Evaluation of Siberian Stone Pine Plantations at the End of the First Age Class

The 40-year-old plantations of Siberian stone pine laid out as a permanent seed plot have been studied. The research purpose is to study the integrity, state and main forest inventory parameters of the Siberian stone pine plantations on the southern line of the species range at the end of first age class; to determine the role of natural renewal of trees and shrubs on the development of the Siberian stone pine plantations; to improve process solutions for efficient renewal of high-value biological resources. The research uses the methods generally accepted in forestry, forest science and forest inventory. It is found that the integrity of Siberian stone pine on the site is about 31 % (678 pcs/ha), wherein 406 pcs/ha are without damage to the trunk. Only about 25 % of Siberian stone pine trees grow under low shade, the rest of them are constantly shaded by natural renewal and have varying degrees of suppression. No generative organs were found in 44-year-old Siberian stone pine trees. At the initial stage of plantations growth, the main factor negatively affecting the integrity and state of trees is the damaging of Siberian stone pine by moose. Traditional improvement thinning with leaving stumps that produce many shoots of deciduous species attracts moose to the site in winter, where they use young growth of deciduous species and the covered with needles part of Siberian stone pine as forage. Subsequently, in the absence of tending, natural renewal negatively affects the Siberian stone pine trees, inhibiting growth and formation. It is necessary to remove the negative influence in the mixed biocenosis in order to prevent further deterioration of the Siberian stone pine state. This requires completely different technological solutions for forestry activities such as ringing or injection of trees of natural renewal, causing drying at the root, which significantly reduces or eliminates the emergence of deciduous young growth. This will decrease the attractiveness of the site for moose and minimize their impact on Siberian stone pine. The clear drying of surrounding trees will enhance the illumination of Siberian stone pine crowns and improve their soil nutrition, ensuring good root, trunk, and crown growth and accelerating the beginning of the formation of generative organs. These technical solutions can be used throughout the forest zone for the artificial cultivation of the high-value species – Siberian stone pine. For citation: Terekhov G.G., Andreeva E.M., Stetsenko S.K. Evaluation of Siberian Stone Pine Plantations at the End of the First Age Class. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 56–68. DOI: 10.37482/0536-1036-2021-6-56-68

30-year cone production dynamics in Siberian stone pine (Pinus sibirica) in the southern boreal zone: a causal interpretation

Background and aims – Siberian stone pine is a keystone species for Siberia, and numerous studies have analyzed Siberian stone pine seeding dynamics in connection with the dynamics of weather conditions. However, all studies were based on observations before 1990. The aim of the study was to expand our knowledge about the balance of weather and climatic factors in the regulation of cone production to enable conclusions about the current reproductive function in Siberian stone pine.Material and methods – We monitored Siberian stone pine cone production in the southeastern region of the Western Siberian Plain, in association with climatic factors, over a period of 30 years. To analyze the relationship with weather conditions, we used the trait mature cone number per tree and weather data obtained from the weather station in Tomsk.Key results – During this period, cone production decreased by about one-third, mainly caused by the complete absence of high yields. The main factor negatively affecting cone production was late spring frost: severe frost occurring with a large accumulated sum of effective temperatures resulted in full cone loss, and light frost substantially reduced cone number. A less important but significant climatic factor was September temperature: as the temperature increased, the cone number decreased in the following year. Over the last 30 years, the sum of the effective temperatures at which the last spring frost occurs, as well as the average September temperature, increased considerably, resulting in reduced cone production.Conclusion – If the current climatic trend is maintained, and especially if it is strengthened, Siberian stone pine cone production in the southern boreal forest zone on the Western Siberian Plane is unlikely to provide for the effective renewal of the species.

