ВЛИЯНИЕ КОНКУРЕНЦИИ МАТЕРИНСКОГО ДРЕВОСТОЯ НА РОСТ ПОДРОСТА КЕДРА СИБИРСКОГО НА ОСНОВНЫХ ТИПАХ СУБСТРАТА

Рассмотрено влияние конкуренции древостоя средневозрастного сосняка бруснично-чернично-зеленомошного, пройденного выборочной рубкой ухода (прореживание), на возобновление и развитие подроста кедра сибирского под его пологом на Среднем Урале. При ежегодной разной интенсивности возобновления кедра обильное появление его всходов наблюдается в первые два года после рубки. Основным фактором, определяющим дальнейший рост и развитие подроста кедра, является уровень перехвата пологом древостоя фотосинтетически активной радиации (световая конкуренция). Корневая конкуренция соснового древостоя за почвенное питание менее выражена, что предполагает определённую адаптацию подроста кедра к ней. Introduction. The abundance of Siberian stone pine undergrowth (Pinus sibirica) under the canopy of derivative pine stands and small-leaved stands, that are considered to be potential Siberian stone pine forests, is observed rangewide. At the same time, the influence of competition of these stands on the regeneration and development of Siberian stone pine undergrowth under their canopy has not been sufficiently studied. The goal of this research is to analyze the competition of the cowberry-bilberry-green moss pine forest stand against the Siberian stone pine undergrowth. Objects and methods. The research was carried out on the basis of the micro-ecosystem approach using the earlier proposed and tested set of light, root and integral competition indices of stands under the canopy of a 75-year-old cowberry-bilberry-green moss pine forest in the northern part of eastern macro-slope of the Middle Urals after a selective care felling. The record of parameters of the stand, environment and Siberian stone pine undergrowth was made in 106 circular plots with a radius of 7 m. The undergrowth age was determined to within one year by the number of annual terminal shoots increase. The dynamics of annual generation of one-year seedlings was reconstructed according to the age structure of the undergrowth and the empirical coefficient of the survival curve. Results. Against the background of almost continuous annual Siberian stone pine regeneration of different intensity (0.1–0.8 ths. trees/ha) under the canopy of pine forest, an abundant emergence of Siberian stone pine seedlings is mainly observed in the first two years (1.7 and 1.3 ths. trees/ha) after the care felling for the stand (thinning). In 28 years after felling, the parameters of 23-35-year-old Siberian stone pine undergrowth growing in the gaps of the stand (in place of felled single trees) exceed the parameters of the trees growing in the areas under a closed canopy, where trees were not cut down by 1.5-1.8 times; in former technological corridors (skidders) - by more than twice. But over the past five years, the averaged vertical growth of terminal shoots of undergrowth is negatively closely related (R2 = 0.68) with light competition of the stand (the level of photo-synthetically active radiation interception by the canopy), and the relationship with its root competition for soil nutrition is expressed to a lesser extent (R2 = 0.31). The tightness and reliability of negative relationship (R2 = 0.68) of the average growth of terminal shoots with the complex index of integral competition of the stand, which characterizes the joint influence of these factors, is closely related to the private index of light competition. Conclusion. The thinning of pine forest by selective felling helps to reduce the competition of the stand, contributes to the successful subsequent regeneration of Siberian stone pine and development of its undergrowth. With the combined influence of factors of light and root competition of the stand, light competition is the decisive one. Less expressed root competition suggests a certain adaptation of Siberian stone pine undergrowth to the conditions of pine forest.

