Search Results (58)

Fraxinus sogdiana Bunge is a class II key protected plant in China, known as the “living fossil of broad-leaved trees”. It is commonly found in multi-stemmed cespitose forms created by the sprouting of its root systems and stumps. We sampled plots in the east and west of the Kashi River in the Xinjiang Yili F. sogdiana National Nature Reserve. We investigated the cespitose F. sogdiana by using population ecology methods in order to provide scientific information for the conservation and sustainable development of the species as well as for the management of the reserve. We chose diameter class structure instead of age class structure to establish a population static life table, draw population survival and mortality curves, calculate a population dynamic index, and use spectral analysis to explore the fluctuation cycle of the population. The results show that age classes II–IV, comprising 74.72%, 91.53%, and 81.77% of the two cespitose populations in the east and west of the Kashi River and the total population, respectively, showed that the populations had a growing age structure. Still, there were very few individuals in age class I. The survival curves tended to be the Deevey–II type, with peak mortality occurring at age class IX in the east of the Kashi River and age class V in the west of the Kashi River. The dynamic index of populations changed the V_pi in the east and west of the Kashi River and the total population were greater than 0, indicating they were growing-type populations, and the V′_pi of the east of the Kashi River population was closer to 0, meaning that this population was relatively more resilient to external disturbances. Spectral analysis revealed that the periodic fluctuation of the population was mainly controlled by the biological characteristics of the population. Additionally, the east of the Kashi River population and the total population exhibited obvious multi-harmonic small periodic fluctuations. We suggest that the habitat of the cespitose F. sogdiana populations should be protected and improved to strengthen the nurturing management of individuals of age classes I and II for maintaining the natural renewal and development of the population. Full article

Many natural areas are colonised by the invasive species Ailanthus altissima (Mill.) Swingle. Its presence in natural ecosystems damages the ecological richness while competing with native flora. A. altissima is one of the most widespread weed species in natural areas of temperate regions such as conservation parks, archaeological sites and communication corridors. Not many active ingredients are available to control this weed since the most popular, glyphosate, has been banned by many municipalities. To test the efficacy of alternative herbicides, naturally occurring populations in Collserola Conservation Park in Barcelona (Catalonia, Spain) were treated with different herbicides using three different techniques. Aclonifen, metribuzin, flazasulfuron, metsulfuron-methyl, fluroxypyr, isoxaflutole + thiencarbazone-methyl and triclopyr mixed with 2.4-D, fluroxypyr, aminopyralid and clopyralid were applied by stem injection, cut stump injection or basal bark techniques to trees of about 5 cm diameter. Cut stump and stem injection both gave almost total control of the trees while basal bark showed more varied results depending on the herbicide. The best control was achieved when flazasulfuron or triclopyr were present as active ingredients and poorer control was observed when using metsulfuron-methyl or isoxaflutole + thiencarbazone-methyl. Aclonifen showed no damage to the trees. Metribuzin worked better if the cut stump injection technique was used. These results showed that several alternatives are available to the use of glyphosate, which has been banned for some uses due to environmental concerns. Full article

Thinning is a crucial approach to the near-natural conversion of plantations, contributing to the sustainability of forest management. However, over a rotation, the effects of thinning on tree growth, structure, and species diversity, as well as their scale-dependent outcomes, remain unclear. Ten years after conducting individual tree thinning in a Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) monoculture in southwest China, we analyzed the thinning effects within the influence zone (r = 0–2.5 m) centered around stumps and center trees. The results indicate that (1) individual tree thinning did not significantly promote the increment of diameter at breast height, volume, and biomass of Chinese fir. The four nearest Chinese fir around stumps and center trees were in a state of random distribution, high mixing, and dominance; (2) individual tree thinning significantly promoted the formation of species abundance and richness at r = 2–2.5 m. With increased scale, more species were found, leading to increased stability in diameter and species distribution. Linear and nonlinear relationships between diameter classes, mingling, and dominance became more stable; (3) later-coming populations within both modes exhibited a common characteristic of random distribution, high mixing, and disadvantage at each scale, but with significant differences in species composition (k_j = 0.22–0.61). These results suggest that individual tree thinning has limited impacts on the growth and structure of retained trees in Chinese fir plantations but significantly enhances the formation of species diversity, demonstrating scale effects. This underscores the feasibility of individual tree thinning in the near-natural conversion of plantations. Full article

