At lower elevations, the many fires that have raged over the region have left it with a mixed forest where oak and pine predominate. Several large areas of Norway spruce were planted on the north slopes of Windham High Peak during reforestation efforts following state land acquisitions in the 1930s. Due to the history of fires and logging on the northern sections of the range, there are very few areas of first-growth remaining outside of the boreal plots. The largest is the summit of Blackhead; the largest hardwood first-growth is likewise the around the summit of Windham High Peak. The eastern hemlocks around Spruce Creek below Kaaterskill Falls are also a virgin stand. They survived the era when tanners sought the species for the tannin in its bark since the steep and perilous nature of that terrain made them too difficult to profitably extract. It and many of the other ravines draining into Kaaterskill Clove also support some plants species rare in New York State, such as roseroot stonecrop and fragrant cliff fern (listed as threatened and endangered at the state level, respectively).