Together with the rapid industrialization of the world, urbanization is also uncontrollably increasing. Such an increase in urbanization exerts the greatest pressure on natural resources, obligating people to live in intense structural spaces and increasing the need for green spaces in cities. Because of the expensive costs of horizontal surfaces being “green”, urban places are faced with serious green-infrastructure problems. In recent years, alternatives have been searched for to eliminate such deficiencies. These alternatives, such as rain gardens, green walls (GWs), ecological designs, and green roofs, are commonly included in urban landscape designs. Besides rocky or steep-slope natural green walls (NGWs), natural green covers over buildings, walls, and so forth, structural members are also encountered in urban or rural places. On the other hand, artificial green walls (AGWs) have recently been used as a significant component of urban design. Although the AGWs are able to address various functional needs, they have not yet gained the desired popularity because of construction costs, static loads, constructional damages, and maintenance costs. In addition, such sites are largely left to exotic species with limited ecological requirements; these species are far from meeting ecological functions and resistance to extreme conditions. This study was conducted for a benchmarking assessment of artificial and natural green walls (A&NGWs) with a high potential in urban landscape design not only for esthetics, but also for ecological and economical purposes. Plant species, initial establishment, maintenance costs, and some other parameters of selected GWs were assessed. The study was considered as pioneering research for low-cost minimum-maintenance AGWs to be included in urban landscape designs. It was concluded, on the basis of the present findings, that the GW systems established with natural plant species, rock, and other materials already existing in natural landscapes could be constructed at fairly low costs, and such wall systems could have great ecological contributions.

Roadside plantings along urban and rural road corridors are designed to create visual effects as well as to provide functional benefits such as shading, screening or routing. Considering their potential for daily public use, roads and road corridors, as significant visual impact centers, can attract people’s attention and affect their points of view. Poplar species, which grow rapidly and easily along road corridors and can adapt to different ecological conditions swiftly, are used widely in both urban and rural landscapes in Turkey. The main objective of this study was to determine the visual structures dependent on the road-plant relationships of the poplar compositions that play an important role in shaping the roadside landscapes. For this purpose, compositions of poplar trees in selected urban and rural road corridors throughout Turkey were photographed and visual analysis techniques (VATs) were applied to determine visual preferences. Participants (n= 35) were shown 30 photographs, selected from the nearly 1000 taken, of road corridor poplar plantings and their evaluations were recorded in a questionnaire. In this survey, the people were requested to evaluate their appreciation levels towards the plantings as well as to express their other visual preferences and to assess visual quality. In addition, the association of all these evaluations with the demographic characteristics of the participants were determined. A correlation analysis was then performed to identify the relationships among all the visual assessments and a cluster analysis was conducted according to the visual status of the photographs in order to determine their groups. In the results of the study, the poplar trees, either individually or in the form of compositions, were reported to have a significant visual diversity. Moreover, the cluster analysis found the resulting three groups to be associated with leaf density, seasonal conditions and the trees as individuals or in groups. The seasonal variation factor in particular was shown to be visually effective in the poplar compositions. It was determined that visual perception of the poplar plantations differed in accordance with the demographic differences. This work established that poplar plantations as single trees or in groups and their proximity to the road altered visual preferences, and consequently, some suggestions were made concerning the use of poplars in roadside landscape planning.

This study investigated the effects of drought stress on the physiological and biochemical responses of the medicinal and aromatic plant Hypericum perforatum (St. John’s Wort). Changes were determined in leaf length, relative water content (RWC), osmotic potential, chlorophyll fluorescence (Fv/Fm), lipid peroxidation (TBARS), hydrogen peroxide (H2O2), and proline content as well as in the antioxidant system enzyme activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), and glutathione reductase (GR). These responses were examined in relation to the tolerance of drought stress in H. perforatum. Ninety-day-old seedlings were subjected to drought for three weeks. The physiological parameters of leaf length, RWC, Fv/Fm, and osmotic potential were reduced under drought. The H2O2, TBARS, and proline levels were increased significantly under drought stress. Moreover, the proline content increase was greatly pronounced (25.9-fold) compared to the control groups. The high accumulation of proline may have resulted from the 83.8% leaf RWC still remaining under drought stress. On the other hand, the SOD, CAT, and GR enzyme activities were enhanced, whereas the POX and APX activities were reduced. The results indicate that improved tolerance to drought stress in H. perforatum plants may be accomplished through increased capacity of the antioxidative defense system

Drought is one of the main abiotic stress factor that limits plant growth and development. Drought stress effects on Borago officinalis L. (borage) plants in terms of physiological and antioxidant responses have been evaluated in this study. In parallel with this purpose, relative growth rate (RGR), leaf relative water content (RWC), osmotic potential, chlorophyll fluorescence (Fv/Fm), lipid peroxidation, hydrogen peroxide (H2O2) level, superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities were determined under drought treatment in a controlled greenhouse. RGR, RWC and osmotic potential were significantly decreased, while lipid peroxidation expressed thiobarbutiric acid reactive substances (TBARS) and H2O2 contents were increased under drought stress. On the other hand, significant increases in POX, CAT, APX and GR activities did not prevent the increase in lipid peroxidation. To the best of our knowledge, this is the first study conducted on the enzymatic antioxidants of the defense system of Borago officinalis L. under drought stress.

This study analyses the decrease in soil organic carbon (SOC) stocks due to changes in land use following the earthquake in Düzce, Turkey, 1999. The primary objective of the study is to determine the changes in land use within Düzce and to provide a multi-dimensional approach to the spatial and quantitative distributions of SOC losses. Corine Land Use- Land Cover (LULC) within the study is used to determine the change in land use. The loss of LULC and carbon stocks were identified by means of LULC with transfer matrix method and GIS-based analysis. The study of land-use change caused by urbanisation and agricultural activity shows that the limited green spaces around the urban core created by degrading natural areas do not compensate for the loss of SOC. SOC stocks decline after the land use changes from agricultural regions to artificial areas (− 5%), Natural- Semi-natural (N-SN) regions to artificial areas (− 15%), N-SN areas to agricultural areas (− 20.9%) and agricultural areas to water bodies (− 9%), and SOC stocks increase after land use changes from artificial areas to N-SN areas (+ 29.6%), artificial areas to agricultural areas (+ 8%), agricultural areas to N-SN areas (+ 25%). However, in some agricultural areas, SOC stocks are similar to semi-natural and natural areas. For instance, in sparsely vegetated areas, SOC stocks from fruit and berry plantations may be poor. Although it is generally assumed that SOC loss can occur on land transformed from natural areas, this rule of thumb may be revised in some particular circumstances. Therefore, local ecological restoration decisions should not be based on land cover generalisations.