The creation of artificial snags, so-called high stumps, within forest management operations is a recently established tool to enrich standing deadwood as a habitat for saproxylic species. In this study, we analysed the impact of active high stump management on saproxylic beetle species. We selected 63 high stumps in six Bavarian forest districts (Germany), which were felled and subjected to close examination, focusing on beetle (Coleoptera) colonization. We identified 63 emerged coleopteran species belonging to 29 families; a further 10 taxa were identified only at the genus or family level, respectively. Moreover, 17% of the obtained taxa are listed in the German Red List of Coleoptera. Furthermore, 32% of the examined high stump trunks, predominantly broad-leaved tree species, harboured Red List beetle taxa. In particular, trembling aspen (Populus tremula) showed a disproportionately high number of Red List beetle species. The total species richness of beetles was independent of the height, diameter and decay stage of the snags. High stumps (snags) containing Red List beetle species tended to have higher amounts of deadwood in their surroundings, but the difference was not significant. According to the results of our study, actively creating high stumps proved to be a suitable method for creating habitats and serve as stepping-stones for endangered saproxylic species. Proactive high stump management during harvest can be a valuable component of deadwood management and biodiversity protection in forests. Full article

Tropical forest management has a potential role in forest conservation if it is sustainable. This study of a forest under management in Bolivian Amazonia strongly suggests that the management project is not sustainable and that no potential changes in management would be likely to make it so. In a 216.41 ha harvested area, 278 commercial trees from 10 families, 15 genera, and 15 species were measured. The density of commercial species with diameter at breast height (DBH) ≥ 50 cm was 1.28 trees ha⁻¹, and the harvestable commercial volume was 12.40 m³ ha⁻¹. Due to market restrictions, the actual amounts harvested were much lower: 96 trees were harvested with commercial boles totaling 2.7 m³ ha⁻¹. Of the total impact on biomass and carbon (above- and belowground), the logs removed from the area represented only 13.4%, while 86.6% was from losses in the forest as follows: 14.5% from the stumps, crowns, and roots of harvested trees (DBH ≥ 50 cm) plus 72.1% from the trees (DBH ≥ 10 cm) in the forest lost to roads, log landings, and skid tracks and the gap openings caused by felling the harvested trees. The estimated expenses exceeded the gross revenue of the management company (USD 519.15 ha⁻¹), a fact confirmed by the company’s subsequent bankruptcy. The project’s low harvest intensity reduces the environmental impact per hectare but increases the impact per cubic meter of wood harvested because producing a given volume of wood requires disturbing a larger area and because more kilometers of access roads and skid tracks have to be installed to extract a given volume of wood. Because many costs are fixed regardless of harvest intensity, small harvest volume can render such projects financially unfeasible, increasing the likelihood that they will be abandoned and not provide long-term “sustainable” forest protection. However, this does not mean that higher harvest intensity results in sustainability, as other constraints apply to high-intensity projects. We conclude that conservation alternatives to maintain the forest would be more beneficial than management for timber. Full article

