Thinning should promote the optimal growth and good health of a forest ecosystem. However, several residual trees usually suffer mechanical damage in stands after thinning operations. This research was conducted to determine the extent, cause and location of damage to residual trees during felling operations and timber extractions in the cut-to-length system in hemiboreal forests in Järvselja, Estonia. Field measurements were carried out in 30 thinning sites in 2017 and 2019. There were 57.6 damaged trees per hectare (7.8% of residual trees) on average. The number of damaged trees per hectare was not dependent on the method (harvester or manual felling) and season (winter period or summer period) of felling, however it was dependent on stand density. There were 23% root damage, 9% root collar damage and 68% stem damage out of all damaged trees. The common causes of residual tree damage were driving damage, falling tree damage and harvester saw damage. The strip roads covered 19% of the thinning area; the mean width of strip roads was 3.76 m. Thinning is certainly an important silvicultural measure whereas careful planning and execution should keep direct and consequential damage to the stand as minimal as possible.
Forest seedling size is still a subject of debate in plant production for reforestation programs in a semiarid Mediterranean area. The aim of the study was to assess the effect of initial morphological traits of Tetraclinis articulata (Vahl.) Mast. containerized seedlings on survival rate and growth performance after 11 months of outplanting in a semiarid Mediterranean site. The rooting depth of dead and alive seedlings was also explored to determine the effective depth for survival optimization and consequently to characterize the critical minimal soil water content necessary for seedlings to overcome drought season. The survival probability of T. articulata seedlings was strongly influenced by the initial seedling collar diameter, showing an increasing pattern with a critical minimum of 3.24 mm. The sturdiness index affected the survival probability, showing a trend downwards with a critical maximum of 5.93 cm mm−1. The shoot height relative growth rate of the seedlings was significantly affected by the initial morphological class, giving more advantage to small seedlings, while the collar diameter relative growth seemed to be insensitive to the initial seedling size. The evaluation of the rooting depth in relation to seedling survival allowed the characterization of a minimum depth of 57.74 cm that the roots must exceed in order to reach the wettest soil layers; this soil depth corresponds to a minimum critical gravimetric water content of 12% below which the roots cannot survive. These results suggest that in semiarid regions, where rainfall is scarce and soil moisture is uncertain, planting shortstemmed seedlings with a large collar diameter can enhance survival and shoot growth during the first year after planting.
Although parabolic approximations of sawlogs have become widespread, in current specialized literature, there are no parameter values of such approximations or dependencies for their calculation that could be used to analyze the influence of log dimensions on the volume yield of edged boards. The developed technique for determining the parameters of a truncated paraboloid, which approximates a sawlog, is based on Nilson’s formula for estimating its volume. Based on this, the equation of the generatrix of the truncated paraboloid as a function of the top diameter and the length of the sawlog (considering the species) and the formula for calculating its taper (in particular, total and main) are derived. The error of approximating sawlogs with a paraboloid was determined by comparing the taper estimate with literature data on the taper of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), and common oak (Quercus robur L.) sawlogs in Ukraine, Sweden, and Finland. This error ranges from -36% to -9%. Using the method of parametric identification of taper distributions based on literature data on their statistical characteristics (unbounded metalog distribution with four parameters and normal distribution were used), the probability that a sawlog has a taper smaller than its estimate was calculated. These probabilities range from 20% to 36%. The third quartiles of the sawlogs’ taper distributions are, respectively, between 200% and 150% of the taper estimate. Therefore, the obtained formulas for determining the parameters of the approximating paraboloid led to a rather conservative estimate of the taper (however, acceptable for use in log sawing planning), which confirms their suitability for analyzing the influence of log dimensions on the yield of edged boards.
Climate change poses significant challenges to the survival of ecologically and economically important tree species. This study uses species distribution modelling to assess the current and future potential habitats of Afzelia africana and Pterocarpus erinaceus in Benin under moderate (RCP4.5) and high (RCP8.5) climate change scenarios. They are multipurpose trees listed on the IUCN Red List due to threats such as illegal logging and low natural regeneration rates. By integrating bioclimatic variables and occurrence data using the method of the Maximum Entropy under MaxEnt program, the results reveal critical habitat shifts, including significant contractions in highly suitable areas under severe climate conditions. Under current climatic conditions, approximately 85% of Benin’s territory is identified as a potentially suitable habitat for Afzelia africana and Pterocarpus erinaceus, indicating a significant area for their conservation. Future projections suggest that national parks, some of which currently include unsuitable zones, will offer increasingly suitable habitats, emphasizing their importance in climate adaptation strategies. The extensive availability of suitable habitats highlights the potential for future reintroductions or natural population expansions, ensuring the continued survival and ecological roles of these species in the region. Practical implications include conducting spatial prioritization using habitat suitability maps to extend current protected area networks, and focusing restoration efforts on medium-suitability areas. These findings provide a foundation for informed conservation strategies that align with climate adaptation goals.