Сосна сибирская (кедр сибирский) ( Pinus sibirica Du Tour) имеет три экологические формы, определяющиеся условиями возобновления и формирования древостоев: возобновление свежих гарей, возобновление под пологом лиственных пород и формирование кедрового подроста под пологом светлохвойных пород, но не достигающего верхнего полога. Первые две формы возобновления наблюдаются в экотопах соответствующих условиям произрастания сосны сибирской, но сценарии формирования кедровников различны. Исследования проводились в двух типах лесорастительных условий: Западно-Саянский округ горно-таежных и подгольцово-таежных кедровых лесов (Абазинское участковое лесничество) и Южно-Хакасский округ горно-таежных темнохвойных лесов (Матурское и Копьевское участковые лесничества). В Абазинском лесничестве усредненная периодичность плодоношения кедрового насаждения составила 5 лет, а в Кузнецком Алатау - 3 года. Плодоношение кедра - прогнозируемое явление, но разнос и прорастание семян кедра - сложные процессы, связанные с зоохорным распространением и мощным воздействием трофического фактора потребителей орехов. По радиальному приросту деревьев, определенному по пням на лесосеках (санитарные рубки) Абазинского лесничества, кедровники имеют пирогенное происхождение, хороший рост в течение жизни и усыхание без потери прироста. В современной истории лесоведения вспышечная активность корневых патогенов встречается впервые. Прогноз возобновления усыхающих кедровников в среднегорной части Западного Саяна положительный. В Кузнецком Алатау подроста кедра недостаточно и лесовозобновление в крупнотравных типах леса возможно только со сменой пород. Вырубка древостоя, как и его усыхание с последующим разрастанием травостоя, способствует росту плотности населения потребителей кедровых орехов и соответственно исключает возобновление кедра. Сохранение подроста на вырубках 30-летней давности дало положительные результаты формирования плодоносящих кедровников. Организация орехопромысловых зон с запретом рубки кедра и его последующее усыхание привели к экономическим потерям ценной древесины и побочного ресурса прижизненного использования кедровых насаждений. Siberian stone pine ( Pinus sibirica Du Tour) has three ecological forms, determined by the conditions of renewal and formation of forest stands: renewal of fresh burnt areas, renewal under the canopy of deciduous trees and the formation of the Siberian stone pine undergrowth under the canopy of light coniferous species, but not reaching the top canopy. The first two forms of renewal are observed in ecotopes corresponding to the growing conditions of the Siberian stone pine, but the scenarios for the formation of the forests are different. The study was carried out in two types of forest conditions: the Western Sayan district of mountain-taiga and subgoltsy-taiga Siberian stone pine forests Abaza forestry district) and the South Khakass district of mountain-taiga dark coniferous forests (Maturskoe and Kop’evskoe forestry district). In Abaza forestry, the average periodicity of fruiting of the Siberian stone pine stands was 5 years, and in the Kuznetsk Alatau - 3 years. Fruiting of the Siberian stone pine is a predictable phenomenon, but the spread and germination of the Siberian stone pine seeds are complex processes associated with zoochoric distribution and the powerful influence of the trophic factor of nut consumers. According to the radial growth of trees, determined from stumps in cutting areas (forest health felling) of the Abaza forestry, Siberian stone pine forests are of pyrogenic origin, have good growth throughout life and dry out without loss of growth. In the modern history of forestry, outbreak activity of root pathogens occurs for the first time. The forecast for the regeneration of drying Siberian stone pine forests in the mid-mountain part of the Western Sayan is positive. In Kuznetsk Alatau, the Siberian stone pine regrowth is insufficient and reforestation in large grass forest types is possible only with a change in species. The cutting of the tree stand, as well as its drying out with the subsequent growth of the grass stand, contributes to an increase in the population density of consumers of the Siberian stone pine nuts and, accordingly, excludes the regeneration of the trees. Preservation of undergrowth in clearings 30 years ago has yielded positive results in the formation of fruit-bearing Siberian stone pine forests. The organization of nut fishing zones with a ban on Siberian stone pine logging and its subsequent drying out led to economic losses of valuable wood and a by-product resource during the lifetime use of the Siberian stone pine stands.

For the first time, a comparative analysis of crown morphogenesis in Siberian stone pine (Pinus sibirica), Siberian dwarf pine (P. pumila), their hybrids and backcrosses was carried out using the example of 10-year-old seed offspring from the Northern Baikal natural population. The goal is to “decompose” the life form phenomenon into elementary traits, to trace their formation at the beginning of ontogenesis on two contrasting examples (an upright tree vs. prostrate tree) and inheritance after interspecific hybridization. The parent species differed fundamentally in (1) stem inclination and (2) apical dominance at two levels (1-year-old shoots and perennial branches). The phototropic slope of the Siberian dwarf pine stem “triggered” the mechanism of prostrate tree formation. Apical dominance in the system of perennial branches was the main factor in the crown formation. It, in turn, consisted of two key characteristics: strength and selectivity. In Siberian stone pine, apical dominance was strong and nonselective. In Siberian dwarf pine, apical dominance was weak and selective: some of the largest branches did not obey him. All key traits were inherited by hybrids and backcrosses strictly intermediate in accordance with the proportion of species in the offspring genome.

