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Although the American Society for Bone and Mineral Research definition of atypical femoral fracture excludes periprosthetic fractures, fractures around the prosthesis with clinical features of atypical femoral fractures have been reported in the literature. All fractures reported thus far have been distal to the prosthetic segment; however, we encountered a case of a stress fracture in the middle of the femoral component segment. An 86-year-old woman with a history of bisphosphonate osteoporosis treatment and revisional total hip arthroplasty visited our outpatient clinic complaining of pain in the left thigh and groin. We diagnosed an incomplete atypical femoral fracture around the hip prosthesis; medical treatment was implemented. Two months later, the patient visited the emergency department with a complete subtrochanteric fracture with stem breakage. Without revision of the broken stem, two plates were applied after reduction. In this case, we recognized the possibility of a stress fracture but overlooked the possibility of stem breakage in an atypical femoral fracture. Even if it is not evident on the radiograph before complete fracture, clinicians should be alert to the signs of stress fracture in the middle of the femoral component segment, as they may be clues to atypical periprosthetic femoral fracture with stem failure. Isolated medical treatment plans are not recommended for incomplete subtrochanteric atypical periprosthetic femoral fracture. Instead, concomitant prophylactic plate fixation is recommended.

The duration of tree seedling persistence in the understory varies greatly between forests and across environmental conditions within a forest ecosystem. To examine species‐level variation in understory persistence and passage to the sapling life stage, we followed 5236 seedlings in single‐tree canopy gaps and closed canopy conditions over three years and simulated seedling passage times and the number of seedlings required to produce one 1.5‐m tall sapling of five common tree species in a hemlock–hardwood forest of Massachusetts, USA. Averaged across species, it took 26 years in gaps and 31 years under closed canopies to go from a first‐year seedling to a 1.5‐m sapling. Across species, the average number of seedlings needed for one sapling was 294 in gaps and 2674 in closed canopy environments. We observed high interspecific variation in passage times and number required for one sapling. Betula congeners and Pinus strobus took less time and significantly fewer individuals than Acer rubrum and Tsuga canadensis, which are generally regarded as more tolerant of understory conditions. The largest intraspecific difference in gaps versus closed canopy environments was for Quercus rubra, where we estimated the number of seedlings required to produce one sapling in closed canopies to be 172 times higher than in gaps. Stem breakage also increased the number of seedlings needed per sapling, especially in closed canopy environments. We evaluated our estimates in the lab by aging cross‐sections obtained from seedlings in gap and closed canopy conditions. Compared to our empirical age‐to‐height relationships, most simulations tended to underpredict seedling age for a given height, suggesting that passage times may be even longer than our simulations indicated. Our study shows that trees can persist for decades in the seedling life stage, highlighting a need for better‐parameterized recruitment processes in demographic forecasting.

Post-disturbance salvage logging mitigates economic loss after windthrow, and the value of salvaged timber is strongly linked to its quality and dimensions. We studied the occurrence of wind-induced damage of aspen in the hemiboreal forests of Latvia based on data from the National Forest Inventory and additional measurements. Individual tree data from three re-measurement periods were linked to follow a tree condition (live, broken, uprooted) and to link tree characteristics to a respective snag. Three linear models were developed to assess factors affecting the snapping height. An assortment outcome was calculated for undamaged and salvaged trees using the bucking algorithm, and timber value was calculated at three price levels. Wind-induced damage occurred for 3.4–3.6% of aspen trees, and among these, 45.8–46.6% were broken. The mean height of the broken trees was 27.3 ± 0.9 m, and it was significantly higher (both p < 0.01) compared to the height of undamaged and uprooted trees. The tested models indicated tree height as the main explanatory variable for relative snapping height, with higher trees having a lower point of the stem breakage. The other significant factor was the forest type group, indicating that trees growing on dry mineral soils had lower relative snapping height than trees growing on drained mineral soils. Stem breakage significantly (p < 0.001) reduced the volume of assortments, as compared to the volume of undamaged trees. Relative volume loss of sawlogs showed a logarithmic trend with a steep increase up to snapping height of 6 m, and it correlated tightly (r = 0.83, p < 0.001) with relative value loss of the total stem. Timber value loss had a strong, positive relation to tree diameter at breast height and fluctuated by 0.4% among different price levels. The mean volume reduction was 37.7% for sawlogs, 11.0% for pallet blocks, and 8.9% for technological wood.

