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In the United States, the forest cover by state and territory is estimated from tree-attributes using the basic statistics reported by the Forest Inventory and Analysis (FIA) program of the Forest Service. [2] Tree volumes and weights are not directly measured in the field, but computed from other variables that can be measured. [3] [4]
This is a list of countries and territories of the world according to the total area covered by forests, based on data published by the Food and Agriculture Organization of the United Nations (FAO). In 2010, the world had 3.92 billion hectares (ha) of tree cover , extending over 30% of its land area.
When taking forest inventory the following are important things to measure and note: species, diameter at breast height (DBH), height, site quality, age, and defects. From the data collected one can calculate the number of trees per acre, the basal area, the volume of trees in an area, and the value of the timber. Inventories can be done for ...
Forest cover in the Eastern United States reached its lowest point in roughly 1872 with about 48 percent compared to the amount of forest cover in 1620. The majority of deforestation took place prior to 1910 with the Forest Service reporting the minimum forestation as 721,000,000 acres (2,920,000 km 2) around 1920. [8]
Proportion and distribution of global forest area by climatic domain, 2020 [1] A forest is an ecosystem characterized by a dense community of trees. [2] Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function.
The normalized difference vegetation index (NDVI) is a widely-used metric for quantifying the health and density of vegetation using sensor data. It is calculated from spectrometric data at two specific bands: red and near-infrared. The spectrometric data is usually sourced from remote sensors, such as satellites.
When stocking, a tree's basal area is measured. The basal area is a cross-sectional area of the stump taken about 4.5 feet (1.4 m) above the ground. [7] The equation for calculating the basal area of trees in a stand is Basal Area = 0.005454 DBH 2, where DBH is the diameter of the tree at the aforementioned measuring height. [7]
Global Forest Watch (GFW) is an open-source web application to monitor global forests in near real-time. GFW is an initiative of the World Resources Institute (WRI), with partners including Google , USAID , the University of Maryland (UMD), Esri , Vizzuality and many other academic, non-profit, public, and private organizations.