Silvicultural Treatments Research Articles

Response of Ips bark beetles (Coleoptera: Curculionidae: Scolytinae) to prescribed fire in South Carolina

Ips bark beetles (Ips species; Coleoptera: Curculionidae: Scolytinae) play an important role in forest ecosystems by attacking injured, stressed, or dying pine (Pinus) trees. Management of Ips bark beetles has largely focused on prevention by maintaining tree health through silvicultural treatments including thinning to reduce basal area or prescribed fire. However, there is conflicting evidence of whether prescribed fire leads to increased bark beetle populations and, subsequently, increased tree mortality. Recent outbreaks of Ips bark beetles in the southeastern U.S. have caused renewed interest in the interactions between pine management and bark beetle populations. We monitored Ips populations following prescribed fire in intensively managed pine stands and quantified Ips damage. We captured over 361,000 Ips bark beetles with I. avulsus being the most abundant of the three species collected. While we found high variation among Ips populations across study sites and years, there was a significant increase in bark beetle populations after prescribed fire followed by a significant decline the next year. While Ips populations increased up to three-fold after prescribed burns, damage ratings in burned stands were no different than unburned stands which had significantly lower bark beetle populations. Unburned stands had higher basal area and a higher average tree damage rating, but the lowest number of Ips bark beetles. A total of 14,071 facultative (e.g., Monochamus = 9775) and obligate (e.g., Thanasimus dubius = 4296) predators were collected during the study across all sites and the ratio of predators:Ips also significantly increased following prescribed fire. These data suggest that while Ips are ubiquitous and abundant in pine forests being managed with prescribed fire, natural mechanisms such as predator activity mediate their overall damage and impact to southeastern pine stands.

Růst douglasky tisolisté v mlazinách v závislosti na výchově a konkurenčním tlaku borovice lesní na živinově chudších stanovištích

The article focuses on the growth response of young stands of Douglas-fir and mixtures of Douglas-fir with Scots pine on nutrient-poor sites. The experiment was established in a seventeen-year-old naturally regenerated stands using a block design with two replications. The silvicultural intervention (thinning) involved reducing the number of trees to 1,800 per hectare in the stand without pine representation and reducing it to approximately 4,000 trees in the less mature stand in the mixture with pine. The results of a thirteen-year time series since the implementation of the initial thinning are presented. The diameter growth of Douglas-fir on these sites is significantly lower compared to Scots pine. Without thinning, Douglas-fir is gradually being displaced by Scots pine in the stand, leading to a decrease in its representation and basal area. The silvicultural intervention have positively influenced diameter increment and improved the static properties of the trees, as expressed by their height-diameter ratio (HDR). In the thinned plot without pine occurrence, it was even possible to temporarily reduce the HDR values of target Douglas-fir trees. In the thinned plot with pine competition, the rate of HDR increase was only reduced compared to the control.

Assessing experimental silvicultural treatments enhancing structural complexity in a central European forest – BEAST time‐series analysis based on Sentinel‐1 and Sentinel‐2

AbstractAssessing the dynamics of forest structure complexity is a critical task in times of global warming, biodiversity loss and increasing disturbances in order to ensure the resilience of forests. Recent studies on forest biodiversity and forest structure emphasize the essential functions of deadwood accumulation and diversification of light conditions for the enhancement of structural complexity. The implementation of an experimental patch‐network in managed broad‐leaved forests within Germany enables the standardized analysis of various aggregated and distributed treatments characterized through diverse deadwood and light structures. To monitor the dynamics of enhanced forest structure complexity as seasonal and trend components, dense time‐series from high spatial resolution imagery of Sentinel‐1 (Synthetic‐Aperture Radar, SAR) and Sentinel‐2 (multispectral) are analyzed in time‐series decomposition models (BEAST, Bayesian Estimator of Abrupt change, Seasonal change and Trend). Based on several spatial statistics and a comprehensive catalog on spectral indices, metrics from Sentinel‐1 (n = 84) and Sentinel‐2 (n = 903) are calculated at patch‐level. Metrics best identifying the treatment implementation event are assessed by change point dates and probability scores. Heterogeneity metrics of Sentinel‐1 VH and Sentinel‐2 NMDI (Normalized Multi‐band Drought Index) capture the treatment implementation event most accurately, with clear advantages for the identification of aggregated treatments. In addition, aggregated structures of downed or no deadwood can be characterized, as well as more complex standing structures, such as snags or habitat trees. To conclude, dense time‐series of complementary high spatial resolution sensors have the potential to assess various aggregated forest structure complexities, thus supporting the continuous monitoring of forest habitats and functioning over time.

