Forest Stands Research Articles

Sustainable forest development in the face of global warming: Optimizing Robinia pseudoacacia L. stands to alleviate soil moisture depletion

To foster sustainable forest development amid global warming, it is imperative to enhance the quality of existing forest stands while avoiding excessive depletion of soil moisture. This study established 24 Robinia pseudoacacia L. standard plots (40 × 40 m2) in the Caijiachuan watershed, located in the gully region of the Loess Plateau, Shanxi Province, China, to monitor soil moisture content from 2007 to 2021. Additionally, the study examined the influence of 19 ecological factors, including climate, topography, and stand characteristics, on soil moisture. The findings indicated a sustained decline in soil moisture storage across the 0–200 cm soil profile, with significant depletion at 0–140 cm. The soil moisture content at depths of 80–200 cm was critically low, resulting in a “dry soil layer” during years with low precipitation. Climatic factors (average annual temperature and annual precipitation) and stand factors (uniform angle index, stand density, litter thickness, and Simpson diversity index of the shrubs) emerged as dominant factors impacting soil moisture variations. An increase in average annual temperature due to global warming, compounded by suboptimal stand density, primarily drove soil moisture depletion. Using a multivariate optimization equation to model the relationship between dominant factors and soil moisture storage, this study recommends a dynamic stand management strategy. This strategy involves selective thinning or replanting of Robinia pseudoacacia L. trees, targeting a gradual reduction in optimal stand density from 1500 to 1000 plants·ha−1 over the next two decades. Additionally, transitioning stand spatial arrangements from uniform or clustered to random distributions, maintaining ideal litter thickness (2.43–2.47 cm), and enhancing shrub diversity are advisable. Such measures can alleviate soil moisture deficits in Robinia pseudoacacia L. stands attributable to global warming, thereby promoting the Loess Plateau's sustainable forestry advancement.

Impact of seasonality and forest stand age on ion deposition inrehabilitated forests.

This study examines the critical interaction between seasonal precipitation variability and forest maturity in determining ion deposition patterns in rehabilitated forest ecosystems. This research was conducted in rehabilitated forest sites in Bintulu, Sarawak, Malaysia that had ecologically similar plant distribution, species, and age in each planting area. This facilitated the standardization of rainfall deposition in the different study plots which streamlined the study of these specific facets of ecosystem dynamics. The goal is to understand how seasonal changes and the age of the forest influence the chemical composition of the flux that relates to the movement and deposition of nutrients through the forest ecosystem. This flux is a key factor in the health of the forest ecosystem and nutrient cycling. Using ion exchange resin (IER) samplers, we accurately measured and compared the deposition of different ions (Ca2+, Na+, Fe2+, Cu2+, NO3 -, NH4 + and SO4 2-) across different seasons and forest ages. The deposition of Ca2+ and NH₄+ was significantly lower in the low-precipitation season than in the high-precipitation season in all forest stands, regardless of the year they were established (1996, 1999, 2002, 2005, and 2009). In contrast, ions such as Na+, Fe2+, Cu2+, NO3 - and SO4 2- showed no clear seasonal fluctuations. In addition, the study shows that through-fall in forest stands from 2002, 2005 and 2009 had higher concentrations of Ca2+ in both seasons than in 1996 and 1999. Interestingly, forest stands from 2009 and 2002 had elevated levels of Na+ and SO₄2- in seasons with low precipitation, while stands from 1996 had higher levels in seasons with high precipitation. Our results emphasize the crucial role of precipitation amount and canopy age in determining ion deposition in forest ecosystems. By demonstrating the significant influence of precipitation seasonality and forest maturity on the chemical composition of throughfall, this study contributes to a deeper understanding of nutrient dynamics in developing forest landscapes and provides valuable insights for ecological restoration measures.

