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

SHRUBS AS AN ELEMENT OF THE PARK ENVIRONMENT

Ornamental shrubs are one of the elements of the formation of the park environment and an integral part of urban landscaping. The paper presents the results of studying the species diversity of shrubs in park plantations in the city of Voronezh. The range includes more than 30 species, decorative forms and varieties of plants. Deciduous species are predominant, while coniferous species account for not much more than 10 %. Deciduous shrubs growing in the parks of the city of Voronezh belong to 14 families. Among them, there are beautiful flowering and decorative deciduous species, as well as plants with attractive fruits. Coniferous species belong to two families-pine and cypress. The cypress family is characterized by the greatest species (form, variety) diversity. The most popular types and varieties of coniferous trees are Western thuja "Smaragd", Western thuja "Danika", Cossack juniper, Cossack juniper"Tamariscifolia". The main types of shrub plantings in park stands are hedges and row plantings. The most common hedges are made of brilliant dogwood and Wanguttaspirea. Less often, groups and tapeworms are used in park plantings. The analysis of the geographical origin of shrubs showed that the largest number of species are introduced − their participation is more than 90%, the share of local species is less than 10%.

Assessment of the volume of harvested wood in accordance with the vital state of wood species

During selective felling on the territory of 3.9 ha, 181 m3 of wood, 35% of which is dead wood. Among them, pine (16 m3), spruce (27 m3), birch (8 m3) and aspen (12 m3) were found. The volume of cut viable wood was 118 m3, including 50 m3 of pine, 44 m3 of spruce, 14m 3 of birch and 10 m3 of aspen. The values obtained do not exceed the forest declaration data. To determine the stumps from dead coniferous trees, the following criteria were tested: complete or partial absence of bark, the presence of traces of the vital activity of insect pests and abundance worm dust. Species-specific criteria are proposed: in pine – the presence of rot of the peripheral part of the wood, brown color of sapwood and bast; spruce – the presence of heart rot and wood destroying fungi. In deciduous species, the main criterion for isolating stumps from dead trees has been tested – the presence of wood-destroying fungi, in aspen – heart rot caused by tinder fungi. We recommend using these criteria to resolve legal claims against forest users in the removal and assessment of harvested wood.

Phenology explains different storage remobilization in two congeneric temperate tree species with contrasting leaf habit

The dependence of trees on carbon and nutrient storage is critical to predicting the forest vulnerability under climate change, but whether evergreen and deciduous species differ in their use and allocation of stored resources during spring phenology is unclear. Using a high temporal resolution, we evaluated the role of spring phenology and shoot growth as determinants of the carbon and nutrient storage dynamics in contrasting leaf habits. We recorded the phenology and shoot elongation and determined the concentrations of total non-structural carbohydrates (NSC), starch, soluble carbohydrates (SC), nitrogen (N) and phosphorus (P) in buds, expanding shoots and previously formed shoots of two sympatric Nothofagus species with contrasting leaf habit. Species reached similar shoot lengths, though shoot expansion started 35 days earlier and lasted c. 40 days more in the deciduous species. Thus, while the deciduous species had a relatively constant shoot growth rate, the evergreen species experienced a conspicuous growth peak for c. 20 days. In the evergreen species, the greatest decreases in NSC concentrations of previously formed shoots and leaves coincided with the maximum shoot expansion rate and fruit filling, with minimums of 63% and 65% relative to values at bud dormancy, respectively. In contrast, minimum NSC concentrations of the previously formed shoots of the deciduous species were only 73% and occurred prior to the initiation of shoot expansion. Bud N and P concentrations increased during budbreak, while previously formed shoots generally did not decrease their nutrient concentrations. Late spring phenology and overlapping of phenophases contributed to the greater dependence on storage of proximal tissues in the studied evergreen compared to deciduous species, suggesting that phenology is a key determinant of the contrasting patterns of storage use in evergreen and deciduous species.

