Larix Kaempferi Research Articles

Comparative analysis of variability of morphological characteristics of European and Japanese larches with their hybrids

Hybridizing European larch with Japanese larch A S Yablokov and M I Dokuchaeva pointed to their better silvicultural and decorative characteristics compared to their parent species. Moreover, E G Bobrov described Larix marschlinsii hybrid as a faster-growing species, he also recommended this hybrid larch for afforestation in many countries. In this study, the vegetative and generative organs of European and Japanese larch hybrids are compared with their parent species. Such characteristics as the cones length, the cones width, the number of scales in the cones and the needles length were considered. A comparative analysis of larch trees DNA was also carried out. As a result of the study, we found that by morphological characteristics, the hybrids occupied an intermediate position between the parent species, except for the length of the needles. The spectra samples electrophoregram of larch total DNA indicated some similarity between hybrids and parent species, meanwhile, hybrids have their own distinctive features.

Ethylenediurea (EDU) effects on Japanese larch: an one growing season experiment with simulated regenerating communities and a four growing season application to individual saplings

Japanese larch (Larix kaempferi (Lamb.) Carr.) and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere. Ground-level ozone (O3) concentrations have increased since the pre-industrial era, and research projects showed that Japanese larch is susceptible to elevated O3 exposures. Therefore, methodologies are needed to (1) protect Japanese larch against O3 damage and (2) conduct biomonitoring of O3 in Japanese larch forests and, thus, monitor O3 risks to Japanese larch. For the first time, this study evaluates whether the synthetic chemical ethylenediurea (EDU) can protect Japanese larch against O3 damage, in two independent experiments. In the first experiment, seedling communities, simulating natural regeneration, were treated with EDU (0, 100, 200, and 400 mg L−1) and exposed to either ambient or elevated O3 in a growing season. In the second experiment, individually-grown saplings were treated with EDU (0, 200 and 400 mg L−1) and exposed to ambient O3 in two growing seasons and to elevated O3 in the succeeding two growing seasons. The two experiments revealed that EDU concentrations of 200–400 mg L−1 could protect Japanese larch seedling communities and individual saplings against O3-induced inhibition of growth and productivity. However, EDU concentrations ≤ 200 mg L−1 did offer only partial protection when seedling communities were coping with higher level of O3-induced stress, and only 400 mg EDU L−1 fully protected communities under higher stress. Therefore, we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O3-induced stress is that of 400 mg EDU L−1. The results of this study can provide a valuable resource of information for applied forestry in an O3-polluted world.

Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO2 Assimilation Capacity of the Canopy Top with Changing Environment.

Japanese larch (Larix kaempferi = L. leptolepis) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (Psat) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in Psat in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.

Effects of residual lignin and cellulose swelling on the rate of enzymatic saccharification of softwood and hardwood acid sulfite pulps

We estimated the effect of residual lignin and pulp swelling on the rate of enzymatic saccharification to increase production of ethanol from acid sulfite pulp (SP) by means of enzymatic treatment. The resolution ratio of hardwood (Acacia mearnsii) SP after the enzymatic treatment was lower compared to softwood (Larix leptolepis) SP even though lignin content of hardwood SP was lower. The pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) analysis revealed that the residual lignin in hardwood SP could more easily adsorb enzyme compared to softwood SP, and the residual lignin in hardwood SP should interfere with the binding of the enzyme to cellulose. The beating treatment of pulp increased the swelling of pulp. The enzymatic saccharification rate was increased by the beating treatment. On the other hand, the delignification treatment was more effective than the beating treatment at enhancing enzymatic saccharification of both hardwood and softwood SPs. We found that the delignification process should be considered a high-priority technique for enhancing enzymatic saccharification of SP.

