نتایج جستجو برای: pine cones

تعداد نتایج: 28479  

2013
William D. Stock Hugh Finn Jackson Parker Ken Dods

Pine plantations near Perth, Western Australia have provided an important food source for endangered Carnaby's Cockatoos (Calyptorhynchus latirostris) since the 1940s. Plans to harvest these plantations without re-planting will remove this food source by 2031 or earlier. To assess the impact of pine removal, we studied the ecological association between Carnaby's Cockatoos and pine using behavi...

2015
Avni Hajdari Behxhet Mustafa Gresa Ahmeti Bledar Pulaj Brigitte Lukas Alban Ibraliu Gjoshe Stefkov Cassandra L. Quave Johannes Novak

Pinus mugo Turra, is a native pine species in central and southern Europe, growing in high mountains area (altitudes 1.800-2.300 m.a.s.l.). In Kosovo, it is one of the native pines too, distributed in high altitudes in the Sharri Mountains and Albanian Alps Mountains. Its populations represent an important wealth of essential oil resources available, which make this species very important in te...

Journal: :Journal of The Royal Society Interface 2009

2006
Vesa Juntunen Seppo Neuvonen

Two different datasets were analyzed in order to clarify the factors that affect regeneration success of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) in the climatically extreme areas in northern Finland. First, pine seed maturity and the number of cones in the trees were investigated at five pairs of study sites during the period 1997–2003. Secondly, the rate of seedling estab...

Journal: :Evolution; international journal of organic evolution 2004
Adam M Siepielski Craig W Benkman

Repeated patterns among biological communities suggest similar evolutionary and ecological forces are acting on the communities. Conversely, the lack of such patterns suggests that similar forces are absent or additional ones are present. Coevolution between a seed predator, the red crossbill (Loxia curvirostra complex), and lodgepole pine (Pinus contorta var. latifolia) exemplifies the ecologi...

Journal: :Journal of the Royal Society, Interface 2009
E Reyssat L Mahadevan

We consider natural and artificial hygromorphs, objects that respond to environmental humidity by changing their shape. Using the pine cone as an example that opens when dried and closes when wet, we quantify the geometry, mechanics and dynamics of closure and opening at the cell, tissue and organ levels, building on our prior structural knowledge. A simple scaling theory allows us to quantify ...

Journal: :Ecology 2008
Adam M Siepielski Craig W Benkman

Strongly interacting species often have pronounced direct and indirect effects on other species. Here we focus of the effects of pine squirrels (Tamiasciurus spp.), which are a dominant pre-dispersal seed predator of many conifers including limber pines (Pinus flexilis) and whitebark pines (P. albicaulis). Pine squirrels depress seed abundance by harvesting most limber and whitebark pine cones ...

Journal: :Evolution; international journal of organic evolution 2001
C W Benkman W C Holimon J W Smith

The geographic mosaic theory of coevolution posits that the form of selection between interacting species varies across a landscape with coevolution important and active in some locations (i.e., coevolutionary hotspots) but not in others (i.e., coevolutionary coldspots). We tested the hypothesis that the presence of red squirrels (Tamiasciurus hudsonicus) affects the occurrence of coevolution b...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
James E Cresswell Kevin Henning Christophe Pennel Mohamed Lahoubi Michael A Patrick Phillipe G Young Gavin R Tabor

In many pine species (Family Pinaceae), ovulate cones structurally resemble a turbine, which has been widely interpreted as an adaptation for improving pollination by producing complex aerodynamic effects. We tested the turbine interpretation by quantifying patterns of pollen accumulation on ovulate cones in a wind tunnel and by using simulation models based on computational fluid dynamics. We ...

Journal: :Western North American Naturalist 2010

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