See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/260683953 Meteorological influences on stemflow generation across diameter size classes of two morphologically distinct deciduous species Article in International Journal of Biometeorology · March 2014 DOI: 10.1007/s00484-014-0807-7 · Source: PubMed CITATIONS READS 13 52 3 authors, including: John Toland Van Stan Jarrad Van Stan Georgia Southern University Harvard Medical School, Massachusetts Gen… 64 PUBLICATIONS 398 CITATIONS 25 PUBLICATIONS 105 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Canopy influences over microbial processes in forest critical zones View project Effects of Urbanization on Forest Canopy Ecohydrology View project All content following this page was uploaded by John Toland Van Stan on 16 July 2015. The user has requested enhancement of the downloaded file. Int J Biometeorol (2014) 58:2059–2069 DOI 10.1007/s00484-014-0807-7 ORIGINAL PAPER Meteorological influences on stemflow generation across diameter size classes of two morphologically distinct deciduous species John T. Van Stan II & Jarrad H. Van Stan & Delphis F. Levia Jr. Received: 15 November 2013 /Revised: 11 February 2014 /Accepted: 19 February 2014 /Published online: 11 March 2014 # ISB 2014 Abstract Many tree species have been shown to funnel sub- meteorological conditions). Multiple regressions performed on stantial rainfall to their stem base as stemflow flux, given a leafless canopy stemflow resulted in an inverse relationship favorable stand structure and storm conditions. As stemflow is with wind speeds, likely decoupling stemflow sheltered solely a spatially concentrated flux, prior studies have shown its on bark surfaces from VPD influences. Leaf presence generally impact on ecohydrological and biogeochemical processes increased direct stemflow associations with rainfall intensity, can be significant. Less work has been performed examining yet diminished stemflow-rainfall relationships. F. grandifolia stemflow variability from meteorological conditions com- canopies (exemplifying structures of smoother bark and greater pared to canopy structural traits. As such, this study performs branch angle) strengthened differences in stemflow associations multiple regressions: (1) to examine stemflow variability due with rainfall/mean wind speed between leaf states. These find- to event-based rainfall amount, intensity, mean wind speeds, ings are placed in a conceptual interception loss path analysis, and vapor pressure deficit; (2) across three diameter size which shows the potential to alter common interception loss classes (10–20, 21–40, and >41 cm DBH); and (3) for two estimates in high stemflow stands. common tree species in the northeastern USA of contrasting canopy morphology—Liriodendron tulipifera L. (yellow pop- Keywords Stemflow . Fagus grandifolia . Liriodendron lar) versus Fagus grandifolia Ehrh. (American beech). On the tulipifera . Canopy structure . Meteorological conditions . whole, multiple regression results yielded significant positive Tree size correlations with stemflow for rainfall amount, intensity, and mean wind speed and a significant negative correlation for vapor pressure deficit (VPD). Tree size altered stemflow- Introduction meteorological condition relationships, where larger trees strengthened indirect stemflow-VPD and direct stemflow- Forest canopy cover drastically alters hydrologic cycling at rainfall and stemflow-intensity associations. Canopies of rough- the surface through the physical interception and rerouting of er bark and lower branch angle (represented by L. tulipifera) precipitation inputs. Much of the intercepted rainfall, for in- enhanced correlations for nearly all meteorological conditions stance, is stored on canopy surfaces until evaporation back to via greater stemflow residence time (and longer exposure to the atmosphere (Carlyle-Moses and Gash 2011). The remain- ing rain droplets reach the forest floor via leaf and branch J. T. Van Stan II (*) pathways as a drip flux (throughfall) or a funneled flow down Department of Geology and Geography, Georgia Southern the main trunk (stemflow) (Levia et al. 2011). Of these two University, Statesboro, GA 30640, USA rainfall redistribution pathways, throughfall covers a larger e-mail: [email protected] infiltration area and represents the dominant proportion of J. H. Van Stan rainfall: approximately 75 % on average (Llorens and Center for Interprofessional Studies and Innovation, MGH Institute Domingo 2007; Levia et al. 2011). Throughfall has also been of Health Professions, Boston, MA 02114, USA linked to spatial patterns in soil moisture (Raat et al. 2002; Guswa 2012), fine roots (Ford and Deans 1978), groundwater