Liubov Ishchuk(1)*, Ivan Kosenko(2), and Halyna Ishchuk(3)

1. Department of Landscape, Bila Tserkva National Agrarian University, Soborna area, 8/1, 09111 Bila Tserkva, Ukraine. *E-mail: ishchuk29@gmail.com
2. National Dendrological Park ’Sofiyivka’ of National Academy of Sciences of Ukraine, 12A Kyivska str. 20305 Uman, Ukraine. Е-mail: ndp.sofievka@gmail.com
3. Department of Forestry, Uman National University of Horticulture, 1 Instytutska Str., 20305 Uman, Ukraine. E-mail: sobaka.kot2011@gmail.com

The growth and development of vegetative and generative organs of Populus alba L., P. balsamifera L., P. bolleana Lauche, P. × canescens (Ait.) Smith., Р. deltoides Bartr. ex Marsh., P. nigra L., P. nigra cv. Italica (Du Roi) Moench, Р. simonii Corr., P. tremula L., and European-American P. deltoides × P. nigra hybrids ʹI-45/51ʹ, ʹBlanc du Poitouʹ, ʹGelricaʹ, ʹMarilandicaʹ, ʹRobustaʹ, ʹSerotinaʹ, ʹTardif de Champagneʹ, and P. × hybridа clones ʹWeresinaʹ and ʹWitschtejnaʹ were studied outdoor for seven years under current climate change. The development of most Populus species and hybrids started in the second half of March – beginning of April when the phase of bud swelling was reached in correspondence of a significant temperature sum from 68 to 112 °С, depending on the species/hybrid considered. In most species, flowering began on April 20th and lasted 9 to 16 days, temperature sum of 93–139 °С, depending on the species. The duration of linear shoot growth was shorter in native species of the genus Populus (118–130 days) than in introduced species (135–140 days). Fruiting began when the temperature sum reached 217– 234 °С in P. tremula, while in P. balsamifera it required 413 °C. The other species required an intermediate temperature sum (299–329 °С) to reach the same phase, which was accumulated in the first ten-day period of June. Discolouration of leaves depended on the date of first autumn frosts and during the study period was shifted by two to three weeks later. After analyzing the timing of phenological phases of growth and development, species and hybrids were assigned to phenological groups characterized by early, mid or late beginning and end of the vegetation period. The knowledge of thermal requirements for key phenological stages is expected to be useful for modelling and predicting growth, flowering and fruiting of poplars, which is crucial to create efficient and productive bioenergy plantations and to take anti-allergic measures during fruiting in the Right-Bank Forest-Steppe of Ukraine.

Petar Zhelev(1)*, Nikolay Tsvetanov(1), Ina Aneva(2), and Dimiter Ivanov(2)

1. Department of Dendrology, University of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, Bulgaria. *E-mail: petar.zhelev@ltu.bg
2. Department of Plant and fungal diversity and resources, Institute of Biodiversity and Ecosystem research, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., block 23, 1113 Sofia, Bulgaria.

Species of genus Tilia (lime) still did not gain the attention they deserve by researchers and forest managers. Their importance as a significant part of forest biodiversity is expected to increase, especially in the light of changing environment, due to climate change and other factors. We present a mini-review about the genetic resources of Tilia species in Bulgaria. The survey starts with species diversity, including the standing taxonomic problems, and continues with genetic variation. A thorough evaluation of lime species’ genetic resources and their conservation in Bulgaria is performed, facilitated by a specially developed database. Knowledge gaps are identified and some domains for prospective studies are outlined.

