Лісівничий і санітарний стан в'язових деревостанів Київського полісся та їх оздоровлення
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Дисертація на здобуття наукового ступеня кандидата сільськогосподарських наук зі спеціальності 06.03.03 «Лісознавство і лісівництво». Національний університет біоресурсів і природокористування України. Київ, 2019. Дисертацію присвячено дослідженню лісівничого і санітарного стану в’язових порід Київського Полісся та їх оздоровлення. Акцентується увага, що деградація та масове всихання в’язових насаджень досягли глобального рівня і відзначені як в Україні, так і світі. Обраховано індекс санітарного стану, який характеризується середнім ступенем пошкодження та дає змогу встановити, що насадження досліджуваного регіону належать до категорії сильно ослаблених. В’язові деревні види виявлено в наступних типах лісорослинних умов: свіжих суборах – до 10 %; свіжих складних суборах – 56; у мокрих складних суборах – 21; у сирих дібровах – 4; у вологих борах, сухих і складних суборах, вологих та мокрих дібровах – менше 1–2 %. В’язові деревостани та насадження за участю в’язових ростуть за середнім класом бонітету І,5, 60 % із них мають відносну повноту 0,7–0,8. Спостерігається значне переважання стиглих і перестійних насаджень за участю в’язових як головної породи, оскільки їхня частка сягає 83 %. Найменшу частку становлять молодняки – 2 %, що свідчить про зменшення використання рослин роду Ulmus L. як головної породи у створенні штучних насаджень. Аналізуючи зміни показників популяції за фазами розвитку осередків, слід зазначити, що досліджувані насадження у динаміці з 2004 по 2006 рр. знаходилися у стані розсіювання або, так званої, «кризи», тоді як, починаючи з 2007 р., – у стані власне спалаху осередку. Наявні осередки стовбурових шкідників характеризуються високим, середнім і низьким ступенем заселення дерев. Виявлено осередки поселення наступних видів заболонників: Scolytus scolytus, S. multistriatus та S. pygmaeus. За обрахованим коефіцієнтом Жаккара найбільша відмінність популяцій в осередках притаманна заболоннику руйнівнику і заболоннику пігмею (коефіцієнт Жаккара 28 % подібності). Найподібніші види, що формують спільні популяції в насадженнях, це заболонник руйнівник і заболонник струменистий – 71,4 % подібності
Опис
Thesis for a candidate degree in agricultural sciences in the specialty 06.03.03 «Forest Science and Silviculture». National University of Life and Environmental Sciences of Ukraine. Kyiv, 2019. The thesis is devoted to research of forests and sanitary state of the elm species of Kyiv Polissya Region and their improvement. A focus is made on the global scale of the elm trees degradation and massive drying which are registered in Ukraine and the world. The Dutch disease poses the most danger to the elm trees, which spread is rapid and dynamic. Affection and spread of the Dutch disease pathogenic agent is mainly due to synchronization between life cycles of a plant-feeder (the trees of the genus Ulmus L.), an infectious agent (the fungi of the genus Ophiostoma) and a «pathogenic insect» (representatives of Coleoptera trunk pests (Curculionidae and Scolytinae) – the main vectors of the pathogenic agent spread). According to our observation’s elm plantings weakened by the influence of abiotic and biotic, including parasitic factors, have been losing their resistance, which led to reduction of plant resistance to phytophagous insects and unsatisfactory recovery of assimilation apparatus. The research has experimentally confirmed the well-known pattern that phytophagous insects are only one of succession processes elements and their spread and species composition are inherent to certain types of trees. Forest pathology survey was conducted in forestry enterprises of Kyiv Polissya and on the territory of the Holosiivskyi National Nature Park with the purpose of experimental research and theoretical justification of the problem. It has been established that the most common pathological factors of the elm trees drying according to our research are bacteriosis and fungal etiology diseases, which are widespread and affect quality of plant life significantly. Affecting vital organs, they are able to cause not only a significant weakening, but also lead to tree drying. Plantations with the participation of the elm tree occupy a total area of 1419.8 hа on the territory of the investigated region and, almost one third of the forest stand grows with ordinary oak. The most represented are the wych-elm and the field elm, which are components of broad-leaved oak forests. At the same time, the wychelm can often be found in river floodplains and on lake banks as an understory tree. The field elm is often serve as associate tree species and plays an important role in purification of air, soil and groundwater from harmful to humans, forest flora and fauna substances, in enrichment of soil with nutrients and provides the proper conditions for the formation of the main species – ordinary oak. The largest area is occupied by plantations with density 0.6–0.9. It should be noted that the most typical forest site type for the elm trees are С2 conditions, the area of planting with the participation of the