A quantitative evaluation of wood chemical components for some tree species in a forest area from east-northern Romania is presented here, through a comparative study from 1964 to 2000. Investigation upon the wood tree-rings in a Quercus robur L. tree species, as a dominant species, as regards its chemical composition and structure of the natural polymer constituents cellulose and lignin was al...

So-called annual banding has been identified in a number of speleothems in which the number of bands approximates the time interval between successive U-series dates. The apparent annual resolution of speleothem records, however, remains largely untested. Here we statistically compare variations in band thickness from a late Holocene stalagmite in Carlsbad Cavern, Southern New Mexico, USA, with...

The best result of image processing is depends on the fundamental steps, that is, to point out the true edges. Hence, it is very important to choose the edge detector, which fit best to the processing. This paper is a first step for analysing the rings in the tree ring image. In this paper we compare the various edge detection techniques towards the tree ring image and find out which fit best f...

Tree rings have frequently been used to identify the effects of earthquakes on forests, but little is known about spatial variation in the response of trees to intraplate normal faulting. This paper documents and describes the effects of tree location (distance from and position above or below the fault scarp), size and age on the response of tree rings to the 1959 magnitude 7.5 Hebgen Lake ear...

This paper presents a visualization algorithm for wood fracture simulation based on science and internal structure reconstruction. The can simulate reasonable realistic effect. First, the 3D point-cloud data of bark are obtained using laser scanner, cross-section branch is by voxelization surface mesh model. Then, outer contour shrunk inward to reconstruct annual rings fiber bundles, structures...

A centuries old lava flow, spreading from the base of the now dormant Khorgo volcano in Central Mongolia, seems an unlikely place to find history lessons. However, on spotting it, Amy Hessl wanted to explore. In this lava flow, Hessl supposed, could be clues to how, many centuries ago, a small band of nomadic horsemen took overmost of the easternworld. “We were driving by on our way to a differ...

Let Γ be a graph. The (unlabelled) configuration space UCnΓ of n points on Γ is the space of n-element subsets of Γ. The n-strand braid group of Γ, denoted BnΓ, is the fundamental group of UCnΓ. We use the methods and results of [10] to get a partial description of the cohomology rings H∗(BnT ), where T is a tree. Our results are then used to prove that BnT is a right-angled Artin group if and ...

Investigation of tree growth in Isle Royale National Park in Michigan revealed the influence of herbivores and carnivores on plants in an intimately linked food chain. Plant growth rates were regulated by cycles in animal density and responded to annual changes in primary productivity only when released from herbivory by wolf predation. Isle Royale's dendrochronology complements a rich literatu...

Annual growth ring variations in Arctic trees are often used to reconstruct surface temperature. In general, however, the growth of Arctic vegetation is limited both by temperature and light availability, suggesting that variations in atmospheric transmissivity may also influence tree-ring characteristics. Here we show that Arctic tree-ring density is sensitive to changes in light availability ...

The stable isotope ratios of carbon, oxygen, and hydrogen have been measured for a German oak in wood samples of roughly three years each, for the years 1712-1954 A.D., and correlated with the existing weather records from England, Basel, and Geneva to evaluate the empirical temperature coefficients. Isotope ratios in a second official oak, measured for the years 1530-1800 A.D., show the cold t...