Reproduction of red-book introduced plants of arboretum (on the example of Eastern Transbaikalia)

The paper presents the results of seed and vegetative reproduction of woody and shrubby introduced plantsincluded in the List of Objects of the plant world listed in the Red Book of the Trans-Baikal Territory. The objects of thestudy are red-book woody and shrubby plants growing on the territory of the arboretum: Picea obovata var. coeruleaMalyschev; Euonymus maackii Rupr.; Corylus heterophylla Fisch. ex Trautv.; Armeniaca sibirica (L.) Lam. The aim of thestudy is to preserve the gene pool of red-book woody and shrubby plants-introduced by seed and vegetative reproduction;to study the timing of cuttings, the effect of various root formation stimulators on the rooting process. Special attentionis paid to the development of methods of vegetative reproduction with the use of various growth stimulators, taking intoaccount the weather conditions of the Trans-Baikal Territory on coniferous and deciduous species. The features and termsof harvesting cuttings are studied. As a result, a favorable period for the process of rooting of coniferous species wasnoted – the phenophase “bud swelling”. The greatest number of roots was formed in cuttings harvested with a “heel”, nottreated with root formation stimulators (“control”). The greatest rooting of green cuttings of shrub species was observed inexperiments with the use of “Kornevin”. Propagation of Armeniaca sibirica showed good results by seed method.

TYPES PRODUCTIVITY IN CONDITION OF THE SOUTH URAL TAIGA SUBZONE

По данным материалов 10 постоянных пробных площадей (ППП) рассмотрены лесоводственно- таксационные показатели древостоев сосняков ягодникового типа леса, пройденных выборочными руб- ками (первый приём равномерно-постепенной рубки). Все ППП были заложены на территории Ураль- ского учебно-опытного лесхоза. Изучаемые древостои характеризуются высокой относительной пол- нотой до рубки (0,76–1,0), I–III классами бонитета в возрасте 110–130 лет и высокой густотой. Запас стволовой древесины варьируется до рубки от 323,0 до 619,0 м3/га, что указывает на высокую эксплуа- тационную ценность сосновых насаждений ягодникового типа леса. Преобладающей породой в составе всех пробных площадей является сосна. Встречаются и другие хвойные породы – ель, пихта и листвен- ница. Доля участия в составе последних сильно варьирует. Из лиственных пород доминирует береза. Также в состав лиственных пород входят липа и осина, на их долю приходится не более одной единицы состава. Формула состава древостоя существенно не изменилась через 4 года после рубки, сосна оста- лась преобладающей породой. Средний показатель диаметра увеличился на 2,3 см, высоты – на 1,3 м. Густота в среднем сократилась на 193 дерева/га. Запас деревьев сосны снизился на 148 м3/га, запас сухо- стойных деревьев – на 2 м3/га. Проведенные исследования доказывают, что при вырубке в первый прием равномерно-постепенной рубки в условиях сосняка ягодникового удаляются сухостойные, отставшие в росте, фаутные деревья и деревья 4 и 5 класса роста по Крафту. Отмечается положительное изменение лесоводственно-таксационных показателей насаждений. В частности, улучшаются их эстетические ха- рактеристики и антропогенная привлекательность, а также рубки способствуют повышению продуктив- ности и производительности насаждений. According to the materials of 10 permanent sample plots (PPP), silvicultural and taxation indicators of forest stands of berry-type pine forests passed by selective felling were considered (the fi rst method of uniformly gradual felling). All permanent test plots were laid on the territory of the Ural training and experimental forestry enterprise. The studied stands are characterized by a high relative density before felling (0,76–1,0), I–III quality classes at the age of 110–130 years and high density. The stock of stem wood varies before felling from 323,0 to 619,0 m3/ha, which indicates a high operational value of pine plantations of berry forest type. Pine is the predominant species in all sample plots. There are also other conifers – spruce, fi r and larch. The share of participation in the composition of the latter varies greatly. The dominant deciduous species is birch. Also, the composition of deciduous species includes linden and aspen, they account for no more than one unit of composition. The formula of the stand composition did not change signifi cantly 4 years after logging, pine remained the predominant species. The average diameter increased by 2,3 cm, height by 1,3 m. The average density decreased by 193 trees/ha. The stock of pine trees decreased by 148 m3/ha, the stock of dry trees by 2 m3/ha. The conducted studies prove that when cutting down in the fi rst step of evenly-gradual felling in the conditions of a berry-type pine forest, the queue of dry, stunted, faut trees and trees of the 4th and 5th growth class according to Craft contributes to a positive change in the forestry and taxation indicators of plantings, this improves their aesthetic and anthropogenic attractiveness, and also contributes to increasing the productivity and productivity of such plantings.