Effect of site, silviculture and tree social status on internal checking variation in plantation-grown Eucalyptus nitens

ABSTRACT Internal checking is a wood-drying defect that affects many tree species, including eucalypts, and can adversely affect the recovery of high-quality timber. We studied the patterns of within- and between-tree variation in wood checking from three Eucalyptus nitens silvicultural trials and determined the predictability of wood checking from wood properties. We hypothesised that changed wind exposure and inter-tree competition due to thinning would increase wood checking. In total, 144 trees from two silvicultural treatments (thinned/unthinned) and three social status classes per site (dominant/subdominant/suppressed) were sampled. Regardless of site, social status and silvicultural treatment, longitudinal and radial variation within trees was the major source of variation in checking. Checking was concentrated longitudinally in bottom logs and radially in the middle of wedges, with a shift in checking towards the cambium in the thinned treatment. On average, dominant trees in the thinned treatment had higher levels of checking than dominant trees in unthinned treatments at all sites, but the opposite trend was found for suppressed trees. Wedge checking was poorly predicted using non-destructive traits assessed on standing trees. Our models accounted for at most 22% of the variation in wedge checking and the best predictors were the destructive measures of wedge collapse. With most checking occurring in lower logs, future studies should concentrate on reducing checking in bottom logs, which are typically pruned for clearwood products.

Effect of pruning intensity and picking on Acacia senegal for gum arabic yield in Northern Jigawa State, Nigeria

Climate significantly impacts dryland trees, influencing their adaptation, survival, production, and role in the ecosystem. Acacia senegal is a valuable dryland tree planted for gum arabic production and ecological benefits. However, gum arabic production has declined due to the adverse effects of climate and improper management. Thus, silvicultural intervention such as pruning is essential for the health, growth, and gum yield of A. senegal. This study investigates the effects of different pruning intensities and pickings on gum arabic yield at Madana and Garin-ladan in the Gumel district of northern Jigawa State, Nigeria. The experiment involved five levels of pruning intensity and eight pickings, conducted using a randomized complete block design with three replicates. The gum yield was collected, dried, and weighed, and ANOVA was performed using Statistix 10.0 software, with Shapiro-Wilk and Turkey tests for data normality and mean comparison. The result showed significant differences (p < 0.05) in gum yield among the pruning intensities for most of the pickings at the two sites. The 1st, 2nd, 3rd, 5th, 6th, and 3rd, 5th, 8th pickings are significantly different except 4th, 7th, 8th; and 1st, 2nd, 3rd, 6th, and 7th at Madana and Garin-ladan respectively. The highest gum yield is 52.5a, 46.7a, 50.1a, and 43.5a g/picking, respectively. The lowest is 0.8a and 0.9a g/picking, respectively. Pruning intensity significantly differs (p< 0.05) in total gum yield per tree. Pruning intensities B3 and B4 demonstrated the highest total gum yield (251.8a and 147.6a g/tree) at both sites, respectively. At the same time, B0 exhibited the lowest gum arabic yield (97.2c and 38.5b g/tree) at both locations. These findings prove that pruning intensities B3 and B4 are the most effective in promoting gum yield and may enhance the gum productivity of A. senegal trees in northern Jigawa State.

