Regeneration dynamics of subalpine fir (Abies fargesii) forest across the altitudinal range in the Shennongjia Mountains, central China

Aims Age structure and regeneration dynamics have been used to infer population response to environmental events and reconstruct forest development history.The aim of this study was to characterize and examine the differences of the age structure and regeneration dynamics of subalpine fir(Abies fargesii)forest across the altitudinal range in the north and south aspects in the Shennongjia Mountains,central China.Methods Ten plots(20×20 m)at each altitudinal zone(i.e.the low elevation,the middle elevation and the high elevation)were established in both the north and south aspects of the Shennongjia Mountains,central China.Dendroecological techniques were applied to obtain information about ages of the trees in the plots.The population age structure was analyzed to investigate the regeneration dynamics across the altitudinal range.Important findings Fir regeneration dynamics and age structure were similar in both aspects,and a unimodal population age structure was found at different altitudinal sites of both aspects,indicating that environmental factors might play an important role in shaping the regeneration dynamics and age structure of A.fargesii across its altitudinal range.There was a sustained recruitment during the 19th century,but the regeneration was rarer in the last century at low and midelevations.A significant greater number of fir seedlings and saplings recruited at high elevations in the last century,and fir tree density at high elevations was significantly higher than that at low elevations.Thus,the fir population at the high elevations showed a significant increase in recruitment and stem density in the last century,and we propose that the gradual infilling of fir seedlings might result in changes in regeneration dynamics and stand structure of the subalpine fir forest at high elevations in the Shennongjia Mountains,central China.

Regeneration Potential of Woody Species at the Side of Secondary Roads Post-Logging of Loundoungou-Toukoulaka Forest Management Unit, Republic of the Congo

Natural regeneration is the basis of a dynamic and demographic balance of plant populations. The objective of this study was to assess the natural regeneration potential of woody species along secondary roads post-logging abandoned since 2008 and 2018. In the two Annual Allowable Cuts (AAC 2008 and AAC 2018), 24 regenerating sub-plots (i.e. 12 sub-plots for AAC 2008 and 12 sub-plots for AAC 2018) with a unit area of 5 m × 5 m were delimited with a total area of 0.06 ha (i.e. 0.03 ha for each AAC). The abundance and diversity of woody species were respectively inventoried and estimated. Two estimators of the specific richness were used to estimate the floristic diversity of each Annual Allowable Cuts (AAC). The results reveal globally 88 woody species in the AAC 2008 and 241 woody species in the AAC 2018, with respective average densities of 2933 stem/ha and 8033 stem/ha. There was a very highly significant difference between the mean densities of the two AAC (Kruskal-Wallis test;H = 2.36, p-value < 0.000). The results also highlight a great diversity and a relatively high abundance of woody species in the 2018 AAC compared to the 2008 AAC. Also, the spatial structuring of the sub-plots on the basis of Principal Component Analysis (PCA) demonstrates that the floristic composition of the two AAC is globally different. The study suggests silvicultural interventions and the long-term assessment of regenerating woody species along abandoned secondary roads in order to guarantee the sustainable management of their population.

Comments on:Perioperative von Willebrand factor dynamics are associated with liver regeneration and predict outcome after liver resection

Recentlythearticle"PerioperativevonWillebrandfactordynamics are associated with liver regeneration and predict outcome afterliver resection" was published in Hepatology[1].Prof.Starlinger et al. aimed to assess the association of von Willebrand factor (vWF) levels and clinical outcome in patients with liver cancers post-liverresection(LR).Basedonthemechanismthatplatelets accumulation in the liver may promote liver regeneration after partial LR in mice, they found the vWF-dependent pattern of platelets accumulationduringliverregenerationinpatientsaftersurgery.

Species richness, forest types and regeneration of Schima in the subtropical forest ecosystem of Yunnan, southwestern China

Background: Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia.Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown.Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species' roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China.Method: We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan.Results: Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long lifespan. Four species(Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species(Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S.khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species' regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances.Conclusions: Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant(rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species.

Exploring Factors Influencing Species Natural Regeneration Response Following Harvesting in the Acadian Forests of New Brunswick

In the Acadian Forest Region of northeastern North America, forest managers are under increasing public pressure to restore the forest to a more historic, natural condition by reducing in clearcutting and promoting partial-cut treatments that more closely emulate historic, local natural disturbance regimes. However, although numerous studies on the effects of partial-cutting on forest regeneration response have been conducted in surrounding temperate and boreal forest ecosystems, there are few studies that directly explore responses to various forms of harvesting within the Acadian Forest ecosystem, with its unique mixture of northern hardwoods and boreal forest species. Here, we conducted one of the first retrospective studies on forest regeneration following a variety of harvesting methods in the Acadian Forest using univariate and multivariate regression trees to assess regeneration response in 50 naturally-regenerating, harvested forest sites in New Brunswick, Canada. Our study shows that regeneration was highly influenced by harvest type, overstory composition, and environmental conditions as reflected by ecoregion classification. Canopy opening size (as controlled by harvest method) significantly influenced the dominance of regenerating species. The presence of conspecific overstory trees increased the likelihood of their regeneration following disturbance, supporting the direct-regeneration hypothesis, especially for species with limited seed dispersal (e.g., sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.). Despite reported problems elsewhere in eastern North America, neither American beech nor balsam fir (Abies balsamea (L.) Mill.) constituted significant competition for the desired species on a broad scale, but the presence of beech was a significant deterrent for yellow birch (Betula alleghaniensis Britt.).

Dynamic microenvironment and multiple damaged tissue regeneration in a de novo and synchronized manner

Regenerative medicine has rapidly developed over the past decade and created new opportunities to repair or replace tissue or organ function lost because of congenital defects, age, diseases, or serious damage （Cheng et al., 2016a; Cheng et al., 2016b）. Regenerative medicine strategies in- clude the transplantation of bioactive factors, stem cells, or biomaterials, even the induced regeneration in a de novo, depending on the application （Fu, 2014a; Huang and Fu, 2014）. However, there are several limitations to the use of regenerative medicine in the clinic with respect to using stem cells and biomaterials.

Forest characteristics and population structure of a threatened palm tree Caryota obtusa in the karst forest ecosystem of Yunnan,China

Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China,India,Myanmar,Thailand,Laos and Vietnam.It is an economically important and threatened species and appears as a canopy dominant in some karst areas in Yunnan.We aim to clarify the forest structure,species diversity,population status and regeneration dynamics of C.obtusa in the karst forest ecosystem of Yunnan,China.We established 56 vegetation plots dominated by C.obtusa in 10 counties of southern Yunnan.Based on the plot data,we analyzed the community stratification,floristic composition and C.obtusa’s population structure.We used questionnaires to interview local people and recorded the human activity history in C.obtusa-dominated forests.Caryota obtusa palm forests were distributed on limestone mountain slopes and gullies.There were seven forest community types.The stratification of each community included arborous layer,shrub layer and understory.The communities had rich species composition.For all the plots as a whole of each community type,Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to 3.8.The diameter at breast height(DBH)-class frequency distribution of C.obtusa was a multimodal type.The regeneration was sporadic and dependent on intermediate natural disturbances.In the current population structure,a number of C.obtusa trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human disturbances.Intensive human activities terribly hindered recruitment of C.obtuse,followed by the medium intensity of human activities.