Сучасний стан насаджень дендропарку "Володимирівський" ДП "Гутянське лісове господарство" та перспективи його розвитку

Визначено сучасний стан, виявлено назрілі проблеми та встановлено пріоритети подальшого розвитку дендропарку "Володимирівський" державного підприємства "Гутянське лісове господарство". Проведено збір даних і впорядкування відомостей про досліджувану дендрологічну частину парку. На підставі аналізу дослідних даних визначено найважливіші цінності дендрологічної частини: природні, соціально-економічні, культурні, рекреаційні, естетичні, еколого-освітні; окреслено пріоритети щодо їх збереження, охорони та відтворення. Проаналізовано фактори впливу на цінності та функціональність дендрологічної частини лісового фонду із ранжуванням проблем. Виділено 21 просторовий складовий елемент. Територія дендропарку поділена на дві частини – заповідну (лісову прогулянкову) зону та зону регульованої рекреації, що умовно розділені модриновою алею, яка бере свій початок від центральної брами в північній частині парку і закінчується біля бесідки для відпочинку відвідувачів у південній частині. Підтверджено, що особливої природної цінності та неповторності парк набуває завдяки 12 дубам-велетням 100-річного віку, із середнім діаметром 56 см і середньою висотою 23,5 м, що утворили куртину площею 0,21 га. Проаналізовано стан панівної за площею породи Pinus sylvestris L. і встановлено, що насадження цієї рослини штучного походження 50-60-річного віку із чагарниковим підліском займає площу 0,28 га, а природні 8-12-річного віку – 3,35 га, що разом становить 3,63 га, або 51 % від площі дендропарку. Відзначено, що на площі 1,1 га сосна звичайна зростає із природним поновленням Betula pendula Roth., Populus tremula L., Acer platanoides, Acer negundo. З'ясовано, що серед зелених насаджень парку переважають деревостани ІІ класу віку, а переважаючою повнотою насаджень парку є повнота 1,0. За результатами оцінювання сучасного стану подано рекомендації щодо розвитку території дендропарку.

Linking absorptive roots and their functional traits with rhizosphere priming of tree species

Woody plant roots can be classified into absorptive roots and transport roots based on root functions, order and traits. While there is an emerging view that living roots actively affect soil organic carbon (SOC) decomposition via the rhizosphere priming effect (RPE), the linkages of the RPE with C allocation to absorptive roots (relative to total roots) and their functional traits across soils are virtually unknown. Here, we investigated the RPE by growing a tree species (Chinese fir, Cunninghamia lanceolata) in three isotopically-distinct C4 soil types with different soil properties such as C/nitrogen (N) ratio and texture, and by growing three tree species (Chinese fir, larch (Larix kaempferi) and ash (Fraxinus mandshurica)) with wide variations in root functional traits in one of the C4 soils. We classified living roots into absorptive roots (first and second orders) and transport roots (third and higher orders) and then quantified their C allocation (relative to total roots) and morphological and chemical traits associated with economic construction, rhizodeposition and resource acquisition. We found that the RPE of Chinese fir across the three soils decreased with an increase in soil C/N ratio. This result conflicted with the N mining hypothesis and suggests that soil C stabilization mechanisms associated with clay minerals may play an important role. Further, significant differences in the RPE among tree species were largely accounted for by the C allocation to absorptive roots. Moreover, there was a significantly negative relationship between specific surface area of absorptive roots and the specific RPE (per unit biomass of absorptive roots) among tree species, suggesting that absorptive root traits shaping the extent of the rhizosphere may regulate the RPE. Taken together, our results provide evidence that absorptive roots play a predominant role in causing the RPE. These findings present an important step toward improving our capability to predict plant effects on SOC decomposition through linking the RPE to absorptive root functional traits.

Transcriptional and post-transcriptional regulation of the miR171-LaSCL6 module during somatic embryogenesis in Larix kaempferi

Key messageExpression analysis of Larix kaempferi mature miR171s and their primary transcripts and target gene LaSCL6 during somatic embryogenesis revealed the transcriptional and post-transcriptional regulation of the miR171-LaSCL6 module.Somatic embryogenesis provides a useful experimental system for studying the regulatory mechanisms of plant development. The level and activity of microRNA171 (miR171) fluctuate during somatic embryogenesis in Larix kaempferi, but the underlying mechanisms are still unclear. Here, in L. kaempferi we identified five members of the miR171 family, which cleave LaSCL6 mRNA at different sites. In addition, we improved the method of measuring miRNA activity in a more direct way. Furthermore, we measured the expression patterns of mature miR171s and their primary transcripts during somatic embryogenesis in L. kaempferi and found that their patterns differed, indicating that the transcription of MIR171 genes and the subsequent cleavage of their intermediate products are regulated. Taken together, our findings not only offer a means to study the regulation of miRNA activity, but also provide further insight into the regulation of L. kaempferi somatic embryogenesis by miR171-LaSCL6.