Evaluation of the Energy Use of Pruning Dipteryx alata Trees

Pruning is equivalent to the removal of whole branches or parts, living or dead, of a plant, to promote balance in the development of the species, therefore, the generation of waste portrays an indispensable and ever-present consequence. The residues derived from pruning come from silvicultural treatments and evidently have great potential to be used in energy generation. Briquetting, in addition to its energy advantage and practicality, collaborates with the mitigation of environmental impacts from encouraging the use of renewable energies to reducing the emission of greenhouse gases, as they are strongly recommended for replacing fossil coal. The main objective of this work was to evaluate the possibility, related to quality and productivity, of the energy use of residual biomass from urban pruning of Dipteryx alata, focusing on the production of briquettes, thus encouraging further studies related to native species of the Cerrado and the use of renewable energy. The contents of volatile materials, ash and fixed carbon, higher calorific value, basic and energetic density were determined, and briquettes were produced in a laboratory briquetting machine. The quality of the briquettes was determined through physical-mechanical analyses: apparent density, durability, tensile strength by diametral compression and expansion. The energy density of the biomass had a considerable increase after briquetting, confirming the increase in energy concentration per unit volume in densified materials. Therefore, it was concluded that the use of urban pruning residues of Dipteryx alata proved to be suitable for making briquettes to produce renewable and sustainable energy.

Bornean tropical forests recovering from logging at risk of regeneration failure.

Active restoration through silvicultural treatments (enrichment planting, cutting climbers and liberation thinning) is considered an important intervention in logged forests. However, its ability to enhance regeneration is key for long-term recovery of logged forests, which remains poorly understood, particularly for the production and survival of seedlings in subsequent generations. To understand the long-term impacts of logging and restoration we tracked the diversity, survival and traits of seedlings that germinated immediately after a mast fruiting in North Borneo in unlogged and logged forests 30-35 years after logging. We monitored 5119 seedlings from germination for ~1.5 years across a mixed landscape of unlogged forests (ULs), naturally regenerating logged forests (NR) and actively restored logged forests via rehabilitative silvicultural treatments (AR), 15-27 years after restoration. We measured 14 leaf, root and biomass allocation traits on 399 seedlings from 15 species. Soon after fruiting, UL and AR forests had higher seedling densities than NR forest, but survival was the lowest in AR forests in the first 6 months. Community composition differed among forest types; AR and NR forests had lower species richness and lower evenness than UL forests by 5-6 months post-mast but did not differ between them. Differences in community composition altered community-weighted mean trait values across forest types, with higher root biomass allocation in NR relative to UL forest. Traits influenced mortality ~3 months post-mast, with more acquisitive traits and relative aboveground investment favoured in AR forests relative to UL forests. Our findings of reduced seedling survival and diversity suggest long time lags in post-logging recruitment, particularly for some taxa. Active restoration of logged forests recovers initial seedling production, but elevated mortality in AR forests lowers the efficacy of active restoration to enhance recruitment or diversity of seedling communities. This suggests current active restoration practices may fail to overcome barriers to regeneration in logged forests, which may drive long-term changes in future forest plant communities.

The Impact of Group- and Single-Tree-Selection Cuttings on Runoff and Sediment Yield in Mixed Broadleaved Forests, Northern Iran

