Biological invasion is a growing problem, and species of the genus <i>Pinus</i> are known to be a problem in the forests southern Brazil, including Conservation Units (CUs). Here, we studied the ecology of <i>Pinus taeda</i> invasion at Rio Canoas State Park (PAERC) based on forest inventory, soil seed bank analysis and seed rain assessment in three distinct successional stages inside the park denoted as “Pinus invasion”, “Old Growth Vegetation” and “Initial Vegetation”. Forest inventory of 33 (20x20m) plots, found <i>Pinus</i> in 2 of the 3 evaluated environments. Seed rain was collected bimonthly using 33 (1x1m) seed traps for a period of one year. The major seed distribution periods were in April and June, confirming data found in the literature. The seed bank was analyzed in February (summer) and June (winter) of 2018. Samples were kept in a greenhouse for a period of 120 days each. Summer evaluation showed no emergence of <i>Pinus taeda</i> seedlings, but the winter evaluation (June) did show the emergence of seedlings. Results showed that the soil seed bank is not persistent. Accordingly, the <i>Pinus</i> invasion reported at PAERC requires a restoration program, as well as one that controls reinfestation.