In this paper we consider the scalability issues of a classical data structure used for multidimensional indexing: the R-Tree. This data structure allows for an efficient retrieval of records in low-dimensional spaces and is de facto standard of the industry. Following the design guidelines of the GiST model we have implemented a prototype which supports concurrent (parallel) access and provides read committed isolation level. Using our prototype we study the impact of threads and cores on the performance of the system. In order to do this, we evaluate it in several scenarios which may occur during the course of DBMS operation.