Pinus sibirica and P. pumila hybrid zone have a vast territory. Previously, seed production was determined only in hybrids from the western part of the hybrid zone. The earlier established introgression of the species in the northeastern part of the hybrid zone gives more relevance to the study of the hybrid seed production in this area. The paper presents the results of the cone structure analysis in Siberian stone pine, Siberian dwarf pine and their hybrids, and also shows the dynamics of ovule development into a filled seed with a well-developed embryo. The final seed efficiency, i. e., the portion of sound seeds from the ovule number, was 65, 51, and 37 % for Siberian dwarf pine, hybrids, and Siberian stone pine, respectively. Low seed efficiency in P. sibirica was related with high portion of empty seeds in some individuals. The atypical seed efficiency in Siberian stone pine and hybrids could be explained by the lack of pure P sibirica, consequently, by the lack of F1 hybrids.

QuestionsWhat are the effects of root competition from mature plants and soil type on the survival and growth of dominant grass and succulent shrub seedlings at an ecotonal site between arid grassland and succulent shrubland? Do these factors explain the occurrence of separate grass‐dominated and shrub‐dominated communities along the ecotone?LocationEcotone between Bushmanland arid grassland and Namaqualand succulent shrublands in the Karoo, South Africa.MethodsSeedlings of Stipagrostis brevifolia, a perennial C4 grass, and Ruschia robusta, a leaf‐succulent shrub were transplanted into naturally occurring openings within separate Stipagrostis brevifolia and Ruschia robusta communities. The effects of root competition were tested by exposing seedlings to roots of neighbouring adult plants or by excluding the influence of neighbouring roots using metal partitions. The influence of soil on the survival and growth response of seedlings was tested by comparing the response of each species grown in soil of their own community with their response when grown in soil of the other community.ResultsAll S. brevifolia seedlings died within the first 3 mo of the experiment, irrespective of competition exclusion or whether they were grown in grassland or shrubland soils. Root competition from mature plants reduced the survival of R. robusta seedlings in the grass community, but not in the shrub community. When seedlings of R. robusta were not exposed to root competition, their survival and biomass in the grass community soil type did not differ from that in the shrub community soil type.ConclusionsExcluding root competition in the grass community provided favourable conditions for R. robusta seedlings to establish, suggesting that root competition from the grass is more important in maintaining separate grass communities, and that any differences in soil properties are less important in influencing such processes. Our study presents an example where a species' fundamental niche may be differerent from its realized niche, as a result of competitive interactions.

Interplant competition in soybean [Glycine max (L.) Merr.] influences plant growth. Because of the difficulty of evaluating root competition, studies to date have concentrated on competition within the canopy. We used a below‐ground porous membrane to isolate and evaluate the effects of root and canopy competition on soybean growth. Field studies were conducted in 1985 and 1986 on a Captina silt loam (fine‐silty, siliceous, mesic Typic Fragiudult) with four competition treatments imposed on ‘Forrest‘ soybean: (i) no competition, (ii) root competition only, (iii) canopy competition only, and (iv) root and canopy (combined) competition. At growth stage R4, leaf area was reduced 29% by root competition and 48% by canopy competition. Root competition reduced net assimilation rate by 48% in 1985 and 10% in 1986, while canopy competition resulted in a 28% reduction both years. Combined competition reduced total plant dry weight an average of 78%, with intermediate dry weights for root or canopy competition. At R4 and R8, shoot dry weight was reduced 31 and 43% with root competition, and 57 and 62% with canopy competition, respectively. Canopy competition reduced root dry weight at R4 by 43% in 1985 and 70% in 1986. Root competition reduced root dry weights in both years by 24 and 42% at R4 and R8, respectively. Canopy and combined competition resulted in taller plants with smaller stem circumferences while root competition did not alter shoot structure. Results suggest that canopy competition may have a greater influence on plant development than root competition.

There is much evidence that plant competition below ground is size symmetric, i.e. that competing plants share contested resources in proportion to their sizes. Several researchers have hypothesized that a patchy distribution of soil nutrients could result in size-asymmetric root competition. We tested this hypothesis. In a greenhouse experiment, Triticum aestivum (wheat) individuals of different initial sizes were grown alone or with below-ground competition from one neighbour, in 1 m tall, narrow containers in a nitrogen-poor field soil with (i) no added nitrogen, (ii) nitrogen fertilizer mixed into the upper 50 cm, and (iii) the same amount of fertilizer mixed into a 20–30 cm deep layer. We measured total leaf length throughout the experiment, and above-ground biomass and nitrogen concentration at harvest. We also measured root depth and frequency over time in a subset of containers. Competing plants were half the size of non-competing plants, meaning that root competition was very strong. Root competition was size-asymmetric to some degree in all soil treatments. Neighbours larger than the target plant showed a greater per-unit-size effect on target growth than neighbours smaller than the target. Size variation increased over time for competing individuals, but decreased for non-competing pairs. Contrary to expectations, the presence of a high-nutrient patch reduced the strength and size asymmetry of competition temporarily. Size asymmetry in poor, deep soils may result from directionality in resource interception as roots compete for limited nutrients by growing deeper into soil layers that have not yet been exploited. Root competition can be size asymmetric, but not to the same degree as competition for light.

