Urban stands are becoming increasingly important in improving the environmental health and liveability of cities. However, they weaken as a result of technogenic air pollution and become vulnerable to pests, particularly to non-native forest insects. The aim of this research was to assess potential harmfulness (bionomically determined harmfulness [BDH]), environmentally determined harmfulness (EDH) and generally expected harmfulness (GEH) of the gnawing phyllophagous lepidopterous insects in the green stands of Kharkiv (Ukraine). All supplementary parameters were assessed by analysis of publications and the own experience of authors. BDH was evaluated as a product of the duration of larvae nutrition (p1) and an index of larvae nutrition (p2). An index of larvae nutrition (p2) was considered being proportional to their imago wingspan. EDH was evaluated as a product of the value of damaged tree species (p3), location of plant damage (p4), the period of loss decorative effect (p5) and the prevalence of certain insect species in the stands (p6). GEH was estimated as a product of BDH, EDH and the ability of insect species to the outbreaks (p7). A modified approach for evaluation BDH, EDH and GEH was suggested and implemented, considering phyllophagous leaf miner insects and phyllophagous insects with open lifestyle in the deciduous stands of streets, parks, and Forest Park of Kharkiv city. EDH of insects with an open lifestyle depends on their size and prevalence in the stand. EDH and GEH of all revealed insects with an open lifestyle increase from streets to Forest Park. Among the insects with an open lifestyle, Lymantriidae and Notodontidae had the highest BDH due to the large size and long feeding period of larvae. Among the insects with hidden lifestyle, Cameraria ohridella had the highest BDH due to the highest prevalence and the large duration of feeding period with its several generations.

The production of phosphoric acid produces “waste heaps” that have not yet been tapped, but which have the character of weak fertilizers and can perhaps be reintroduced into the elemental cycle in the forests. Two variants of mixing with organic ash and with sewage sludge were carried out. One-year-old pine seedlings (Pinus sylvestris L.) from the Trzebieź forest district (northern Poland) were planted in pots with soil that also came from the same field. Preparations containing phosphogypsum were applied topically to the soil in four doses (1, 2, 3 and 5 t/ha). The trial, which lasted one growing season, was conducted in four replicates. At the end of the trial, the height of the above-ground parts and root length, needle and root area, root neck diameter and photosynthetic performance were measured. The phosphogypsum-based preparations used showed no harmful (toxic) effects on the potted pine seedlings during the six-month trial period. The loosely prepared preparation made from a mixture of phosphogypsum and organic ash began to have a positive effect on the development of the seedlings’ root system, and it was also easier to mix with the soil surface than phosphogypsum with sewage sludge, which also contained a sticky form. The photosynthetic performance of one-year-old pine seedlings decreased after one growing season following the application of phosphogypsum preparations and most of the growth parameters tested did not differ from the control, so observations over a longer period (at least two to three growing seasons) are required. However, dosages of 1 and 2 t/ha seem to be the most promising, and these lower dosages are more economical to manage in nurseries or plantations, especially on poor sites. Formulations should be tested for heavy metals and their effects on seedling development. Testing should also be continued to monitor changes in the microbiome.

Heterobasidion annosum (Fr.) Bref. sensu lato (s.l.) is a dangerous forest pathogen causing root and butt rot disease in most conifers of the northern hemisphere. This pathogen is most widespread in the forests of Europe and North America. The economic impact on forestry related to tree mortality, reduction in timber yield, and wood rot is calculated in millions of dollars and euros. The genus Heterobasidion (Basidiomycota; Russulales) has been relatively recently separated into three genetically distinct groups (H. annosum, H. insulare and H. araucariae) comprising a total of 12 species and one newly described hybrid taxon. These species are the best studied in terms of the ecology, the physiology of control methods, and the tree’s resistance to the pathogen. The article gives an overview of the symptoms and the etiology of the disease and provides information on ways to recognize the disease and limit the economic damage.

На території Ботанічного саду Харківського національного університету (ХНУ) ім. В. М. Каразіна на хвойних породах визначено 4 види короїдів: короїда-типографа (Ips typographus L.), гравера звичайного (Pityogenes chalcographus L.), соснового короїда-крихітку (Crypturgus cinereus Herb.) та тайгового короїда-крихітку (C. subcribrosus Eg.). Відзначено, що з роду Abies лише п’ять видів не мали ознак заселення, а саме: A. balsamia, A. cephalonica, А. concolor, A. grandis, А. violacea. Picea koraiensis та P. alba не були заселені короїдами, але на стовбурі помічено спроби заселення. Встановлено, що форму P. obovata «Glauca» заселяли всі визначені види короїдів. Найбільш поширеним на ялині серед інших видів короїдів виявився Ips typographus. Серед 198 обстежених дерев визначено: живих із відсутністю ознак заселення короїдами – 27,3 %, зі спробами заселення – 9,1 %, заселених короїдами – 63,6 %.

The present study was inspired by scientific reports describing the positive effects of silicon preparations on fruit and vegetables in horticulture. The use of silicon preparations in forest protection represents a new research application, especially in the cases of oak seedlings that are damaged by oak powdery mildew. Additionally, these preparations increase the photosynthetic efficiency of the seedlings, and thus promote increased biomass and better nutritional value of the root systems. The new idea of using silicon formulations in forestry, based on the initial test results, is particularly important for seedlings in the post-planting period in forest plantations. In particular, these preparations increase yield and plant growth, and improve plant health. So far, no comparable studies have been conducted on forest tree species. To this end, one year-old pine (Pinus sylvestris L.) and two year-old English oak (Quercus robur L.) seedlings were sprayed with silicon preparations of different concentrations, and changes in growth parameters and photosynthetic efficiency were observed. The main objective of the study was to determine the effect of the silicon preparation on the seedlings during their first life span, i.e., the first year after planting. In this study, 50 pine and 50 oak seedlings were sprayed three times with the silicon preparation, in five variants (control; concentrations of 1%, 2%, 3% and 5%), as well as the chlorophyll fluorescence, height, thickness and biomass of the roots, were measured. It was found that the treatment with a concentration of 2% was better and statistically, significantly different from the other variants, e.g., in terms of increasing photosynthetic efficiency.