Forest influences on snow accumulation and snowmelt at the Hubbard Brook Experimental Forest, New Hampshire, USA

Abstract

Many factors influence snow depth, water content and duration in forest ecosystems. The effects of forest cover and canopy gap geometry on snow accumulation has been well documented in coniferous forests of western North America and other regions; however, few studies have evaluated these effects on snowpack dynamics in mixed deciduous forests of the northeastern USA. We measured snow depth and water equivalent near the time of peak snowpack accumulation and, again, during snowmelt to better understand the effect of forests on snowpack properties in the northeastern USA. Surveys occurred in openings and under the forest canopy at plots with different characteristics (e.g. aspect, elevation, forest composition) within the Hubbard Brook Experimental Forest in New Hampshire, USA. Snow water equivalent (SWE) was significantly greater in openings ( p = 0.021) than in forests on north‐facing plots but not on south‐facing plots ( p = 0.318) in early March 2009. One month later, SWE was more variable but remained greater in openings on north‐facing plots ( p = 0.067), whereas SWE was greater ( p = 0.071) under forests than in clearings on south‐facing plots, where snowmelt had sufficiently progressed. During peak accumulation, SWE decreased with increasing conifer cover on north‐facing plots. During the snowmelt period, SWE on south‐facing plots decreased with increasing basal area, sky view factor and diameter at breast height of trees on the plots. These results have implications for spring streamflow and soil moisture in the face of changing climate conditions and land use pressures in the forests of northern New England. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Can sugar maple establish into the boreal forest? Insights from seedlings under various canopies in southern Quebec

“…Therefore, lower mean annual soil temperature and VWC during the growing season under conifer‐dominated stands (Table ) is not uncommon (e.g., greater interception of light [Penn et al. ] and of rainfall [Carleton and Kavanagh , Lovett et al. , Barbier et al.…”

“…To germinate, maple seeds require moist stratification at temperatures slightly above freezing and below 10°C for 35-90 d Carl 1968, Godman et al 1990). Therefore, lower mean annual soil temperature and VWC during the growing season under conifer-dominated stands (Table 2) is not uncommon (e.g., greater interception of light [Penn et al 2012] and of rainfall [Carleton and Kavanagh 1990, Lovett et al 1996, Barbier et al 2009] by the persistent and dense conifer canopies). This has the potential to further (negatively) affect maple seed germination and seedling survival at early stages of growth.…”

Drivers of increased organic carbon concentrations in stream water following forest disturbance: Separating effects of changes in flow pathways and soil warming

“…Second, the water cycling in soils is altered. During spring snowmelt higher snow accumulation [Boon, 2012;Jost et al, 2007;Varhola et al, 2010] and differing melting patterns in clear-cuts may increase stream runoff at least during some years [Penn et al, 2012;Schelker et al, 2013]. However, the largest impact of forest clear-cuts on soil and stream hydrology is observed during summer, where increased discharge has been quantified [Andréassian, 2004;Bosch and Hewlett, 1982;Hornbeck et al, 1997].…”

Referee comment

“…There is evidence that snowmelt water is enriched in heavy isotopes compared to cumulative snowfall (Koeniger et al 2008, Claassen et al 1995, Ala-aho et al 2017, Earman et al 2006. Particularly so for catchments with significant snow interception, which I understand is the case in Hubbart Brook catchment (Penn et al 2012). The (few) studies reporting canopy-influenced snow enrichment over the whole snow season show enrichment of 2-3 ‰ in d18O, translating to ∼15-25 ‰ in d2H.…”