Forest canopies cause significant reduction and redistribution of rainfall. The spatial and temporal variability of the resultant throughfall has implications for many aspects of forest econloy, including the distribution of soil moisture, soil nutrients, microbial activity, and root growth as well as influencing the processes of erosion and pedogenesis. Various properties of vegetation influence throughfall patterns suggesting that throughfall will differ where forest composition creates distinct canopy environments. The complexities of canopy-rainfall interactions necessitate on-site studies and intensive sampling to understand throughfall patterns in any given forest. This study examined the effect of forest stand characteristics on the spatial and temporal variability of throughfall with a New England forest in Whately, MA. Three stands were characterized by their overstory tree species, stage of stand development, and vertical and horizontal structures. Throughfall was collected in a fixed gird of 25 collectors in each stand for 8 multi-event periods in October and November of 2007. Data were analyzed and compared both within and among stands, seasons, and storm magnitudes. Gross precipitation, stand type, and small-scale analysis of canopy cover, were strong predictors of throughfall depth (p<0.001, R-sq=91.3%). Distance from stem, contribution of extremely wet and dry points, and metrological variables, were also important. Throughfall distribution patterns were highly variable through space and time (CVs=19.2-86.7%), but exhibited some consistencies within stand types and rainfall magnitudes, and a strong correlation with canopy cover (p<0.001,R-sq=54.4%). In addition to providing insight into the complexities of throughfall distribution, this is an important early investigation into the hydrology of Smith's property in Whately for use in further scientific research.
Webster, Alex, "Effect of stand characteristics on throughfall in a New England forest" (2008). Theses, Dissertations, and Projects. 1431.
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