Floral biology in relation to meiotic system in Buxus wallichiana Baill.: an endemic temperate tree species of North-West Himalayas

The Nucleus ◽  
2017 ◽  
Vol 60 (1) ◽  
pp. 63-68
Author(s):  
Eshan Sharma ◽  
Uma Bharti ◽  
Upvan Bhushan ◽  
Namrata Sharma
Keyword(s):  
Tree Species ◽  
Floral Biology ◽  
North West ◽  
Meiotic System

scholarly journals Resource allocation in relation to meiotic system in two species ofArtemisiafrom North-West Himalayas

Caryologia ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 351-356 ◽  
Author(s):  
Indu Sharma ◽  
Eshan Sharma ◽  
Namrata Sharma
Keyword(s):  
Resource Allocation ◽  
North West ◽  
Meiotic System

Redescription of Basiria gracilis (Thorne, 1949) Siddiqi, 1963 (Rhabditida, Tylenchidae) from South Africa

Zootaxa ◽  
2020 ◽  
Vol 4758 (2) ◽  
pp. 387-396
Author(s):  
EBRAHIM SHOKOOHI ◽  
JOAQUÍN ABOLAFIA ◽  
PHATU WILLIAM MASHELA
Keyword(s):  
South Africa ◽  
Body Length ◽  
Tree Species ◽  
Female Body ◽  
Lateral Field ◽  
North West ◽  
Line Drawings ◽  
Female Tail ◽  
Ornamental Tree ◽  
First Time

Basiria gracilis is redescribed from North West Province, South Africa, associated with willow (Salix sp.), which is a dominant ornamental tree species in the province. B. gracilis is characterised by its female body length (692–994 µm), lateral field with two longitudinal incisures, weakly cuticularised labial framework, high lip region lacking annuli, stylet 8–13 µm long, axial spermatheca filled with small rounded sperm, conical-elongated female tail with round to pointed terminus (103–146 µm, c=6.1–7.4, c’=8.8–12.1). Morphologically, B. gracilis is closely related to B. paragracilis but the taxa are differentiated on the basis of lip region and stylet morphology. In addition, B. gracilis is reported for the first time from South Africa. Line drawings, LM and SEM illustrations are given for the species. 

Pittosporum eriocarpum Royle (Pittosporaceae): An Endemic, Endangered Species of North-west Himalaya facing threat

2016 ◽  
Vol 39 (2) ◽  
pp. 169-172
Author(s):  
Amber Srivastava ◽  
S. Srivastava ◽  
L. R. Dangwal
Keyword(s):  
Endangered Species ◽  
Tree Species ◽  
Conservation Status ◽  
North West ◽  
Conservation Measures ◽  
West Himalaya ◽  
Present Distribution

The paper deals with the present distribution and conservation status with possible conservation measures of Pittosporum eriocarpum, an endangered and endemic tree species of Shiwaliks in Uttarakhand.

scholarly journals Reproductive ecology and isolation ofPsittacanthus calyculatusandP. auriculatusmistletoes (Loranthaceae)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2491 ◽  
Author(s):  
Sergio Díaz Infante ◽  
Carlos Lara ◽  
María del Coro Arizmendi ◽  
Luis E. Eguiarte ◽  
Juan Francisco Ornelas
Keyword(s):  
Breeding System ◽  
Tree Species ◽  
Floral Biology ◽  
Host Tree ◽  
Sympatric Populations ◽  
Trait Divergence ◽  
Ecological Isolation ◽  
Hand Pollination ◽  
Host Tree Species ◽  
Seed Dispersers