Marlena Baranowska(1)*, Barłomiej Meres(2), Jolanta Behnke-Borowczyk(3), and Robert Korzeniewicz(1)

1. Poznań University of Life Sciences, Faculty of Forestry, Department of Silviculture, 71A Wojska Polskiego Srt., 60-625 Poznań, Poland. E-mails: marlena.baranowska-wasilewska@up.poznan.pl*; robert.korzeniewicz@up.poznan.pl
2. Forestry Experimental Station in Murowana Goślina, Forest Arboretum in Zielonka, 6 Zielonka Str., 62-095 Murowana Goślina. Poland. E-mail: arboretum@up.poznan.pl
3. Poznań University of Life Sciences, Faculty of Forestry, Department of Forest Pathology; 71C Wojska Polskiego Str., 60-625 Poznań, Poland. E-mail: jolanta.behnke-borowczyk@up.poznan.pl

The fruits of the black cherry are food for a variety of different species of animals. Therefore, animals have an important role in the spread of black cherries by zoochory. The aim of this study was to determine how the digested black cherry seeds by the badger (Meles meles) digestive system affects the germination efficiency of these seeds after voiding in the badger’s faeces. It was hypothesized that seeds of black cherries collected from badger faeces will show greater germination efficiency in the first year after sowing than non-stratified seeds, stratified seeds and seeds with an exocarp. Black cherry seeds were collected in autumn 2018 at the Forest Arboretum in Zielonka from badger faeces, which comprised the first treatment group of the experiment and from standing trees, and among these seeds there were further variants of treatment. Seeds collected from standing trees were: without pericarp (treatment group), without pericarp and stratified, not cleaned but stratified and seeds untreated (control sample). The first seedlings to emerge were from seeds collected from badger faeces (206 days after sowing). The seeds with intact pericarp had the longest period of emergence, germinating 221 days after sowing. The highest seed germination capacity was noted for seeds from badger faeces (66.4 %), and the lowest one was observed for seeds sown with intact pericarp (15.2 %). Pericarp inhibits seed germination in the first year after sowing.

Biser Hristov

University of Forestry, 10 K. Ohridski Blvd., Sofia 1797, Bulgaria. E-mail: bisseru@gmail.com

The main components of the cation exchange capacity (CEC) are assessed in order to study the physicochemical properties in Phaeozems. These soils in Bulgaria usually have high humus accumulation, soil texture differentiation, high base saturation and soil reaction suitable for crops. They are spread in plains, valleys, forests and low hills with temperate continental climate. Soil-forming materials are Pliocene and Quaternary sediments, loess and loess-like clays. The soil reaction (pH) varies from slightly acidic to alkaline. Soil alkalinity increases in depth because of high carbonate mineral compounds that mainly contain Ca and Mg. Total acidity and exchange acidity are in very low values. Exchangeable Ca consists about 78 % of CEC. It is established that soil colloids are occupied by Ca and Mg ions, which determined the stability of clay minerals. Phaeozems have favorable physicochemical properties with high cation exchange capacity and base saturation. These soils are highly valued for their fertility potential.

Fedir F. Markov(1)*, Maryna V. Shvets(1), Andrii O. Pitsil(1), and Maria S. Gurkova(2)

1. Faculty of Forestry, Zhytomyr National Agroecological University, 7, Stary Blvd., Zhytomyr, 10008, Ukraine. *E-mail: markovfedir1987@gmail.com
2. University of Forestry 10, Kliment Ohridski Blvd., Sofia, 1797, Bulgaria.

In this article it is considered the current state of heritage parks of the Zhytomyr region. We conducted an ecological, geographical, phytosociological, and taxonomic analysis of trees and shrubs in 6 parks out of 18, according to Kolesnikov, Takhtajan, Vernander and others. In heritage parks, 71 species and 3 varieties of trees and shrubs were revealed, belonging to 44 genera, 20 families, which come from five floristic regions. The most abundant Magnoliophyta family is Rosaceae, which is represented by 21 species (28.2 % of the total number of species). We analyzed the correspondence of woody plants to the conditions of their growth. A lot of species that did not fit soil types were planted in heritage parks. About 20 % of megatrophs grow in soils with low fertility. More than 84 % of the tree species of the parks belong to the Red List of the International Union for Conservation of Nature, and only one species is endangered. The aesthetic evaluation of plantations is low. We recommend cutting diseased and weakened trees and shrubs, also planting highly decorative bio-groups. It is offered a list of trees and shrubs recommended for planting in old parks in the Zhytomyr region.