YAF - Young Americans for Freedom

YARU - the Yale Arbovirus Research Unit (HHS)

Yarding - A method of bringing logs into a roadside area or landing, for truck transport.  Moving the cut trees from where they fell to a centralized place (landing) for hauling away from the stand.  Methods may include forms of skyline cable logging systems, ground-based skidding, balloon, helicopter, etc.

YCBR - You Could Be Right

YCIAS - The Yale Center for International and Area Studies

YCL - Young Communist League

YDS - You Don’t Say

YE - Year Easement

Year - See Climatic year; Water year. – USGS

Year-Long Grazing - Continuous grazing for a calendar year.

Yellowcake - A solid uranium-oxygen compound (U3O8) that takes its name from its color and texture. It is a product of the uranium milling process and is the feed material used for fuel enrichment and fuel pellet fabrication. - Nuclear Regulatory Commission

The Yellowstone Park Act of 1872 - Commanded the Secretary of the Interior to "provide for the preservation from injury or spoilation of ... natural curiosities or wonders within said park, and their retention in their natural condition." 

YEI - Youth Education Institute

YEP - Youth Entrepreneurship Program

YER - Young Executive Report

YGTNPWUSEIS - Yellowstone and Grand Teton National Parks Winter Use Supplemental Environmental Impact Statement

Yield - 1) Total volume of water flow from a drainage basin over a stipulated long period of time, for example, annual yield; 2) (of renewable resources) see maximum sustainable yield. (UN)

YIMBY - Yes in My Backyard  

YM - Yes Man

YMISL - The Yellow Mountain Institute for Sustainable Living

YN – Yuba Nation (formerly “American Lands Alliance”)

YNP - Yellowstone National Park (UN Biosphere Reserve)

Young-of-year - Young (usually fish) produced in one reproductive year.  Small fish, hatched from eggs spawned in the current year, are considered young-of-year (age 0).

Young Forest – See Early Successional Forest.

Young People's Participation in World Heritage Preservation and Promotion - The Young People's Participation in World Heritage Preservation and Promotion is an inter-regional project coordinated by the UNESCO World Heritage Centre and UNESCO's Associated School's Project (coordinated by UNESCO's Sector for Humanistic, Cultural and International Education).  The project was launched in 1994 in order to sensitize young people at secondary school level to the importance of World Heritage.  The project's aim is to initiate or reinforce teaching and activities in the area of World Heritage Education (WHE) and to produce an education kit to this end. - Glossary of World Heritage Terms

Youth - The age group between 15 and 24. (UN)

YRC - Yellow Ribbon Coalition

YTD - Year To Date

Y2Y - Yellowstone to Yukon Conservation Initiative

YWCA International - Young Women’s Clubs of America International