 One of Rolls' most-cited conclusions is that the forest used to be an open woodland forest and that European influence has enabled the cypress pine to dominate.However, many scientific authors now disagree with much of Rolls' analysis, quoting historical records from as early as the 1870s which suggest that the plant communities in the scrub have not undergone the level of alteration that Rolls suggests.However most of his history of the region is uncontested and his book remains an invaluable document for understanding the region.