Diversity of the hybrid forms between Siberian stone pine and Siberian dwarf pine

Siberian stone pine (Pinus sibirica) and Siberian dwarf pine (P. pumila) are Russian five-needle pines withdifferent life forms, namely upright tree and prostrate tree, respectively. Hybridization of the species was considered in thepaper from the point of view of the habitus of their natural hybrids. In early studies, it was always noted that the hybridswere intermediate in comparison with the parental species. Crown structure in hybrids are largely determined by twomain factors. These are deflection of the tree stem from the vertical axis and the selectivity of apical dominance. Hybridsgrowing in open places under full lighting conditions are characterized by strictly intermediate growth form. In a forestwhere there is no enough light, hybrid reaches for sun but gradually deviates to the side, which ultimately leads to a branchbreak or even the roots of the entire tree being upturned from the soil. In the mountains, hybrids can form uniform trunkbranches, forming a cup-shaped crown, similar to how it happens in Siberian dwarf pine. Thus, the previously notedintermediate morphology of hybrids represents a series of forms, from almost vertical multi-stemmed trees to pumila-likeones with a cup-shaped crown.

Genetic polymorphism of mountain-taiga populations of siberian stone pine in Kusnetsky Alatau

Aim. Study of DNA polymorphism of 7 coenopopulations of Siberian stone pine (Pinus sibirica) growing in theKuznetsk Alatau. Methods. Nuclear microsatellite loci developed for P. sibirica were used as genetic markers. Results. 44 allelic variants were identified from 11 nuclear microsatellite loci, which significantly differ in the composition and frequency of occurrence of the studied P. sibirica coenopopulations. The highest level of allelic diversity is found in loci Ps_80612 and Ps_1502048, where 8 and 7 alleles were identified, respectively. The calculation of the main parameters of genetic diversity showed a relatively low level of polymorphism in the studied samples (NA = 3.078; NE = 1.877; HE = 0.445; HO = 0.401). The assessment of the degree of genetic differences between populations using the Nei genetic distance (DN) showed that, despite the low genetic differentiation (DN varies from 0.019 to 0.061), the differences between them can be traced quite clearly. Conclusions. Differences in the level of genetic polymorphism of P. sibirica is defined by the presence of orographic and phytocoenotic barriers between coenopopulations, as well as a high degree of ecological and anthropogenic extremity of individual growth sites. Keywords: Pinus sibirica, Kuznetsk Alatau, microsatellites, genetic diversity, heterozygosity.

Intrapopulation variation of Siberian stone pine cones and seeds quality in spaced planting plots

For Siberian stone pine (Pinus sibirica Du Tour), a valuable nut-bearing species, the development of a system of selectively significant signs of crop quality is relevant, which is necessary for the introduction of this species into culture. Were studied the level and nature of variability in the quality of cones and seeds in 32 trees on a 42-year-old plantation with sparse planting trees of 8×8 m (south of the Tomsk region). The used system of traits reflects the sequence of the crop formation process — from cone differentiation to seed ripening. We are establish that the maximum level of variability is observed in characters characterizing deviations in seed embryogenesis, leading to an increase in the proportion of underdeveloped, empty and incomplete seeds. The level of variability of traits caused by the influence of the mother plant is much lower on the features of the establishment, differentiation, and growth of cones (the number of scales and seeds). The signs characterizing the number of different elements of the cones have a normal distribution. Positive asymmetry and kurtosis are characteristic of the distributions of signs reflecting the level of abortion of the ovules at different stages of their development. As the final selection trait with a high level of intrapopulation variability, we are proposing to use the mass of full tree seeds per unit area of the horizontal projection of the crown. The use of this trait is promising for the search for trees combining a narrow crown with a large mass of seeds.