Effect of the irregular shelterwood system on soil organic carbon stock and soil quality of Shorea robusta Gaertn. f. forest in Nepal

The effective management of forests relies on the crucial role played bysilvicultural systems. However there exist a significant knowledge gap regarding impact of these systems in Nepalese forests. Therefore, this research was conducted to assess the effects of the forest management activities under irregular shelterwood system on soil organic carbon (SOC) stock and the overall soil quality of Sal (Shorea robusta Gaertn. f.) forests in Terai region of Nepal. Stratified random sampling method with 1.67 % sampling intensity was adopted in this study where management of stands was used as basis of strata. A total of 30 composite soil samples (15 each from managed and unmanaged forest stands) were collected from a depth of 0–30 cm, taken from the four corners and the center of each plot. Soil quality index (SQI) method was used for soil quality assessment using indicators on the basis of prior studies conducted in Nepal. Our study found significant difference in soil parameters except organic carbon, pH, silt, and clay among the managed and unmanaged forest stands (p < 0.05). SOC stock of unmanaged forest stands (48.87 ± 1.34 ton ha−1) was significantly greater than managed forest stands (27.76 ± 1.27 ton ha−1). Similarly, unmanaged forest stands demonstrated better soil quality with higher SQI value (0.66) than managed forest stands (0.50). This negative impact of irregular shelterwood silviculture system highlights the necessity for management interventions to enhance SOC stock and overall soil quality. To establish a robust conclusion, further replication of similar studies at different soil depths and in other management regimes, along with longitudinal studies, is essential.

The Influence of Climatic and Anthropogenic Factors on the Productivity of Forest Stands in the Ecotone of the Northern Treeline on the Yamal Peninsula

The Influence of Climatic and Anthropogenic Factors on the Productivity of Forest Stands in the Ecotone of the Northern Treeline on the Yamal Peninsula

Possibilities for reproduction and archiving resulting in a clone collection of a unique grey poplar (Populus × canescens Aiton Sm.) population in the Czech Republic

Abstract Floodplain forests as one of the most endangered ecosystems in Europe have recently been impacted by fungal pathogens Phytophtora sp. and Hymenoscyphus fraxineus (chalara). Grey poplar (Populus × canescens Aiton Sm.) can be used as one of well adapted tree species for the reforestation of withering stands of ash (Fraxinus sp.). A unique population of grey poplar (Populus × canescens Aiton Sm.) characterized by desirable phenotypic traits was used for this purpose. The gender distribution was asymmetric; out of 155 individuals, 113 were female. Out of 33 different genotypes determined in the population, 15 were used as a source of approved forest reproductive material. Vegetative reproduction methods (ex situ clonal reproduction by micropropagation and cuttings) were developed and used, to rapidly initiate the recovery of forest stands of grey poplar. In total, 940 explants were successfully micropropagated and adapted to natural conditions, to ensure a genetically diverse source of viable plants used for reforestation. Moreover, we used methodological procedures of micropropagation for setting up cryopreservation technique. With respect to long-term storage of valuable grey poplar genotypes, modulation of gene expression by cold hardening during cryopreservation revealed significant changes in a few candidate genes involved in plant cellular processes.

SPATIO-TEMPORAL ANALYSIS OF CHANGES IN ECOSYSTEMS OF MUNICIPAL WASTE LOCALISATION AREAS USING GIS AND REMOTE SENSING DATA

The Zdovbytsia municipal solid waste (MSW) dump (the Rivne region, Ukraine) as a case study allows demonstrating informativeness of identifying waste dump sites and the adjusted areas using the spectral characteristics and texture of earth’s covers obtained from the satellite images for the different years. To identify the MSW dump in the surveyed area, direct coding features were considered, which characterized the properties of the object and are directly represented in the images. These are such features as geometric (shape, shadow, size), brightness (phototone, brightness level, color, spectral image), structural (texture, structure) ones. In addition, satellite images reliably identified the presence of discharging from the dump area, their directions, areas of unloading, the damage to herbaceous cover and other vegetation, etc. The informativeness of the study of dynamics for dump geometrical parameters, the change of its internal “structure,” the functional changes in the surrounding ecosystem elements (first, the changes in the forest stands and agricultural lands) is demonstrated. In particular, satellite image data for the period of 2003 to 2021 allow identifying the increase in a number of the Zdovbytsia MSW dump sites at the expense of adjacent forest stands. Thus, in 2003 one site of the dump is operated, whereas in 2019—already three ones, that integrated in 2021. The study of dynamics for the change of the total area of dump has revealed the increase of this area by approximately 6.25 times (from 6 521 m2 in 2003 to 20 438 m2 in 2021). In addition, the total perimeter along the contours of its stages has enlarged more than 3.35 times (from 438 to 1 466 m, respectively). The use of satellite images of higher spatial resolution in the area of about 0.6 m/pixel will specify the cases of unsatisfactory condition of the dump.

