Mixed Stands Research Articles

Soil microbial community response to ectomycorrhizal dominance in diverse neotropical montane forests

Ectomycorrhizal (EM) associations can promote the dominance of tree species in otherwise diverse tropical forests. These EM associations between trees and their fungal mutualists have important consequences for soil organic matter cycling, yet the influence of these EM-associated effects on surrounding microbial communities is not well known, particularly in neotropical forests. We examined fungal and prokaryotic community composition in surface soil samples from mixed arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) stands as well as stands dominated by EM-associated Oreomunnea mexicana (Juglandaceae) in four watersheds differing in soil fertility in the Fortuna Forest Reserve, Panama. We hypothesized that EM-dominated stands would support distinct microbial community assemblages relative to the mixed AM-EM stands due to differences in carbon and nitrogen cycling associated with the dominance of EM trees. We expected that this microbiome selection in EM-dominated stands would lead to lower overall microbial community diversity and turnover, with tighter correspondence between general fungal and prokaryotic communities. We measured fungal and prokaryotic community composition via high-throughput Illumina sequencing of the ITS2 (fungi) and 16S rRNA (prokaryotic) gene regions. We analyzed differences in alpha and beta diversity between forest stands associated with different mycorrhizal types, as well as the relative abundance of fungal functional groups and various microbial taxa. We found that fungal and prokaryotic community composition differed based on stand mycorrhizal type. There was lower prokaryotic diversity and lower relative abundance of fungal saprotrophs and pathogens in EM-dominated than AM-EM mixed stands. However, contrary to our prediction, there was lower homogeneity for fungal communities in EM-dominated stands compared to mixed AM-EM stands. Overall, we demonstrate that EM-dominated tropical forest stands have distinct soil microbiomes relative to surrounding diverse forests, suggesting that EM fungi may filter microbial functional groups in ways that could potentially influence plant performance or ecosystem function.

Root overlap and allocation of above- and belowground growth of European beech in pure and mixed stands of Douglas fir and Norway spruce

Site conditions and species identity have a combined effect on fine root growth of trees in pure and mixed stands. However, mechanisms that may contribute to this effect are rarely studied, even though they are essential to assess the potential of species to cope with climate change. This study examined fine root overlap and the linkage between fine root and stem growth of European beech (Fagus sylvatica) growing in pure and mixed stands with Douglas fir (Pseudotsuga menziesii) or Norway spruce (Picea abies) at two different study sites in northwestern Germany.The study sites represented substantially different soil and climate conditions. At each site, three stands, and at each stand, three pairs of trees were studied. In the pure beech stand, the pairs consisted of two beech trees, while in the mixed stands each pair was composed of a beech tree and a conifer. Between each pair, three evenly spaced soil cores were taken monthly throughout the growing season. In the pure beech stands, microsatellite markers were used to assign the fine roots to individual trees. Changes in stem diameter of beech were quantified and then upscaled to aboveground wood productivity with automatic high-resolution circumference dendrometers.We found that fine root overlap between neighboring trees varied independently of the distance between the paired trees or the stand types (pure versus mixed stands), indicating that there was no territorial competition. Aboveground wood productivity (wood NPP) and fine root productivity (root NPP) showed similar unimodal seasonal patterns, peaking in June. However, this pattern was more distinct for root NPP, and root NPP started earlier and lasted longer than wood NPP. The influence of site conditions on the variation in wood and root NPP of beech was stronger than that of stand type. Wood NPP was, as expected, higher at the richer site than at the poorer site. In contrast, root NPP was higher at the poorer than at the richer site.We concluded that beech can respond to limited resources not only above- but also belowground and that the negative relationship between above- and belowground growth across the study sites suggests an ‘optimal partitioning’ of growth under stress.

