taiga

Taiga is a humid, subarctic biogeographic region of northern Asia, Europe, and North America. It is characterized by coniferous evergreens growing with a groundcover of lichens and mosses, although some broadleaf trees (aspens, birches, willows) adapted to the cold climate do occur. The taiga is found just south of tundra.

taiga soils

Acidic soils of a taiga biome due to the coniferous vegetation that typically grows there. When the coniferous needles drop, they release acids as they decompose.

taungya system

A form of agroforestry system in which short term crops are grown in the early years of the plantation of a woody perennials species in order to utilize the land, control weeds, reduce establishment costs, generate early income and stimulate the development of the woody perennials species.

taxonomy

The science of classification of organisms; the arrangement of organisms into systematic groups such as species, genus, family, and order.

natural pruning

The natural dying and breaking off of the lower branches of trees due to shading from the upper canopy.

natural resources

All the parts of the Earth that are not human-made and which people use, like fish, trees, minerals, lakes, or rivers

National Ambient Air Quality Standards

Standards which define the levels of air quality which the U.S. Environmental Protection Agency judges are necessary to provide an adequate margin of safety to protect the public health

neutral oil

An oil obtained by distillation, which is untreated with either acid or alkali

non-vascular plants

Plants, such as mosses, liverworts, and hornworts, which do not contain the specialized vascular tissue (xylem and phloem) such as is found in the ferns, gymnosperms, and angiosperms

nonrenewable resources

Natural resources that cannot be regenerated or grown at a sustainable rate to meet demand, including fossil fuels, metals, and minerals

normalized difference vegetation index

A transformation of satellite-based measurements computed as the ratio of reflectance in the red and near-infrared portions of the spectrum. Reflectance in the red region decreases with increasing chlorophyll content of the plant canopy, while reflectance in the infrared increases with increasing wet plant biomass. The index value represents greenness, density, and vigor of vegetation

nutritive value

An indication of the contribution of a food to the nutrient content of the diet. This value depends on the quantity of a food which is digested and absorbed and the amounts of the essential nutrients (protein, fat, carbohydrate, minerals, vitamins) which it contains

O-antigens

The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell.

ocean acidification

Increased concentrations of carbon dioxide in sea water causing an increase in acidity of ocean waters (i.e., a reduction in ocean pH).

oilseed cakes

The solid byproduct or residue obtained after extracting oil from oilseeds.

oilseed crops

Primarily soybeans, and other crops such as peanuts, cottonseed, sunflower seed, flaxseed, safflower seed, rapeseed, sesame seed, castor beans, canola, rapeseed, and mustard seeds used to produce edible and/or inedible oils, as well as high-protein animal meal.

old-growth forests

Stands of forest trees of either seral or climax species growing singly or in association with other tree species.

oligopeptides

Peptides composed of two to twelve amino acids joined together by peptide (amide) bonds between adjacent amino acids

olive cake

The solid byproduct or residue derived from olive pressing, that consists of pulp and pit of the olive fruit

omega-3 fatty acids

A group of fatty acids, often of marine origin, which have the first unsaturated bond in the third position from the omega carbon.