The "Flora of Russia" project on iNaturalist brought together professional scientists and amateur naturalists from all over the country. Over 10,000 people were involved in the data collection.
Within 20 months, the participants accumulated 750,143 photo observations of 6,857 species of the Russian flora. This constitutes the largest dataset of open spatial data on the country’s biodiversity and a leading source of data on the current state of the national flora. About 87% of all project data, i.e. 652,285 observations, are available under free licences (CC0, CC-BY, CC-BY-NC) and can be freely used in scientific, educational and environmental activities.
Height and diameter at breast height are basic variables that are measured in a forest inventory. Generalized models do not require measuring tree heights or number of measurements is minimal. The purpose of this study was to obtain 24 new generalized height-diameter models based on simple basic models, compare them with 9 generalized models selected from other studies, and develop an appropriate height-diameter model for birch in the European Russia. To select models which better describe the relationship between the heights and diameters of the trees, six metrics were used – root mean square error (RMSE), mean absolute percentage error (MAPE), coefficient of determination (R2), adjusted coefficient of determination (R2-adj.), Akaike information criterion (AIC) and Bayesian information criterion (BIC). Results show that there are slight differences between all models. The performance statistics showed that model M24 is the most suitable and recommended for predicting the height-diameter relationships for birch trees in this study area. The predicting variables for applying developed generalized models to estimate total tree height require less sampling effort and are derived from conventional forest inventory data which allows to reduce costs and time consumption in field work.
In the Forest Experimental Station of the Russian State Agrarian University–Moscow Timiryazev Agricultural Academy, since 1862, experiments have been carried out to study the methods of planting, the geographical origin of seeds, methods of thinning for forest growth. Over 150 years, significant changes have occurred in the climatic conditions of the Forest Experimental Station. There have been changes in the species composition of the forested area of the Forest Experimental Station. At the time of the first forest inventory in 1862, there were 5.7 units for pine, 1.6 units for birch and 1.4 units for oak. In the subsequent dynamics of the species composition of forest stands, there is a decrease in the share of pine to 3.9 units and an increase in the share of birch (1.6 units), oak (2.3 units) and larch (1.8 units) by 2009.
The accuracy of determining the height of trees is essential both in forestry and in scientific research. Height is usually determined using specific models, where it is a function of the diameter at breast height. On the materials of 23 sample plots with the measurement of model trees in birch stands, the parameters were determined for 29 two-parameter and three-parameter models that are most often found in literary sources. The following metrics evaluated the quality of the models: root mean square error, mean absolute percentage error, coefficient of determination, adjusted coefficient of determination, Akaike information criterion, and Bayesian information criterion. Three-parameter models of the dependence of height on diameter by a set of metrics show somewhat better quality than two-parameter models. Nevertheless, in general, the differences between most models are minor. Along with the models selected as the best, the Näslund and Chapman-Richards equations, which are often used in the literature as the most flexible, showed good quality. The methodology of this study allows you to repeat the same work for tree species and forest conditions, for which information on the nature of the relationship of height with diameter is incomplete or missing.
One of the methods of environmentally friendly irrigation is drip irrigation, which also improves the quality and yield of agricultural and fruit crops. The aim of the work was to study the effect of different moisture content of the soil on the growth and development of plum seedlings grown in a fruit nursery in the conditions of the Non-Black Soil Zone of European Russia. For the rational use of irrigation water and obtaining high-quality plum planting material in the nursery, it is recommended to use an irrigation regime with maintaining soil moisture in the range of 80-100% lowest moisture capacity with a soaking depth of 30 cm in the first year and 40 cm in the second year.
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