Санітарний стан берези повислої у Лівобережному Лісостепу України

Abstract

Наведено результати аналізу просторово-часової динаміки показників санітарного стану насаджень берези повислої в Лівобережному Лісостепу. Складено шкалу оцінювання санітарного стану цієї породи з урахуванням рівня дефоліації, поширення сухих гілок і водяних пагонів. Встановлено, що березові насадження в Лівобережному Лісостепу представлені 37 типами лісу, причому переважають типи у свіжих і вологих суборах, свіжих і вологих сугрудах і свіжих грудах. Прогнозовано тенденції зміни стану та відпаду дерев берези повислої різних категорій санітарного стану у лісових і паркових насадженнях. Виявлено 22 види стовбурових комах на березі повислій, серед яких 4 види є масовими. Визначено види комах, спроможні вплинути на санітарний стан дерев (фізіологічна шкідливість) і на якість деревини (технічна шкідливість). Вдосконалено методику ранньої діагностики бактеріальної водянки берези, обґрунтовано роль стовбурових комах у перенесенні її збудника. Виявлено особливості зміни радіального приросту дерев в осередках цієї хвороби. Запропоновано заходи щодо пом’якшення наслідків ураження та пошкодження березових насаджень.

Приведены результаты анализа пространственно-временной динамики показателей санитарного состояния насаждений березы повислой в Левобережной Лесостепи. Составлена шкала оценки санитарного состояния этой породы с учетом уровня дефолиации, распространения сухих ветвей и водяных побегов. Установлено, что березовые насаждения в Левобережной Лесостепи представлены 37 типами леса, причем преобладают типы в свежих и влажных суборах, свежих и влажных сугрудках и свежих грудах. Прогнозированы тенденции изменения состояния и отпада деревьев березы повислой разных категорий санитарного состояния в лесных и парковых насаждениях. Выявлено 22 вида стволовых насекомых на березе повислой, среди которых 4 – массовые. Определены виды насекомых, способные повлиять на санитарное состояние деревьев (физиологическая вредоносность) и на качество древесины (техническая вредоносность). Усовершенствована методика ранней диагностики бактериальной водянки березы, обоснована роль стволовых насекомых в переносе ее возбудителя. Выявлены особенности изменения радиального прироста деревьев в очагах этой болезни. Предложены мероприятия по смягчению последствий поражения и повреждения березовых насаждений.

