Perennials, defined

The parameters related to soil-related, data (to define soil solution status such as pHss, DOM or DOC, SPM) influences on HM toxicity for biota. These data should be either measured (in a few plots only) or simulated since this information is mainly not perennially monitored for forested areas of Russia. Soil pH data (water or KC1 extraction) are more available parameters as depending on soil type. The same FAO soil map with added attributive tables containing soil pH values can be used for this purpose. 

Native to tropical America, sweet potato (I. batatas) is a perennial morning glory vine that has been cultivated for over 5,000 years for its edible tubers in Mexico, Central and lowland South America, and the West Indies. Today, sweet potato is cultivated around the world, especially in developing countries (Plate 4). A decoction made from the leaves of this plant is used in folk remedies as a gargle to treat mouth and throat tumors, and poultices are prepared for inflammatory tumors (64). In Mexico, leaf decoctions are considered to be of cold nature , to reduce excessive body heat, contemporarily defined as such illnesses as diarrhea, dysentery, heart disease, stomach distress, fever, and gastrointestinal infection. In Chinese traditional medicine, the tubers have been used as a medicinal herb to eliminate secretion in perceived abnormal quantities of blood or other body fluids (79). 

The definition of a forest according to FAO (2001) is an ecosystem that is dominated by trees (defined as perennial woody plants taller than 5 m at maturity), where the tree crown (or equivalent stocking level) exceeds 10% and the area is larger than 0.5 ha. The term includes all types of forests, but excludes stands of trees established primarily for agricultural production and trees planted on agroforestry systems. 

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