The granulometric composition of turf-podzolic soils and the moisture content at different depths in the places of declining trees and in the healthy part of the VI-age-class pine stand affected by Heterobasidion annosum Fr.(Bref) were studied by the laying of boreholes to a depth of 1.5 m. The results of the analyses show that the higher the content of physical clay in the upper 10–30 cm layer of soil, the worst of the condition of the stand and, conversely, increase in the proportion of physical clay in the soil layers at a depth of 110–130 cm leads to its improvement. In the layers of soil at a depth of 130–150 cm, on the contrary, an increase in the proportion of physical sand contributes to drainage and removing water, and the stand condition deteriorates, whereas the increase in the physical clay in these layers, on the contrary, contributes to its holding, which positively affects the condition of the stand. Mortality-induced gaps caused by Heterobasidion annosum allow the direct rainfall on the surface and can increase the water balance of the stand by 5–25 mm depending on the gap area. Taking into account the general decrease in the growth of trees inside the decline centers and partially in the healthy part of the pine stand due to the chronic effects of the pathological process, additional rainfall input through the gaps of the decline centers are realized in the growth of part of the stand with a preserved structure.