The primary goal of forest modelling is to accurately describe various forest processes and estimate stand- or tree-level indicators through mathematical models. Developing an accurate height-diameter model is a critical step in the creation of forest growth and yield models. The height-diameter curve is a mathematical equation with tree diameter at breast height as an input value and tree height as an output value. The objective of this research was to assess 50 different height-diameter curves to identify the most suitable ones for predicting dominant height using individual tree data from the Estonian Network of Forest Research Plots (ENFRP). Dominant height is defined as the mean height of 100 largest trees per hectare. For the evaluation we used measurement data collected from ENFRP plots between the years 1995 and 2021. The evaluation of height-diameter curves was based on their mathematical properties and the prediction error of dominant height. Among the evaluated equations, a modified version of the Hossfeld IV equation, was identified as the most accurate for predicting dominant height. The same equation, with Artur Nilson’s parameterization, yielded similar results. The results of this study can be used for developing generalized height-diameter models.
Zanthoxylum armatum DC. (Z. armatum), known as the prickly ash or toothache tree, shows higher productivity and interesting agronomic features for spices, oilseeds and medicinal values. Waterlogging is one of the major stresses restricting the growth, development and production of Z. armatum in Southwest China due to flash rainfall and floods. However, the effects of waterlogging stress on the growth and antioxidant responses in Z. armatum seedlings have not been reported. In this study, the physiological responses in Z. armatum seedlings were investigated under waterlogging with different depths (2.7, 5.5, 11 cm above the ground level) and durations (2, 4 and 6 days). No significant differences in the averages of height, stem diameter and number of leaves were observed. However, the apical leaflets of seedlings that were submerged to a depth of 11 cm above the ground become soft on day 6. Chlorophyll and malondialdehyde (MDA) content rose significantly with the waterlogging levels on different treatment days compared to the control. There were no significant differences in the relative electrical conductivity between the control and treatments on day 2, but the values of the treatment groups were higher than those of in the control on days 4 and 6. The generally increased content of soluble sugar and soluble proteins within a small range with prolonged duration of the stress showed little differences between waterlogging stress and the controls. Superoxide dismutase (SOD) and peroxidase (POD) activity showed different changes in different tested groups at different treatment times, as compared with controls. The morphological and physiological characteristics had different responses to stress duration and waterlogging degree as well as their interactions. These findings were strong evidence that these plants may develop strategies and have a certain tolerance to short-term waterlogging, especially mild waterlogging.
The study analysed 2019–2022 summertime canopy height predictions (HICESat) given in ICESat-2 ATLAS dataset ATL08 for hemiboreal forests growing on an area of 40,000 km2 in Estonia around 25.6° E, 58.8° N. In total 12,711 ATL08 20×20 m pixel observations were used from 3,065 forest stands with homogenous canopy structure. Regression modelling was used to explain variability in ground surface elevation estimates, and relationships of HICESat to basal area weighted mean tree height given in the forest inventory database (HFI) and to the 95th percentile of the vertical distribution of airborne laser scanning pulse return (HALS). The other explanatory variables were the ICESat-2 ATLAS observation geographic location, ICESat-2 ATLAS track and beam energy indicators, forest canopy cover, evergreen coniferous tree dominance indicator, and deep peat soil indicator. The linear model between the Estonian digital terrain model elevation and ATL08 ground elevation had a determination coefficient of R2=99.97% and residual standard error of δ=0.51 m when a geographic location was included. The HFI can be predicted from HICESat with R2=85% and δ=2.7 m. A comparison of means indicated that, on average, HICESat was about 0.3 m greater than HFI. All the predictive variables (except the geographic location) were significant in canopy height models, and the best models fitted HICESat with R2=95% and δ=1.6 m, however, there was no notable increase in R2 if more predictors than HALS were added in the models. In practical applications using ATL08 data for forest inventories, the inclusion of weak energy beam observations increases the number of observations, but the beam energy indicator has to be included in the models.