Silvicultural treatment and the forest harvesting operations using different methods can lead to an increase in the production of runoff and sediment by changing the canopy and soil surface where they are conducted. In order to investigate this issue, sampling plots were established in the Namkhaneh district of the Kheyrud forest with three replications for every treatment: control stand and tree harvesting systems using single-selection cuttings and group-selection cuttings. The amount of runoff and sediment was collected and estimated from precipitation over a period of one year. Also, some soil physical properties such as bulk density, penetration resistance, sand, silt, and clay content, soil moisture, and soil organic matter were measured. The results showed that tree harvesting systems has a significant effect on runoff, the runoff coefficient, and sediment but the season (growing season and fall) and the combined effect of tree harvesting systems and the season have no significant effect on the runoff coefficient and sediment. The mean runoffs of each rainfall event for the control, single-tree, and group-selection treatments were 5.67, 8.42, and 10.28 mm, respectively, and the sediment amounts were 3.42, 6.70, and 11.82 gr/m2, respectively. Furthermore, the total annual erosion amounts of the control, selection, and grouping treatments were 0.427, 0.838, and 2.178 t/ha, respectively. The bulk density, penetration resistance, and percentage of sand and silt were positively related and the percentages of clay and organic matter were negatively related with the amount of runoff and sediment. In the method of individual selection cuttings, the damage to the forest in terms of the amount of runoff and soil erosion was less than for the group-selection cuttings. Forest harvesting by the selection method (single-selection and group-selection) has caused different changes in the vegetation canopy. The final summary of our results could be the advice to predominantly use the single-selection method in high-slope stands.

Выращивание культур кедра сибирского в условиях повреждаемости дикими животными

The research of 26-year-old mixed plantations of Siberian spruce and Siberian stone pine cultivated by biogroups of about 300 pcs/ha (2–5 stone pine seedlings alternating 4–9 spruce seedlings in a row) has shown that the damage rate by moose to them is much lower than to pure stone pine plantations or the mixed ones of Siberian stone pines and Scots pines we have studied before. The share of biogroups containing damaged stone pine trees is 18 %. A third of this number is plantations with damage to all the trees. This is most pronounced in biogroups of 4 to 5 stone pines as well as in case of frequent alternation of biogroups in a row. 76 % living stone pines have been preserved (89.3 % of them without damage to the stem). About two thirds of them (about 500 pcs/ha) grow in the crown of spruce trees adjacent to stone pine biogroups. Prolonged exposure to growing in a spruce tree crown negatively affects the growth of a stone pine’s central shoot and crown. We are the first in the Middle Urals to propose a scheme for cultivating sustained productive mixed plantations of Siberian stone pines and Siberian spruce trees (or Norway spruce trees). Stone pines are planted in biogroups of 2–3 seedlings, beginning the planting strictly on one side of the site. The first biogroup in odd-numbered rows (1, 2, 3, 5, etc.) is planted after 3 spruce seedlings from the beginning of the row, the second and subsequent biogroups in these rows – after 9 spruce seedlings. The first biogroup in even-numbered rows (2, 4, 6, 8, etc.) is planted after 9 spruce seedlings from the beginning of the row, maintaining this sequence until the end of the row. Every row in mixed plantations is concluded with planting no less than 3 spruce seedlings. During silvicultural treatment procedures natural regeneration is completely removed: softwoods – by mechanical means, and hard woods – by ringing or injection of environmentally friendly water-based chemicals. These measures reduce or eliminate the appearance of coppice and, accordingly, food reserve for wild animals. Spruce trees adjacent to stone pine biogroups are cut down while lightening and thinning, which creates the possibility for the growth of stone pines. The proposed method for cultivating plantations of Siberian stone pines and Siberian spruce trees has been patented. It can be introduced into silvicultural practice in the taiga zone where stone pines are grown.

Height increment patterns in Pinus pinaster seedlings emerging in naturally regenerated gaps