Background: Below-ground competition as a major structuring force in plant communities can be either symmetric or asymmetric with important consequences for the coexistence of plants. It is a matter of controversy whether asymmetry in competition increases with resource availability or not. Aims: This study tested the hypotheses that root competition between mature Fagus sylvatica and Quercus petraea trees is asymmetric and that asymmetry is more pronounced in non-water-limited environments. Methods : Initially equal-sized tree fine roots were grown for 365–390 days in root growth chambers in situ and exposed to competition by either a conspecific or an allospecific root. Relative root growth rate was used to determine asymmetry in root competition. Different soil moisture regimes were considered by conducting a throughfall reduction experiment and by including data from earlier experiments with contrasting moisture regimes. Results: The competitive interaction between Fagus and Quercus fine roots is asymmetric; root morphology appears to depend on the presence of a competitor; and asymmetry in root competition increases with increasing soil moisture availability. Conclusions: Below-ground competition in temperate broad-leaved mixed forests can be as asymmetric as competition for light, with asymmetry decreasing with increasing water shortage.

Impacts of regional climatic fluctuations on radial growth of Siberian and Scots pine at Mukhrino mire (central-western Siberia)

How pollen shapes forests and forestry can be illustrated using Siberia’s boreal forests which have historically produced some of the highest pollen concentrations in the Northern Hemisphere. Pollen’s contributions are categorized as follows: 1) forests and timber, 2) nontimber products and services and 3) emerging research at the forest-atmosphere interface. Examples are drawn from Pinus sylvestris (Scots pine), Pinus sibirica (Siberian stone pine) and Pinus koreansis (Korean pine). Pine pollen is not only vital to timber and nontimber products but it serves as a well-studied model system for atmospheric studies.

Current evidence suggests that competition belowground is a ubiquitous phenomenon in many natural and semi-natural types of vegetation. In reviewing 23 studies that separated root and shoot competition under controlled conditions, Wilson (1988) found that root competition was usually the more intense form of interaction. Even in relatively productive soils where plants produce large canopies and competition for light may be expected to be an important factor, root interactions may still play a significant role. Several studies (Belcher et al. 1995; Gerry and Wilson 1995; Cahill 1999) have confirmed the significance of belowground interactions in competition under field conditions.KeywordsRoot ProliferationRoot CompetitionBelowground CompetitionSoil PatchPerennial Grass SpeciesThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The purpose of the research is to examine the causal relationship between stock prices and the variables representing the real sector of the economy for example real GDP, and real investment, in Pakistan. In this study, annual data is used (quarter-wise) from December 1980 to June 2007 and the correlation analysis has been applied, to investigate the relationship. For better understanding of the Market’s Behavior, data has been grouped in to Liberalization periods; Preliberalization and Post-Liberalization. The stock market in Pakistan provides an average quarterly return of 2.86%.The average annual growths in real variables are just lower than 1% for GDP and returns slightly over 1% in investments. A comparison of the descriptive statistics between the two sub-periods indicates decline in the average growth in real variables. Real GDP fell ,and real investment also decreased. The decline is significant both in GDP and investment. Though the magnitude of the average growth in stock price index increased in the second period it is not significantly different from that of the first period. The descriptive statistics indicates a much higher expansion in stock prices relative to real variables. However, the stock prices also experienced higher volatility during the sample period whereas the real variables seem to be stable