Ecological and socio-economic factors influence stand biodiversity

Biodiversity is associated with functional protection, adaptation to external conditions, and ecosystem resilience. Therefore, maintaining forest ecosystems with high biodiversity is essential for improving resistance and resilience to disturbances. In addition to the ecological factors influencing forest ecosystems, various socio-economic factors associated with forests can influence the ecosystem. However, socio-economic impacts on forest biodiversity have rarely been addressed. In this study, we investigated whether tree species diversity (TSD) of forest stands varies with ownership status (national vs. private forests). In addition, selected ecological (stand characteristics, site conditions, and climate) and socio-economic (regional forest management sectors, population, forestry population, forest coverage, and forestry income) factors influencing TSD were determined using data from the National Forest Inventory in South Korea. National forests had higher TSD than private forests, reflecting differences in management objectives. Among ecological factors, stand structural diversity (SDivI) was the most influential in both national and private forests. Socio-economic factors, such as population, forest coverage, forest income, and forest management bodies, significantly influenced the TSD, although the impact was smaller compared to ecological factors. Our results suggest that securing stand growth and development is essential for increasing stand structural diversity, which leads to an increase in TSD. Furthermore, our study shows that socio-economic factors can influence forest conditions over time. To better understand the factors influencing the state of forests and manage forests sustainably in the future, collaborative research bridging ecological and sociological fields is necessary.

Diversity and Distribution of Monocot Understory Herbs during Tropical Forest Succession in Northeastern Costa Rica

Broad-leaved monocot herbs form one of the most common and diverse growth forms of Neotropical plants. Their significance and frequency of occurrence is particularly notable in the understories of tropical rainforests, where they form a dominant element. We assessed and quantified changes in the cover and diversity of understory herb communities in a chronosequence of 1 ha permanent plots established as part of a multidisciplinary study on tropical forest regeneration in the Atlantic lowlands of northeastern Costa Rica. Sampled were two young stands cleared 12 years ago, two secondary forests with 21 and 39 of years of recovery since clearance, and two stands in old-growth primary forest. Changes in species composition during succession were assessed using Chao’s Jaccard similarity index. Observed species richness ranged from 15 to 26 species in individual plots, with the greatest number of species in the 21-year intermediate-age and fewest in the young 12-year plots. Herb species sampled represented 6 families, 15 genera, and 39 species, with the Araceae contributing the largest number of species. Ten species were sampled in all six stands, while fourteen species were found exclusively in one plot. Herb density (ramets m−2) showed a hump-shade trend, with peak density in the intermediate stands and a lower level in mature and young secondary forests. Mean herb cover in 25 m2 quadrats ranged from 2.0% (young stand) to 22.7% (intermediate-age stand) and differed significantly both among stand types and among sites. Both observed and estimated species richness increased along the chronosequence as a whole, with the highest number of species in primary forest, although only slightly higher than in intermediate-age stands. Over half of the species exhibited some degree of clonal growth, with the extent of clonal spread varying among species and forest stands. Although we did not find a clear pattern between clonality and forest age, we observed a greater number of clonal patches in secondary over primary forest stands.

