Nitrogen transformations and management interactions in forests

Nitrogen is often the most limiting nutrient, and often the most limiting o f all environmental constraints, to the productivity of forests. The N cycl e is also one of the most complicated of all elemental cycles in terrestria l ecosystems. Consequently, it is important to understand its regulation in order to understand the effect that forest management practices have on N cycling and sustainable productivity of forests. Harvesting and site prepar ation result in an immediate removal of N from the site and can result in e levated losses of N for a period of time as a result of increased N turnove r. The long-term impact of these management practices depends upon the size of the remaining soil N pool, how quickly it takes for N consumptive proce sses to come back into balance with the enhanced production of NH4+ and NO3 -, and an ameliorative efforts to add N to the site through fertilization o r use of N-2-fixing plant symbioses. This recovery of the N cycle is site d ependent, of course, but can likely be achieved on many sites by carefully balancing N inputs with N removals and using the principles that regulate N cycling to design management strategies that minimize N losses and time to recovery.