One reason for their high productivity is their ability to fully use such soils. Light textured soils, such as sandy loams abd silt loams, are generally best, but heavier textured soils can produce excellent growth if the soil is relatively loose and friable. Even in similar climates, susceptibility to local diseases can limit hybrid growth. Cold Injury - Most serious cold injury has resulted from sudden cold in fall. Low temperatures occurring later, when the trees are fully dormant, is of little concern.
Spring frosts can injure newly emerging leaves and succulent stems.
Such damage occurs both east and west of the Cascades in Washington, but rarely kills trees. The other type of cold injury noted with older specimens of certain clones is frost cracking of the trunk. Choosing the spacing - If trees will be harvested as biomass fuel, small sized trees as young as one year can be used. Under such conditions, use close spacing - 2 x 4 feet or 4 x 4 feet. Spacing for longer cycle cuttings can range up to 20 x 20 feet, depending on the size of the tree desired .