scholarly journals Vegetation dynamics and mesophication in response to conifer encroachment within an ultramafic system

2015 ◽  
Vol 63 (4) ◽  
pp. 292 ◽  
Author(s):  
J. Burgess ◽  
K. Szlavecz ◽  
N. Rajakaruna ◽  
S. Lev ◽  
C. Swan

The biological, ecological, and evolutionary significance of serpentine habitats has long been recognised. We used an integrated physiochemical dataset combining plot spatial data with temporal data from tree cores to evaluate changes in soils and vegetation. Data suggest that this unique habitat is undergoing a transition, endangering local biodiversity and endemic plant species. The objective of this work was to analyse the vegetation dynamics of a xeric serpentine savanna located in the Mid-Atlantic, USA. We employed vegetation surveys of 32 10 × 15 m quadrats to obtain woody species composition, density, basal area, and developed a spatial physiochemical dataset of substrate geochemistry to independently summarise the data using regression and ordination techniques. This information was interpreted alongside historical, dendrochronologic and soil stable carbon isotopic data to evaluate successional dynamics. Comparisons among geologic, pedologic and vegetation environmental drivers indicated broad correlations across an environmental gradient, corresponding to a grassland to forest transition. The woodland communities appear to be part of a complex soil moisture and chemistry gradient that affects the extent, density, basal area and species composition of these communities. Over the gradient, there is an increase in α diversity, a decrease in the density of xeric and invasive species, and an increase in stem density of more mesic species. Dendrochronology suggests poor recruitment of xeric species and concomitant increase in more mesic species. The data indicated that former C4-dominated grasslands were initially invaded by conifers and are now experiencing mesophication, with growing dominance by Acer, Nyssa and more mesic Quercus and Fagus species.

2020 ◽  
Vol 5 (1) ◽  
pp. 27
Author(s):  
Abir Dey ◽  
Aklima Akther

The study aimed to quantify and discuss the current condition of the tree species composition and natural regeneration of southeast parts of Bangladesh (Cox’s Bazar North Forest Division). A total of 121 stems having dbh ≥10cm and 3481 stems of regenerating tree species (dbh <10cm) per hectare were recorded. A large trees comprised of 17 species belonging to 10 families and 14 genera and 30 regenerating tree species belonging to 19 families and 27 genera have been found. The forests were highly non-uniform, with three or four species represented most of the stands. The values of diversity indices indicated limited plant diversity, which is dominated by two or three tree species. Stems of 10-30 cm dbh contributed almost 90% of the total stem density, whereas more than 80% of the total basal area still belonged to trees with dbh 100 cm or above. Dipterocarpus turbinatus was the most dominant species which have the highest Importance Value Index (IVI) with 135.82 and embodied 37.71% of the total stand density and 72.19% of total basal area. The study will provide scientific basis for the future implementation of forest conservation strategies in tropical forests of Southeast Asia, particularly in Bangladesh. This study may also pave the way to further research on regeneration potentials of the native species for conservation and enhancement of forests in future.


2019 ◽  
Vol 7 (1) ◽  
pp. 12-21
Author(s):  
Alemayehu Haiemicael Mezgebe ◽  
Alemayehu Hailemicael Mezgebe

In sacred forests of indigenous communities, landscapes are deemed sacred and are protected through social norms and spiritual values. The main objective of this study was to analyze the woody species composition of Shawo forest and explore the traditional governing systems that safeguard the sacred forest up to the present. Systematic sampling method was used to collect data. Accordingly, 42 quadrats each with 400 m2 (20 m X 20 m)  was laid along the 14 transect lines. All woody plant species were collected and identified in each of these quadrats. Vegetation parameters such as DBH an Height of each quadrat were recorded. Interview and group discussion were held with local community to gather socio-cultural information. From the result,  16 plant species were found. The average plant density was  499 individual ha-1 with  DBH and H value of  9.21 cm and 10.43 m respecitively.. The  maximum mean plant height was 39.43 m (Syzygium guineense).The total basal area of all plant species was found to be 56.1 m2.ha-1. From the total plant species of Shawo forest Syzygium guineense has the largest basal area 35.77 m2.ha-1 (63.77%) occurring in all 42 plots. The most important plant species of Shawo forest was Syzygium guineense with important value index (IVI) of 151.7 contributing to  50.57% of  total IVI. For future sustainability of Shawo forest, community traditional conservation practices should be appreciated and supported.