The article investigates the historical presence and current status of larch trees within the parks of five former manors in South Estonia: Kastre and its Peravalla forest district (now Järvselja Educational and Experimental Forest Centre), Mäksa, Kabina and Mõniste. Before 1918, South Estonia was part of the province of Livonia in the Russian Empire. The analysis encompasses taxonomy, habitats and the introduction of various larch species. Selected larch trees within these parks were dated using dendrochronological methods. The research revealed a consistent pattern of larch tree planting over a century, occurring in seven distinct rounds between the 1820s (Kastre Park) and the 1940s (Järvselja) as follows: 1) 1820 and 1895 (Kastre), 2) 1907 and 1920–1940 (Järvselja), 3) 1825–1840 (Mõniste), 4) 1855–1865 (Kabina), and 5) 1870–1880 (Mäksa). Genetic characterization was applied to determine individual tree species based on morphometric determinations. The majority of larch trees within the parks were genetically confirmed as European larches, which was consistent to the morphological assessments conducted at Kastre, Järvselja and Mäksa. The analysis revealed that a younger, naturally propagated larch located at Kastre with morphological characteristics of European larch showed subtle genetic indicators of Japanese larch. The cause of this unexpected finding remains vague. It is hypothesized that this specific tree might represent a hybrid of European and Siberian larches, given its inclusion within a stand hosting both species in proximity. At Järvselja, the genetic method confirmed the morphological identification of four larches as Japanese and two as Dunkeld larches. Six Siberian larches (sensu lato) located at Kastre and Järvselja were genetically identified as hybrids of Japanese and European larches while the cause of this hybridization remains unclear. Utilization of genetic markers not validated for Russian (L. archangelica), Siberian (L. sibirica s. str.), and hybrid (L. decidua × L. sibirica and L. sibirica × L. decidua) larches makes the obtained results inconclusive. In the case of Mäksa, both morphological and genetic analyses confirmed the presence of Japanese and Euro-Japanese larches, which was previously confirmed. It is important to note that the classification of L. leptolepis × L. decidua proposed by Bobrov is considered incorrect. Trees displaying similar characteristics, especially older specimens, should be classified according to Bobrov’s description as L. decidua f. kaempferi or f. marschlinsii.
The uncontrolled rise in heavy metal pollution due to anthropogenic activities has become a global environmental concern. Lebanon's Ezer forest, dominated by Quercus cerris L., is exposed to vehicular activity along its northern edge due to an unpaved public road and intensive recreational activities in its center. This study aimed to determine the concentrations of metals in Q. cerris leaves and soil across three distinct forest stands: S1 and S2 (polluted sites) and Ctrl (control site). Cadmium, chromium, lead, and aluminium were extracted via the wet digestion method and analyzed by Atomic Absorption Spectrometry. Additionally, hydrogen peroxide levels, the total carbohydrate and phenolic content in Q. cerris leaves, as well as the activity of antioxidant enzymes, were measured. The results revealed that Ezer forest is at risk of heavy metal contamination, with a significant increase in hydrogen peroxide levels at the polluted sites compared to the Ctrl site. The total carbohydrate and phenolic content was notably reduced at the polluted sites, while peroxidase and catalase activity increased, indicating that Q. cerris has developed adaptive mechanisms to cope with oxidative stress. National strategies to raise public awareness and reduce heavy metal contamination in the forest are urgently needed to protect the rare Q. cerris species.
The current research was performed in the Morni Hills, a part of the outer Himalayas. Floristic assessment is critical for a plant community, reflecting both the gene pool and adaptability of the community. For this, different parameters like density, frequency, basal area, IVI, and various diversity indices were calculated by dividing the area into two altitudinal ranges, i.e. 400–600 m AMSL (AR_1) and 600–800 m AMSL (AR_2). The vegetation sampling was done by randomly selecting 30 plots in the selected area. The study showed that AR_2 (118 plant species: 31 trees, 17 shrubs, 58 herbs, and 12 climbers) had a higher number of plant species in comparison to AR_1 (106 plant species: 26 trees, 14 shrubs, 54 herbs, and 12 climbers) with Poaceae being the family with the greatest number of species. The area was seen to be dominated by Acacia nilotica (L.) willd. Ex Delile, Cassia fistula L., and Leucaena leucocephala (Lam.) de Wit in AR_1 while by Pongamia pinnata (L.) Pierre, Cassia fistula, and Oroxylum indicum (L.) Kurz in AR_2. The upper range, i.e. AR_2 was also more diverse than AR_1 because of a high Shannon Wiener Diversity Index value and a lower Simpson Index value. Whereas the population structure study demonstrated that girth class D (CBH=61–90 cm) had the highest number of tree species in both altitudinal ranges, followed by girth class C (CBH=31–60 cm). Moreover, the forest was also observed to be occupied by various invasive plant species as well as under anthropogenic pressure, hence in immediate need of proper management and conservation.
