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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. Cehyrfo-Med (CGL2017-86839-C3-2-R funded by MCIN/AEI /10.13039/501100011033/ and FEDER a way to make Europe), SilvAdapt.net (RED2018-102719-T funded by MCIN/AEI /10.13039/501100011033), RESILIENT-FORESTS (LIFE17 CCA/ES/ 000063), JSPS KAKENHI (JP 18H04152 and JP 19H03088), contract RE21NOR-029 (British Columbia Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Canada), and the Canadian NSERC CRD (CRDPJ 485176-15) partly supported this work. Open access was funded by CRUE-Universitat Politècnica de València.

Dünyada sulak alan ekosistemlerini etkileyen en önemli insan müdahalelerinden biri arazi kullanımının değiştirilmesidir. Bu çalışmanın amacı, Sultan Sazlığı örneğinde sulak alandan tarıma dönüştürmenin sulak alan ve civarı topraklarda organik karbon ve bazı toprak özellikleri üzerindeki etkilerini ortaya koymaktır. Bu amaçla sulak alan ekosisteminde bulunan sazlık (Örtülüakar ve Kepir Sazlıkları) ve tarıma dönüştürülmüş alanlardan doğal yapısı bozulmamış toprak örneklemesi yapılmış (0-40 cm) ve 10 ar cm’ lik derinlik kademesine ayrılarak her bir derinlik kademesindeki organik karbon miktarı (TOK) ile hacim ağırlığı belirlenmiş ve karbon depolama kapasiteleri hesaplanmıştır. Ayrıca her bir arazi kullanım şeklinden iki derinlik kademesinden (0-20 cm ve 20-40 cm) alınan toprak örneklerinin toprak tekstürü, pH, elektriksel iletkenlik (EC), ateşte kayıp, agregat stabilitesi özellikleri belirlenmiştir. Tarıma dönüştürme Sultan Sazlığı ekosistemindeki çeşitli toprak özelliklerini etkilemiştir. Arazi kullanımı dönüşümlerinden etkilenen toprak özellikleri; organik karbon, karbon depolama kapasitesi, agregat stabilitesi, kum, kil, toz içeriği, hacim ağırlığı, ateşte kayıptır. Toprak derinliği değişiminden etkilenen toprak özellikleri ise organik karbon, karbon depolama kapasitesi, pH, kil, kum içeriği ve hacim ağırlığıdır., One of the most important human interventions affecting wetland ecosystems in the world is land use change. The aim of the study is to reveal the effects of land use conversion (wetland to farmland) on soil organic carbon and some soil properties of wetlands in the case of the Sultan Marshes. Undisturbed soil samples were collected from a depth of 0-40 cm in marshlands (Örtülüakar and Kepir Marshes) and in those converted to farmland in the wetland ecosystem and the amount of soil organic carbon (SOC), bulk density and carbon storage capacity of soils at each land use types were calculated by dividing into 10 cm soil depth levels. In addition, disturbed soil samples were taken at two soil depths (0-20 cm and 20-40 cm). Some physical and chemical properties of soils were analyzed using this samples such as particle size distribution, pH, electrical conductivity (EC), loss on ignition and aggregate stability. Soil organic carbon, carbon storage capacity, loss on ignition, aggregate stability, clay, silt, sand contents and bulk density were the soil properties affected by land use conversion. Soil organic carbon, carbon storage capacity, pH, clay, sand contents and bulk density were the soil properties showed changes with soil depth.

During the past century, the experimental catchment studies around the globe revealed the negative correlation between biomass and water yield. Unfortunately, if the assessment relies solely on this negative relationship then a biased perception arises stating that “water yield increases proportionally as the forest cover decreases with cuttings”. This paper explains why this perception should be changed and suggests a new forest planning paradigm. Taking into account climate change and similar risks, forest planning for the objective of water production should go parallel with watershed planning using methods and principles that will boost the capacity of riparian ecosystems with the best management practices”. To come up with this conclusion we used three major data sources and approaches. These are; (1) Meta-analysis, (2) Project results and (3) Initial assessment for Marmara region. The relevant project outputs for the last 10 years points out the need for integration with watershed based planning, climate adaptation and the riparian ecosystems to the forest planning processes. To realize this, a Hydrologic Assessment Report (HAR) and Riparian Ecosystems Management Report (REMR) should be prepared prior to forest planning process. With this approach, we think that water production and soil conservation functions will be incorporated into whole forest areas and forestry activities as an upper level planning function., Dünya genelinde geçen yüzyıl içinde gerçekleştirilen deneysel havza çalışmaları biyokütle ile su verimi arasındaki negatif korelasyonu ortaya koymuştur. Fakat sadece bu negatif korelasyon dikkate alınıp önemli detaylar göz ardı edildiğinde “orman ne kadar şiddetli aralanır veya kesilirse o kadar yüksek seviyede su verimi artırılabilir” şeklinde yanlış bir algı oluşmaktadır. Bu makalede bu yaklaşımın neden terk edilmesinin gerektiği açıklanmakta ve su üretim amacına yönelik yeni orman planlama paradigması ortaya konulmaktadır. İklim değişikliği ve benzer riskler dikkate alınarak, su üretim amaçlı orman planlama, havza planlama ile eşgüdüm içinde, akarsu kıyı ekosistemlerinin kapasitesini üst düzeye taşıyacak şekilde iyi yönetim uygulamaları prensipleri çerçevesinde planlamaya konu olmalıdır. Bu sonuca ulaşmak için 3 temel yaklaşım ve veri kaynağı benimsenmiştir: (1) Meta analiz, (2) Proje sonuçları ve (3) Marmara Bölgesi kapsamında ön değerlendirme. Orman planlamada havza bazında entegrasyonu, iklim değişikliğine uyum ve akarsu kıyı ekosistemlerinin planlamaya aktarılması için planlama öncesi Havza Hidrolojik Değerlendirme Raporu (HDR) ve Dere Kıyısı Ekosistemleri Yönetim Planları (DKYP) hazırlanmalıdır. Bu yaklaşımla fonksiyonel planlamada su üretimi ve toprak koruma fonksiyonları birer üst planlama fonksiyonu mantığıyla tüm ormanlara ve ormancılık faaliyetlerine dahil edilmiş olacaktır.

WOS: 000255898500014, The paper presents a synthesis of a set of experiments, implemented to investigate the acid buffering mechanism of Belgrad Forest soils. Previous studies carried out in the region, pointed out the exposure of Belgrad Forest ecosystems to acid deposition. Between 1999 and 2001, we performed a set of supplementary studies, focusing on the hydrogen buffering, part of the issue. Ceramic cup lysimeters were installed to various soil depths, and the soil water ionic composition was monitored to determine the main buffering, zones among the horizons. The upper 20 cm, litter layer and Ah horizon, were identified to have the main exchange mechanisms, decreasing the hydrogen ion activity from 22.82 mu eq L-1 to 0.56 mu eq L-1. To identify the role of litter layer, a litter removal parcel study was employed. After the litter removal, soil samples were taken bimonthly from two depths (0-12 and 12-20 cm) for a 1-year period of time, to determine changes in soil properties. Organic matter content and pH were slightly higher in the upper 12 cm. Finally, the exchange capacities of single-valenced base cations, Na+ and K+ were compared with a retention curve experiment in laboratory. The cation retention capacities of the soil samples rich in organic matter were lower than the ones with less organic matter. The results of the three experiments revealed that, even though the upper soil horizons were responsible of hydrogen buffering in the region, the litter layer or humus layer did not have a particular role.