Interdependence of stocking rate and relative density in mixed spruce-dominated stands of the Yenisei ridge

The study is focused on a particular issue in the field of analysis of the stands horizontal structure, which is of practical importance. The aim of the present research is to study the interdependence of stocking rate and relative density in mature and overmature mixed spruce-dominated stands of the Yenisei Ridge. The research was based on the materials obtained from 15 research plots where we felled and measured 159 model trees. Stocking and density are interrelated. Nevertheless, the relationship is complex since the stocking undergoes through two main stages - an increase in the number of trees and the following thinning of forest stands. The research was conducted in mature and overmature mixed Siberian spruce-dominated stands of different stocking rates. All the studied forests stands were of the same stage of development. As a result, we revealed the extent to which stands characteristics depend on stocking (at stand-wide level and for forest-forming species separately). We also defined equations stating the correlation between relative density and stocking.

Species heights of Siberian spruce on the Yenisei Ridge

The work is based on materials from 15 sample plots laid out in mixed spruce stands of the Yenisei Ridge, with a relative completeness in the range of 1.62-1.27, belonging to the green moss group of forest types. Based on the data obtained, the features of changes in spruce species heights and their interdependence with other taxation characteristics were established. The results of data processing indicate the need to develop a set of taxation standards for the Yenisei Ridge region.

How to utilize natural regeneration of birch to establish mixed spruce-birch forests in Finland?

Mixed forests are known for their ability to provide a wide range of ecosystem services. Such forests have higher biodiversity compared to monocultures, are resilient against disturbances and may mitigate the effects of climate change. Despite well-known benefits, there is still little information on how these forests should be established and managed. The aim of this study was to describe the early growth dynamics of current boreal young mixed stands of planted Norway spruces (Picea abies (L.) Karst.) and naturally regenerated birches (Betula spp.). We collected data from 9 stands planted for spruce 8–14 years ago in Southern and Central Finland. Stem analysis was conducted to 144 spruces and to 144 birches to determine previous growth. We modelled the height and diameter development of individual trees in relation to tree age at stump height using non-linear mixed Chapman-Richards model. There were no significant differences between spruce and seed-origin birch in diameter growth at stump height, but the initial height increments of natural birches were larger than those of planted spruces. However, planted spruces were able to keep up with the height development of birches, if spruces received a head start over naturally regenerated seed-origin birch for two growing seasons. Thus, naturally regenerated birch admixture can be utilized to establish single-storied spruce-birch mixtures, and the admixture should be retained during the early cleaning of planted spruce stands.

Formation of siberian stone pine forests by chemical care for mixed stands in Western Siberia

Formation of siberian stone pine forests by chemical care for mixed stands in Western Siberia

The effects of data aggregation on long-term projections of forest stands development

Forest management planning often relies on Airborne Laser Scanning (ALS)-based Forest Management Inventories (FMIs) for sustainable and efficient decision-making. Employing the area-based (ABA) approach, these inventories estimate forest characteristics for grid cell areas (pixels), which are then usually summarized at the stand level. Using the ALS-based high-resolution Norwegian Forest Resource Maps (16 ​m ​× ​16 ​m pixel resolution) alongside with stand-level growth and yield models, this study explores the impact of three levels of pixel aggregation (stand-level, stand-level with species strata, and pixel-level) on projected stand development. The results indicate significant differences in the projected outputs based on the aggregation level. Notably, the most substantial difference in estimated volume occurred between stand-level and pixel-level aggregation, ranging from −301 to +253 ​m3⋅ha−1 for single stands. The differences were, on average, higher for broadleaves than for spruce and pine dominated stands, and for mixed stands and stands with higher variability than for pure and homogenous stands. In conclusion, this research underscores the critical role of input data resolution in forest planning and management, emphasizing the need for improved data collection practices to ensure sustainable forest management.