Long-term forest carbon modelling is helpful in climate change mitigation actions. Estimating potential carbon sequestration in forests can be considered the long-term strategy for low carbon and climate resilience in the National Determination Contribution. In Hungary, the black locust (Robinia pseudoacacia) and poplars (Populus sp.) are prominent and dominant species in reforestation and afforestation projects. The research aimed to estimate the carbon dynamics of black locust and white poplar long rotation plantations in some forest management scenarios. Thirty-six forest management scenarios were developed from two species, six yield classes, and tree wood utilization. CO2FIX modelling projected carbon dynamics for 45 years of rotation. Our findings have shown that class yield I resulted in the highest carbon stock compared to class yields II–VI. Black locust plantations have stored carbon to a larger extent than white poplar plantations. In terms of wood utilization, harvested black locust or white poplar wood contributed the most extensive carbon stock if used for pulp. In conclusion, from 36 forest management scenarios, the best scenario was black locust plantation in class yield I and the aim for pulp that stored the carbon at the end of rotation was 101.75 Mg C/ha. In all forest management scenarios, the soil carbon stock was higher than carbon in biomass, products, and bioenergy. Thus, conserving the soil as the dominant carbon pool is vital for future policy recommendations.
Cola nitida is a key multipurpose fruit tree species widely distributed across African countries. Several studies have investigated different aspects of the species, but there is a lack of synthesis on the current state of available literature and prospects for sustainable conservation and management of the species. Using the PRISMA approach for systematic review over the last three decades (1990–2022) in Africa, this study gathered key existing research findings on C. nitida. A total of 280 scientific publications were finally retained for this review. Several studies were focused on the socio-economic importance of the species (n = 139 ~ 50%), nutritional and chemical properties of its organs (n = 48 ~ 17%), improvement of its propagation methods (n = 30 ~ 11%), pest and pesticide control (n = 39 ~ 14%), morphological and genetic diversity (n = 21 ~ 7.5%), its botanical description and ecology (n = 2 ~ 0.7%), and climate change threats on the species (n = 1 ~ 0.3%). The review revealed a gap in knowledge on the methods for improving the species’ resilience to climate variability. Future research on the species should focus on its ecophysiological traits, the identification of elite accessions, and the type of agroforestry system that could optimize its productivity. The review provides a baseline for developing innovative management programs for C. nitida in Africa. Moreover, it highlights the need for more research efforts in the Central and East African native range of the species.
The purpose of the work was to determine trends in land cover dynamics in a case study of a small town for the period from 1991 to 2021 using GIS technologies to find measures to prevent negative anthropogenic impacts. The object of the study is the territory of the small town of Kaharlyk, Kyiv region, Ukraine, and its landscaping system. Dynamic processes in the town were monitored using freely available Landsat time series. The land cover was classified into five categories: forest, grassland, cropland, urban (buildings) and wetland (water). Using the Morphological Spatial Pattern Analysis, the dynamics of connectivity of elements of the urban forest was determined. Despite the relatively high rates of provision of the population with green infrastructure and a large forested area, the urban forests have an insular (fragmentary) nature and low connectivity. This does not contribute to the creation of a cohesive network and ecological framework of the town. It was established that there were no significant changes in the land cover of the town, however, some negative trends emerged, which should be taken into account in future urban planning.