Theoretical generalization and analysis of experimental data about the spatial and temporal dynamics of health condition indices of the silver birch stands in the left-bank Forest-Steppe is presented in the dissertation. The harmfulness of stem insects is evaluated in birch stands. The first signs of the birch damage by bacterial wet wood disease, the role of stem insects in the vectoring of its pathogen and the features of radial growth of trees in the foci were determined. Measures have been suggested to mitigate the effects of birch damage. Birch stands in the left-bank forest-steppe are represented by 37 forest types with predomination of fresh and humid relatively poor site conditions, fresh and humid relatively fertile site conditions, and fresh fertile site conditions. It was found, that the age of 56.9 % of birch trees is over 40 years old in inspected stands of Poltava region, 78.4 and 83.3 % in Kharkiv and Sumy region respectively. Birch survival increases in the stands with the highest site index and in mixed stands. The health condition of birch stands was the best in Poltava region (Ic1–6 = 1.7±0.03 %; Ic1–4 =1.5±0.02 %). The trees with defoliation over 10 % were the most spread in inspected stands of Poltava and Sumy regions (41.7 and 40 %), trees with dieback in Kharkiv and Sumy regions (14,1 and 9,6 %), trees with epicormic shoots in Sumy region (15.9 % of inspected trees). The trend to the worsening of health condition was proved for birch stands up to III–IV age classes with further improvement, that is the most resistant trees survive with increasing age over 40 years old. The health condition of birch stands is the best in fresh relatively poor site conditions (B2) and the worst in fresh fertile site conditions (D2). As a result of research at permanent sample plots during 2015–2019, it is estimated that the probability of mortality of birch trees of any category of health condition is the highest in the fresh fertile site conditions and the lowest in the relatively poor site conditions. The probability of birch mortality for 4 years of the I, II, III and IV categories of health condition is 3.9, 16.4, 30.4 and 62.4 % in forest stands and 3.5, 10.7, 36.9 and 84.6 % in park stands. It was found that the birch stands with the trees of the І–ІІІ categories of health condition is able to improve its health condition, while the birch stands with the trees of the IV category of health condition is likely to worsen it. Fruit bodies of wood-destroying fungi and indirect signs of tree damage by rot are most often found in the birch stands of Sumy and Kharkiv regions (8.2 and 6.9 % of trees, respectively), signs of bacterial wet wood disease – in the stands of Kharkiv region (8.4%), and insect damage in Sumy region (12.4%). In the silver birch stands of the left-bank forest-steppe of Ukraine, 22 xylophagous insect species are identified. Among them, 4 species are widespread (Agrilus viridis, Xylotrechus rusticus, Xyleborinus saxeseni and Xyleborinus attenuates); 3 species are common (Xiphydria longicollis, Tremex fuscicornis and Agrilus angustulus), 6 species are rare (Tremex magus, Dicerca furcata, Agrilus betuleti, Mesosa curculionides, Saperda scalaris and Scolytus ratzeburgi) and the rest species are single. The highest diapason of physiological harmfulness is evaluated for Tremex spp., Сhrysobothris affinis, Agrilus viridis, Xylotrechus rusticus and bark beetles. The highest technical harmfulness is evaluated for wood wasps (Tremex sp.), jewel beetles Dicerca sp., longhorn beetle Xylotrechus rusticus and xylomycetophages – Xyleborinus sp. Wood wasps are the most spread in Poltava and Sumy regions (2.7 and 2,3 % of inspected trees respectively). Xyleborinus sp. and Agrilus sp. were the most common in Kharkiv region (2 and 1,7 % birch trees respectively), Scolytus ratzeburgi in – Sumy region (1.5 % trees). The distribution of individual insect species by category of the health condition of trees is evaluated. The method for estimating the spread and harmfulness of stem insects was improved and for the first time used to evaluate their physiological and technical harmfulness in birch plantations. It has been shown that birch trees affected by the bacterial wet wood disease have a smaller diameter, greater crown transparency and a higher health condition index than those unaffected, two years before the signs of the disease on the stem. The radial growth of infected by birch trees in 2009–2016 was 22% lower than that of healthy trees. It is statistically proven that colonization of viable birch trees by Tremex fuscicornis and Xyleborus saxeseni increases the likelihood of birch contamination with the bacterial wet wood disease. The data obtained are of practical importance for forestry practice. The decrease in the survival of birch stands with age is the ground for reducing the age of the main felling in them if there is risk of reducing the wood quality before the stands reach the age of the maturity in accordance with the current standards. The basis for birch trees planning to sanitary felling can be the first symptoms of the bacterial wet wood disease, and improved scale of birch health condition considering the defoliation, dieback, and epicormic shoots spread as well as the rating of stem pest damage considering the previous action of other damage agents. The table of terms and signs of a survey of highly harmful and moderately harmful birch stem pests is a constituent of the “Methodological guidelines for the survey, assessment, and prediction of the spread of forest pests and diseases for the plain part of Ukraine”, approved by the Scientific Council of URIFFM and Scientific and Technical Council of the State Agency of Forest Resources of Ukraine. Methods on the diagnosis of the causes of birch damage and prediction of its health condition as well as recommendations on its improvement are implemented in the “Myrgorodske Forest Enterprise”, “Trostyanetske Forest Enterprise”, “Skrypaivske Educational & Research Forest Enterprise”, in the parks of Kharkiv National Agrarian University named after V. V. Dokuchayev, as well as in the educational process of this high school while teaching disciplines: "Integrated forest protection", "Forest science" and "Forest protection"