Water and nutrient use efficiency of three tree species in monoculture and mixed stands and potential drivers in the Loess Hilly Region, China

Water and nutrient use efficiency of three tree species in monoculture and mixed stands and potential drivers in the Loess Hilly Region, China

An assessment of seasonal changes in forests using the segmentation and cluster analysis of Landsat space images

For the purposes of monitoring the state of forest ecosystems, it is most effective to use the capabilities of remote methods. On multispectral Landsat satellite images (a time series of summer and autumn images for 2000, 2001, 2013, 2014) of the territory of the Olekminsky State Nature Reserve, fragments of forests dominated by Gmelin larch (Larix gmelinii Rupr.) with an area of 250 km2 (scale 1:5000). Then the polygons were saved at three levels of segmentation (scaling) – 4, 16, 64 with scales of 1:2500, 1:1250, 1:625. During decryption, uncontrolled classification of polygons using the ISODATA (Iterative Self-Organizing Data Analysis Technigue) method into 2,4,10 classes was carried out. Classification into two classes was used to calculate the forest cover index. Seasonal changes were determined by the difference in the forest cover index values of the polygons in summer and autumn. It has been shown that the greater the difference, the greater the proportion of larch in mixed forest stands. Distribution curves of forest cover index values were constructed for polygons of the 3rd scaling level. Based on the results of classification into 4, 10 classes, statistical processing was carried out with the calculation of indicators of difference and similarity of polygons - dispersion of the general population and Fisher's test (F-test). The results of changes in population dispersion and F-test at different levels of segmentation and in different years are considered.

Broadleaf Trees Increase Soil Aggregate Stability in Mixed Forest Stands of Southwest China

In soils, high aggregate stability often represents higher quality and anti-erosion ability; however, few studies have systematically analyzed how different forest stands affect soil aggregate stability. We selected five typical mixed forest stands on Jinyun Mountain in Chongqing, China, as research sites to evaluate soil aggregate stability. Within these sites, we analyzed the factors influencing soil aggregate stability in different stands by measuring soil characteristics and root traits. Soil aggregation stability, plant root traits, and soil properties varied among the mixed forest stands. The broadleaf tree mixed forest improved soil aggregate stability by 57%–103% over that of the Pinus massoniana mixed forest. The soil organic carbon, cation exchange capacity, Fe-Al oxides, and fine root proportion were positively correlated with soil aggregate stability. The specific root length and very fine root proportion were negatively correlated with soil aggregate stability, whereas the fine root proportion was positively correlated with this property. Specifically, we found that arbuscular mycorrhizal fungi did not affect soil aggregate stability in acid rain areas. Structural equation modeling indicated that soil aggregate stability was closely related to soil physicochemical properties and plant root characteristics. Predictive factors accounted for 69% of the variation in mean weight diameter, and plant root traits influenced soil aggregate stability by affecting soil organic matter, texture, and Fe-Al oxides. This study elucidated the impact of soil physicochemical properties and plant root characteristics on soil aggregate stability in different forest stand types, which has crucial implications for optimizing the management of various forest types.

Understory changes in mixed elm stands in response to canopy dieback in Latvia

In the eastern Baltic region, warming is favouring the advance of thermophilic tree species and the formation of mixed stands with a higher share of broadleaves, thus contributing to productivity and other ecosystem services of forests. However, the accelerating environmental changes often trigger the spread and intensification of biotic disturbances such as disease outbreaks at unprecedented rates, which might alter the course of stand development. Within the region, elms (Ulmus sp.), which are of low importance as a source of timber, yet highly important in terms of other ecosystem services, are suffering varying degree of dieback due to the Dutch elm disease, which can threaten the existence of species. Still, there are explicit local differences in the susceptibility of trees, which add uncertainties regarding the sustainability of elms. A permanent sampling plot network was established to monitor changes in mixed elms stands in response to the dieback caused by the disease; canopy and understory trees were accounted. Two surveys in 2016 and 2021 have been made. Canopy elms have suffered moderate dieback during the first wave already before the surveys, as ca. 17% of canopy elms were already dead. However, the susceptibility differed among the species (Ulmus glabra exceeded U. laevis), likely due to the preference of the vectors of the disease. In response to canopy openings, self-regeneration occurred, though the balance between the advance regeneration and undergrowth species was affected by the intensity of canopy dieback. The advanced growth of the former canopy species including elms was sufficient under moderate changes in the canopy, while low and high changes favoured undergrowth, suggesting the formation of shrubland. Accordingly, the additional mortality of elms due to Dutch elm disease tended to diverge the development course of the mixed broadleaved stands; hence further monitoring is advised. Keywords: Ulmus sp.; Ophiostoma sp.; advance growth; undergrowth; Dutch elm disease; succession

