An accuracy assessment of the Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation continuous field (VCF) tree cover product using two independent ground-based tree cover databases was conducted. Ground data included 1176 Forest Inventory and Analysis (FIA) plots for Arizona and 2778 Southwest Regional GAP (SWReGAP) plots for Utah and western Colorado. Overall rms. error was 24% for...

To determine if a graph has a spanning tree with few leaves is NP-hard. In this paper we study the parametric dual of this problem, k-INTERNAL SPANNING TREE (Does G have a spanning tree with at least k internal vertices?). We give an algorithm running in time O(2 log k · k + k · n). We also give a 2-approximation algorithm for the problem. However, the main contribution of this paper is that we...

An ex situ germplasm collection of the endangered Cycas micronesica was established in a transition zone between biodiverse native forest and mature stands of the invasive species Leucaena leucocephala. Soil chemical properties were determined for the 2 tree cover types to inform management decisions. Total carbon, total nitrogen, calcium, and net ammonification were greater in native forest co...

To detection of suitable sampling method to study tree canopy cover in the northern Zagros forest, Baneeh region forest, Kurdistan province, and west of Iran was selected. 40 square sample plots one hectare (100×100 m) were selected and perfect inventoried. In every sample plot the position of tree, kind of species and two diameter of crown (m) were recorded. To study of canopy cover different ...

To detection of suitable sampling method to study tree canopy cover in the northern Zagros forest, Baneeh region forest, Kurdistan province, and west of Iran was selected. 40 square sample plots one hectare (100×100 m) were selected and perfect inventoried. In every sample plot the position of tree, kind of species and two diameter of crown (m) were recorded. To study of canopy cover different ...

a r t i c l e i n f o Airborne Laser Scanning (ALS) data for generating Digital Terrain Models (DTM) at national level are often collected during leaf-off seasons. Leaf-off data are useful for classifying evergreen and deciduous trees since echoes at lower intensity are returned from deciduous trees when compared to evergreen trees. In addition to this, the proportion of echoes from the ground ...

Understanding the spatio-temporal dynamics of land surface phenology is important to understanding changes in landscape ecological processes of semi-arid savannas in Southern Africa. The aim of the study was to determine the influence of variation in tree cover percentage on land surface phenological response in the semi-arid savanna of Southern Africa. Various land surface phenological metrics...

Observed bimodal tree cover distributions at particular environmental conditions and theoretical models indicate that some areas in the tropics can be in either of the alternative stable vegetation states forest or savanna. However, when including spatial interaction in nonspatial differential equation models of a bistable quantity, only the state with the lowest potential energy remains stable...

Global change will likely affect savanna and forest structure and distributions, with implications for diversity within both biomes. Few studies have examined the impacts of both expected precipitation and land use changes on vegetation structure in the future, despite their likely severity. Here, we modeled tree cover in sub-Saharan Africa, as a proxy for vegetation structure and land cover ch...

Environmental limiting factors (ELFs) are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1) Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2) How are the ELFs distributed spatially? 3) To what extent are unmeasured environmental factors limi...