Snow damage on natural stands is an important problem concerning mountainous forest management. In the present research, the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees, stand and topography were studied in mountainous forests of northern Iran. A systematic sampling design was applied to the study area (140 ha), with 122 circular plots. The grid dimension was 100 m and each plot area was 1000 m 2 . The four types of snow damage to trees include: crown damage (8.6%), stem breakage (5.4%), uprooting (3.2%), and bending (1.4%). The frequency of crown damage grew with an increase in the diameter at breast height (DBH), while the frequency of stem breakage, uprooting and bending decreased with an increase the DBH. The frequency of crown damage, stem breakage, and total damages was related to tree species ( p  < 0.01). Not all tree species were equally susceptible to snow damage. The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth. Young trees (DBH < 25 cm) were more susceptible to snow damage than other trees. Snow damage decreased by as the trees in the stand became more mixed in age. The susceptibility of trees to snow damage increased by height and slenderness coefficient. With adequate silvicultural operation, snow damage can be reduced to a minimum level in these natural forests.

Coastal forests can protect coastal areas from the effects of tsunamis. However, the coastal forests of Tohoku were destroyed by the Great East Japan Tsunami, which was triggered by a gigantic earthquake in the Pacific Ocean on 11 March 2011, causing considerable loss of life and widespread socioeconomic damage. To ensure they have a role in protecting coastal areas from the effects of tsunamis, we need to quantitatively evaluate the resistance of coastal forests to the effects of tsunamis. In this study, the critical velocities required to overturn or break the stems of Pinus thunbergii Parlat. trees were calculated from data collected during a field survey in Aomori Prefecture, Japan. The results showed that the damaged and undamaged trees had small and relatively large critical velocities, respectively. Further, trees with larger diameters tended to be overturned rather than broken. Our results are consistent with those of previous studies, which suggests that the critical velocity could be used to evaluate quantitatively evaluate the resistance of coastal forests to the effects of tsunamis.

Wind affects the structure and functioning of a forest ecosystem continuously and may cause significant economic loss in managed forests by reducing the yield of recoverable timber, increasing the cost of unscheduled thinning and clear-cuttings, and creating problems in forestry planning. Furthermore, broken and uprooted trees within the forest are subject to insect attack and may provide a suitable breeding substrate, endangering the remaining trees. Therefore, an improved understanding of the processes behind the occurrence of wind-induced damage is of interest to many forest ecologists, but may also help managers of forest resources to make appropriate management decisions related to risk management. Using fundamental physics, empirical experiments, and mechanistic model-based approaches in interaction, we can study the susceptibility of tree stands to wind damage as affected by the wind and site and tree/stand characteristics and management. Such studies are not possible based on statistical approaches alone, which are not able to define the causal links between tree parameters and susceptibility to wind damage. The aim of this paper is to review the recent work done related to tree-pulling and wind tunnel experiments and mechanistic modeling approaches to increase our understanding of the mechanical stability of trees under static loading.

Freezing rain is a frequently occurring, but relatively rarely studied disturbance in Europe, although ice accumulation may occasionally cause severe damage for forestry. We aimed to characterize ice-accumulation damage to overstory trees in spruce stands, assess the probability of damage based on the stand and individual tree parameters, and define the most significant parameters that affect the probability of individual tree damage in all stands and in recently thinned stands. Among the studied stands, the proportion of damaged overstory spruce ranged from 1.8% to 60.9% and was higher (p < 0.001) in recently thinned stands (27.8% ± 1.9%) than in the other stands (20.4% ± 1.6%). Stem breakage was the prevalent (98.5% ± 1.1%) damage type. At the stand level, the probability of damage decreased for older, less dense stands with a larger mean diameter. Within stands, overstory trees were more damaged (23.5% ± 1.2%; p < 0.001) than those in the lower stand layers, but, within overstory, trees with larger dimensions and a higher social position (high relative diameter and low slenderness ratio) and a higher proportion of crown were less damaged. The probability of breakage to overstory trees was most accurately predicted using almost the same variables for all stands and recently thinned stands. The site type, tree height, relative diameter, and crown ratio were common for both, with the addition of mean diameter at breast height for all stands and the stand density for recently thinned stands. Our results indicate the importance of the tree and stand characteristics on the resistance of individual tree to ice accumulation and the need for management practices that balance increased growth and the stability of trees throughout the rotation.