The European beech (Fagus sylvatica L.) is one of the most common tree species in Romania, with importance both economically and environmentally. Accurate methods of biomass assessment at the tree compartment level (i.e., stump, stem, branches, and leaves) are necessary for carbon stock estimation. Wood density (WD) is an important factor in determining biomass and, ultimately, the tree’s carbon content. The average tree density was found to be 578.6 kg/m³. For this study, WD was evaluated by the weighting method related to tree volume. Also, to investigate a practical approach to determining the weighted wood density (WWD_st), models were run using density at the base of the tree (WD_Base), density at breast height level using discs (WD_DBH), the wood core density (WD_ic), and the diameter at breast height (DBH) as predictors. The biomass assessment was conducted using different model evaluations for WWD_st as well as allometric equations using the destructive method. From the results, it was noted that using the WWD_st, the total biomass was underestimated by −0.7% compared to the biomass measured in the field. For allometric equations that included DBH and tree height as independent variables, the explained variability was around 99.3% for total aboveground biomass (AGB_total), while it was 97.9% for allometric function using just the DBH. Overall, the distribution of biomass across different compartments was as follows: 73.5% in stems, 23.8% in branches, 1.9% in stumps, and 1.3% in leaves. The study findings offer valuable insights into WD, biomass distribution among different components, and biomass allometric quantification in natural beech forest environments in mountainous areas. Full article

Efforts to enhance carbon storage in forest ecosystems through policy and management decisions rely on accurate forest biomass assessments. However, most forest inventories consider tree mortality the only form of aboveground biomass loss, overlooking other important factors, such as wood decay in living trees. In this study, using linear mixed-effects models, we delve into the sustainability of mature and over-mature deciduous forests in Latvia by conducting a comprehensive analysis of stem rot severity, identifying species for which the impact of stem rot on their carbon stock reduction was most significant. The analysis focused on determining the proportion of discolored wood, decomposed wood, and hollow spaces within the stems of 190 living deciduous trees commonly found in hemiboreal forests. The study reveals a greater extent of stem rot and more extensive decay in Populus tremula trees than in Betula spp., Alnus glutinosa, and Alnus incana. It emphasizes the influence of tree species, age, and diameter at breast height on stem rot proportions. The stump rot area significantly predicts the amount of decomposed and discolored wood within the stem. The study provides valuable insights for sustainable forestry practices and highlights challenges in estimating stem rot severity, emphasizing the need for comprehensive diagnostic methods. Full article

Smooth muscle tumors of unknown malignant potential (STUMP) represent a group of heterogeneous uterine neoplasms showing worrisome histological features, raising concerns for a malignant behavior, but do not satisfy the diagnostic criteria for leiomyosarcoma. The existing literature remains scarce due to its rarity; therefore, there is no consensus regarding diagnostic criteria, malignant potential, treatment of choice, and follow-up. The authors report their case series to analyze the heterogeneous features of this poorly understood neoplasm. A retrospective, monocentric cohort study of all patients who underwent surgery diagnosed with STUMP at the Garibaldi-Nesima Hospital in Catania from February 2018 to August 2021 was conducted. Each patient’s age at diagnosis, symptoms, surgical treatment, tumor features, postoperative management, and follow-up were recorded. Nine STUMP cases were included. All patients reported menometrorrhagia and pelvic pain. In all women, the tumor lesion was single and intramural, and the mean diameter was 7.5 cm. Four women underwent laparotomic conservative surgery. The mean postoperative follow-up time was 36 months, and recurrences were observed in two patients. In conclusion, STUMP cases should be systematically discussed by tumor boards, pathologists with good expertise in gynecological diseases should examine the histological samples, and close surveillance is mandatory because of the possibility of recurrence or metastasis. Full article

In this study, a quasi-stumps group structure was proposed and placed upstream of the bridge piers to mitigate the scour of the waterflow on the riverbed. Both experiment and numerical simulations using FLOW 3D were employed to study the protective effect of this structure. The numerical results were in good agreement with the experimental findings. It was found that the quasi-stumps group can effectively reduce the flow velocities around the bridge piers, thereby promoting the deposition of suspended sediment. As a result, there was no erosion around the piers, and instead, siltation was formed, which contributed to the stability of the piers. The deposition height around the piers increased as the L (the horizontal distance between the quasi-stumps group and the piers) decreased and both the P (the height of the quasi-stumps group) and S (the ratio of the area of a single leaf on the quasi-stumps group to the cross-sectional area of a single pier) increased. As the L, P, and S increased, the quantity of suspended sediment deposition over the entire riverbed increased. The optimal combination of the quasi-stumps group’s protective effect was determined to be L = D (pier diameter), P = H (water depth), and S = 0.148. Full article