This study aimed to assess and compare the impact of priming with gibberellic acid (GA3) and N-hexanoyl-L-homoserine lactone (C6-HSL) on acorn germination, seedling growth, and the balance of endogenous phytohormones in 47-day-old seedlings of pedunculated oak (Quercus robur L.). We hypothesized that exogenous GA3 and C6-HSL induce changes in hormonal homeostasis, which activate the germination of acorns and growth of seedlings. Acorns were soaked for 24 hours in water (control) and solutions of gibberellic acid (50 mg/L) and C6-HSL (300 ng/ml). The dynamics and distribution of endogenous cytokinins, abscisic (ABA), indole-3-acetic (IAA), gibberellic (GA3 and GA4) and salicylic (SA) acid in 47-day-old seedlings' organs of Q. robur were analysed using HPLC-MS. Priming with GA3 solution resulted in 85.8% of acorn germination, surpassing the control by 24.6%, whereas priming with C6-HSL solution led to 93.4% germination, surpassing the control by 32.2%. GA3-primed plants (GA3+plants) showed enhanced shoot growth, while C6-HSL-primed (C6-HSL+plants) plants had intensive root development. GA3 also caused epicotyl shoot thickening. Both regulators increased cytokinins, mainly active zeatin forms, with pronounced changes in shoots under C6-HSL and in roots under GA3. ABA content increased in both GA3+ and C6-HSL+plants, with a more significant effect in the roots of C6-HSL+plants. Both regulators negatively impacted IAA accumulation, with GA3 exhibiting a more pronounced effect, causing IAA accumulation to shift from shoots to roots post priming, whereas IAA dominance occurred in the shoots of non-primed acorns (C-plants) and C6-HSL+plants. The total gibberellin content increased in primed seedlings, with GA4 accumulating in GA3+plants and GA3 in C6-HSL+plants, surpassing GA3+plants by 40.7%. GA3+plants exhibited decreased SA in roots, contrasting with increased SA in the roots of C6-HSL+plants. In conclusion, both growth regulators optimized acorn germination, induced changes in hormonal homeostasis and enhanced seedling growth, with increased root growth in C6-HSL plants and shoot growth in GA3 plants.
Environmental monitoring networks such as the Integrated Carbon Observation System (ICOS) in Europe, the National Ecological Observatory Network (NEON) in the U.S., or the Terrestrial Ecosystem Research Network (TERN) in Australia deploy different sampling schemes for in situ measurements. We report on the intercomparison of measurements of the canopy gap fraction with different digital hemispherical photography setups adopting ICOS, NEON, and TERN sampling schemes. The test was carried out at the Järvselja Radiation Transfer Model Intercomparison (RAMI) birch stand. Results show that spreading out sampling points which cover more of the plot is important for a good representation of the forest as a whole. The NEON tower plot layout scheme may be more prone to errors in overall canopy properties estimation than ICOS or TERN due to its compact sampling layout and should always be used in conjunction with its distributed plots. Different camera setups involving different camera operators, camera bodies, lenses and settings yield slightly varied results, and it is important to ensure that the images are taken in such a way that they would not be over or underexposed, or out of focus. As a conclusion we recommend always to carry out intercomparison measurements with old and new cameras when devices are upgraded. Our study contributes towards establishing the uncertainty and evaluating potential error budget stemming from collecting in situ measurements using different sampling schemes and camera setups.
In a managed forest landscape, the high degree of human intervention has caused significant shifts in natural processes, and preservation of remaining natural ecosystem features is crucial to safeguard ecosystem functioning and support ecosystem services. While drainage ditches, subject to regular maintenance, are anthropogenically created and maintained infrastructure elements, they may still support diverse environmental conditions and provide habitats for a variety of plant species, including flowering plants important for pollinators. We assessed vegetation composition changes on recently reconstructed and unmanaged forest ditches and ditch edges in a commercial forest in Central Latvia in two surveys (one and five years after the ditch reconstruction). We used generalized linear mixed-effects models to analyze the impact of environmental variables on species richness and detrended correspondence analysis to analyze plant species composition. We found higher total plant species richness and insect-pollinated plant species richness along recently reconstructed ditches. The differences were mainly explained by better light availability beside reconstructed ditches. Anthropogenically created and managed ecosystems may support biodiversity and directly and indirectly contribute to the provision of different ecosystem services, including pollination.
