Canopy precipitation interception in urban forests in relation to stand structure

Abstract

Urban forests provide important ecosystem services. In terms of hydrological benefits, forest ecosystems in urban environments represent qualitative and quantitative filter for rainwater. We quantified the canopy interception in relation to urban forest stand structure and rainfall intensity in an urban transect of the mixed (upland) forest in the city centre, towards a riparian pine forest and a floodplain hardwood forest in the City of Ljubljana, Slovenia. Bulk precipitation in open areas and throughfall were measured with fixed rainfall collectors in each forest. Stemflow was estimated from a review of relevant literature. We found that canopy interception in selected urban forests was mainly affected by tree species composition and other stand structure variables, such as canopy cover and tree dimensions. Average annual canopy interception was highest in the mixed forest (18.0% of bulk precipitation), while the riparian pine forest had the lowest level (3.9% of bulk precipitation) and the floodplain hardwood forest had the intermediate level for interception (7.1% of bulk precipitation). The mixed forest exhibited the stand structure factors that contributed to the highest canopy interception among the studied forests: high assemblage of dominant coniferous trees, denser canopy cover and the highest growing stock. Furthermore, rainfall intensity has proven to be an important factor for the seasonal partitioning (comparing the leafed and leafless period) of canopy interception. A better understanding of precipitation interception processes in urban forests is needed to assist urban forest managing and planning, aiming at maximizing canopy interception for the mitigation of stormwater runoff and flooding in urbanized watershed.

Influence of Rainfall on Canopy Interception in Mixed Broad-Leaved—Korean Pine Forest in Xiaoxing’an Mountains, Northeastern China

“…For example, Chen et al [32] and Alan and Ali [35] reported that the canopy interception ratio was inversely proportional to the rainfall intensity. Kermavnar and Vilhar [36] found that seasonal variation in canopy interception was due to different rainfall intensities. However, Li et al [37] and Peng et al [38] found that the rainfall intensity had no significant effect on canopy interception.…”

“…Some studies found that the canopy interception amount was significantly associated with the maximum rainfall intensity within the first 30 min rather than with the average rainfall intensity [39]. And several studies have reported that rainfall intensity did not have an evident impact on canopy interception in some forest types [36,40]. Therefore, whether there is an impact of rainfall intensity on canopy interception or not is still on debate.…”

“…The factors of extreme weather (e.g., typhoons, rainstorms, hailstorms, freezing disasters, etc.) [41], human activities (e.g., forest management and forest planting) [42], and urban environments [6,36] can also have a strong impact on the canopy interception. Therefore, it would be more valuable if rainfall characteristics were integrated with other influence factors (e.g., canopy characteristics, meteorological characteristics, human activities, etc.)…”

Influence of Canopy Interception of Soybean and Corn on Water Distribution of Center Pivot Sprinkling Machine

“…The previous research of canopy interception mainly tackles the impact of rainfall on canopy interception of plants [11][12][13]. Many scholars [14][15][16][17] proved that the water loss of forest ecosystem is partially attributable to the rainfall loss caused by canopy interception and the subsequent atmospheric evaporation.…”

Three Decades of Urban Forest and Green Space Research and Practice in Croatia and Slovenia

“…They cover master's theses and scientific papers mainly published by authors associated with the Faculty of Civil and Geodetic Engineering, University of Ljubljana and Slovenian Forestry Institute. The majority dealt with the effects of urban forests or urban trees in built environment, such as surface runoff [127][128][129][130][131][132][133] or quality of groundwater [134]. Thus, the hydrological aspect of urban forests seemed to be the most important.…”