BackgroundRelationships between floral biology and pollinator behavior are important to understanding species diversity of hemiparasiticPsittacanthusmistletoes (c. 120 species). We aimed to investigate trait divergence linked to pollinator attraction and reproductive isolation (RI) in two hummingbird-pollinated and bird-dispersedPsittacanthusspecies with range overlap.MethodsWe investigated the phylogenetic relationships, floral biology, pollinator assemblages, seed dispersers and host usage, and the breeding system and female reproductive success of two sympatric populations ofP. calyculatusandP. auriculatus, and one allopatric population ofP. calyculatus. Flowers in sympatry were also reciprocally pollinated to assess a post-mating component ofRI.ResultsHummingbird assemblages differed betweencalyculatuspopulations, while allopatric plants ofcalyculatusopened more but smaller flowers with longer lifespans and produced less nectar than those in sympatry. Bayesian-based phylogenetic analysis indicated monophyly forcalyculatuspopulations (i.e. both populations belong to the same species). In sympatry,calyculatusplants opened more and larger flowers with longer lifespans and produced same nectar volume than those ofauriculatus; populations shared pollinators but seed dispersers and host usage differed between species. Nectar standing crops differed between sympatric populations, with lower visitation incalyculatus. Hand pollination experiments indicated a predominant outcrossing breeding system, with fruit set after interspecific pollination two times higher fromcalyculatustoauriculatusthan in the opposite direction.ConclusionsGiven the low genetic differentiation betweencalyculatuspopulations, observed trait divergence could have resulted from changes regarding the local communities of pollinators and, therefore, expected divergence for peripheral, allopatric populations. UsingRIestimates, there were fewer heterospecific matings than expected by chance inP. calyculatus(RI4A= 0.629) as compared toP. auriculatus(RI4A= 0.20). When considering other factors of ecological isolation that affect co-occurrence, theRI4Cvalues indicate that isolation by hummingbird pollinators was less effective (0.20) than isolation by host tree species and seed dispersers (0.80 and 0.60, respectively), suggesting that host usage is the most important ecological isolation factor between the two species. Accordingly, the absolute and relative cumulative strength values indicated that the host tree species’ barrier is currently contributing the most to maintaining these species in sympatry.

scholarly journals Tree species for sheltering hill pasture: some establishment results from a North Canterbury site

1990 ◽  
pp. 69-74
Author(s):  
J.W. Sturrock
Keyword(s):  
Tree Species ◽  
Growth Habit ◽  
Robinia Pseudoacacia ◽  
Species Hybrid ◽  
North West ◽  
Seasonally Dry ◽  
Pests And Diseases ◽  
Acacia Species ◽  
Successful Establishment ◽  
Derivatives Of

Species of Eucalyptus, Acacia, Robinia pseudoacacia, and 8 clonal derivatives of 3 species of hybrid cypresses were planted as a one-row shelterbelt on an exposed, unimproved and seasonally dry pasture in North Canterbury. Plots were single trees, replicated 4 times. The trial is located at 500 m altitude on a sunny, 30" slope exposed to north-west Fohn winds. Supplementary water, essential on such country, was applied initially to aid establishment. The performance of the 19 species and clones 4.5 years after planting is reported, based on survival, height growth, habit, and resistance to pests and diseases. Species are classed as 'acceptable', 'promising' and 'unsuitable', and include both tall (dominant) and complementary or 'infiller' shelter species. Currently, favourable species include Eucalyptus gunnii, E. nicholii and possibly E. tennairamis as dominants, and Acacia floribunda and x Cupressocyparis leylandii 'Leighton Green' as infillers. The importance of management for successful establishment and maintenance of effective shelter is stressed. Keywords shelter, drought, hill pasture, shelter tree species, tree clones, Euca!yptus species, Acacia species, Robinia pseudoacacia, x Cupressocypark species, hybrid cypresses, shelter management

Distribution and cytology of Quercus baloot Griff.; an endemic tree species of North-West Himalayas

The Nucleus ◽  
2013 ◽  
Vol 56 (3) ◽  
pp. 191-195 ◽  
Author(s):  
Eshan Sharma ◽  
Upvan Bushan ◽  
Geeta Sharma ◽  
Namrata Sharma
Keyword(s):  
Tree Species ◽  
North West

Do Koalas Phascolarctos cinereus use trees planted on farms? A case study from north-west New South Wales, Australia.

2014 ◽  
Vol 20 (3) ◽  
pp. 302 ◽  
Author(s):  
Susan G. Rhind ◽  
Murray V. Ellis ◽  
Martin Smith ◽  
Daniel Lunney
Keyword(s):  
Tree Species ◽  
Public Funding ◽  
Eucalyptus Species ◽  
Phascolarctos Cinereus ◽  
Faecal Pellets ◽  
North West ◽  
South Wales ◽  
Trees On Farms ◽  
Close Proximity ◽  
Source Populations

