Biomass production of Betula pendula stands regenerated in the region of allochthonous Picea abies dieback

The paper deals with production of above-ground biomass of silver birch ( Roth) stands in the Czech Republic. One-year biomass dynamics was studied within chronosequence of birch stands at the age of 4â5, 8â9, 17â18 and 22â23 years. With the exception of the youngest stand, which was established by seeding, all experimental birch stands were regenerated naturally after the allochthonous spruce stands. Above-ground biomass (AB) was calculated from plot inventory data and biomass equations were parameterized from destructive sampling of biomass component of sampled trees. Results reveal that the peak of the mean annual increment (MAI) of birch stands can be expected at the age from 15 to 20 years. Additionally, the stand age, the value of basal area (BA) should be considered as a predictor of stand productivity. If the value of BA varied from 25 to 35 m ha, the MAI of the birch stands reached the range from 5.0 to 6.5 t of dry biomass per ha y at the age ranging between 15 and 25 years. The stem/branch proportion increased with stand age, the stem relative proportion ranging from 75 to 90% of total above-ground biomass. According to the results of this study, birch stand biomass production and utilization is one of the approaches in terms of forest recovery management in large disturbed areas. Although, no silvicultural treatments were occurred in all analysed stands, the pre-commercial thinning method could increase stand productivity and stability as well.Betula pendulaABtotal2â1â

Growth Response of Sessile Oak and European Hornbeam to Traditional Coppice-with-Standards Management

Research Highlights: The influence of litter raking and livestock grazing on the development of juvenile sessile oak and European hornbeam sprouts as well as on sessile oak standards were studied. Such experiments are very rare, especially in central Europe where these activities have been prohibited for several decades. Little is known on how these ancient management activities affect tree growth. Background and Objectives: Traditional management practices in coppice forests such as grazing and litter raking have been abandoned, but have recently been studied as to whether these practices can substantially contribute to an increase in the species diversity of coppices. The important question is, however, how these practices influence the growth of coppice-with-standards. Therefore, this study focused on the effect of grazing, litter raking, and their combination on both sprouts and adult trees in a coppice-with-standards system one year after harvest. Materials and Methods: The experiment was carried out in the area of the Training Forest Enterprise Masaryk Forest Křtiny, Czech Republic, in a forest stand dominated by sessile oak and European hornbeam. We analyzed 132 oak polycormons, 132 hornbeam polycormons, and 163 oak standards. Results: The number of sprouts per stump was affected by the stump size and management practice: (A) coppice-with-standards, litter raking, and sheep grazing; (B) coppice-with-standards and sheep grazing; (C) coppice-with-standards and litter raking; and (D) coppice-with-standards), but not by tree species. The number of the sprouts as well as their height increased with the stump size. In contrast, grazing resulted in a smaller height of the sprouts while thinner sprouts were found under a combination of grazing and raking. When comparing the species, the oak sprouts were higher and thicker when compared to the hornbeam sprouts. The increment of standards increased after stand harvest. This, however, was not the result of grazing or raking, but the response to the reduction of tree number and thus of competition between neighboring trees. Conclusions: The results showed that there were rather negative impacts from the implemented traditional management practices on the growth of sprouts. This may lead to the question of whether ecological diversity resulting from the traditional practices may prevail their negative effect on the growth of the coppices.O

Soil Microbial Functional Diversity under the Single-Season Influence of Traditional Forest Management in a Sessile Oak Forest of Central Europe

This one-year study focuses on the responses of a soil environment to the implementation of traditional forest management practices in oak-hornbeam stands with the following treatments: cut (C), cut + litter raking (CR), cut + grazing (CG), cut + litter raking + grazing (CRG) and control (Ctrl). The cut was conducted in 2018 through extremely heavy thinning. In autumn of 2017 and 2018, we sampled the soils, focusing on microbial functional diversity (FD) assessments using BIOLOG EcoplateTM. After one season, the FD was the highest in the Ctrl stand and the lowest in the CRG stand. Furthermore, we detected significant seasonal differences in soil reaction, nitrate nitrogen content, phosphatase activity and microbial biomass among the treatments. In particular, the Ctrl stand was defined via FD indices and biochemical and biological soil properties that contrasted mainly with those of the CRG stand defined by the content of mineral nitrogen forms. The soil properties did not differ substantially in the remaining treatments. Of the 31 carbon sources defining FD, 6 were treatment-specific (putrescine, L-arginine, L-serine, L-threonine, D-cellobiose and glycogen), while the remaining carbon sources mainly displayed either uniform high or low activity across the treatments.O

Development of sessile oak and European hornbeam sprouts after thinning

We observed the growth of juvenile sprouts at stool level in an oak-hornbeam selective coppice after selective thinning. We tested the relations of sprouting probability, number and height of new sprouts, and stool biometric characteristics with thinning intensity and light conditions. We compared the results between the two species. The sprouting probability, number of new sprouts, and height of new sprouts were modelled using different types of regression (logistic, generalized linear, and multiple linear regression) evaluated from 84 sessile oak (Quercus petraea Matt. Liebl.) and 139 European hornbeam (Carpinus betulus L.) stools with the same site conditions. There were no significant relations between sprouting probability and the tested parameters because nearly all stools re-sprouted. The growth (number and height) of new sprouts depended on the stool basal area before thinning and on thinning intensity. Light conditions (indirect site factor) only influenced the number of new European hornbeam sprouts in 2016 and the height of new sessile oak sprouts. The number of new sprouts in European hornbeam was higher than in sessile oak.O

A Multicenter, Long-Term Study on Arrhythmias in Children with Ebstein Anomaly

To assess the prevalence, history, and treatment of arrhythmias, in particular preexcitation and Wolff–Parkinson–White (WPW) syndrome, in patients with Ebstein anomaly (EA) during childhood and adolescence, we performed a multicenter retrospective study of all consecutive live-born patients with EA, diagnosed, and followed by pediatric cardiologists between 1980 and 2005 in The Netherlands. During a follow-up after EA diagnosis of 13 years 3 months (range: 6 days to 28 years 2 months), 16 (17%) of the 93 pediatric EA patients exhibited rhythm disturbances. Nine patients showed arrhythmic events starting as of the neonatal period. Supraventricular tachycardia was noted in 11 patients. One patient died in the neonatal period due to intractable supraventricular tachycardia resulting in heart failure and one patient died at 5 weeks of age most probably due to an arrhythmic event. The 14 surviving patients all show preexcitation, albeit 4 of them intermittently, and all have a right-sided accessory pathway location. Nine patients underwent catheter ablation of an accessory pathway. Only four patients are currently on antiarrhythmic drugs. The 17% prevalence of rhythm disturbances in pediatric EA patients, most commonly supraventricular arrhythmias, is significantly lower than in adult EA patients. Life-threatening rhythm disturbances are not frequent early in life. Symptomatic patients are well treated with radiofrequency catheter ablation