Wood decay and Norway spruce vulnerability to wind-inflicted mortality in monospecific and mixed stands in hemiboreal forests

Pathogen-caused stem and root decay are becoming increasingly common in Norway spruce (Picea abies (L.) H. Karst) which is believed to contribute to greater stand instability and susceptibility to wind-inflicted damage. Thus, this study aims to assess the effect of root and stem decay on Norway spruce vulnerability to wind-inflicted mortality in monospecific and mixed stands, to widen our base of knowledge on potentially more resilient spruce forest management approaches in hemiboreal forest zone. In this study we used data from: i) the National Forest inventory (NFI), ii) 34 observation plots established in wind-affected stands, iii) two transects (9200 m long, 36.8 ha inspection area combined), iv) and monospecific spruce plantation thinning experiment (five thinning intensities with two repetitions of each) affected by wind. We found that the total mortality of spruce during the NFI four five-year re-measurement cycles (2003–2007, 2008–2012, 2013–2017, 2018–2022) was 2.28 %, during which the main disturbance-causing agents were wind at 0.86 %, pests at 0.41 %, intra/interspecific competition at 0.37 %, and diseases at 0.36 %. NFI data-based multinomial logistic regression model revealed that the probability of wind-inflicted spruce mortality is dictated by soil moisture regime, stand age, stand stocking level, and tree decay presence. Results from the 34 established observation plots show that wood decay is a potential risk factor associated with wind damage occurrence in spruce stands. In a spruce stand, when a group of trees are damaged by wind the proportion of undecayed trees increases. Whereas a single tree is more likely to be attributed to decay caused wind damage.Results point towards deciduous broadleaf admixture having a positive effect on mitigating wind damage among non-decayed spruce trees: however, decayed trees, are more likely to be affected in such stands. The thinning experiment portion of this study suggests that increasingly intensive thinning in monospecific spruce stands will lead to an increasing spread of root and stem decay and thus the risk of wind damage. Therefore, from this perspective, the main goal is to reduce the root and stem decay presence in the stand and thus increase wind stability. We suggest further research to be directed into finding the optimal initial spruce seedlings density with a combination of coniferous and deciduous broadleaf species in order to mitigate root and stem decay presence and wind-inflicted spruce mortality in the forest stands.

Potential applicability of SPLAT® Verb for management of European spruce bark beetle, Ips typographus (L.)

AbstractThe European spruce bark beetle, Ips typographus (L.), is the most important forest pest in Europe due to the profound impacts of periodic outbreaks on ecosystem goods and services. Herein, we evaluated the responses of I. typographus to different doses of verbenone (SPLAT® Verb, 10% (−)‐verbenone by weight; ISCA Inc., Riverside, CA, USA) in traps baited with its aggregation pheromones. Results are based on 1,492,289 I. typographus collected in five experiments over 3 years. SPLAT® Verb inhibited the response of I. typographus to baited traps out to 14 m from the point of release (dollop) and for &gt;80 days at a dose of 75 g per dollop. Reductions in trap catch ranged from 34% to 93% depending on the dose of verbenone, age of SPLAT® Verb dollops, distance from dollops and the environment. In forest stands, significant reductions in trap catch were observed at distances up to 14 m from the point of release, with the largest reductions observed at 0 m (93%) and 2 m (64%). In an open area, significant reductions in trap catch were observed at distances up to only 2 m from the point of release, with the largest reduction observed at 0 m (66%). The much lower active inhibitory range of verbenone in the open area appears to be explained by less stable accumulations of verbenone in the surrounding air. There was a significant negative correlation between trap catch and the amount of verbenone measured in air in the vicinity of traps. We also observed inhibition of the sixtoothed spruce bark beetle, Pityogenes chalcographus (L.), another important forest pest in Europe, at all doses (20, 40, 75 and 100 g) of SPLAT® Verb that were evaluated. The implications of these and other results to the management of I. typographus are discussed.

