These effects on tree growth, which may persist for several decades (Hatchell et al. 1970, Butt 1987, Miller et al. 1996), may lead to shortand long-term reductions in tree growth and forest productivity. The level of soil disturbance will vary with soil texture, forest floor thickness, and soil water content at time of harvest (Miller and Sirois 1986, Corns 1988). In addition, machine type, si...

Methodologies to improve Landsat TM forest classifications of alpine regions through the removal of some radiometric and geometric distortions are tested. Besides correcting for sensor and system induced errors, geometric corrections are performed using a digital elevation model. Then scene related effects such as differences in illumination as well as the height dependent atmospheric influence...

The present study deals with the estimation of tree biomass by non destructive method in tropical dry deciduous forest (DDF) and tropical mixed deciduous forest (MDF) in 0.1 ha permanent plots, established at seven sites each in seven districts of state of Madhya Pradesh in central India. Tree volume was calculated using site specific volume equation. The biomass of each species was estimated t...

Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ran...

Tree trunks are important links between the forest floor and canopy, especially for flightless invertebrates that move from the forest floor to feed or breed in the canopy. Traps were used to sample invertebrates moving up and down on mahoe (Melicytus ramiflorus), hinau (Elaeocarpus dentatus), hard beech (Nothofagus truncata), and kamahi (Weinmannia racemosa). In 19 months 22 696 invertebrates ...

Wheel slip may increase the risk for wheel rutting and tear up ground vegetation and superficial roots and thereby decreasing the bearing capacity of the ground, but also reducing the growth of nearby standing forest trees. With increased slip, more energy is consumed for making wheel ruts in the ground, with increased fuel consumption as a result. This paper proposes a novel method for measuri...

Our goal in this paper is to develop a practical framework for obtaining a uniform sample of users in an online social network (OSN) by crawling its social graph. Such a sample allows to estimate any user property and some topological properties as well. To this end, first, we consider and compare several candidate crawling techniques. Two approaches that can produce approximately uniform sampl...

Extracting digital elevationmodels (DTMs) from LiDAR data under forest canopy is a challenging task. This is because the forest canopy tends to block a portion of the LiDAR pulses from reaching the ground, hence introducing gaps in the data. This paper presents an algorithm for DTM extraction from LiDAR data under forest canopy. The algorithm copes with the challenge of low data density by gene...

Airborne laser scanning is a promising technique for efficient and accurate, remote-based forest inventory, due to its capacity for direct measurement of the three-dimensional structure of vegetation. The main objective of this study was to test the usability and accuracy of an individual tree detection approach, using reFLex software, in the evaluation of forest variables. The accuracy assessm...

Wild leek, an endangered plant species of Eastern North America, grows on forest floors and greens up to approximately three weeks before the trees it is typically found under, temporarily allowing it to be observed through the canopy by remote sensing instruments. This paper explores the accuracy with which wild leek can be mapped with a low-flying UAV. Nadir video imagery was obtained using a...