The effects of urea fertilization on carbon sequestration in Douglas-fir plantations of the coastal Pacific Northwest

摘要: Abstract If long-term carbon (C) sequestration can be quantifiably attributed to forest plantation nitrogen (N) fertilization, the net C credits could used offset rising cost of fertilization and released during production, transportation, application N fertilizer effect NO x volatilized after application. The purpose our study was determine change in following second-growth Douglas-fir ( Psuedotsuga menziesii [Mirb.] Franco) plantations Pacific Northwest. content trees, understory vegetation, floor, mineral soil quantified at age 26–33 five sites, each with a fertilized plot that received total 896–1120 kg N ha − 1 as urea over 16 years paired an unfertilized control plot. Tree biomass estimated using biometric equations by subtracting difference between treatment year site establishment from final measurement. Understory vegetation on plots contained significantly more than (0.2 Mg C ha , S.D. 0.2). Nitrogen increased sequestered per tree 2.2 Mg C ha (S.D. 1.8), but there no significant increase trees No found A horizon, subsoil contents due fertilization. These results indicate that, while is greater amount stored difficulty accessing mortality assumed variability plots.