Weather Conditionality of Siberian Stone Pine (Pinus sibirica Du Tour) Seeding

The dynamics of Siberian stone pine sexual reproduction in the South-Eastern part of the West Siberian Plain was studied by 13-year stationary observations. The stand age was 160–180 years, the average tree height was 22 m, and the average diameter of the trunk at breast height was 53 cm. On average, 50–60 trees were analyzed annually (in different years from 25 to 100). Cones were counted and samples were collected annually from August 10 to August 20. The resercher (usually the author of this paper) climbed each tree, knocked down the cones with operating tools (a bat and a rod), and then their number was counted on the ground. A sample of 10–15 cones was taken from each tree. Afterwards, a complete morphological analysis was performed: the number of sterile and fertile scales, and underdeveloped and developed seeds were counted. Developed seeds were analyzed by the X-ray method. To determine the weight, only perfectly full seeds selected by the X-ray pattern were used. Information on weather conditions was used according to data from the Tomsk station of Roshydromet. The main factor in the cone initiation was the amount of precipitation during 2 years before the start of this process: with an increase in the amount of precipitation, the number of cones increases. However, the final seed productivity depends to a greater extent not on the number of initiated cones, but on the success of their further development. The most important stage in the cone development was spring in the year of pollination and the main negative factor was late frosts. The degree of their negative impact is determined by the sum of the effective (above 5 °C) mean daily temperatures at which the return of frost with temperature from –3 to –4 °C occurred. Complete abortion of cones occurred only when the sum of effective temperatures was 150–180 °C. The same frost at the accumulated temperature sum of 100–150 °C killed a significant part of the cones, and the rest strongly disrupted the development. When the sum of accumulated temperature was about 50 °C, a strong frost significantly increased the loss of seedbuds at all stages of their development, thereby reducing the number of full seeds. The average temperature of September in the pollination year was an important factor in seed production. The loss of seedbuds increased significantly with its increase. The only important trait that is formed in the year of cone maturity is the weight of full seeds: it increases with the amount of precipitation from April to June of the current year.

NATURAL FOREST RESTORATION IN THE PLANTS OF THE NATURE MONUMENT «NIZHNESALDINSKAYA CEDAR GROVE»

Статья содержит результаты оценки естественного лесовосстановления под пологом насаждений памятника природы областного значения «Нижнесалдинская кедровая роща». Целью исследований явилось изучение особенностей формирования подроста кедра как в естественных, так и в искусственных древостоях. В основу исследований положен метод пробных площадей. В результате исследований установлено, что кедровая роща в настоящее время испытывает серьезные рекреационные нагрузки со стороны местного населения. При этом основное воздействие приходится на подрост и живой напочвенный покров. В составе древостоев достаточно много перестойных деревьев кедра с низкой интенсивностью плодо- ношения и с наличием повреждений антропогенного и природного характера. Естественное лесовосстановление кедра под пологом древостоев наблюдается на площади 13,3 га (71,9 % общей площади покрытых лесной растительностью земель). Насаждения с отсутствием подроста кедра представлены культурами кедра в возрасте не старше 59 лет (молодняками), а также ольшаником в пойме ручья с полным отсутствием кедра в составе древостоя. Плодоношение в возрасте 45–59 лет наблюдается только у отдельных деревьев кедра. В составе подроста кедра преобладают экземпляры высотой до 0,5 м. Доля жизнеспособного подроста с увеличением высоты подроста, а соответственно, и его возраста уменьшается. Результаты исследования имеют практическое значение и могут быть использованы при планировании и проведении работ по воспроизводству лесов и организации рекреационной деятельности на территории памятника природы «Нижнесалдинская кедровая роща». The article contains the results of assessing the natural reforestation under the canopy of the natural monument of regional signifi cance «Nizhnesaldinskaya cedar grove». The aim of the research was to study the features of the formation of Siberian stone pine undergrowth both in natural and artifi cial stands. The research is based on the trial plot method. As a result of research, it was found that the cedar grove is currently experiencing serious recreational stress from the local population. In this case, the main impact falls on undergrowth and living ground cover. There are a lot of overmature cedar trees with a low fruiting intensity and with the presence of anthropogenic and natural damage in the forest stands. Natural reforestation of cedar under the canopy of forest stands is observed on an area of 13,3 hectares (71,9 % of the total area covered with forest vegetation). Plantations with no cedar undergrowth are represented by cedar cultures not older than 59 years (young stands), as well as alder in the stream fl oodplain with a complete absence of cedar in the stand. Fruiting at the age of 45–59 years is observed only in individual cedar trees.The specimens up to 0,5 m in height predominate in the composition of Siberian stone pine undergrowth.The proportion of viable undergrowth decreases with an increase in the height of the undergrowth and, accordingly, its age.The results of the study are of practical importance and can be used in planning and carrying out works on forest reproduction and organization of recreational activities on the territory of the natural monument «Nizhnesaldinskaya cedar grove».