Objectives: to analyse the clinical–pathological characteristics, treatment, and evolution of uterine smooth muscle tumours with uncertain malignant potential (STUMP) diagnosed in the Salamanca University Hospital with the implementation of the 2014 WHO criteria. Materials and methods: a retrospective descriptive study of patients diagnosed with STUMP from January 2015 to March 2023 at the Salamanca University Hospital. Demographic data, preoperative clinical data, treatment, complications, therapeutic results, anatomopathological findings and recurrence time were obtained. Results: a total of four patients were identified and included in the study. The mean age at diagnosis was 48 years (range 36–67). The surgical indications were abnormal uterine bleeding, compressive symptoms, and the growth of a pelvic mass suspected to be a degenerated myoma from the residual cervix after a subtotal hysterectomy 6 years earlier. In all cases, a laparotomic procedure was performed. A total hysterectomy, sub-total hysterectomy, and the excision of the cervix with STUMP localization were accomplished in two, one, and one patient, respectively. The mean diameter of the tumour pieces was 13 cm (range 8–17 cm), with a mean volume of 816 cc (range 234–1467 cc). The mean follow-up was 47 months, with no recurrence to date. Conclusions: STUMPs are a heterogeneous group of tumours with a difficult-to-predict clinical evolution. In most cases, their diagnosis is histological after performing surgery for suspected leiomyoma. Due to their low incidence, there are no specific guidelines for their treatment and control. However, considering their potential risk of recurrence and metastasis, it is advisable to maintain six-monthly controls for 5 years and then annual controls for 5 years more. Full article

Background and Objectives: The uterine smooth muscle tumors of uncertain malignant potential (STUMP) are tumors with pathological characteristics similar to leiomyosarcoma, but that do not satisfy histological criteria for leiomyoma. These are problematic lesions with intermediate morphologic features; thus, diagnosis and treatment are difficult. This narrative review aims to review data in the literature about STUMPs, particularly focusing on management and therapeutic options and strategies for women who desire to preserve fertility. Material and Methods: authors searched for “uterine smooth muscle tumor of uncertain malignant potential” in PubMed and Scopus databases, from 2000 to March 2023. Pertinent articles were obtained in full-text format and screened for additional references. Only articles in English language were included. Studies including full case description of patients with histopathological diagnosis of STUMP in accordance with Stanford criteria were included. Results: The median age was 43 years old. Symptoms are similar to those of leiomyomas, with a mean diameter of 8.0 cm. Total hysterectomy with or without bilateral salpingo-oophorectomy is the standard care for women if fertility desire is satisfied. Myomectomy alone can be considered for young patients. Although these tumors have not a high malignant potential, several studies described recurrence and metastases. Conclusions: STUMPs are complex uterine smooth muscle tumors, with a rare but reasoned clinical–diagnostic management. Considering the high clinical and histological complexity of these tumors, high level of expertise is mandatory. Full article

This study aimed to evaluate the effect of water immersion on the release of growth stresses in 17-year-old Eucalyptus nitens logs. A total of 18 of 90 trees evaluated in the field were selected. The average diameter at the height breast of all the trees was 37 cm. The first section of the tree, from the stump to 2.44 m, was used. Three stress levels (low, medium, and high) were established. Six logs were studied for each level, which was divided into two groups: three for control and three for water immersion. Peripheral longitudinal strains on standing trees, freshly felling, and after the immersion process were determined by an extensometer. The deflection of the sawn timber and log-end splitting before and after air-drying were evaluated. In addition, the distribution of growth stresses was determined. The results showed that deflection, the log-end splitting index, and stress distribution were reduced in the three levels. The water immersion method allowed a reduction of growth stresses in Eucalyptus nitens logs. Full article

