We develop a parallel O(NlogN) adaptive treecode for microstructural computations in 2D. The code is tested first with randomly generated data for accuracy and time complexity, and then in a boundary integral method for evolution of microstructure in elastic media. In problems
involving multiple precipitates, the number of computational markers N can be large, and an O(N^2) direct summation method becomes computationally prohibitive. It is shown that the serial version of the code is of time complexity O(NlogN), and at the same time fulfils stringent precision requirements prescribed by the spectrally accurate scheme in the boundary integral method.