Abstract The group selection cutting system provides a promising technique for transforming monospecific even-aged stands into uneven-aged, mixed stands. However, this system has scarcely been used to regenerate Mediterranean shade-intolerant species. In this study, we analyze the height increment patterns of Pinus pinaster seedlings emerging in naturally regenerated gaps. P. pinaster is a shade-intolerant pine species distributed throughout the Mediterranean basin. An experimental trial was established in a 50-year-old P. pinaster (maritime pine) plantation located in the mountains of central Spain. Gaps of two different sizes (diameter equal to 1.5 and 2.5 times the dominant height of the stand, 26 and 44 m, respectively) were opened during winter 2017–18. A total of 531 subplots with a 1-m radius were installed in spring 2018, distributed within the gaps as well as in control plots adjacent to the gaps. Seedlings were tagged individually and variables including height, along with other ecological variables, were collected twice a year (in spring and autumn), providing six time intervals for the development of our models. We applied seemingly unrelated regression to analyze the height growth in this polycyclic species, allowing us to model spring and autumn height increments at the same time. Our results showed that seedling height growth depended on the silvicultural treatment, meteorological conditions during the spring growth season, inter-specific scrub competition, position within the gap, and seedling characteristics, such as the ontogenetic development or the size of the seedling itself. This work, along with germination and survival analysis, aims to provide a holistic perspective on the suitability of the group selection cutting system to regenerate maritime pine stands, taking into account current and future climate change scenarios.

Modeling basal area yield using simultaneous equation systems incorporating uncertainty estimators

Abstract Over the last three decades, many growth and yield systems developed for the southeast USA have incorporated methods to create a compatible basal area (BA) prediction and projection equation. This technique allows practitioners to calibrate BA models using both measurements at a given arbitrary age, as well as the increment in BA when time series panel data are available. As a result, model parameters for either prediction or projection alternatives are compatible. One caveat of this methodology is that pairs of observations used to project forward have the same weight as observations from a single measurement age, regardless of the projection time interval. To address this problem, we introduce a variance–covariance structure giving different weights to predictions with variable intervals. To test this approach, prediction and projection equations were fitted simultaneously using an ad hoc matrix structure. We tested three different error structures in fitting models with (i) homoscedastic errors described by a single parameter (Method 1); (ii) heteroscedastic errors described with a weighting factor ${w}_t$ (Method 2); and (iii) errors including both prediction ($\overset{\smile }{\varepsilon }$) and projection errors ($\tilde{\varepsilon}$) in the weighting factor ${w}_t$ (Method 3). A rotation-age dataset covering nine sites, each including four blocks with four silvicultural treatments per block, was used for model calibration and validation, including explicit terms for each treatment. Fitting using an error structure which incorporated the combined error term ($\overset{\smile }{\varepsilon }$ and $\tilde{\varepsilon}$) into the weighting factor ${w}_t$ (Method 3), generated better results according to the root mean square error with respect to the other two methods evaluated. Also, the system of equations that incorporated silvicultural treatments as dummy variables generated lower root mean square error (RMSE) and Akaike’s index values (AIC) in all methods. Our results show a substantial improvement over the current prediction-projection approach, resulting in consistent estimators for BA.

Quality evaluation of Nothofagus pumilio seeds linked to forest management and climatic events

Abstract Background Forest ecosystems undergo significant transformations due to harvesting and climate fluctuations, emphasizing the critical role of seeding in natural regeneration and long-term structural preservation. Climate change further amplifies these dynamics, affecting phenology across species and regions. In Tierra del Fuego (Argentina), Nothofagus pumilio (lenga) forests represent the most important timber resource, and it is managed through different silvicultural strategies. This species demonstrates notable post-disturbance regeneration, yet seed fall exhibits significant variability, leading to variations in seed quality (e.g., viability). This study aims to assess fluctuations in N. pumilio seed quality, determine how it varies concerning forest management strategies, annual productivity, and the co-occurrence of climatic phenomena including El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Results Viable seeds represented 18.4% of the total, notably higher in unharvested than in managed areas. Conversely, empty seeds were more prevalent in harvested areas (&gt; 75%). Seed quality exhibited significant differences across silvicultural treatments, except for insect-predated seeds, which had similar proportions across all areas, though dispersed retention showed higher predation. When considering years with varying production levels, high-production years favoured full and viable seeds, particularly in unharvested forests and aggregated retention, while low-production years saw reduced viability across all treatments. Quadratic models revealed that viability increased with seed production, where unharvested forests achieved the highest values. Climate variability influenced seed proportions, where ENSO+/SAM+ promoting more full and viable seeds, while ENSO–/SAM+ favoured non-predated seeds, especially in unharvested stands. Conclusions Seed quality varies among treatments and years with different levels of seeding. Variations in seed quality, linked to climatic events, influence seed viability. Seed quality plays a critical role in forest regeneration, ensuring a seedling bank for harvested stands to face climate variability. These findings are relevant for forest management and ecosystem services, considering the increasing climate variability and extreme events. Understanding these influences is crucial for Nothofagus pumilio forests' sustainability and global forest adaptation strategies.

