Understory and propagule bank change four and five years after low intensity prescribed burns in a mesic white pine forest

The understory and soil propagule bank of a mature northern mesic white pine (Pinus strobus L.) forest and their reaction to low intensity fire is an important component of understanding this ecosystem.  The historical fire regime includes severe surface or crown fires every 200 to 300 years with low intensity surface fires at 20 to 40 year intervals.  Fire, in proportion to its intensity, influences nutrient cycling and vegetation structure, composition and diversity.  These factors can vary at small scales and in turn affect regeneration, successional processes, wildlife habitat and more.  This study describes four and five year effects of four low intensity prescribed burns on understory vegetation and soil propagule bank. Multi Response Permutation Procedure (MRPP) indicates that richness, diversity index, species density and percent cover of understory vegetation are significantly greater in burned than control areas during spring(p=.009) and late summer(p=.005) four years after treatment.  Burned areas also differ in cover and diversity from pre-treatment conditions.Post-treatment composition will also be analyzed for any effect of varying fire intensity and will be compared to pre-treatment data using Jaccard’s Similarity Index.   The spring, 2007 post-treatment data will provide additional detail for the above comparisons. Pre and post-treatment soil propagule bank composition will be compared using Jaccard’s Index. To date 33 taxa have been identified in the propagule bank.  I expect results of this study to show that low intensity fire has an important role of stimulating understory and propagule bank dynamics which lasts at least five years.