The use of distributed solar photovoltaic (PV) systems is growing more common as solar energy conversion efficiencies increase while costs decrease. Thus, PV system installations are increasing in non-optimal locations such as those potentially shaded with trees. Tree-related shading can cause a significant power loss and an increasing collection of laws have been enacted and are under development to protect the right of PV owners to solar access. This paper provides a new method to predict the shading losses for a given tree species, orientation to a PV array, and geographic location using existing free tools in order to assist in the prevention of conflicts by creating an environment where PV systems and trees can coexist while maximizing PV performance. This methodology is applied to a case study in the Midwest US. Tree growth characteristics including height, crown width, and growth rate were investigated. Minimum planting distances were quantified based on tree species and orientation of planting with respect to the PV system and conclusions were drawn from the results. This novel open low-cost method to predict and prevent tree shading from negatively impacting the performance of roof-mounted PV systems assists in planning of technical design. (C) 2013 Elsevier Ltd. All rights reserved.