Retaining the largest aspen stems during motor-manual release allows to control aspen suckering in young mixedwood stands

Mixedwood stands containing aspens (Populus tremuloides or P. grandidentata) often convert to hardwood-dominated stands after harvesting due to the rapid regeneration of aspen from root suckers, even when sites are promptly replanted with conifer seedlings. Without the use of herbicides, this problem is usually dealt with several passes of motor-manual (“manual”) release of overtopped seedlings. The aim of this study was to test a variation of thinning from below treatment (thinning; only 20% of the largest aspens are retained), and to compare it against two traditional release treatments: broadcast brushing (brushing; 100% removal of aspen) or crop tree release (CTR; removal of competing vegetation 60 to 90 cm around planted spruce) and an un-treated control. The thinning treatment left the 20% larger aspen stems in place, in order that they continue exerting apical dominance on smaller suckers and limit re-suckering of the treated plots. Aspen suckering and growth of planted black spruce seedlings (Picea mariana (Mill.) B.S.P) were measured two- and four-growing seasons following treatments. Results four years after release application showed that the thinning and CTR treatments reduced aspen density by 61% compared to the brushing treatment. In addition, aspen individual stem volume in the thinning treatment was almost 10 times larger than the brushing and twice that of the CTR treatments. Spruce height and ground collar diameter (GCD; 5 cm aboveground line) were both measured, and while height increment was similar in all treatments, diameter increment was greater in the thinning treatment (+42%) compared to the control, brushing and CTR treatments (+17%). Thinning yielded better short-term results than the brushing release in terms of aspen re-suckering and aspen sawlog potential, highlighting the need for adapted silvicultural treatments based on the species’ ecology.

Silviculture treatments hasten seedling growth on seismic disturbances in boreal treed fens

Seismic lines in western Canada's boreal region are linear disturbances that affect the habitat of threatened woodland caribou (Rangifer tarandus caribou). To hasten the return of forest cover and ultimately to restore caribou habitat, restoration managers use silviculture treatments in wet areas that involve the mechanical mounding of seismic lines to create artificial hummocks. Tree planting then takes place on top of these hummocks. However, the effectiveness of this silviculture technique for restoring seismic lines in peatlands is largely untested. Here we sampled incremental height growth of coniferous seedlings at 41 seismic line plots in poor and rich treed fens in northeast Alberta, Canada. We compared lines that had been treated with inverted mounding (a type of mechanical mounding) and subsequent tree planting, to nearby lines that were left untreated for natural recovery. We used generalized linear mixed models to test the effect of silviculture treatments on 5‐year growth increments of black spruce (Picea mariana) and tamarack (Larix laricina). Overall, we found that mounding and tree planting improved seedling growth compared to seismic lines regenerating naturally. However, growth responses were found to vary by species, ecosite, initial seedling size, and light availability. This suggests that site‐specific prioritization of mounding within peatlands may be more efficient considering the widespread nature of seismic lines. Future experiments testing growth responses to other mounding techniques that are designed to preserve the soil profile. It is also important for managers to weigh restoration goals beyond tree establishment and an accelerated return to forest cover.