Spatial Distribution Patterns of the Key Afforestation Species Cupressus funebris: Insights from an Ensemble Model under Climate Change Scenarios

Cupressus funebris Endl. (C. funebris) is an evergreen tree endemic to China that is classified as a national second-class endangered plant. This species plays critical roles in soil and humidity conservation, climate regulation, and ecological restoration. It is also important in silvicultural production, which is crucial for maintaining the stability of the ecosystem in Southwest China. In this study, an integrated modeling approach was used to integrate 10 species distribution models to simulate the potential distribution of C. funebris and predict the impact of future climate change on its distribution and ecological niche. Field surveys were conducted to compare the forest stands of C. funebris under different habitat suitability levels. The results showed that the most suitable areas for C. funebris were mainly located in Sichuan, Chongqing, and Guizhou, covering an area of approximately 15.651 × 104 km2. The productivity of the C. funebris forest stands in these highly suitable areas and was significantly higher than that in low and moderately suitable areas, although understory plant diversity did not show a competitive advantage. Under future climate scenarios, the potential distribution of C. funebris in China will expand and the geographical range of the niche will shift to higher latitudes in northern China as temperatures increase. The extent of this change in the niche’s geographical range intensified as warming increased. Specifically, under the 2090s-SSP585 climate scenario, the highly suitable area for C. funebris is projected to double, suggesting a significant expansion of the geographical range of the niche under this climate model, with more than half of the niche experiencing separation. In summary, the potential distribution of C. funebris may continue to expand and shift to higher latitudes in the context of global warming and its ecological niche’s geographical range will be adjusted accordingly. These findings provide a theoretical basis and practical guidance for in situ conservation, ex situ conservation, and rational utilization of C. funebris genetic resources by conducting niche modeling and climate suitability assessments.

State and ameliorative properties of old original oak stands

The ameliorative properties of forest stands are essential for developing effective measures for environmental protection and sustainable use of forest resources. The purpose of the study was to assess the current condition and performance of erosion control properties of old oak stands of natural origin. The method of assessing the condition of old oak plantations using an integral indicator that takes into account biometric, ameliorative and health characteristics of stands, as well as agrochemical indicators of the soil has been tested. Field work was carried out on four experimental plots, where 794 age-old trees were enumerated. Comprehensive studies included determination of biometric indicators, analysis of root systems, detection of the content of available forms of nitrogen, mobile phosphorus, mobile potassium in soil. Soil hardness was measured with a durometer and soil water permeability using steel cylinders. High values of integral indicators were obtained in the experimental areas, which range from 11.9 to 19.7%. They guarantee the effective performance of erosion control properties by native old-growth forests. It has been researched that the proposed integral indicator of forest stand condition not only allows for assessing their current state but also demonstrates the effective control of erosion and ecological functions of the stand. It was established that essential requirement is to convert the absolute values of various indicators into relative values, with mandatory consideration of their positive or negative impacts on the forest stands themselves. It was found that an integral condition indicator can be used for erosion control plantations of any age range. The results can be used to develop biodiversity conservation programs and establish effective strategies for managing forest resources

Use of woody species in the Caatinga dry forest may lead to higher vulnerability to extirpation: An assessment based on ethnobiological, reproductive and conservation criteria

