摘要：

Low-elevation ponderosa pine (Pinus ponderosa Doug. ex. laws) forests of western Montana are naturally fire maintained ecosystems. However, 80–140 years of fire-exclusion has led to the formation of dense, mixed stands of ponderosa pine and Douglas-fir (Pseudotsuga menzesii (Mirbel) Franco), an understory codominated by graminoids and ericaceous shrubs, and low N availability. Ericaceous...

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