There are no systematic approaches available in current specialist literature when it comes to the optimization of the process of drying out hardwood species of wood, such as birch, aspen, or black alder, all of which find industrial uses in Estonia. In order to investigate the drying of these three hardwood species, this paper has made use of an experimental and theoretical drying optimization methodology which was developed previously for pine sapwood within the framework of the EIC Grant No. 16200 project. The same methodology was used to determine the critical diffusion coefficient and corresponding critical relative humidity levels (RH) in relation to the surrounding air, with those levels being important from the point of view of drying optimization, and calculating those levels separately for each species of hardwood. For alder it was found that the critical diffusion coefficient is Dcr = 36.57 * (10−4 mm2 s−1), while for aspen the figure was Dcr = 30.71 * (10−4 mm2 s−1), and for birch it was Dcr = 16.35 * (10−4 mm2 s−1). It was found that the time dependencies for the total deformation of different tree species tend to differ considerably, although the same drying regime was used for all of those tree species which were incorporated into the experiments.
Phellodendron chinense is an extraordinary medicinal plant, and its stem bark is a famous traditional Chinese medicine in China, containing a number of phytochemicals with biological and pharmacological functions. Studies have shown that the medicinal ingredients in P. chinense from various regions are different, as soil types might be important factors affecting the growth and quality of P. chinense. In this study, the effects of acidic purple soil, alkaline purple soil, yellow soil and red soil on the growth, nutrient element accumulation and partitioning in P. chinense seedlings were studied. Our results showed that the biomass of leaves and stems in acidic purple soil was significantly higher than in other soils, and the root biomass was significantly lower than that in yellow soil. C, N, P and Ca contents cultured in acidic purple soil were the highest compared to other soils, and K and Mg content were the highest in yellow soil and red soil, respectively. The distribution of carbon between different organs can reflect environmental stress. N has become a limiting factor for the growth and development of P. chinense seedlings. C:N and C:P ratios in the leaves were significantly lower than those in the stem and roots. Among four soil types, the highest N:P ratio was 1.65 in P. chinense seedlings. These results suggest that four soil types may significantly affect the accumulation and distribution of biomass and nutrient elements in P. chinense seedlings. The characteristic patterns in different organs have different responses. Acidic purple soil is more suitable for the growth of P. chinense. These findings will help to understand the distribution characteristics and requirements of nutrient elements in P. chinense seedlings, and further provide a theoretical basis and reference for site selection and cultivation strategy.
The reduction of greenhouse gas (GHG) emissions demands a significant increase in the use of wood as a renewable energy source. However, environmental restrictions determine limits on the further growth of harvesting volume. Therefore, a viable solution to enhance the share of energy wood in Estonia’s energy balance involves focusing on less exploited assortments of raw material and implementing precise logistics planning. In recent years, mild winters have posed challenges to the extraction of residues and local transport of wood fuels, taking place on soft and unfrozen soils. In such conditions, ensuring a reliable supply of wood fuels becomes rather complicated. When piles of logging residues on unfrozen soils are inaccessible, there is a need to process older piles. The quality of wood chips from such piles is lower compared to the norm. To investigate the impact of extra long-term storage of residues in piles, a study was conducted at the Järvselja Training and Experimental Forest Centre. In 2010, sample piles were created in birch and spruce final felling areas. Over an eight-year period, samples were regularly taken from the piles to analyse the properties of woody biomass during storage. The study results indicate that the quality of fuel from covered piles changes slowly during the first two years of storage. Subsequently, the degradation speed equalizes in both uncovered and covered piles. Despite extensive degradation and loss of dry matter during long-term storage (approximately 29% for Norway spruce and 55% for silver birch after eight years), the quality of dry fuels still meets standard requirements and remains acceptable for boiler houses.
Understanding how forest ecosystems respond to environmental factors, particularly in the context of global climate change, is essential for devising effective mitigation strategies. This study focuses on quantifying the interaction between forest ecosystems and atmospheric gases. To achieve our objectives, we are using the eddy covariance (EC) flux method to measure air turbulence and gas concentrations above the forest canopy at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) in southern Estonia. We apply a flux footprint (FFP) model to describe the spatial extent and position of the surface area contributing to the turbulent flux measurements. The FFP analysis provides valuable insights into the long-term changes in SMEAR Estonia, the FFP and its relationship with forest management and land use changes. Our findings reveal that the FFP area varies from year to year due to changes in wind speed and direction, affecting the contribution of different land cover elements to the overall FFP. The average changes in the FFP area at a height of 30 meters were approximately 4.9%, while those at a height of 70 meters were only 1.6%. Moreover, human activities, such as thinning and clear-cutting, influence the growing stock and increment of forest stands.