2006 ◽  
Vol 362 (1478) ◽  
pp. 273-289 ◽  
Author(s):  
Robin L Chazdon ◽  
Susan G Letcher ◽  
Michiel van Breugel ◽  
Miguel Martínez-Ramos ◽  
Frans Bongers ◽  
...  

Rates of change in tree communities following major disturbances are determined by a complex set of interactions between local site factors, landscape history and structure, regional species pools and species life histories. Our analysis focuses on vegetation change following abandonment of agricultural fields or pastures, as this is the most extensive form of major disturbance in Neotropical forests. We consider five tree community attributes: stem density, basal area, species density, species richness and species composition. We describe two case studies, in northeastern Costa Rica and Chiapas, Mexico, where both chronosequence and annual tree dynamics studies are being applied. These case studies show that the rates of change in tree communities often deviate from chronosequence trends. With respect to tree species composition, sites of different ages differ more than a single site followed over time through the same age range. Dynamic changes in basal area within stands, on the other hand, generally followed chronosequence trends. Basal area accumulation was more linked with tree growth rates than with net changes in tree density due to recruitment and mortality. Stem turnover rates were poor predictors of species turnover rates, particularly at longer time-intervals. Effects of the surrounding landscape on tree community dynamics within individual plots are poorly understood, but are likely to be important determinants of species accumulation rates and relative abundance patterns.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Clemence Zimudzi ◽  
Christopher Chapano

The diversity, structure, species composition, and above ground biomass of woody plants on Ngomakurira mountain in Zimbabwe were studied. A systematic random sampling approach was adopted to establish 52 sampling plots measuring 10 × 10 m across 3 study strata in the 1266 ha study area. Woody species occurring in each plot were identified and the circumferences of trees with diameters >8.0 cm at 1.3 m height were measured. A total of 91 species belonging to 74 genera and 39 families were identified in the sample plots. A Shannon-Wiener index mean value of 3.12 was obtained indicating high species diversity on the mountain. The DBH size class distribution showed inverse J distribution patterns across the three study strata, but with only 3 individual plants with DBH > 30 cm. Mean basal area was 15.21 m2 ha−1 with U. kirkiana and J. globiflora contributing approximately 30% of the basal area. The estimated above ground biomass ranged from 34.5 to 65.1 t ha−1. Kruskal-Wallis-H test showed no significant differences in species richness, stem density, basal area, above ground biomass, and evenness, across the study strata (p<0.05). Ngomakurira woodland has potential to regenerate due to the presence of many stems in the small diameter size classes.


1985 ◽  
Vol 9 (1) ◽  
pp. 52-54 ◽  
Author(s):  
Charles A. Gresham

Abstract Woody species in a Santee River Swamp area were sampled before and three growing seasons after a summer clearcut. Basal area before harvest was 140 ft², 72% of which was sweetgum (Liquidambar styraciflua), sugarberry (Celtis laevigata), ash (Fraxinus spp.), laurel oak (Quercus laurifolia), and water oak (Q. nigra). Sugarberry dominated the regeneration 3 years after harvest in all but the larger size classes. Reproduction less than 3-feet tall occurred on 39% of the sampled area while 69% of the sampled area contained one or more stems 3 feet or taller. Regeneration species composition and spatial distribution was not considered acceptable and was attributed to the lack of postharvest treatment. Shearing or prescribed fire is recommended to dispose of residual stems and logging slash. Subsequent planting seed or seedlings of cherrybark oak (Q. falcata var. pagodifolia), water oak, or sweetgum should ensure an acceptable species composition.


1989 ◽  
Vol 13 (3) ◽  
pp. 123-126 ◽  
Author(s):  
Katherine C. Ewel ◽  
H. Terrell Davis ◽  
Joel E. Smith

Abstract Vegetation analysis in ten central Florida cypress (Taxodium distichum) swamps was undertaken to determine the response of woody species composition to clearcutting. Line transects through swamps that had been harvested by clear-cutting within the last 5 years demonstrated that all but one of these swamps are likely to recover their original species composition and a normal stem density. Cypress was the major tree species in all swamps examined except one that had been severely burned by a wildfire. Both natural seedlings and vegetative propagation are important avenues of cypress reproduction following clearcutting. South. J. Appl. For. 13(3):123-126.


