Nitrogen content, decay rates, and decompositional dynamics of hollow versus solid hardwood logs in hardwood forests of Minnesota, USA

Decay rates and nutrient dynamics of hardwood logs have been quantified in only a few studies over the last two decades. This study quantified and compared the nitrogen dynamics, residence times, and decay rates of hollow and solid maple and oak logs in decay classes 1 through 4. Decay parameters were not correlated with log age but did correlate with decay class. Hollow logs generally had lower percent original density and higher %N than did solid logs in each decay class. The point of maximum net immobilization of N and initial net N mineralization occurred late in decay class 1 or early in decay class 2. Residence time of logs in each decay class was low in decay class 1 (2 years), high in decay class 2 (17 years), and low in decay classes 3 and 4 (3 and 4 years, respectively). Decay rates varied by decay class, being low in decay classes 1 and 2 and high in decay classes 3 and 4.