Differential impact of liana colonization on the leaf functional traits of co-occurring deciduous and evergreen trees

The present study was carried out to analyse the leaf functional traits of co-occurring evergreen and deciduous tree species in a tropical dry scrub forest. This study also intended to check whether the species with contrasting leaf habits differ in their leaf trait plasticity, responding to the canopy-infestation by lianas. A total of 12 leaf functional traits were studied for eight tree species with contrasting leaf habits (evergreen and deciduous) and liana-colonization status (Liana+ and Liana−). In the liana-free environment (L−), evergreen trees had significantly higher specific leaf mass (LMA) and leaf dry matter content (LDMC) than the deciduous species. Whereas, the deciduous trees had higher specific leaf area (SLA) and mass-based leaf nitrogen concentration (Nmass). The leaf trait-pair relationship in the present study agreed to the well-established global trait-pair relationships (SLA Vs Nmass, Lth Vs SLA, Nmass Vs Lth, Nmass Vs LDMC, LDMC Vs SLA). There was no significant difference between L+ and L− individuals in any leaf functional traits studied in the deciduous species. However, evergreen species showed marked differences in the total chlorophyll content (Chlt), chlorophyll b (Chlb), SLA, and LMA between L+ and L− individuals of the same species. Deciduous species with the acquisitive strategy can have a competitive advantage over evergreen species in the exposed environment (L−) whereas, evergreen species with shade-tolerant properties were better acclimated to the shaded environments (L+). The result revealed the patterns of convergence and divergence in some of the leaf functional traits between evergreen and deciduous species. The results also showed the differential impact of liana colonization on the host trees with contrasting leaf habits. Therefore, liana colonization can significantly impact the C-fixation strategies of the host trees by altering their light environment. Further, the magnitude of such impact may vary among species of different leaf habits. The increased proliferation of lianas in the tropical forest canopies may pose a severe threat to the whole forest carbon assimilation rates.

El Niño-Southern Oscillation affects the water relations of tree species in the Yucatan Peninsula, Mexico

We evaluated the effect of ENSO 2015/16 on the water relations of eight tree species in seasonally dry tropical forests of the Yucatan Peninsula, Mexico. The functional traits: wood density, relative water content in wood, xylem water potential and specific leaf area were recorded during the rainy season and compared in three consecutive years: 2015 (pre-ENSO conditions), 2016 (ENSO conditions) and 2017 (post-ENSO conditions). We analyzed tree size on the capacity to respond to water deficit, considering young and mature trees, and if this response is distinctive in species with different leaf patterns in seasonally dry tropical forests distributed along a precipitation gradient (700–1200 mm year−1). These traits showed a strong decrease in all species in response to water stress in 2016, mainly in the driest site. Deciduous species had lower wood density, higher predawn water potential and higher specific leaf area than evergreen species. In all cases, mature trees were more tolerant to drought. In the driest site, there was a significant reduction in water status, regardless of their leaf phenology, indicating that seasonally dry tropical forests are highly vulnerable to ENSO. Vulnerability of deciduous species is intensified in the driest areas and in the youngest trees.