Complete Chloroplast Genome of Japanese Larch (Larix kaempferi): Insights into Intraspecific Variation with an Isolated Northern Limit Population

Research Highlights: The complete chloroplast genome for eight individuals of Japanese larch, including from the isolated population at the northern limit of the range (Manokami larch), revealed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed in Japanese larch. We detected intraspecific variation for possible candidate cpDNA markers in Japanese larch. Background and Objectives: The natural distribution of Japanese larch is limited to the mountainous range in the central part of Honshu Island, Japan, with an isolated northern limit population (Manokami larch). In this study, we determined the phylogenetic position of Manokami larch within Japanese larch, characterized the chloroplast genome of Japanese larch, detected intraspecific variation, and determined candidate cpDNA markers. Materials and Methods: The complete genome sequence was determined for eight individuals, including Manokami larch, in this study. The genetic position of the northern limit population was evaluated using phylogenetic analysis. The chloroplast genome of Japanese larch was characterized by comparison with eight individuals. Furthermore, intraspecific variations were extracted to find candidate cpDNA markers. Results: The phylogenetic tree showed that Japanese larch forms a monophyletic group, within which Manokami larch can be phylogenetically placed, based on the complete chloroplast genome, with a bootstrap value of 100%. The value of nucleotide diversity (π) was calculated at 0.00004, based on SNP sites for Japanese larch, suggesting that sequences had low variation. However, we found three hyper-polymorphic regions within the cpDNA. Finally, we detected 31 intraspecific variations, including 19 single nucleotide polymorphisms, 8 simple sequence repeats, and 4 insertions or deletions. Conclusions: Using a distant genotype in a northern limit population (Manokami larch), we detected sufficient intraspecific variation for the possible candidates of cpDNA markers in Japanese larch.

Temporal effects of thinning on the composition and growth of regenerated woody plants in Larix kaempferi plantations

Understanding the temporal effects of thinning on the composition and growth of regene-rated broadleaved woody species in coniferous plantations can provide profound references for promoting the conversion of monoculture plantations into mixed conifer-broadleaved forests, which could solve the problem that the production and ecological functions of monoculture plantations cannot be balanced. We compared the composition of regenerated woody plant species in Larix kaempferi plantation with short-term (1-3 years), medium-term (4-9 years) and long-term (>9 years) after thinning. Furthermore, we selected three regenerated tree species with higher importance value and reciprocal symbiosis with L. kaempferi, which differed in shade tolerance, including shade-intolerant species Quercus mongolica, intermediate shade-tolerant species Acer mono, and shade-tolerant species Tilia mandschurica. We analyzed the relationships between light conditions (i.e., canopy density) and the growth (i.e., base diameter and height) of those species in L. kaempferi plantation with different terms after thinning. The results showed that 46 species of regene-rated broadleaved woody plants were recorded in thinned plantations. The common and dominant tree in different terms after thinning was A. mono, and the shrub species were Lonicera japonica and Euonymus alatus. With the increasing time after thinning, species richness of regenerated trees decreased, but the ratio of tree to shrub species increased and the intermediate shade-tolerant tree species took the dominant position. The temporal effect of thinning on the growth of three tree species was affected by shade tolerance ability. Basal diameter and height of T. mandschurica were higher than those of Q. mongolica and A. mono. With the increases of time after thinning, basal diameter of T. mandschurica and height of A. mono were more sensitive to light, indicating that there were respectively "a shade tolerance strategy" and "a shade avoidance strategy" to adapt to the post-thinning environment. The effects of thinning on the composition and growth of regenerated broadleaved woody species in L. kaempferi plantations were significantly time-sensitive. When deve-loping thinning measures to promote the regeneration of broadleaved trees in plantations, we should consider to extend the thinning interval appropriately to ensure the growth of broadleaved tree seedlings (e.g., T. mandschurica and A. mono) and accelerate their migration into the canopy layer. This would promote the formation of mixed conifer-broadleaved forests and eventually realize the sustainable development of plantations.