The diversity of epixylic bryophytes in relation to dead wood properties and forest management in New Brunswick, Canada

Rotting wood is widely recognized as an important feature for bryophyte diversity in forest ecosystems but forest management practices, focused on high yields, have led to widespread reductions in the quantity and quality of coarse woody debris (CWD). As a result, many epixylic specialists are now uncommon or threatened throughout much of their former ranges. How much CWD is required to maintain desirable biodiversity, and which qualities of CWD do this most effectively is still to be answered. To address this, we analyzed two datasets from mid-rotation and mature plantations from the same landscape to better understand how the epixylic community varies with stand age, wetness, silvicultural treatment, and the abundance and type of CWD. Mature stands were either partially cut with a strip-cut treatment or were untreated. Mid-rotation plantations had a higher richness of non-Sphagnum mosses and liverworts than mature plantations. Both plantation types had a similar Simpson’s diversity indices, but these were lower than those of treated and untreated mature white cedar stands and untreated mature softwood stands. While composition of both plantation types was similar, only mature plantations differed significantly from other stand types. We speculate that this discrepancy between mid-rotation plantations and mature plantations was due to better soil drainage and a longer duration of intensive management in mature plantations, leading to reduced CWD abundance, and therefore to reduced bryophyte diversity. Our results revealed a clear positive relationship between total CWD surface area and liverwort richness and diversity in xeric sites while no relation was detected in mesic sites. More CWD is better in the case of xeric sites, where apparent asymptote of diversity is near the maximum total CWD detected in these stands. Because canopy composition and humidity also had a significant influence on bryophyte diversity and composition, further studies are needed to clearly identify thresholds of CWD surface area that take into account different stand types, soil moisture, fertility regimes, or with regards to the ecosystem in which the managed stands occurs.

Importance of geotechnical soil properties for precision Forest activities in a karst area

Some soil behaviors change significantly as water content varies over time. The particle size distribution of soils has a direct impact on mechanical properties such as soil water content, resistance to dispersion, swelling-shrinkage, fluidity, plasticity, and stickiness. This study was conducted to investigate the usability of Atterberg limits, consistency index and coefficient of linear extensibility (COLE) in the temporal planning of ecosystem restoration activities such as silvicultural interventions, tillage, afforestation, and the construction of forest roads, etc. Surface soil samples were collected from the sections numbered 263, 264, 266, 268, 317, 318, 319, 323, 324,325 and 366 of the degraded forest of the Andırın forestry operations department. The COLE, liquid limit (LL), plastic limit (PL), plasticity index and consistency index values of soil samples were determined. The LL values ranged from 17.5 to 62.4%, the PL values from 8.2 to 46.8% and the PI values from 6.4 to 15.5. The highest COLE value (0.13) was recorded in the section 318, while the lowest COLE value (0.03) was in section 325.The LL and PL values have a positive linear relationship with clay and organic matter content. All sections have karstic characteristics, but the mechanical characteristics of the soils differ significantly between the sections. Silvicultural interventions carried out especially in section 318, which had the lowest consistency index (Ic = 0.70), and sections 263, 264, 317 and 319, where the consistency index is >2,should take mechanical properties into account, and the planting time intervals should be determined, accordingly for sustainable forestry.

PRODUCTIVE FOREST RECOVERY IN LEGAL RESERVE AREA: A CASE STUDY IN EASTERN AMAZON

This study aimed to evaluate a model for Legal Reserve (LR) recovery based on a mixed timber production system (planting + natural regeneration) in the eastern Amazon, state of Pará. For data collection, seven plots of 50 m x 20 m were established, and all individuals with DBH (diameter at breast height) ≥ 5 cm were inventoried. Species diversity, horizontal structure, and commercial wood production were assessed at 13 years of age. A total of 103 species were found, distributed among 69 genera and 33 families. The population density was 1,425 individuals per hectare, and dominance corresponded to 19.45 m².ha-1. The total wood volume was 121.4 m³.ha-1, with 63.3 m³.ha-1 coming from the planted species (S. parahyba var. amazonicum) and 58.1 m³.ha-1 from natural regeneration. Among the regenerating species, Cecropia distachya showed the highest values for the evaluated parameters. The adopted model showed potential for use in LR environmental recovery, reconciling this action with revenue generation through silvicultural interventions that can be applied to the stand, aiming for wood production. To achieve this, adjustments to the regulations governing the forest management of recovering areas are necessary.