Tropical forests play an important role in maintaining, replenishing and conserving a large portion of the planet's biodiversity. However, these forests have been converted into anthropic landscapes, threatening the persistence of wildlife. The exploitation of forest products can result in different ecological impacts at different levels of biological organization. In this study, we propose a vulnerability index to examine the susceptibility of woody plants used by locals in a human-modified landscape of the Caatinga dry forest (i.e., the Catimbau National Park). We contrasted patterns of (1) plant use by local people (risk of use, collection risk, local importance, and diversity of use), (2) plant reproductive strategies (pollination, sexual and reproductive systems, dispersal mode, flowering and fruiting phenology), and (3) the conservation status of the plant species. We combined this information to propose a vulnerability index expressing species sensitivity to human disturbances in 14 regenerating and 14 old-growth forest stands. We tested the hypothesis that regenerating forest stands will harbor more vulnerable plant species compared to old-growth forest stands. Among the 119 plant species registered in regenerating and old-growth forest stands, 80 species (67.2 %) were recorded as useful for local people in Caatinga. Specifically, about 71.8 % and 70.5 % are exploited by the rural population for some type of use in regenerating and old-growth forest stands, respectively. The most frequent type of use was medicinal, followed by construction and fuel in both regenerating and old-growth forest stands. Regarding the potentially collected plant parts, the total removal of the individual and collection of leaves exhibited similar and higher relevance in regenerating, while leaves were the most collected part in old-growth forest stands. Of the 80 plant species analyzed, 62 % and 58.5 %, respectively, were classified as exhibiting moderate and high vulnerability to extirpation in regenerating and old-growth forest stands; thus not supporting our hypothesis. Our results suggest that in the Caatinga dry forest, (1) woody plant species responsible for forest regeneration in the context of slash-and-burn agriculture are exploited for multiple uses, (2) medicinal use is the main type of use of woody plants occurring in regenerating and old-growth forest stands, (3) total removal of the individual and collection of leaves were the most collected plant parts, and (4) both regenerating and old-growth forest stands showed a high vulnerability to human disturbances in the study area. In the long term, the exploitation of vulnerable plant species may negatively affect the composition and structure of the community and, consequently, the rate and trajectory of succession. It can be expected that as populations of vulnerable plant species are reduced or extirpated from the community, ecological interactions such as pollination and dispersal, which are key to ecosystem maintenance, will change along with the services provided.

Soil respiration and organic carbon changes along a chronosequence of Pinus nigra forest stands

Understanding the trajectory of changes in soil respiration (Rs) and soil organic carbon (SOC) with stand ages of the black pine (Pinus nigra Arnold) forest is essential for forest management and carbon budget estimates. In this research, changes of Rs and SOC were studied with respect to stand age in a chronosequence of three age classes of P. nigra plantations consisting of young (0 to 10-year-olds), middle-aged (11- to 20-year-olds), and pre-mature (35- to 45-year-olds) forest stands. Rs rates, soil temperature, and soil moisture were measured using an automated dynamic survey chamber (Li-8100A) for a year, encompassing summer, fall, winter, and spring seasons. Mean Rs significantly increased from young- to middle-aged and then stabilized, with effluxes ranging from 2.46 to 2.94 µmol CO2 m-2 s-1. Forest litter significantly increased with stand age, but not the SOC in the mineral soil layers. The Rs showed a positive correlation with soil temperature (0.77) and air temperature (0.75) but not with soil moisture (-0.43). The present results highlight the importance of stand age in assessing carbon budget and provide essential information for forest managers and stakeholders in evaluating the potential of P. nigra forests as tools for carbon sequestration and mitigating global warming impacts.

Trade-offs between stump-to-roadside lead time and harvesting cost, when using different number of operators in a harvester-forwarder system

AbstractFor customer-oriented wood supply, buffering is required for flexibility to handle interactions in the wood procurement system. This includes balancing lead-time and operational cost by using stocks and production capacity as buffers. Despite the well-known challenge to balance the interactions between harvesting and forwarding in Nordic mechaniced CTL-operations, there has been limited research on how the machine groups can be staffed to enable flexibility and more focus on other measures to create flexibility. Therefore, this study explored trade-offs between wood lead-time and harvesting cost in the stump-to-roadside part of the wood supply chain by altering the numer of full-time working operators in the harvesting groups. This was done using discrete-event simulations implemented in Anylogic software. Input data included information about operational conditions in 1500 forest stands. The results revealed that the best balance was to have sufficient harvesting capacity to adjust wood lead times at the expense of increased harvesting costs. Of the tested options, the best balance was achieved when staffing a two-machine group with three operators, and thereby allocating 50% of the used work-shifts to regulating the field wood stock between the two machines. This resulted in the shortest lead times and the smallest harvesting cost increase. Compared to the option with no flexibility for stock adjustment (4 operators), the average lead-time could be reduced to one tenth at a cost increase of 3.4%. These findings have the potential to improve decisions of how harvesting groups are staffed to balance specific objectives of desired lead times and costs, which migh prove to be a valuable addition to the already used measures to manage wood flow.

