The effect of cultivation technique on root architecture of young Sitka spruce (Picea sitchensis (Bong.) Carr.) trees on surface water gleys

The research on the impact of soil cultivation / drainage practices upon root architecture of young Sitka spruce (Picea sitchensis (Bong.) Carr.) trees reported in this article was carried out in the period from 1995 to 1997. A total of 279 trees between five and eight years of age were excavated on three sites in the mid-west of Ireland. The general soil type was surface water gley. Horizontal and vertical root spread was found to be related to the size of the tree. Larger trees in the machine mound and mole and mound treated plots tended to have greater root spread compared to the smaller trees in the moled and uncultivated plots. Between the two sampling periods in 1995 (at the age of 5 years) and 1997 (at the age of 7 or 8 years) the percentage root distribution decreased close to the root stock and increased further out. However, at all three sites very little of the root cross sectional area was found beyond 60 cm from the root stock in either the vertical or the horizontal directions, even after 7 growing seasons. Generally the location of the centre of gravity of the tree root systems was not affected by cultivation treatment, nor was it found to differ significantly from the ideal co-ordinates of (0,0). Therefore, most of the root systems appeared to be symmetrical.