In the present investigation catena approaches to assess the landscape diversity of the “Dnipro-Orilsky” natural reserve was developed. Catena which lies in the reserve embraces flood and arena biogeocoenoses. The research was performed during the 2014– 2018. The two profiles were made at the “Dnipro-Orilsky” natural reserve within which main geomorphological landscape elements are presented. There are 29 sampling polygons within these p rofiles. The soil profile description, vegetation investigation, soil and soil animals quantitative assessment was carried out in each of them. In this publication we presented the results of sampling polygons 1–4, 25 and 26. The profile 1 best reflects the traditional view of catena: it goes from the highest places of the sand terrace (arena) to the lowest place (floodplain). But relief diversity is increased by the availability of small river Protich. It floodplain provides an alternative transit and accumulation gradient. It should be noted that the main part of the main slope profile does not fully meet the transit regime, as compiled by sandy soils, which are char- acterized by high filtration capacity. Therefore, the slope profile position is largely corresponded to eluvial regimes. The accumulative part of the profile which corresponds to the floodplain of Dnipro river is significantly influenced by impact of the flood factor than the accumulative part of the profile which corresponds to the floodplain of Protich river. The soils within floodplain of Protich river have more quantity of clay. Clay soils are characterized by capillary properties, as soil salinization is common in the floodplain of Protich river. Alternative profile 2 includes Orlov valley. This element of the landscape is accumulative, but not affected by flood factor. In the biogeocenotic context catena sampling points were considered as being composed of pedocatena, phytocatena and zoocatena. The biogeocenotic approach is the chain that connects the landscape structure, the diversity of soil cover, and diversities of the plant and animal communities. The functional, spatial and temporal properties of ecosystems in landscape context can be expressed by catena. The biogeocoenosis concept is a basis for integration of the pedocatena, phytocatena and zoocatena. Catena approach is the framework for a monitoring system landscape diversity both at the level of individual component biogeocoenosis (edaphotop, phytocenosis, and zoocenosis) and biogeocoenosis level in terms of its horizontal and vertical structure and at the landscape level as a whole intercon- nected system. The traditional idea of catena as a set of eluvial, transit and accumulative positions in a complex and diverse landscape is not able to cover the most important environmental gradients modes. The complexity of the landscape is due to relief diversity and the effects of anthropogenic transformation biogeocenotic cover. Catena therefore can be seen as a multilevel hierarchical system of the biogeocenotic polygons needed to consider the diversity of physiographic conditions and anthropogenic gradients.

Climatic changes in the environment are becoming more noticeable each year. Nonetheless, trends in the reaction of radial growth of forest trees to climate change should be studied in different climatic regions due to significant local variability in climatic conditions which are specific for any particular area. We conducted a correlation analysis of the relationship between the parameters of radial increment of black locust (Robinia pseudoacacia L.) and Scots pine (Pinus sylvestris L.) and meteorological factors of the environment in forest areas located in thenorthern steppe zone of Ukraine. We performed surveys in plantations of black locust, growing in hill slope and interfluve areas and also in sandy terrace plots of Scots pine. Over the period of intense vegetatative growth, black locust requires moisture 50% higher than the norm, and Scots pine 43% higher than the norm. It was determined that maximum increment for the studied plants occurred under the influence of a combination of factors involving reduction of the air temperature by 2.6–2.7 °С below the norm for black locust and by 2.3–2.5 °С for Scots pine. During the period of lower vegetative activity, Scots pine demonstrated lower sensitivity compared to black locust. This paper provides a statistical characteristic of the radial increment of trees in the conditions of changes in meteorological factors which limit their growth. The article provides data on multiple correlation of radial increment of the tree stands in relation to growth locations; demonstrates correlation dependency of radial increment of the studied trees on the precipitation and mean monthly temperatures over different time periods and during particular months. Radial increment of Scots pine exhibited most positive correlation with the total of precipitations throughout the period. For the stands of black locust, correlation coefficients were higher and distinguished by both positive and negative values. In the current increment of this species, a negative correlation relation was observed with the total precipitation in July, August and September, and positive correlation with the remaining months of the year. By contrast, radial increment of black locust and Scots pine positively correlated with air temperature during all time periods and particular months.