Effects of habitat heterogeneity on bird communities in the forests of northeastern Germany

Habitat heterogeneity is a key factor for regulating biodiversity in temperate lowland forests. Specifically, stands associated with late forest development phases provide important habitat structures for many rare and threatened forest bird species. However, how forest stands that differ in their structural complexity, canopy conditions and tree species composition affect forest bird assemblages both at the local and landscape scale remains largely unclear. In a young moraine lake landscape of northeastern Germany, we assessed correlations of bird diversity and bird composition with stand properties. We used data from 48 transects (400 m) established in (1) unmanaged, closed-canopy, mature stands that were dominated by Fagus sylvatica (UDS), and (2) diverse managed, mixed coniferous stands with a mosaic of open and closed canopy patches (MCS). We found that bird communities of the UDS strongly differed from those in the MCS, with open habitat species being more frequent in the MCS. By contrast, differences in diversity measures were less distinct. Moreover, we identified nine indicator species for the UDS (Columba oenas, Cyanistes caeruleus, Muscicapa striata, Leiopicus medius, Certhia brachydactyla, Ficedula parva, Dryobates minor, Sturnus vulgaris, Ficedula hypoleuca) and seven indicator species for the MCS (Periparus ater, Pyrrhula pyrrhula, Regulus regulus, Prunella modularis, Lophophanus cristatus, Emberiza citronella, Anthus trivialis). Several famous ancient beech forest patches in Müritz National Park and the UNESCO Biosphere Reserve “Schorfheide-Chorin” were found to harbour the set of the UDS indicator species. The UDS support of bird coenosis is typical for old mature broadleaved forests and can be considered as an effective tool for bird conservation. Our results further indicate that the combination of unmanaged and managed stands associated with different habitat complexities would benefit forest bird assemblages at the landscape scale. Key words: forest specialist birds, bird conservation, non-managed forests, old-growth patches, Ficedula parva, Leiopicus medius, coniferous forest

Stand Structure and Composition and Model for Estimating Stand Volume Potential at the Citragaluh Sustainable Community Forest Management Unit, Subang Regency, West Java

In general, community forest management is still limited to the management of individual farmers so that it affects diversity, especially in the form of stands. This study aimed to explore the stand structure and composition characteristics and develop a model for estimating the potential stand volume at the Citragaluh community forest management unit with 55 observation plots based on a combination of slope and density classes. The data taken includes slope; plant species; plant coordinates; planting pattern and spacing; tree diameter, tree height, and canopy density. The results of plot observations showed that the cropping pattern of Citragaluh Community Forest Management Unit (CFMU) consisted of monoculture (10.9%), mixed stands (20%), agroforestry (29%), dry fields (27.27%), wet fields (9%), bamboo stands (1.8%) and built-up area (1.8%). The trees species found were Jeungjing, Mahogany, Teak, Tisuk, Sobsi, Akasia, and Puspa. Based on the results of stratification, diameter distribution, and stand volume, mixed gardens were the best cropping pattern. This research proves the role of community forest as a transition between plantation forest and natural forest based on the stand form and composition. The stand volume potential estimator model chosen was linear with the equation Y = 0.074X1 + 2.924 X2 - 1.679 where X1 = slope and X2 = Normalized Difference Vegetation Index (NDVI). The values of R2 models are 51.3%. The average potential for the Citragaluh is 119,835 m3/ha, which tends to be higher than other community forest studies.

The admixture of Quercus sp. in Pinus sylvestris stands influences wood anatomical trait responses to climatic variability and drought events.