Stocking Diagrams for Silvicultural Guideline in Korean Pines and Japanese Larch

Appropriate management of stand density is necessary to avoid wasted growing space and overcrowding-induced self-thinning and therefore to optimize profitability. We developed a Gingrich-style stocking chart for Korean red pine (Pinus densiflora), Korean white pine (P. koraiensis), and Japanese larch (Larix kaempferi) in Korea. Datasets for even-aged stands were categorized into two censored datasets via relative density based on species-specific stand density indices to assign adequate plots for tree allometry. Censored plot data for maximum density on full stocking were used to develop A-level stocking based on mean individual tree area. In censored plot data for minimum density on full stocking, individual trees represented open-grown trees, and a crown competition factor of 100 was proposed as B-level stocking. Based on parameters estimated from allometry, stocking diagrams comprising quadratic mean diameter, number of trees, and basal area were correctly expressed. A-level stocking at the same quadratic mean diameter revealed that Korean white pine had the most trees and largest basal area, while Japanese larch had the fewest trees and smallest basal area. In contrast, B-level stocking disclosed that Japanese larch had the most trees and basal area, whereas Korean white pine had the fewest trees and smallest basal area. The stocking diagrams suggest that silvicultural treatments for these species should be species-specific.

Effective Placement Methods of Vermicompost Application in Urban Tree Species: Implications for Sustainable Urban Afforestation

Knowledge on growth and nutrient uptake characteristics of urban trees and effective strategies to grow trees can help accomplish the goal of urban afforestation initiatives in a sustainable way. Thus, the study investigated the effects of different vermicompost (VC) application placements on the growth and nutrient uptake of three contrasting tree species (fast-growing Betula platyphylla and Larix kaempferi and slow-growing Chamaecyparis obtusa) to provide implications for growing tree stocks for sustainable urban afforestation programs. Five placement methods were used in the greenhouse trial: no fertilization (CON), surface placement (VCs), subsurface placement at 6-cm depth (VCc), bottom placement (35-cm depth (VCb)), and mixed with soil (VCm). We measured the growth parameters such as height, root collar diameter (RCD), and biomass and analyzed foliar nutrient concentrations in response to different placement treatments of VC. Relative height growth was the highest at VCc (132% (B. platyphylla), 114% (L. kaempferi)) and VCs ((57%) C. obtusa). Significant improvement in aboveground and belowground biomass growth of all species at VCs and VCc compared to the other treatments was also observed. Generally, VC treatments significantly increased N concentration compared to CON in all species. In conclusion, fertilizing the fast- and slow-growing urban tree species using VCs and/or VCc is relevant to growing high quality planting stocks for sustainable urban afforestation purposes.

Estimating polymorphic growth curve sets with nonchronological data.

When we collect the growth curves of many individuals, orderly variation in the curves is often observed rather than a completely random mixture of various curves. Small individuals may exhibit similar growth curves, but the curves differ from those of large individuals, whereby the curves gradually vary from small to large individuals. It has been recognized that after standardization with the asymptotes, if all the growth curves are the same (anamorphic growth curve set), the growth curve sets can be estimated using nonchronological data; otherwise, that is, if the growth curves are not identical after standardization with the asymptotes (polymorphic growth curve set), this estimation is not feasible. However, because a given set of growth curves determines the variation in the observed data, it may be possible to estimate polymorphic growth curve sets using nonchronological data.In this study, we developed an estimation method by deriving the likelihood function for polymorphic growth curve sets. The method involves simple maximum likelihood estimation. The weighted nonlinear regression and least‐squares method after the log‐transform of the anamorphic growth curve sets were included as special cases.The growth curve sets of the height of cypress (Chamaecyparis obtusa) and larch (Larix kaempferi) trees were estimated. With the model selection process using the AIC and likelihood ratio test, the growth curve set for cypress was found to be polymorphic, whereas that for larch was found to be anamorphic. Improved fitting using the polymorphic model for cypress is due to resolving underdispersion (less dispersion in real data than model prediction).The likelihood function for model estimation depends not only on the distribution type of asymptotes, but the definition of the growth curve set as well. Consideration of these factors may be necessary, even if environmental explanatory variables and random effects are introduced.