Effect of silvicultural treatments on forest diversity and structure in temperate forests under management in Durango, Mexico

&lt;p&gt;The present study evaluated the effect of silvicultural treatments on the diversity and structure of species in temperate forest ecosystems in the Municipality of Pueblo Nuevo in the State of Durango, Mexico; it was carried out to know if forest use modifies the diversity, mixture of species, spatial distribution, and dimensional differentiation of individuals in these ecosystems. The evaluation was carried out by comparing 10 plots with management history, which were measured before the application of the treatment and five years later. The diversity indices of Shannon, Simpson and Margalef were compared, as well as indices of structure of mixture of species, spatial distribution, and dimensional differentiation. According to the silvicultural treatments applied, the values of the indices do not present significant differences in their evaluations (p&amp;gt; 0.05), which indicates that forest use does not modify the diversity and structure of species of the tree stratum of this plant community.&lt;/p&gt;

Silvicultural Practices for Diversity Conservation and Invasive Species Suppression in Forest Ecosystems of the Bundala National Park, Sri Lanka.

Forest ecosystems in Sri Lanka are under pressure from intensive human activity and climate change. Invasive species are one of the greatest threats to autochthonous species and ecosystems. In Bundala National Park of Sri Lanka, there are efforts to control and limit the spreading of unwanted invasive Prosopis juliflora (Sw.) DC. and Opuntia dillenii (Ker-Gawl.) Haw., which poses a significant risk to natural ecosystem conservation. Nine different treatment variants (four replications) were used to test which management approach provides the control of Prosopis juliflora. This research is based on nine repeated measurements from 2017 to 2021 on 36 permanent research plots (each 625 m2) with 27 observed plant species and a total of 90,651 recorded plant individuals. The results confirmed that the dynamics of species richness, heterogeneity, and evenness showed significant differences between treatments during the five years of dynamics. The lowest species diversity was found in the control variant, followed by treatments based on the hard pruning and thinning of Prosopis juliflora trees. In contrast, strategies emphasizing the complete uprooting of Prosopis juliflora trees, replanting, and support of the natural regeneration of native species showed high species diversity and a high overall number of plant species. Generally, treatments had a significant effect on species diversity and the number of individuals of Prosopis juliflora, while changes in the overall number of plant species were more affected by time and succession. Silvicultural treatments including pruning, uprooting, and thinning have proven to be essential tools for nature conservation across various sites, aimed at enhancing habitat diversity in the face of ongoing climate change.

Responses at the stand and tree level to ice storm injuries in beech forests in eastern Serbia

The paper presents the study on the condition and structural stability of European beech (Fagus sylvatica L.) stands after the 2014 ice storm disturbance. The research was conducted in three pure beech stands on the Rtanj mountain in eastern Serbia. The stand condition after the ice storm was analyzed using changes in taxation elements. The assessment of tree damage was done according to the ICP Forests methodology, while the structural stability of the stands and individual trees was analyzed using the slenderness coefficient. The obtained results indicate very heterogeneous responses of beech stands to the negative impact of the ice storm. Heterogeneity is not only expressed between stands but also within individual stands. The stands after the ice storm are characterized by significantly reduced values of production indicators, but also by satisfactory stability, considering that the trees from the understory suffered the most. Statistically significant differences in the stability of trees of different dimensions expressed through the slenderness coefficient were determined. Consequently, the stands have maintained an appropriate level of stability thanks to the survival and resistance of the dominant trees that are the bearers of functions in these stands (trees with dbh &gt; 40 cm). This indicates the great potential of silvicultural treatments that can increase the stability and resistance of stands in areas with a high risk of such phenomena. In addition, repressive action in the form of salvage logging has a very important role with the aim of ensuring the continuity of stands after damage has occurred.