehensive but too numerous to integrate into management activities. Two highest ranking indicators were ‘Trees species composition’, and ‘Erosion protection and maintenance of soil condition’. Many managers were aware of suitable alternative species, but also stressed that greater resources should focus on exploring adaptable provenances. Demonstration sites and interactive guides were ranked highest for communication and dissemination; however, online multimedia tools and workshops were also ranked highly. Local perspectives on providing more relevant CSF ranged from silviculture systems, finance and funding, education and training, and social awareness, to tree species mixes and development of protective functions. In summary, forest managers were generally open to CSF, but required greater guidance and proof of application.
In July 2021, Rize province (Turkey) was struck by two intense rainstorms that caused two widespread landslide disasters with a short turnaround between them. Dozens of landslides were triggered, ...resulting in casualties, damages, and interruption of services. The objective of this technical note is to investigate if the knowledge and technical level available before 2021 was enough to calibrate an effective landslide early warning system (LEWS) and to propose a prototypal version for future landslide risk management in the province. A landslide dataset for the period 1990–2020 was compiled, coupled with the available rainfall records, and used to define a LEWS composed of a forecasting model based on I-D rainfall thresholds and a newly developed warning model calibrated on the severity of the past events. Afterwards, the year 2021 events were used to test the model, highlighting points of strength and weaknesses of the proposed prototype: the prototype would have been an effective tool to assist the management of landslide risk during the recent disastrous events, and it is also expected to be useful in the future, as climate change projections highlight that similar meteorological events are likely to happen again, with a slightly higher frequency. The prototype could be implemented in a short time and a roadmap is proposed to keep the system running while gradually updating it with more complex features. For instance, the rainfall forecasts segment of the system is identified as one of the priorities to be improved. The lesson learnt in this case study demonstrates the effectiveness of purposely calibrated warning systems and their utility in risk management procedures.
Thinning is a common harvesting method in Turkey that is assumed to be an environmental-friendly and hydrological-effective forestry technique. This assumption, however, does not rely on sound ...knowledge since the eco-hydrological database in the region is poor. This paper presents a paired watershed experiment that has been established to measure the hydrological impacts of 11% thinning in a deciduous forest ecosystem. The treatment was a selective cutting to remove 11% of the standing volume in a uniform pattern throughout the watershed. The suppressed or unhealthy trees from major diameter classes were removed in this procedure. Precipitation in the post-treatment year was within 0.2
mm of the calibration period average. At least 8
mm of additional water was maintained in the winter months of the first year according to paired watershed regression analysis. Observed and predicted monthly streamflows were compared in the post-treatment year, and the observed values outside the prediction interval were assigned as statistically significant (
p
<
0.05). Additionally, flow duration curves were used to investigate post-treatment flow patterns. The hydrologic features of the experimental watersheds are also presented in detail to evaluate the effects of the treatment.
Aim of study: Countries will be affected by climate change in different levels and ways. Therefore, it is necessary to focus on methods and options specific to regions. Basin approach, the ...sustainability of the basins and their capacity to be exposed to the possible effects of climate change, adapting to and resisting climate change should be addressed with an integrated approach. “Basin vulnerability analysis” methods are developed to ensure ecosystems sustainability and reveal their adaptive capacities. The purpose of these analyses is to calculate the basin’s vulnerability to all anthropogenic stress factors, especially climate change, for prioritizing investments and measures.
Area of study: This study applied in Balıkesir-Susurluk sub-basins.
Material and methods: This study applied a vulnerability analyses and mapped in Balıkesir-Susurluk sub-basins. The vulnerability analysis results were evaluated together with land use and resilience capacity.
Main results: We obtained a high correlation (r2=0.788) between the vulnerability values and the water quality scores. The used method was verified and found to be successful and applicable.
Highlights: The dissemination of the method with its application to other basins is critical in analyzing the vulnerability at the basin scale and directing the basin restoration investments.
Urban forests are becoming more critical as climate-induced disasters and disturbances tend to increase and affect cities. Forest managers are the responsible technical people on the ground to ...implement forestry-related climate policies. There is limited knowledge on the capacities of forest managers related to climate change issues. In this study, we surveyed 69 forest district managers of 28 provinces and compared their responses with actual data to understand their perceptions of urban green areas and climate change issues. We used a set of digital maps of the 1990–2015 period to identify land cover changes. To calculate the urban forest cover in the city centers, we used the city limit delineation shapefiles produced by the EU Copernicus program. We also employed the land consumption rate/population growth rate metric and a principle component analysis (PCA) to identify and discuss the provinces’ land and forest cover changes. The results showed that forest district managers were aware of the general condition of the forests in their provinces. Still, there was a considerable inconsistency between actual land use changes (i.e., deforestation) and their responses. The study also revealed that the forest managers were aware of the increasing influence of climate change issues but were not knowledgeable enough to establish the connection between their tasks and climate change. We concluded that the national forestry policy should prioritize the urban-forest interaction and develop the capacities of district forest managers to improve the efficiency of climate policies on a regional scale.
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