By Mike Allen Written for the Lee Valley Tools newsletter August, 2007 <a href="http://www.leevalley.com/newsletters/Gardening/2/4/article3.htm">http://www.leevalley.com/newsletters/Gardening/2/4/article3.htm</a> Gardeners often face tough decisions regarding the sizes of their mature trees, especially if the trees are crowding each other and casting heavy shade over shrubs, perennials and grass.