Wg. Thies et al., REMOVAL OF STUMPS FROM A PHELLINUS-WEIRII INFESTED SITE AND FERTILIZATION AFFECT MORTALITY AND GROWTH OF PLANTED DOUGLAS-FIR, Canadian journal of forest research, 24(2), 1994, pp. 234-239
A 2 X 4 set of factorial treatments of stump removal in combination wi
th nitrogen fertilization was applied to 0.04-ha circular plots within
a clearcut on the west slope of the Cascade Range (44 degrees 21'N, 1
22 degrees 39'W). Treatments included stump removal (either all stumps
removed or the plot left undisturbed) and broadcast fertilization wit
h ammonium nitrate (0, 336, 672, or 1345 kg N.ha(-1)). Diameter at bre
ast height and height of Douglas-fir (Pseudotsuga menziesii (Mirb.) Fr
ance) seedlings, planted 4 months after treatment, were recorded five
and nine seasons after outplanting. Soil bulk density in the upper 20
cm was measured with a single-probe neutron densimeter. Stump removal
reduced the number of seedlings killed by laminated root rot (Phellinu
s weirii (Murr.) Gilb.) but had no significant effect on seedling grow
th. Stump removal increased soil bulk density only 7% as measured 9.7
years after treatment. Fertilization increased the growth in diameter
at breast height, and height growth of the seedlings. Elevated total s
oil nitrogen could still be detected on fertilized, nonstumped plots 9
.7 years after treatment.