D. F. Levia Jr. Departments of Geography and Plant & Soil Sciences, University of recharge (Guswa and Spence 2012), and streamwater chem- Delaware, Newark, DE 19716, USA istry (Inamdar and Mitchell 2007). As a result, throughfall has 2060 Int J Biometeorol (2014) 58:2059–2069 historically been more researched than stemflow (Levia and Kuraji et al. 2001; Levia et al. 2011) and prevailing wind Frost 2003; Levia et al. 2011). Yet, for particular species or directions show the potential to further augment stemflow storm conditions, the stemflow process is capable of applying yield by preferentially saturating dominant canopies substantial water loads over small infiltration areas around the (Herwitz and Slye 1995) or canopies of a particular structure stem (e.g., Herwitz 1986;Germeretal.2010; Van Stan and (Van Stan et al. 2011). Atmospheric moisture conditions— Levia 2010). Where this occurs, researchers have linked i.e., vapor pressure deficit (VPD)—are also expected to stemflow to the distribution of epiphytes and forest floor influence stemflow generation as Llorens et al. (1997) vegetation (Crozier and Boerner 1984; Hauck et al. 2002), noted enhanced evaporation under drier atmospheric runoff generation (Neave and Abrahams 2002), preferential conditions (which could diminish water entrained on groundwater recharge (Durocher 1990;Liangetal.2011), canopy surfaces contributing to stemflow). Muzylo soil solution chemistry (Chang and Matzner 2000), and et al. (2012) also suggested the need for analysis on hydropedological processes (Li et al. 2009)—increasing stemflow generation including VPD, indicating that it interest from the scientific community regarding the investi- may account for some of the high variability observed gation of factors controlling stemflow variability (e.g., Germer in past research (e.g., Staelens et al. 2008). et al. 2010; Levia et al. 2011). This study seeks to examine stemflow variability due to Stemflow variability has been linked to canopy structure storm meteorological conditions across three diameter size and meteorological conditions (Levia et al. 2011; Pypker et al. classes (10–20, 21–40, and >41 cm DBH) for two species of 2011). Structural traits within tree canopies—bark microrelief, contrasting canopy morphology: the rough-bark, low branch leaf and gap patterns, branch angle, etc.—are naturally het- angle, thin canopy of Liriodendron tulipifera L. (tulip poplar) erogeneous across space and time, which can hamper or versus the smooth-bark, high branch angle, thick canopy of facilitate rain droplet capture and entrainment as stemflow Fagus grandifolia Ehrh. (American beech). Specific questions (Crockford and Richardson 2000; Van Stan and Levia 2010; to address with multivariate regressions include the following: Frost and Levia 2014). Intuitively, trees of larger diameter at (1) How do storm meteorological variables influence breast height (DBH), projected crown area, and canopy den- stemflow from these species? Moreover, which meteorologi- sity can generate greater stemflow volumes (Ford and Deans cal factors exert greater control over stemflow after account- 1978; Aboal et al. 1999; Park and Hattori 2002; Pypker et al. ing for rainfall amount? (2) Do individual meteorological 2011). However, this simple tree size-to-stemflow yield rela- variables controlling stemflow, or the order of influence tionship varies considerably with the geometric orientation of among these variables, differ between the two morphological- branching and leaf surfaces, where more steeply inclined ly contrasting species? (3) Are meteorological controls differ- branches and leaves (erectophile) enhance stemflow genera- ent across trees of different sizes regardless of species? An- tion compared to more moderately (plagiophile), zero- swers to these questions would improve our understanding of (planophile), or negatively sloped branching patterns trunk storage and drainage processes in interception loss (Hutchinson and Roberts 1981; André et al. 2008; Van Stan models—e.g., the most commonly used Rutter- and Gash- et al. 2011; Frost and Levia 2014). Stemflow generation can type models (Rutter et al. 1971;Gashetal.1995; Valente be further affected by bark structure of the branches and trunk. et al. 1997)—and stemflow’s interactions with reliant Smoother bark and bark with tighter, high frequency ridge ecohydrological processes. patterns have lower water storage capacities, allowing earlier (and greater) drainage of rain droplets entrained on the branches as branchflow and ultimately stemflow (Brown and Site description Barker 1970; Levia et al. 2010; Van Stan and Levia 2010). A direct relationship between stemflow volume and rainfall Stemflow and