Temporal Variations in Aboveground Biomass, Nutrient Content, and Ecological Stoichiometry in Young and Middle-Aged Stands of Chinese Fir Forests.

Understanding the ecological dynamics of forest ecosystems, particularly the influence of forest age structure on soil carbon (C), nitrogen (N), and phosphorus (P) content, is crucial for effective forest management and conservation. This study aimed to investigate the nutrient storage and ecological stoichiometry across different-aged stands of Chinese fir forests. Soil samples were collected from various depths (0-15 cm, 15-30 cm, and 30-45 cm) across four age groups of Chinese fir forests (8-year-old, 12-year-old, 20-year-old, and 25-year-old) in the Forest Farm, Pingjiang County, China. Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) were measured, and their stoichiometries were calculated. The results showed that both individual tree biomass and stand biomass, along with SOC, TN, and TP content, increased with stand age, highlighting the significant importance of stand age on biomass production and nutrient accumulation in forests. Specifically, soil C and P contents significantly increased as the forest aged, while variation in N content was relatively minor. Soil C/N and C/P ratios exhibited variation corresponding to forest age, suggesting alterations in the ecological stoichiometry characteristics of the forests over time. These findings are crucial for understanding the dynamics of ecosystem functioning and nutrient cycling within Chinese fir forests and provide a solid scientific basis for the effective management and conservation of these vital forest ecosystems.

Insight into the variation of soil hydraulic properties under beech and spruce forest—A case study in the forest of Tharandt, NE Germany

AbstractBackgroundThe increasing vulnerability of forests in the temperate zone due to climate change has led to modification in the forest structure to secure woody raw materials and ecosystem benefits. Such changes will influence hydrological processes both at the stand and catchment scale. Soil hydraulic properties (SHP) play an important role in assessing the water cycle in these ecosystems. Yet, knowledge regarding the effect of forest‐ and site‐specific conditions on SHP in temperate climates is scarce.AimsThis work addresses this research gap by assessing the variation of SHP under two common European forest stands, Fagus sylvatica and Picea abies (1) with comparable site conditions, and (2) across differing site conditions.MethodsWe determined the soil water retention curve (WRC) and the hydraulic conductivity curve (HCC) in several plots with the bimodal Kosugi–Mualem's hydraulic model. These functions were determined using combined field and laboratory measurements, including hydraulic conductivity and water content from soil samples.Results(1) We observed distinct variations in SHP between beech and spruce forest stands with comparable site conditions; however, no clear pattern in the variation was discernible. (2) A noticeable effect of the site‐specific characteristics on the SHP was detected. Moreover, SHP in each analysed forest type presented individual variations.ConclusionsThis study demonstrates that SHP present a wide range of variations in terms of both forest‐ and site‐specific conditions. Hence, due to its heterogeneity, we emphasise the need for more research to better characterise SHP in temperate zone forests. Moreover, this study underlines the urgent use of a minimum set of parameters in studies when addressing SHP (e.g., tree age, soil texture).

Use of airborne LiDAR to predict fine dead fuel load in Mediterranean forest stands of Southern Europe

BackgroundMediterranean forests are increasingly threatened by wildfires, with fuel load playing a crucial role in fire dynamics and behaviors. Accurate fuel load determination contributes substantially to the wildfire monitoring, management, and prevention. This study aimed to evaluate the effectiveness of airborne Light Detection and Ranging (LiDAR) data in estimating fine dead fuel load, focusing on the development of models using LiDAR-derived metrics to predict various categories of fine dead fuel load. The estimation of fine dead fuel load was performed by the integration of field data and airborne LiDAR data by applying multiple linear regression analysis. Model performance was evaluated by the coefficient of determination (R2), root mean squared error (RMSE), and mean absolute error (MAE).ResultsThrough multiple linear regression models, the study explored the relationship between LiDAR-derived height and canopy cover metrics and different types of fine dead fuel load (1-h, 10-h, 100-h fuel loads, and litter). The accuracy of these models varied, with litter prediction showing the highest accuracy (R2 = 0.569, nRMSE = 0.158). In contrast, the 1-h fuel load prediction was the least accurate (R2 = 0.521, nRMSE = 0.168). The analysis highlighted the significance of specific LiDAR metrics in predicting different fuel loads, revealing a strong correlation between the vertical structure of vegetation and the accumulation of fine dead fuels.ConclusionsThe findings demonstrate the potential of airborne LiDAR data in accurately estimating fine dead fuel loads in Mediterranean forests. This capability is significant for enhancing wildfire management, including risk assessment and mitigation. The study underscores the relevance of LiDAR in environmental monitoring and forest management, particularly in regions prone to wildfires.