Some Acacia hybrid plantations in Vietnam are prone to heavy branching and poor stem form. The age of the stock plants used to produce cuttings for clonal propagation and/or high rates of fertiliser application at planting have been suggested as causal factors. Their effects on growth, stem form and branch size of three Acacia hybrid clones were examined in south Vietnam. Experimental treatments were: fertiliser: F-0 (no fertiliser) and F-H (high fertiliser, i.e. a mix of superphosphate and NPK (nitrogen-phosphorus-potassium) fertiliser in the planting hole at rates equivalent to 16, 45 and 8 g tree-1 of N, P and K respectively) and planting stock raised from cuttings taken from stock plants aged 1 and 4 years. Stock plant age had no effect on growth and form traits, nor were there differences between clones. Fertiliser increased growth during the first three years, but by age 4 years, had no significant effect on stem diameter or stand volume.

PurposeThe study examines the emancipatory potential of entrepreneurship for women in STEM who have experienced a mid-career break. As studies on this subject are rather scarce, it also makes an important contribution to the literature by providing key insights into the entrepreneurial journeys of women in STEM who have experienced a career break and have started their own enterprises. The findings could be used by governments to intervene in the identified areas of difficulty and to facilitate the entrepreneurial endeavours of women in order to bring this community back into the workforce.Design/methodology/approachThe study maps the entrepreneurial journeys of 23 women with a STEM background who turned into entrepreneurs after experiencing a career break. Qualitative data was collected through personal interviews with women entrepreneurs and was then analysed to interpret the results.FindingsWhile the study confirms the emancipatory potential of entrepreneurship among well-educated middle-class women with a STEM background who face constraints related to career advancement and work–life balance, it also provides insights on various aspects related to their entrepreneurial development. This includes aspects such as their motivation to start a business, major barriers they face in developing their businesses and the strategies they use to handle those barriers. Suggestions for policy development are also proposed.Originality/valueIn addition to studying the entrepreneurial aspect of a rather underexamined segment of women in STEM who have experienced a career break, the study also examines the scope of the emancipatory potential of entrepreneurship for this segment of women. To the best of our understanding, no such study on STEM women has been carried out in developing nations in spite of the fact that this segment of women forms an important techno-economic resource which remains largely underutilised in developing economies.

Naturally regenerated birch (Betula spp.) stands, to a large extent formed on abandoned agricultural lands, is a notable part of the privately owned forests in Latvia. Birch is fast growing and less frequently affected by abiotic and biotic factors (like dendrophagous insects, cervids, drought) than other main commercial tree species in Latvia. However, wind storms, predicted to increase in frequency in future, is an important risk in birch stands. Therefore, the aim of our study was to assess the snapping height of young birch stands in private forests and the financial losses caused by the damage. Information of the wind snapped trees was obtained from LSFRI Silava and height of damage was measured for 113 trees, with diameter at breast height (DBH) between 8 and 16 cm, in different private properties. Trees in naturally regenerated stands on relatively fertile (in comparison to other forest types) mineral soils with normal moisture regime or drained (corresponding to forest types Oxalidosa, Aegopodiosa and Myrtillosa mel., Mercurialiosa mel., respectively) were selected. Height of the damaged trees was measured as a sum of length of remaining high-stump and broken top, where possible, or estimated from the height curve of the specific stand. Value loss of the damaged wood was assessed as a difference in assortment price in comparison to timber from an undamaged tree of the same dimensions. Trees with DBH 8.1 to 12 cm had the mean snapping height at 5.3±1.0 m. For the larger trees significant differences between sites with normal moisture regime and drained soils were found and the height was 8.1±1.5 and 4.4±1.3 m, respectively, even so the mean DBH in both groups of trees was not significantly different. Consequently, higher financial damages were caused in stands on drained mineral soils, where the most valuable logs were affected. Overall, the wind damage caused value loss of 28 to 37% from the total stem value.