Forests are threatened by increasingly severe and more frequent drought events worldwide. Mono-specific forests, developed as a consequence of widespread management practices established early last century, seem particularly susceptible to global warming and drought compared with mixed-species forests. Although, in several contexts, mixed-species forests display higher species diversity, higher productivity, and higher resilience, previous studies highlighted contrasting findings, with not only many positive but also neutral or negative effects on tree performance that could be related to tree species diversity. Processes underlying this relationship need to be investigated. Wood anatomical traits are informative proxies of tree functioning, and they can potentially provide novel long-term insights in this regard. However, wood anatomical traits are critically understudied in such a context. Here, we assess the role of tree admixture on Pinus sylvestris L. xylem traits such as mean hydraulic diameter, cell wall thickness, and anatomical wood density, and we test the variability of these traits in response to climatic parameters such as temperature, precipitation, and drought event frequency and intensity. Three monocultural plots of P. sylvestris and three mixed-stand plots of P. sylvestris and Quercus sp. were identified in Poland and Spain, representing Continental and Mediterranean climate types, respectively. In each plot, we analyzed xylem traits from three P. sylvestris trees, for a total of nine trees in monocultures and nine in mixed stands per study location. The results highlighted that anatomical wood density was one of the most sensitive traits to detect tree responses to climatic conditions and drought under different climate and forest types. Inter-specific facilitation mechanisms were detected in the admixture between P. sylvestris and Quercus sp., especially during the early growing season and during stressful events such as spring droughts, although they had negligible effects in the late growing season. Our findings suggest that the admixture between P. sylvestris and Quercus sp. increases the resilience of P. sylvestris to extreme droughts. In a global warming scenario, this admixture could represent a useful adaptive management option.

Infestation intensity by the invasive oak lace bug, Corythucha arcuata (Say) in mixed and pure oak stands

AbstractThere has been accumulating evidence for effects of tree species composition on herbivory with many examples of lower damage by specialist feeders in tree species rich forests. In a joint study in five Central and Southeastern European countries, we studied the effect of tree species richness on infestation intensity of the oak lace bug, Corythucha arcuata (Say) (Heteroptera, Tingidae), an invasive pest on oak trees that has spread rapidly across the Balkan Peninsula and Central Europe. Intensity of infestation by C. arcuata on oaks was assessed on three or four study plots with high (pure stands) and three or four plots with low percentage of oak (mixed stands) in each country. Ordinal regression analysis showed that intensity of infestation of trees by C. arcuata differed between countries; no significant effect of stand type (mixed or pure) on infestation levels was detected. When analysing the percentage of trees in the highest infestation class, stand type had a significant effect with more intensive infestation in pure stands. We conclude that mixed stands will not prevent severe infestation but may help mitigating the impact of established C. arcuata populations.

Harvest block aggregation as a driver of intensive moose browsing pressure on hardwood regeneration in a temperate forest

In many regions of the world, browsing pressure by ungulates has increased over the last century, often reaching unsustainable levels. Overbrowsing by ungulates is threatening biodiversity and causing delays in the establishment of forest regeneration. Moose (Alces alces) is considered as an ecological engineer, as it can cause severe impacts on stand structure, composition, quality, and succession through overbrowsing. In conifer-dominated stands, moose browsing pressure has been shown to vary with the distribution of forage and cover patches across the landscape, but such spatial relationships have not been explored in hardwood-dominated landscapes, where intensive forest management can create clustered patches of good-quality forage and cover, ideal conditions for wintering moose. We investigated the influence of local and landscape variables on browsing by North American moose (Alces alces americana) on commercial and non-commercial woody regeneration in an intensively managed forest landscape of northwestern New Brunswick, Canada. We predicted that browsing pressure at the local scale (vegetation sampling plot) would increase with moose winter counts in the surrounding landscape (1 to 3 km radius). We modeled moose counts as a function of environmental features and road density, using a quasi-Poisson regression. According to an aerial survey (25 km2 sampling plots), moose counts increased with the proportion of forage patches (disturbed stands < 20 years old), whereas they decreased with the proportion of mixed mature stands > 80 years old, which offer both forage and cover. We extrapolated this model to a 2770 km2 study area and used predicted counts as an independent variable to assess its influence on browsing pressure. In 720 plots of 4.15 m2, browsing pressure was quantified using occurrence (i.e. proportion of seedlings/saplings with at least one twig browsed during the previous winter) and intensity (i.e. mean proportion of twigs browsed per stem) on commercial and non-commercial tree seedlings and saplings. We explained variation in occurrence and intensity using zero-inflated models with snow precipitation and local vegetation variables as covariates. Browsing pressure increased with predicted moose counts within a 3 km radius, with snow precipitation and with the proportion of coniferous trees in the canopy, whereas it decreased with sapling density. These results highlight the importance of seedlings and saplings in moose winter diet and confirm the attraction of moose toward recent (<20-year-old) harvest blocks during winter. Therefore, we should avoid aggregating harvest blocks to decrease their attractiveness to moose and browsing pressure on natural hardwood regeneration.