SUMMARYIn the article, it was analyzed the main biometric indicators of modal forest stands with Robinia рseudoacacia L. within the Dnieper Steppe of Ukraine. Under conditions of the Dnieper Northern Steppe, forest stands with Robinia pseudoacacia occupy an area of 17683.7 ha, representing 26.9 % of total area covered with forests. The range of habitat conditions in Robinia pseudoacacia varied from A 0 to D 4 . Age-class structure and distribution of Robinia wood stock cannot be evaluated as optimal because over-mature stands amounted the largest share 72.3 % of total Robinia area when small share of young stands. The trend of productivity increasing with age in Robinia forest stands is not established. Taking into account the Robinia normative maturity age amounted 26-35 years, it is necessary to take and implement some silvicultural measures to such type of forest stands growing at the present time.

The aim of this work is the comparative analysis of the productivity of Scots pines in pure and mixed plantations with main and accompanying species in the Northern Steppe of Ukraine We analysed the taxation parameters such as height, diameter, stand density, which vary with the age of the stand and composition of the plantation. Within the study area pines grow mainly in pure stands (81.9%). The share of mixed forest stands in the study area is only 18.1%. The analysis of representation of age structure showed the presence of the same proportion of the young age group in pure and mixed stands, the dominant share being taken up by middle-aged monoculture stands, and thus a smaller area taken up by mature and overmature pines. The average stand density per 1 ha in pure stands of all age groups is 17% higher than in mixed stands. The dynamics of variations of such biometric data as average height, diameter and density for the different compositions of Scots pine stands were measured for 14 age classes. The mean heights of the pure and mixed stands are vere close, while the average diameter gradually increased with age, reaching its maximum in overmature plantations. The research results showed that there is an excess of this parameter in the mixed compared with the pure stands. We did not find significant differences between middle age pure and mixed stands in accumulation of stand density. But pure pine stands show a clear tendency to dominate in wood accumulation in all age classes through the period of growth. The greatest difference between pure and mixed stands in the mean stand density was observed for those of middle-age. The average stand density in the pure stands was up to 32% higher than the mixed. The area distribution of Scots pine stands according to productivity was as follows. The largest area for both pure and mixed stands was occupied by trees of quality class I, which took up 54.3% of the total pure pine acreage and 41.9% of the mixed stand acreage. The second position was occupied by quality class II, which occupied 27.6% of total pure pine acreage and 36.6% of mixed stand acreage with the perecentage of total stand density at 23.6% and 35.1% respectively. In general, the value of the average stand density falls as the quality class decreases, and essentially depends on the composition of plantations: in pure stands, it is higher than in mixed. The investigated values of the biometric parameters are statistically significant for both the pure and the mixed stands.

The simulation of moisture content in Nikopol manganese ore basin technosols was performed using the Penman-Monteith approach and evaluate the role of the dependence of soils surface albedo from the humidity in the intensity of evapotranspiration. The sod lithogenic soils on loess-like loam and pedozem were chosen as the objects of the investigation. The research was conducted during 2012-2014 years at the investigation station of the remediation within Nikopol manganese ore basin (city Pokrov, Ukraine). The evapotranspiration from the soil surface was calculated by means of Penman-Monteith equation. Root zone moisture depletion is evaluated as the difference between soil water content at field capacity (pF = 2.3) and actual soil water content. The Ks value which is a water stress factor equals 1.0 as long as soil water content is higher than readily available water. If soil water content is lower than readily available water, Ks decreases linearly from one to zero according to total available soil water consumed. The soil water balance is performed in ISAREG with a daily time. The evaluation of readily available water content was carried out based on Penman-Monteith model taking into account meteorological data, technosols water-physical properties and the dependence of soil surface albedo on soil humidity. The color of the surface of the sod-lithogenic soil on the loess-like loam varies from yellow (2.5Y 4/2) in wet condition to yellow-red (10YR 6/5) in the dry condition. Albedo of this soil depended on the humidity varies in the range 0.17-0.31. The surface color of the pedozem varies from very dark gray (10YR 3/1) in wet condition to light-gray (2.5YR 6/2) in the dry condition. Albedo of this soil depended on the humidity varies in the range 0.10-0.31. There is a linear relationship between the moisture content in the soil and albedo of the soil surface. Albedo changes along with the humidity are most significant in the sod-lithogenic soils on loess-like loams. This is confirmed by the greatest regression coefficient. Albedo changes along with the moisture content are least significant in the pedozem. The distributionі of this index for different teсhnosols are characterized by a high level of similarity of shape due to the fact that the overall climate factors are crucial in shaping the dynamics of moisture. The distributions can be most good represented as a complex mixture of normal distributions. It was found that water supplies monitoring before the start of the growing season can provide valuable information necessary for the selection of crops for cultivation in the current year. The results indicate the urgency of measures to save the winter rainfall on the fields.