Biodiversity benefits are routinely cited as an outcome of planting trees on farms but there has been too little information to properly substantiate such claims. This study is among the first to examine the use of plantings by arboreal mammals. We examined an important inland koala population and its use of farm revegetation to determine: (1) if koalas use planted trees; (2) patch characteristics correlated with use/non-use by koalas; and, (3) contextual characteristics correlated with use/non-use. Surveys of koala dung, also known as scats or faecal pellets, were conducted under trees in 19 plantings. Fourteen showed signs of koalas and their pellets were recorded under 16 of the 25 tree taxa examined. All sizes and ages of trees were used, including the youngest plantings (six years). Considerable koala activity occurred in the various Eucalyptus species, but some tree species were not used. Koalas made substantial use of inland ironbark species, which are not listed as ‘koala food trees’ in government policy documents. Proximity to potential source populations of koalas was the strongest predictor of a planting being used, but this was further improved by including the age of the planting. There is extensive public funding available for restoration and land care activities. This study demonstrates that certain trees rapidly provide koala habitat when planted on farms and that the first priority should be restoring sites in close proximity to known koala populations. Tree species used should include local recognized food trees, as well as ironbarks and non-eucalyptus species that offer shelter.

scholarly journals Determining Harvester Productivity Curves of Thinning Operations in Birch Stands of Central Europe

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Martyna Rosińska ◽  
Mariusz Bembenek ◽  
Rodolfo Picchio ◽  
Zbigniew Karazzewski ◽  
Andreja Đuka ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Central Europe ◽  
Tree Species ◽  
Betula Pendula ◽  
North West ◽  
Breast Height ◽  
Thinning Operation ◽  
Mean Diameter ◽  
Thinning Operations ◽  
The Mean

Silver birch (Betula pendula Roth) is a popular tree species forming stands in nearly the whole of Europe. In Poland, birch is one of the most representative broadleaved species growing on rather poor soils, very often as a mix species with Scots pine (Pinus sylvestris L.). In Central Europe, birch forms trunk often with sweeps, and at the older age with thick branches. Due to that, a harvester thinning operation in birch stands can be challengeable when trying to process logs from the top part of trees, which can finally impact on productivity. The objective of this research was to determine harvester productivity for birch with particular attention to production of logs from the top part of a tree. The research was carried out in stands of North and North-West Poland. All together 21 tests were completed in 16 stands, in which 9 harvesters were used (8 different models). The mean diameter of harvested trees was 23.7 cm with the mean height of 21.7 m. Obtained productivity without delays was on average 21.98 m3 h-1 and varied from as low as 5.14 to maximum 44.66 m3 h-1, and depended mainly on harvested tree size. It was also confirmed that top diameter of the last log depended on diameter at breast height (DBH). The model developed based on that relationship can be used for prediction of biomass volume from birch stands when harvesters are used for thinning.

Ecological aspects of birch

1984 ◽  
Vol 85 (1-2) ◽  
pp. 65-72 ◽  
Author(s):  
C. H. Gimingham
Keyword(s):  
Special Reference ◽  
Tree Species ◽  
Subsequent Development ◽  
Ground Vegetation ◽  
Bare Ground ◽  
North West ◽  
Ecological Aspects ◽  
Different Types ◽  
The Status ◽  
Extreme North

SynopsisThe respective ecological amplitudes of the two British tree species of Betula are known only imperfectly. B. pendula is better represented on drier, lighter soils and is more of a southern, eastern and lowland species than B. pubescens, which belongs rather to the wetter, colder conditions of north, west and upland Britain. The contribution of the two species to different types of woodland community is briefly reviewed in this paper, and consideration is given to the status of ‘pure’ birchwoods. In some cases, the latter may have been derived from other woodland types; in others, by invasion of heath or grassland. However, some relict birchwoods above the altitudinal limits of dominance by other trees, and in the extreme north and west of Scotland, may be ‘natural’ or ‘climax’ woods.Birches show a number of characteristics of ‘r-selected’ plants and hence tend to be trees of secondary or seral woodlands. Factors determining the capacity of birch species to colonize bare ground or vegetation such as heath and grassland, are reviewed, with special reference to a study of invasion of Calluna heath at Dinnet, Aberdeenshire. The importance of the development of gaps in the Calluna canopy, or alternatively of fire, in providing suitable sites for establishment, is emphasized.Changes in the ground vegetation following the establishment of birch stands are outlined, as well as the subsequent development of seral birchwoods. Attention is drawn to the fact that many upland birchwoods are becoming moribund, and to the effects of grazing and other influences in preventing regeneration. The possibility of reversing this trend is discussed.

Sign in / Sign up

Export Citation Format

Share Document