Canopy height distributions were created from small-footprint airborne laser scanner data for mature coniferous forest in two forest areas in Norway. In total, 82 and 70 georeferenced field sample plots and 39 and 38 forest stands were measured in the two areas, respectively. The average sampling densities were 1.2 m and 0.9 m. Height percentiles, mean and maximum height values, coefficients of...

Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but they likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height because of path-length resistance and gravit...

The key to the safe mining of thick coal seams under rivers is understanding the development patterns of fractured water-conducting zones (FWCZ) when various mining methods are used. To solve this problem, we employed numerical simulation to investigate FWCZ when slice mining and longwall caving mining are performed. When slice mining was carried out, the maximum height of the FWCZ in the highe...

Little is known about tree height and height growth (as annual shoot elongation of the apical part of vertical stems) of coniferous trees growing at various altitudes on the Tibetan Plateau, which provides a high-elevation natural platform for assessing tree growth performance in relation to future climate change. We here investigated the variation of maximum tree height and annual height incre...

This paper outlines a simple algorithm for automated landing of miniature aerial vehicles (MAVs). Utilizing estimates of height above ground from barometric pressure and optic flow measurements, repeated landings were performed with a 1.5 m wingspan MAV. With height above ground estimated from barometric pressure measurements alone, landing errors averaged 7.6 m. When optic flow and barometric ...

A random m-ary leach tree is constructed from a random permutation of 1, . . . , n. A la of large numbers is obtained for the height Hn of these trees by applying the theory of branching random alks . In particular, it is sho n that Ha/log n y in probability as n ---~ oo, here y = y(m) is a constant depending upon m only. Interestingly, as m ---~ 00 , y(m) is asymptotic to 1/log m, the coeffici...

Vegetation provides important functions and services in urban areas, and vegetation heights divided into vertical and horizontal units can be used as indicators for its assessment. Conversely, detailed area-wide and updated height information is frequently missing for most urban areas. This study sought to assess three vegetation height classes from a globally available TanDEM-X digital elevati...

Field data describing the height growth of trees or stands over several decades are very scarce. Consequently, our capacity of analyzing forest dynamics over large areas and long periods of time is somewhat limited. This study proposes a new method for retrospectively reconstructing plotwise average dominant tree height based on a time series of high-resolution canopy height maps, termed canopy...

High-density airborne laser scanner data has been previously shown to provide great opportunities for individual tree detection and measurement of variables characterizing the detected trees. This paper evaluates the effect of laser flight altitude on the tree height estimation at individual tree level in the boreal forest area mainly consisting of Norway spruce, Scots pine and birch. The test ...