We are right at the start of the fall window for street tree planting ­- October 1 through December 31 - with spring dated from March 1 through May 31, 2012. Some building owners or managers opt to wait to have the city do the planting. It will save money, but there is a downside: there may be a wait of a year or longer and N.Y.C. will most likely choose the minimum size tree, not the maximum size tree permitted. Co-op and condo boards may prefer to work with a landscape contractor. In the past, boards could hire a landscape contractor who would plant any size that the tree well(s) would accommodate and the budget would allow. Now, while the city encourages tree planting for beautification and sustainability, it is cracking down on size parameters: 2.5 inch caliper minimum, 4 inch caliper maximum. Though tree wells need to be at least 5 x 5 ft., the city wants to keep them uniform at 5 x 10 ft. if space allows. There are many other rules and regulations regarding tree planting - be sure your landscape contractor is up to date to ensure a pleasant aesthetic and ecological experience! PFI, Plant Fantasies Inc., is a full-service landscape contractor. Teresa Carleo is the president and founder of Plant Fantasies Inc., New York, N.Y.