Burn severity is commonly assessed using Burn Ratios and field measurements to provide land managers with estimates of the degree of burning in an area. However, less commonly studied is the ability of spectral indices and Burn Ratios to estimate field-measured fire effects. Past research has shown low correlations between fire effects and Landsat-derived Burn Ratios, but with the launch of the Sentinel-2 constellation, more spectral bands with finer spatial resolutions have become available. This paper explores the use of several red-edge-based indices and Burn Ratios alongside more ‘traditional’ spectral indices for predicting fire effects, measured from the Maple and Berry fires in Wyoming, USA. The fire effects include ash depth, char depth, post-fire dead lodgepole pine (Pinus contorta; PICO) density/stumps, mean basal diameter, cone density on dead post-fire trees, coarse wood percent cover/volume/mass, percent cover of ghost logs and initial regeneration of post-fire PICO/aspen density. All-possible-models regression was used to determine the best models for estimating each fire effect. Models with satisfactory R² values were constructed for post-fire dead PICO stumps (0.663), coarse wood percent cover (0.691), coarse wood volume (0.833), coarse wood mass (0.838), ash depth (0.636) and percent cover of ghost logs (0.717). Red-edge-based indices were included in all of the satisfactory models, which shows that the red-edge bands may be useful for measuring fire effects. Full article

Site class is a quantitative indicator used to evaluate site quality. It reflects site conditions, mainly climate, the suitability of soil for tree species and soil fertility. Despite the economic and ecological importance of tree competition and site class in sustainable forest management, there has been little research on its impact on the stump and coarse root biomass allocation within plantations. The stump and coarse roots were divided into five components ((stump disc (SD), stump knot (SK), coarse roots (>10 cm in diameter) (CR1), medium coarse roots (5–10 cm) (CR2) and fine coarse roots (2–5 cm) (CR3)), and the biomass of each component was obtained via the weighing method. It was found that the biomass of SD, CR1, CR2 and CR3 was mainly affected by competition (p ≤ 0.01). In the three site classes, the biomass of CR3 increased significantly with the increase in the competition index (CI) (p < 0.01); the biomass of CR1 decreased gradually. In site V, the biomass of SK, sapwood and heartwood increased significantly with the increase in CI. The results show that competition affects the allocation of stump and coarse root biomass mainly by changing the coarse root biomass. The development of stump knots is greatly influenced by site class. This study provides a reference for solving the competition mechanism underlying larch wood forest development, which will in turn promote more effective utilization of larch wood forests. This study also provides a scientific basis for accurately estimating the belowground biomass and carbon storage of artificial plantation forests. Full article

Stumps and coarse roots form an important C pool and nutrient pool in a Larix olgensis (Larix olgensis Henry) plantation ecosystem, and their decomposition processes would affect nutrient cycling dynamics of the overall Larix olgensis plantation. We studied the decomposition and release of nutrients from stumps and coarse roots that were cleared 0, 6, 16, 26 and 33 years ago in Northeast China. The stumps and coarse roots were divided into stump discs (SD), stump knots (SK), coarse roots (>10 cm in diameter) (CR1), medium-coarse roots (5–10 cm in diameter) (CR2) and fine-coarse roots (2–5 cm in diameter) (CR3). During the entire 33-year study period, SK, CR1, CR2 and CR3 lost 87.37%, 96.24%, 75.76% and 91.98% of their initial mass, respectively. The average annual decomposition rate (k) was 0.068 for SD, 0.052 for SK, 0.092 for CR1, 0.068 for CR2 and 0.066 for CR3. After 33 years of decomposition, CR3 lost 5% of its initial C, CR2 lost 2%, and SK accumulated 1%, indicating slow C release. The N residues in SK, CR1, CR2 and CR3 were 186%, 109%, 158% and 170%, respectively. Coarse roots released P significantly faster than SD and SK, with 13% of the initial P released in CR1. SD and SK release cellulose, hemicellulose and lignin faster than coarse roots. The results show that Larix olgensis stumps and coarse roots could contribute to soil fertility recovery and serve as a long-term nutrient reservoir for forest vegetation. Full article