Transcription factor LkWOX4 is involved in adventitious root development in Larix kaempferi.

WUSCHEL-related homeobox4 (WOX4) plays important roles in vascular formation and adventitious root (AR) development. Here, we cloned the WOX4 from the AR of Larix kaempferi, whose cDNA is 1452bp in length and encodes 483 amino acids. LkWOX4 is mainly expressed in the layer formation area of the stem at 10days after cutting and its expression levels in the middles and ends of the ARs were higher than that in the AR tips. The fused protein LkWOX4-GFP localized in the nucleus. The heterologous overexpression of LkWOX4 in 84K poplar significantly increased AR numbers and decreased AR lengths. In LkWOX4 plants, the endogenous jasmonic acid and abscisic acid contents significantly decreased in stems, while the auxin, jasmonic acid and abscisic acid contents significantly increased in ARs. RNA-Seq of those LkWOX4 overexpression poplar plants showed that the expression of plant hormone signaling genes (ARF2, ARF3, ARF7 and ARF18), rooting-related transcription factors (WOX5, LBD29 and SCR) and root development-related genes (CYCD3, GRF1 and TAA1) were affected. Moreover, we found that LkWOX4 interacts with LkPAT18, LkACBP6, and LkCIP7 using yeast two hybrid screening. Thus, we found LkWOX4 involves in the AR initiation and development, which might be regulated through the IAA, JA and ABA signaling pathways.

Flame Retardancy of Wood Products by Spreading Concentration and Impregnation Time of Flame Retardant

The flame retardancy, such as carbonized length and area, of four plank type wood products by the spreading concentration and impregnation time of flame retardant were measured according to standard of the Nation Fire Agency in Republic of Korea. To measure the flame retardancy, Korean pine plywood, Japanese larch plywood, Japanese cypress planks, and perforated birch plywood boards were treated with self-development flame retardant by 300 and 500 g/m2 spreading concentration and those were compared with control specimen. In general, the flame retardant performance of wood products improved as the spreading concentration of flame retardant increased. Except for Japanese larch plywood, there was no significant difference in the flame retardant performance by the spreading concentration. The flame retardant performance of perforated birch plywood board was positively correlated up to 60 minutes of impregnation time, but then gradually decreased. These results about the flame retardancy of wood products by spreading concentration and impregnation time were expected to be basic data for improving flame-retardant treated wood.

Spatial and competition models increase the progeny testing efficiency of Japanese larch

The main purpose of this study was to examine spatial and competition effects on estimates of genetic parameters, as well as on selection options for growth traits, including height (H), diameter at breast height (DBH), and volume (V), in a progeny test of Japanese larch (Larix kaempferi (Lam.) Carrière) at age 20 years. We compared performances among the individual-tree additive genetic base model (B) with design factors only, the spatial effect model (AR1), the competition model (C), and the combined competition and spatial model (CS). We found that spatial heterogeneity had significant effects on growth traits and that plot variance decreased by more than 80% in the AR1 model relative to the B model. Competition had significant effects on DBH and V but a smaller effect on H. In the C model, direct additive genetic variances ([Formula: see text]) for DBH and V increased by 205% and 93%, respectively, whereas residual variances ([Formula: see text]) decreased by 8% and 6%, respectively. In the CS model, the correlations between direct and competitive genetic effects were 0.83, −0.97, and −0.98 for H, DBH, and V, respectively. Competition significantly affected the forward selection. The proportions of selected elite trees were only 39% and 25% common between the B and CS models for DBH and V, respectively, when selection intensity was 5%. For breeding selection, depending on thinning regimes planned, trees of high additive breeding values but low competitive breeding values are preferable for plantation.

