Fungal growth and extension of the tree defense reaction zones in the phloem and in the sapwood of Douglas fir (Pseudotsuga menziesii), three weeks after artificial low density inoculations with various fungal species (three inoculations per fungal species in each tree). Results of statistical tests were not available for phloem reaction zone extension (adapted from Solheim and Krokene, 1998b). In the same tissue, values with the same letter did not differ significantly.