How do different thinning methods influence spatial tree diversity in mixed forest stands of planted Norway spruce (Picea abies L.) and naturally regenerated birch (Betula spp.) in southern Sweden?

Forest biomass has become a viable alternative energy source for replacing fossil fuels, particularly after the European Union acknowledged its sustainability status. To reach zero net greenhouse gas emissions by 2045 in Sweden, new efficient methods of biomass extraction, such as geometrical biomass thinnings, are being explored and tested. These machine-based methods involve the extraction of above-ground biomass in narrow, 1–2 m-wide strips between extraction racks. While evidence-based optimization of biomass extraction mostly focuses on time- and cost-efficiency and on stand growth, criteria such as tree diversity are often overlooked. However, with ongoing climate change, tree diversity is crucial to strengthening the resilience and productivity of future forests, which also enhance the provision of ecosystem services and overall biological diversity. Therefore, we studied the effects of different biomass thinning strategies on spatial tree diversity in southern Sweden using nearest-neighbour summary statistics. We found scientific evidence that different geometrical designs of biomass thinning, especially in 1 or 2 m-wide strips, resulted in higher spatial tree diversity compared to conventional biomass thinning. Hence, in mixed conifer-broadleaved forests, biomass thinning in 1 or 2 m-wide strips is recommended for maintaining spatial tree diversity.

Relict stands of Central European oaks: Unravelling autochthony and genetic structure based on a multi-population study

Central European white oaks expanded rapidly after the last glacial period and reached their current distribution range during the early Holocene. They have been an important resource of timber, fuelwood and animal feed for humans, who actively promoted their presence in forests and other landscape types at least since the early historical times. Besides stands with intensive management, putatively relict populations of three native oak species can be found on unproductive sites with restricted accessibility. Here, we apply chloroplast and nuclear microsatellite markers in order to address the autochthony of relict and managed stands and compare the spatial distribution of genetic variation between them. Based on data from more than 150 populations, we demonstrate that oak autochthony was preserved throughout historical times which is likely the result of traditional silvicultural treatment. This is supported by the fact that the spatial pattern of chloroplast haplotype distribution still reflects the post-glacial recolonization in both relict and old managed stands. We observed significant admixture of haplotypes only in stands established after the Second World War, which is attributable to the transfer of reproductive material used for afforestation. In terms of nuclear genetic variation, we observed marked differences among species. Quercus pubescens exhibited a pronounced genetic structure. Genetic drift and limited gene flow among its small and isolated populations in our study area might have contributed to this pattern. Varying extent of genetic introgression with other sympatric oak species could offer an additional explanation. On the contrary, the gene pools of Q. petraea and Q. robur are highly homogenous, displaying only weak isolation-by-distance. We found no significant differences of genetic diversity and differentiation between relict and managed stands. This suggests that seed transfer mostly occurred within our study area, even in those stands established in post-war times, verifying previous findings which point out limited human interference. We recommend consideration of population genetic structure for gene conservation, with a finer resolution of gene conservation units needed for Q. pubescens due to its spatial genetic structure. Both relict and old managed stands, species-pure or mixed, are suitable for conservation, as they host autochthonous gene pools. Coppice-with-standard management could contribute to preservation of autochthony. In the face of climate change, it is also important to maintain the evolutionary potential of the stands, by facilitating generative reproduction and allowing for hybridization in mixed stands.