2021 ◽  
Author(s):  
Narasimha Hegde ◽  
Shrikanth Vasudev Gunaga ◽  
Hans Joosten

Abstract Sacred forests are of immense value for their ecosystem functions. Traditional indigenous conservation practices have helped maintaining biological diversity over centuries and have resulted in the preservation of some of the best patches of natural vegetation. Exclusive taxa find refuge in the micro-climatic conditions of sacred groves and many rare species are found here. Ten sacred swamps and ten non-sacred swamps in the central Western Ghats region, India, with a similar distance from roads, village settlements, or commercial orchards and with nearly the same size, were compared with regard to their species composition, floristic structure, diversity, occurrence of amphibians, odonates and birds. In the sacred swamps, 122 plant species from 99 genera and 58 families occur against 83 species from 72 genera and 47 families in the non-sacred swamps. Tree stem density was 277 individuals/ha in sacred swamps against 158.4 in non-sacred swamps. Average basal area was 47.57 m 2 /ha in sacred swamps and only 14.60 m 2 /ha in non-sacred swamps. Sacred swamps have higher number of endemic species (28%) when compared to non-sacred swamps. We conclude that the traditional belief system of treating the swamps as sacred has helped to protect these ecologically important forests.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Asadozzaman Nur ◽  
Rajasree Nandi ◽  
Mohammed Jashimuddin ◽  
Mohammed Akhter Hossain

Biodiversity erosion particularly in developing countries is a matter of great concern to the global ecological community. Species composition and regeneration indicate the health of forest. This study explored tree species composition and regeneration of natural hill forest of Shitalpur under Chittagong North Forest Division through 27 sample plots of 20 m × 20 m for trees and 2 m × 2 m for regeneration. A total of 47 tree species belonging to 29 families and 17 regenerating species belonging to 15 families were recorded. The tree stem density, basal area, and wood volume were 0.49 m2/ha, 1425 stem/ha, and 189.9 m3/ha, respectively. Mean regeneration was significantly higher in bottom hill (14374 seedlings/ha) compared to top hill (9671 seedlings/ha). Toona ciliata was highest (4444 seedlings/ha) at the bottom hill compared to other hill positions. The result shows that only 36% of the tree species (17 out of 47) are regenerating in the study area, meaning majority of the tree species (64%) are not getting favorable conditions to regenerate. This might be due to absence of mature tree species as a result of overexploitation by local people. The findings may help in monitoring the species composition changes over time and adopting specific conservation programs for Shitalpur Forest.


2009 ◽  
Vol 17 (5) ◽  
pp. 458 ◽  
Author(s):  
Lü Hao-rong ◽  
Liu Song-song ◽  
Zhu Jian-yun ◽  
Ye Yong-chang ◽  
Chen Hong-yue ◽  
...  

1999 ◽  
Vol 64 ◽  
Author(s):  
D. Van den Meersschaut ◽  
B. De Cuyper ◽  
K. Vandekerkhove ◽  
N. Lust

Natural  stand changes in the forest reserve of Liedekerke were analysed during the  period    1986-1996, using a permanent grid of circular plots. The monitoring  concentrated on natural    changes in species composition, using stem number and basal area as  indicators, and changes    in spatial distribution and colonization capacities of trees and shrubs,  with special interest in the    competition between exotic and indigenous species. After only a decade of  monitoring important    natural changes in the woody layer were detected. The pioneer forest is  gradually maturing    through self-thinning processes and shifts in species composition. The  overall stem number    decreased with 33.6%, while the basal area increased with 20.9%. Birch (Betula pendula/    pubescens) and indigenous oak (Quercus robur/petraea) remained  dominant. More tolerant    exotic species, like red oak (Quercus rubra) and sweet chestnut (Castanea  sativa), are slowly    increasing their share in the species composition and expanding their  range. Pioneer species on    the other hand, like aspen (Populus tremula), willow (Salix  capreaicinerealaurita), alder buckthorn    (Frangula alnus) and  common (Alnus glutinosa)  and grey alder (A. incana),  strongly declined.    Black cherry (Prunus serotina) seems to be slowly invading the forest due to its  massive    natural regeneration. Strong competition may be expected especially from  rowan ash (Sorbus    aucuparia), which showed similar regeneration  and colonization capacities. Elder (Sambucus    nigra) dramatically extented its range, though  its share remains marginal. Beech remained absent    most probably due to the lack of mature trees in the vacinity of the  forest. Finally this    change detection allowed that general predictions could be made on the  future natural development    and composition of this forest reserve, which could serve forest management  decisions.


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