This region includes sections of the Taconic Ridge, the Hudson Valley, the Albany Pine Bush, the northern Catskills, and Leatherstocking area. Vegetation contributing to fuels vary slightly throughout the region but consist mainly of mixed northern hardwoods of oak, beech, birch, maple, hickory, ash, and cherry. The predominant conifer species is white pine, hemlock, and balsam. Shrub oak and mountain laurel are also a big factor in wildfire fuels along with open grass in the agricultural areas. Pitch pine and shrub oak are predominant in the Albany Pine Bush.
In the early spring months of March and April, the lower end of the Hudson Valley in the valley areas of Greene County and Columbia County are typically the first areas to experience wildfires. Snowmelt reveals the dried out light fuels of grasses, pine needles, dead leaves, and twigs coupled along with the lower relative humidity (30 to 40 percent RH) and steady spring winds; the conditions are just needing an ignition source. The ignition sources in the spring are nearly all contributed to human factors most of which is debris burning. As snowmelt progresses steadily north in April and May, the upper Hudson Valley through Rensselaer County, the Schoharie Valley through the Leather stocking area and sometimes the higher elevations of the Taconic Ridge and Catskills begin to also experience the spring wildfire season. Most wildfires during the spring months are surface fires driven by the wind, topography and dried out fuels from the winter. Fire intensity may be low to high with flame lengths usually less than four feet. Spotting and torching out of trees is possible but not likely. Towards the end of the spring, when the new green grass emerges and trees begin to leaf out, the spring wildfire typically comes to an end.
The next few months from May to mid September there is typically a lull in wildfires in this region due to the lush green vegetation, precipitation and higher RHs. Occasionally, prolonged periods of little to no rainfall will dry out fuels and make conditions ideal for wildfires. Because the organic matter in the ground has also dried out during this time, fires may penetrate into the ground and cause hard to extinguish “ground fire”.
Late summer and through the fall months of October and November, vegetation begins to die and fall from the trees accumulating on the forest floor adding accessible fuels to potential wildfires. The late summer and fall wildfire season occurs with periods of low precipitation and high winds are combined with an ignition source. Human cause is still the most likely factor contributing to the start of wildfires during this time but lightning strikes may also start fires. With the organic matter in the ground dried out from the summer causing ground fire and the continuing dropping of leaves, fall wildfires can be very hard to get under control. Fall wildfire season ends typically in the late fall wet pattern and the beginning of snow fall.
Generally, large fires, of 100 or more acres are not common to Region 4. The majority of wildfires are ten acres or less. However, large fire activity is possible during periods of prolonged drought conditions. Major fire years have historically been experienced when periods of lower than normal precipitation exist for three or more years in succession.