Representation of the genus Larix Mill. in the protected areas of Ukrainian Polissia

Larix decidua Mill. may become more important than Picea abies (L.) Karst for reforestation and restoration of the natural balance, and therefore it is necessary to investigate this species. Therefore, the purpose of this study was to conduct an inventory of Larix taxa in the protected areas of the mixed forest zone of Ukrainian Polissia, to analyse their distribution, age structure, and use. Research methods used: route, analytical, comparative analysis, systematisation. It was found that 5 species, one variety and two hybrids of larch grow in the protected areas of the mixed forest zone of Ukraine. It was established that L. decidua is the most widespread – it grows in parks-monuments of landscape art, natural monuments, protected tracts, reserves in pure mixed plantings, alleys, row plantings, groups and as a solitaire tree. L. sibirica, L. kaempferi grow as solitaire trees and in groups of 3 to 10 specimens in 9 and 10 protected objects, respectively. L. gmelinii is present in two arboretums, L. laricina – in one. Larix decidua var. polonica (Racib. ex Wóycicki) Ostenf. &amp; Syrach is not widespread, represented in groups in 6 parks-monuments of landscape art and Bereznivskyi denrorark. Larix × eurolepis A. Henry. is widespread in pure and mixed stands, grows in an alley in the Slavianskyi park-monument of landscape art, in groups – in the Lisova Aleia Botanical Reserve, Bereznivskyi denrorark, and in mixed stands of the Riznolissia General Zoological Reserve. The age structure is quite diverse, represented by L. decidua, L. sibirica, L. decidua var. polonica aged from 100 to 200 years. Other species, varieties, and hybrids are represented by specimens aged from 3 years (L.×eurolepis) to 80 years (L. kaempferi). 69.2% of larch stands are in good condition, 28.9% are in satisfactory condition, and only 1.9% are in poor condition. The results of the research can be used in the further creation of pure and mixed stands, alleys, etc. in the mixed forest zone

Выращивание березы на вырубках с применением гербицидов

Birch, being one of the main forest-forming tree species, has valuable and soughtafter timber. In production forest conditions, natural regeneration and crops of this species experience strong competition from both grass cover and undesirable hardwoods (aspen, gray alder and willow). Without carrying out high-quality maintenance (agrotechnical care, clearing), the formation of economically valuable birch forests is impossible. The most effective and economical is the chemical care method, which involves the use of modern environmentally friendly herbicides. However, if technological regulations and practical recommendations for the use of herbicides have already been developed for the care of coniferous species (pine, spruce and others), then there are currently no such recommendations for birch. The aim of the research is to develop a scientifically based method of caring for natural young birch stands (clearing, agrotechnical care) using selective herbicides on forest fund lands. The objects of research are seed and vegetative regeneration of birch in young stands formed in clear-cut areas, as well as undesirable herbaceous and tree-shrub vegetation. When laying the experiments and evaluating their results, we were guided by the generally accepted methodology for testing herbicides in agriculture. In field production and small-scale experiments with herbicides magnum, magnum super, mortira and anchor-85 in young stands with birch trees, the biological effectiveness of the action of the preparations on a wide range of undesirable vegetation was determined, as well as their selectivity with respect to birch. High efficiency of herbicides magnum (100–300 g/ha) and magnum super (100–200 g/ha) on dicotyledonous species of herbaceous vegetation and deciduous species – willow, aspen, gray alder and mountain-ash, as well as high resistance of birch to them at continuous spraying during the growing season was established. Herbicides mortira (100–200 g/ha) and anchor-85 (100 g/ha) were recognized as unsuitable for birch care. It was found that after a single application of herbicide magnum at rates of 100 and 200 g/ha in mixed young stands dominated by aspen, willow and gray alder and with participation of birch 1–2 composition units, stands dominated by the latter are formed. For citation: Egorov A.B., Postnikov A.M., Bubnov A.A., Pavluchenkova L.N., Partolina A.N. Growing Birch in Clear-cut Areas with Herbicide Application. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 58–74. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-58-74