Machine Learning for Tree Species Classification Using Sentinel-2 Spectral Information, Crown Texture, and Environmental Variables

The most recent forest-type map of the Korean Peninsula was produced in 1910. That of South Korea alone was produced since 1972; however, the forest type information of North Korea, which is an inaccessible region, is not known due to the separation after the Korean War. In this study, we developed a model to classify the five dominant tree species in North Korea (Korean red pine, Korean pine, Japanese larch, needle fir, and Oak) using satellite data and machine-learning techniques. The model was applied to the Gwangneung Forest area in South Korea; the Mt. Baekdu area of China, which borders North Korea; and to Goseong-gun, at the border of South Korea and North Korea, to evaluate the model’s applicability to North Korea. Eighty-three percent accuracy was achieved in the classification of the Gwangneung Forest area. In classifying forest types in the Mt. Baekdu area and Goseong-gun, even higher accuracies of 91% and 90% were achieved, respectively. These results confirm the model’s regional applicability. To expand the model for application to North Korea, a new model was developed by integrating training data from the three study areas. The integrated model’s classification of forest types in Goseong-gun (South Korea) was relatively accurate (80%); thus, the model was utilized to produce a map of the predicted dominant tree species in Goseong-gun (North Korea).

Aboveground conservation acts in synergy with belowground uptake to alleviate phosphorus deficiency caused by nitrogen addition in a larch plantation

While growing evidence has shown the shift in terrestrial ecosystems from nitrogen (N) limitation to phosphorous (P) limitation under increasing N deposition, it is poorly understood how plants adapt to this P limitation. Here, we examined which strategies would be adopted by plants for alleviating P deficiency caused by N enrichment from the perspective of aboveground conservation and belowground uptake. To achieve this objective, we conducted a five-year N-addition experiment (0 and 50 kg N ha−1 yr−1) in a 60-year-old larch (Larix kaempferi) plantation, and measured variables related to ecosystem P status, leaf P resorption, soil exploration by roots and extraradical hyphae of ectomycorrhizal fungi, and rhizosphere effects on soil P cycling. We found that N addition significantly reduced soil available P concentration and enhanced leaf N:P ratio, indicating the increasing degree of P deficiency under N addition. Leaf P resorption efficiency and proficiency were significantly enhanced by N addition, implying the increase in aboveground P conservation. Moreover, N addition significantly increased root length density and decreased ectomycorrhizal extraradical hypha biomass, suggesting the enhanced role of the root pathway in scavenging soil P. Rhizosphere effects on phosphatase activity were significantly enhanced by N addition, indicating the improved capacity of mining P from organic P forms. Collectively, our findings highlight that the larch could concurrently improve aboveground P conservation and belowground P uptake to alleviate P deficiency induced by N addition, and suggest that adjustments in resource allocation associated with these adaptive strategies could have significant consequences on ecosystem functions.

Clonal variations and effects of juvenile wood on lumber quality in Japanese larch

ABSTRACT Wood properties, including Young’s modulus, differ among clones in Larix kaempferi; however, available information is still limited on among-clonal variations of lumber qualities in L. kaempferi. The objectives of this study were to clarify the clonal variations in lumber quality and to identify the effects of juvenile wood on lumber quality in L. kaempferi. A total of 21 logs of 2.5 m in length were obtained from the trees of nine different plus clones of 57-year-old L. kaempferi trees. The logs were sawn into lumber, and the lumber was kiln-dried and planed into 38 × 89 mm in a cross-section. Lumber quality, such as bending properties, was determined. Significant differences were found in wood density, dynamic Young’s modulus, modulus of elasticity, and modulus of rupture of the lumber among the nine clones. The highest repeatability was recorded in wood density. The lumber consisting of juvenile wood showed a lower lumber quality compared to the lumber consisting of mature wood. To produce lumber with a high quality from L. kaempferi, the clonal variation of lumber quality and the existence of juvenile wood should be considered.