Changes in the Composition of Soil Organic Matter after the Transformation of Natural Beech Stands into Spruce Monoculture

The composition of soil organic matter is considered to have a key influence on C sequestration and global climate change and can be associated with changes in vegetation cover in the terrestrial ecosystem. Our study aimed to evaluate the soil chemical structures and various organic components from available or reactive to more stable forms in forest soils affected by acidification and after conversion from fairly close to natural beech (Fagus sylvatica) stands to a spruce (Picea abies) monoculture. Our results revealed that the beech stands had higher contents of dissolved organic carbon and low molecular mass organic acid compared to the spruce stands. The aliphatic CH groups within the soluble alkaline-extractable organic substance (AEOS) gradually disappeared with deeper soil horizons under both forest species, while the presence of aliphatic CH groups in the low-solubility AEOS was more pronounced in the A horizon under spruce and relatively increased with depth under beech stands. The carboxylic groups were more prevalent in deeper soil horizons, while polysaccharide chains and nitrogen functional groups decreased with depth under both forest stands but were more prevalent under beech than under spruce stands. These findings suggest that the stability of organic matter through the forest soil profiles increased due to the transformation of various organic compounds from litter to more stable organic matter with higher amounts of lignin components to greater amounts of carboxylic groups and aromatic groups in deeper soil horizons. Furthermore, a higher number of mobile components of soil organic matter and carboxylic acids, together with lower pH and cation exchange capacity under spruce, resulted in the leaching of nutrients, releasing risk elements into the soil solution and accelerating the podzolization process.

Features of the structure of the herbaceous cover and natural regeneration in the spruce forests of the Kologrivsky Forest Nature Reserve

The aim of the study was to identify the features of the structure of the herbaceous cover and natural regeneration in the southern taiga spruce forests of the Kostroma region using the example of the Kologrivsky Forest Nature Reserve. To achieve this goal, twelve temporary square sample plots (SP) with an area of 0.0625 ha were established. Forest type, canopy density, soil and topography were determined. To characterize the forest stands, a taxonomic survey of the sample plots was carried out. To describe the vegetation cover, a combined method was used, including the Braun-Blanke and Drude-Uranov methods, which assumes the distribution of typical plant complexes over a large number of plant species growing together. Geobotanical descriptions were processed according to the method of D.N. Tsyganov, which consisted in using two tables: ecological amplitudes of species and scales of factors. Correlation analysis was used for data processing. The obtained statistical data set was presented in histograms and graphs for the sake of clarity. The frequency of occurrence, errors, participation rate, and average projective cover of the species were calculated according to generally accepted methods. In the course of the work, all sample plots were characterized by a tree-by-tree census. As the sample plots were located in very different parts of the reserve, the taxonomic indicators varied. In most cases, however, the dominant species was spruce. Its viable regrowth was 95%, indicating a high renewal potential. In the studied forest areas, the dominant species of the living ground cover were Northern linseed (Linnaea borealis) and blueberry (Vaccinium myrtillus), oak fern (Gymnocarpium dryopteris) and wood sorrel (Oxalis acetosella). The practical significance of the conducted research lies in the expansion of the ideas about the structure of the herbaceous cover formed under the canopy of spruce forests in the conditions of the Kologrivsky Forest Nature Reserve, as well as about the peculiarities of the process of natural regeneration in different conditions of the growth site.