elm tree is 747.1 ha, what means 52.6 % of existing tree plants. The elm trees are common in plantations aged from 6 to 92 years, the average age is 42 years, however, this indicator is characterized by a significant variance, indicating a significant sampling range. The maximum diameter is 36 cm, but the average diameter of the elm tree is 15.3 cm. The distribution of age groups according to the species composition makes it possible to note that the planting of Ulmus laevis L. is represented by ripe and overripe stands of 3 % and 97 % of the area respectively, U. parvifolia has 21.8 % of the young stand, but the area of these tree stands is negligible and amounts to 0.5 ha. The index of sanitary condition with an average degree of damage was calculated and it makes clear that, in general, the stand of the studied region belongs to the category of highly weakened. The sanitary index variation on trial areas from 1.16 to 3.64 indicates the uneven nature of the elm forests weakening and reveals number of factors that lead to weakening of the stands. It was identified that in forests with recreational load stands belong to 1–3 classes of resistance to recreational loads and have 1 and 2 digression rates. It was calculated that yearly precipitation distribution was uneven, with the most critical for the region values in 2007 and 2009, reaching a minimum of 2.2 in 2015. There is no doubt that unfavorable meteorological factors, in particular their deviation from the average multi-year indicators, are precondition for the deterioration of the elm plantations sanitary state. The researches have revealed that under unfavorable meteorological conditions the tree stands were weakening and became more susceptible to infectious attack by pathogenic agents of fungal and bacterial etiology and insects-xylophages. Analysis of population changes according to the occupancy areas development stages revealed that the studied plantations were in a state of spreading or so-called crisis in the dynamics from 2004 to 2006 and in a state of explosion since 2007. The existing areas of the majority of trunk pests are characterized by high, medium and low attack rate. We should note that chronic occupancy areas are characterized by the long period of existence, the relatively low, although elevated (in comparison with healthy plantings) number of insects and amount of the current dead trees. The occasional areas of occupancy are characterized by the relatively short (3–5 years) development period, the high number and volume of the current dead trees. In both cases, the reversible and irreversible reactions of forest stands are possible, although in the second case the full destruction of the planting is often observed under condition of mass reproduction. Near the areas of mass reproduction, which are characterized by excessive population density, usually there are migration centers where insects settle in search of new habitats. An attempt was made to investigate the systemic interactions between population indices of scolytid beetles in the centers of the Dutch disease spread. In the course of research, the areas of the majority of the following scolytid beetle species Scolytus scolytus, S. multistriatus and S. pygmaeus were identified. According to the calculated Jaccard coefficient Scolytus scolytus and Scolytus pygmaeus have the largest population difference in areas of the majority of the species (Jaccard coefficient – 28 %). The most similar species that form common populations in plantations are Scolytus scolytus and S. multistriatus Marsh. – 71.4 % similarity. Frequency of Scolytus pygmaeus was from 7.88 to 20.80 %, but this species was characterized by the highest attack rate indicating significant potential for reproduction. Analyzing the results of the trial areas survey, it should be noted that some of the stands (trial areas 1 and 3) are in the maximum numbers phase as a result of the progressive weakening of the tree stand. All other elm plantings are in the phase of increasing numbers, which poses a certain danger to the stands due to gradual transition of the population to the maximum phase. The research of the affected elm trees on the trial areas was conducted, isolates of bacteria according to morphological and physiologico-biochemical properties were separated from tree samples and identified by us as Enterobacter nimipressuralis (Carter 1945) Brenner et al., 1988 (according to Brady C. et al. – Lelliottia nimipressuralis (Carter 1945) Brady et al. 2013). According to our preliminary data, the spread of the bacterial disease caused by E. nimipressuralis in elm plantations of the region of research is uneven and varies from 5 to 45 %
Ключові слова
Київське Полісся, міко- та мікроорганізми, етіологія, голландська хвороба, в’язові насадження, Kyiv Polissya, micro- and macroorganisms, etiology, Dutch disease, elm plantations
Бібліографічний опис
Лісівничий і санітарний стан в'язових деревостанів Київського полісся та їх оздоровлення: автор. дис. ...кандидата с.-г. наук: 06.03.03 "Лісознавство і лісівництво" (сільськогосподарські науки) / М.І. Явний ; Національний університет біоресурсів і природокористування України. - К., 2019. - 24 с.