Tracing radioactive cesium in stem wood of three Japanese conifer species 3\xa0years after the Fukushima Dai-ichi Nuclear Power Plant accident

To understand the dynamics of accident-derived radioactive cesium (137Cs) in stem wood that had a substantial amount of heartwood at the time of the Fukushima Dai-ichi Nuclear Power Plant accident, the radial and vertical distributions of 137Cs activity concentration in stem wood of Japanese cedar (Cryptomeria japonica), cypress (Chamaecyparis obtusa), and larch (Larix kaempferi) were investigated. In addition, the natural distribution of stable cesium (133Cs), rubidium (85Rb), and potassium (39K) concentrations was analyzed to determine the characteristics of 137Cs distribution. Wood disks were collected from the tree stems of six cedars, three cypresses, and two larches at multiple heights in 2014, and the concentrations were measured every 2 cm in the radial direction. 137Cs distribution in stem wood differed among tree species, sampling site, and vertical position of the stem within a tree. Statistical analyses suggested that the radial distribution of 137Cs within the heartwood can be explained by the heartwood moisture content and the distance from the treetop, regardless of species, while the distribution between sapwood and heartwood was dependent on the heartwood cross-sectional area and was additionally different between larch and other species. Similarly, the heartwood/sapwood concentration ratios of stable alkali metals differed between larch and the other species. In the larch, the ratio was ca. 0.5 for all elements, but the ratio was over 1.0 and differed among elements in the other species. Consequently, the species-specific difference in the distribution of 137Cs between sapwood and heartwood was considered to be due to different activity levels of radial transport toward the heartwood. The radial variation pattern of the 137Cs/133Cs concentration ratio showed that less 137Cs was transferred to the inner heartwood compared with the 133Cs distribution pattern in many trees; however, there was also a tree in which 137Cs was excessively transferred to the inner heartwood compared with the 133Cs distribution pattern. Such patterns may result from a combination of significant foliar uptake of 137Cs and poor root uptake after the accident, in addition to the high moisture content of the heartwood.

Larix kаempferi Carr. як перспективний деревний вид для плантаційного лісовирощування у лісостанах Західного Лісостепу України

У Західному Лісостепу України Larix kaempferi відзначається дуже високими інтенсивністю росту (Id-Ie класи бонітету) та конкурентоздатністю в молодому віці, переважно витісняючи зі складу насаджень інші деревні види. 
 У чистих насадженнях L. kaempferi нагромаджує найвищі запаси стовбурової деревини, хоча її середні висота та діаметр тут помітно менші, ніж у мішаних деревостанах. Водночас, у разі встановлення в чистих культурах модрини густоти, близької до оптимальної, середні таксаційні показники хвойної породи наближаються до таких у мішаних насадженнях. 
 Збереженість модрини навіть і в початково чистих насадженнях характеризується високою варіабельністю, причиною чого є різні підходи до інтенсивності проведення рубок догляду. Відсутність конкретної програми вирощування модринових насаджень щодо встановлення близької до оптимальної густоти у різні вікові періоди є причиною неповного використання едафічного потенціалу типів лісорослинних умов, недоотримання значних обсягів деревини.
 Доцільно на території лісового фонду Західного Лісостепу та прилеглих територій створювати чисті насадження модрини Кемпфера з рівномірним розміщенням садивних місць та постійним підтримуванням високої зімкнутості деревостану. Створювати плантаційні насадження цього деревного виду доцільно в умовах дібров і судібров, бучин і субучин, яличин і суяличин. 
 Як об’єкт плантаційного лісовирощування, L. kaempferi задовольняє низку важливих вимог: інтенсивний ріст та швидке нагромадження стовбурової деревини; проста технологія вирощування; відносно широка екологічна амплітуда, можливість успішного культивування в чистих насадженнях, цінна деревина; стійкість проти шкідників і хвороб; широкий діапазон застосування деревини; можливість ведення інтенсивного проміжного користування.