Рассмотрено взаимодействие основных лесообразующих пород Сибири: ели сибирской(Picea obovataLedeb.), березы кустарниковой(Betula fruticosa Pall.), сосны обыкновенной(Pinus sylvestrisL.), осины обыкновенной(Populus tremulaL.), лиственницы сибирской(Larix sibiricaLedeb.) и сосны сибирской кедровой(кедра) (Pinus sibiricaDu Tour) с агросерой почвой. Исследования проводились в специальном многолетнем эксперименте с лесными культурами, заложенном по инициативе проф. Н. В. Орловского в 1968–1969 гг. в южной тайге на территории Кемчугской возвышенности. Выявлено, что биологические особенности и сукцессионное положение древесных пород существенно влияют на все компоненты фитоценоза. Через 45 лет наиболее резкие изменения зафиксированы под пологом раннесукцессионных хвойных (лиственница) и мелколиственных (берёза и осина) пород, тогда как позднесукцессионные породы – ель и кедр – на данном этапе существенно ограничивают развитие подчиненных ярусов. Почвенный профиль в условиях эксперимента формируется вследствие дифференциации пахотного субстрата почвообразующей породы на генетические горизонты. Влияние лесного полога на плантажированную агросерую почву происходит постепенно и усиливается по мере роста и развития культур, образования подстилочного горизонта и охватывает все свойства почвы. Активным современным почвообразованием затронут минеральный слой почвы 0–10 (13) см. Главным фактором образования почвенного профиля являются вертикальные потоки вещества и энергии, поступающие в почву в процессе нарастающей емкости и интенсивности биологического круговорота. Отмечено, что почвы под культурами в условиях многолетнего эксперимента развиваются по зональному типу. The interaction of the main forest-forming species of Siberia: Siberian spruce (Picea obovataLedeb.), bush birch (Betula fruticosaPall.), Scots pine (Pinus sylvestrisL.), aspen (Populus tremulaL.), Siberian larch (Larix sibiricaLedeb.), and Siberian stone pine (Pinus sibiricaDu Tour) with agro-gray soil is considered. The study is carried out in a special long-term experiment with forest crops, initiated by prof. N. V. Orlovskiy in 1968-69 in the southern taiga on the territory of the Kemchug Upland. It was revealed that biological characteristics and successional position of tree species significantly influence all components of the phytocenosis. The biggest changes were recorded under the canopy of early successional coniferous (larch) and small-leaved (birch and aspen) species, while late successional species – spruce and cedar – at this stage significantly limit the development of subordinate layers. Over the 45-year period of growth of forest crops, the soil profile is formed due to the differentiation of the arable substrate of the soil-forming species into genetic horizons. The influence of the forest canopy on planted agro-gray soil occurs gradually and intensifies with the growth and development of crops, the formation of a litter horizon and covers all soil properties. Active modern soil formation affects the mineral soil layer 0–10 (13) cm. Vertical flows of matter and energy entering the soil in the process of increasing capacity and intensity of the biological cycle are the main factor in the formation of the soil profile. The development of soil under forest crops under the conditions of a long-term zonal experiment was noted.

Dactylis glomerata and Holcus lanatus were grown together in boxes with either full competition, root competition only, shoot competition only or no competition between them. The boxes were either fertilized (150 kg ha‐1N, 100 kg ha‐1 K, 80 kg ha‐1 P) or not fertilized. The experiment was continued for 13 months, and a total of six cuts were taken. H. lanatus was more competitive than D. glomerata throughout the experiment, though the effect declined after flowering during the second growing season. The effects of root competition were generally much greater than those of shoot competition and tended to increase during the first year. However, the effects of root competition declined, relative to shoot competition, after flowering in the second growing season.Fertilizer applications slightly increased the root competitive ability of H. lanatus relative to D. glomerata but slightly reduced its shoot competitive ability.

The article discusses the reasons for the low survival capacity of Siberian stone pine (Pinus sibirica Du Tour.) crops in the conditions of the West Siberian mid-taiga plain forest region. The field stage of research was performed in the autumn 2020 and the summer 2022. The survival capacity of forest crops was determined on rectangular trial plots covering 1–2 % of the total area of the surveyed plots. The article provides data on the location and description of the studied areas of Siberian stone pine crops, as well as data on the number of surviving plants and the survival capacity of seedlings in these plots. In the course of the research, it was found that the survival capacity of Siberian stone pine crops in the four studied plots was 7,8 (60,3 %) in 2020, and this figure decreased to 3,6 (39,8 %) in 2022. Along with many other possible causes of excessive death of Siberian stone pine seedlings, the most likely reasons for the poor survival capacity are soaking seedlings and suppressing them with unwanted herbaceous and woody vegetation. In the three study areas, it is recommended to write off forest crops and replant seedlings. In one of the studied crop plots, it is necessary to perform silvicultural maintenance in order to remove unwanted hardwoods and supplement forest crops with enlarged seedlings or seedlings of Siberian stone pine. To increase the survival capacity of Siberian stone pine crops, it is recommended to abandon soil cultivation methods in which the upper fertile soil layer is mixed with the underlying levels, as well as to perform agrotechnical and silvicultural maintenance in a timely manner.