Scots pine (Pinus sylvestris L.) is the most spread forest tree species in Polissya and the most damaged by foliage browsing and stem insects. The aim of this study was to reveal the changes in the distribution of different forest site conditions for 2010–2019 in Scots pine forests of the selected forestry enterprises of Polissya and possible consequences for the spread of foliage browsing insects. Database of Production Association ‘Ukrderzhlisproekt’ (by 2010 and 2019) was analysed for five State Forest Enterprises (FE) that are located in the Central (Zhytomyr Region) and Western (Rivne and Volyn Regions) Polissya, where the large scale outbreaks of stem pests were registered last decade.The types of forest site conditions were designated in accordance with the Ukrainian typology. Distribution of the forest area by trophotops and hygrotops was evaluated for the forest-covered area, for Scots pine stands, and for pure Scots pine stands in 2010 and in 2019.For 2010–2019, the area of all Scots pine forests and its proportion in the forest-covered area has significantly decreased in the most of analysed forest enterprises. The change for 2010–2019 in the distribution both by the tropho-tops and by hygrotops of the entire forest-covered area, the area of all Scots pine forests and pure pine forests is not statistically significant. However, in assessment year 2019, the proportion of stands in the moist types of forest site conditions slightly increased. It may be the result of the stands’ mortality in the driest sites after an outbreak of bark beetles. A greater decrease in the proportion of Scots pine forest area in the dry poor, fresh poor, and dry relatively poor forest site conditions was found in the western direction. Therefore, the noted decrease in the foci areas of foliage browsing insects in Polissya in 2010–2012 compared to the 2000–2002 could be associated with a decrease in the most preferred stands, namely the poorest and driest types of forest site conditions.
This is the first review of life cycles of trematodes with parthenitae and larvae in freshwater gastropods from forest biocoenoses of Ukrainian Polissia. Altogether 26 trematode species from 14 families were found circulating in 13 ways in molluscs from reservoirs connected with forest ecosystems of the region. Three-host life cycle is typical of 18 trematode species, two-host life cycle has found in 7 species, and four-host cycles has found in one species. Alaria alata Goeze, 1782, has three-host (Shults, 1972) and four-host cycles. Opisthioglyphe ranae (Froehlich, 1791) can change three-host life cycle to two-host cycle replacing the second intermediate host (Niewiadomska et al., 2006) with the definitive host. Species with primary two-host life cycle belong to Notocotylidae Lühe, 1909, Paramphistomidae Fischoeder, 1901 and Fasciolidae Railliet, 1758 families. Trematodes with three-host cycle have variable second intermediate hosts, including invertebrates and aquatic or amphibious vertebrates. Definitive hosts of trematodes are always vertebrates from different taxonomic groups. The greatest diversity of life cycles is typical for trematodes of birds. Trematodes in the forest biocoenoses of Ukrainian Polissia infect birds in six ways, mammals in three, amphibians in four, and reptiles in one way. The following species have epizootic significance: Liorchis scotiae (Willmott, 1950); Parafasciolopsis fasciolaemorpha Ejsmont, 1932; Notocotylus seineti Fuhrmann, 1919; Catatropis verrucosa (Frölich, 1789) Odhner, 1905; Cotylurus cornutus (Rudolphi, 1808); Echinostoma revolutum (Fröhlich, 1802) Dietz, 1909; Echinoparyphium aconiatum Dietz, 1909; Echinoparyphium recurvatum (Linstow, 1873); Hypoderaeum conoideum (Bloch, 1782) Dietz, 1909; Paracoenogonimus ovatus Kasturada, 1914; Alaria alata Goeze, 1782.
The aim of the research was to reveal the features of Scots pine stands decline in Zhytomyr (Central) Polissya using the case of Korostyshiv Forest Enterprise. The investigations included statistical and comparative analysis of the database of forest fund of the State Association "Ukrderzhlisproekt", the data of forest pathological survey of pine stands in Korostyshiv Forest Enterprise and reports on sanitary felling in 2014-2017. Bark beetles (72.4-95.8 %), fungal diseases (0.4-9.1 %) and weather conditions (3.5-27.5 %) were the main causes of Scots pine decline. A high proportion of pure Scots pine stands and the stands over 50 years old are the main predisposing factors of forest decline. Abnormal increase in air temperature and a decrease in Selyaninov's Hydro-thermal Coefficient to the level of Steppe zone were inciting factors of forest decline, and bark beetles were a contributing factor to it. K e y w o r d s : Scots pine (Pinus sylvestris L.), forest decline, Selyaninov's Hydro-thermal Coefficient, forest composition, age structure, relative density of stocking. *
Досліджено особливості поширення усихання сосни звичайної (Pinus sylvestris L.) в осередках верхівкового (Ips acuminatus (Gyllenhal, 1827)) та шестизубчастого (Ips sexdentatus (Boerner, 1767)) короїдів (Curculionidae, Scolytinae) у лісах Державного підприємства "Володимирецьке лісове господарство" Рівненського обласного управління лісового та мисливського господарства. Встановлено, що площа всихаючих соснових насаджень лісгоспу впродовж 2017 р. збільшилася і перевищила 2000 га на кінець року. Частка площі осередків короїдів у площі всихаючих соснових насаджень зросла від 3,1 % у першому кварталі до 75 % у другому, до 90,8 % у третьому та до 100 % у четвертому. Виявлено, що чисті соснові насадження становлять 50,3 % від площі всіх насаджень лісгоспу, в котрих сосна є головною породою, і 64,6 % від площі осередків короїдів. З'ясовано, що у віковій структурі соснових насаджень лісгоспу на V-VIII класи віку припадає 61,1 % від площі всіх соснових насаджень і 90,9 % від площі осередків короїдів. Розраховано, що середня зважена повнота соснових насаджень лісгоспу становить 0,73 одиниці, а в осередках короїдів – 0,7 одиниці. Статистично підтверджено приуроченість осередків короїдів до чистих середньоповнотних соснових насаджень V-VIII класів віку.
This study focused on the occurrence of xylophagous beetles and nematodes in the different parts of Pinus sylvestris L. trees of different health condition in the pure stands in Zhytomyr region (Central Polissya). Stem fragments with thin, thick and transitional bark, branches and twigs were examined in each of 12 model trees. Xylophagous beetles were identified by adults or by galleries. Nematodes were isolated from wood samples in the laboratory using the Baermann method and identified by morphometric characteristics. Among 10 species of xylophagous beetles, Ips acuminatus (frequency 16.7%; dominance 17.9%) and I. sexdentatus (frequency 11.1%, dominance 54.6%) dominated, which prefer the fragments with thin and thick bark respectively. No xylophagous beetle was found in the healthy and slightly weakened trees. Among 15 nematode species, 40% were saproxylic, 33.3% entomophilic, 13.3% phytophagous, and by 6.7% predators and species associated with fungi. An entomophilic nematodes Cryptaphelenchus macrogaster f. acuminati was common in all parts of stem and branches (frequency of occurrence 25–33.3%). An entomophilic nematodes Parasitorhabditis acuminati and a predator Fuchsia buetschlii acuminati had the highest frequency of occurrence (41.7%) under the thin bark and in the branches. The frequency of these species in colonized with xylophagous insects stem fragments with thin bark was significantly higher than in respective not colonized fragments.
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