ORIGINAL PAPER Spatial and temporal variability of urban tree canopy temperature during summer 2010 in Berlin, Germany Fred Meier & Dieter Scherer Received: 4 January 2011 / Accepted: 8 March 2012 / Published online: 29 March 2012 # Springer-Verlag 2012 Abstract Trees form a significant part of the urban vegetation. Their meteorological and climatological effects at all scales in urban environments make them a flexible tool for creating a landscape oriented to the needs of an urban dweller. This study aims at quantifying the spatio-temporal patterns of canopy temperature (T C ) and canopy-to-air temperature difference (ΔT C ) in relation to meteorological conditions and tree- specific (physiological) and urban site-specific characteristics. We observed T C and ΔT C of 67 urban trees (18 species) using a high-resolution thermal-infrared (TIR) camera and meteorolog- ical measurements in the city of Berlin, Germany. TIR images were recorded at 1-min intervals over a period of 2 months from 1st July to 31st August 2010. The results showed that ΔT C depends on tree species, leaf size and fraction of impervious surfaces. Average canopy temperature was nearly equal to air temperature. Species-specific maximum ΔT C varied between 1.9±0.3 K (Populus nigra), 2.9±0.3 K (Quercus robur), 3.2± 0.5 K (Fagus sylvatica), 3.9±1.0 K (Platanus acerifolia), 4.6± 0.2 K (Acer pseudoplatanus), 5.0±0.5 K (A. platanoides) and 5.6±1.1 K (A. campestre). We analysed ΔT C for a hot and dry period (A) and a warm and wet period (B). The range of species-specific ΔT C at noon was nearly equal, i.e. 4.4 K for period A and 4.2 K for period B. Trees surrounded by high fraction of impervious surfaces showed consistently higher ΔT C . Knowledge of species-specific canopy temperature and the impacts of urban structures are essential in order to optimise the benefits from trees in cities. However, comprehensive evaluation and optimisation should take the full range of cli- matological effects into account. 1 Introduction From previous studies about urban vegetation and in partic- ular urban trees, we know that trees produce distinct mete- orological and climatological effects at all scales in urban environments (Heisler 1986; Oke 1989; Voogt and Oke 1997). This includes the influence of tree cover on the local-scale surface energy balance (Grimmond et al. 1996) and the reduction of canopy air temperature in comparison to the built environment by evapotranspiration and shadow- ing. However, the cooling effect differs from site to site and during the course of a day (Souch and Souch 1993; Spronken- Smith and Oke 1998; Upmanis et al. 1998; Shashua-Bar and Hoffman 2000; Potchter et al. 2006; Bowler et al. 2010). Trees reduce surface temperatures of the near surroundings (Hoyano 1988; Robitu et al. 2006; Shashua-Bar et al. 2009; Meier et al. 2010) and the building energy use (Rosenfeld et al. 1995; Akbari et al. 2001), and help to improve human thermal comfort by modifying the human energy balance (Mayer and Höppe 1987; Brown and Gillespie 1990; Streiling and Matzarakis 2003; Thorsson et al. 2004; Gulyás et al. 2006). Trees also modify the wind field in street canyons. This is important in relation to dispersion processes of pollutants (Gromke and Ruck 2007; Litschke and Kuttler 2008). However, there are only few studies regarding the spatial and temporal variation of canopy temperature of urban trees and their response to the urban environment (Montague and Kjelgren 2004; Mueller and Day 2005). According to F. Meier (*) : D. Scherer Department of Ecology, Technische Universität Berlin, Rothenburgstraße 12, 12165 Berlin, Germany e-mail: fred.meier@tu-berlin.de D. Scherer e-mail: dieter.scherer@tu-berlin.de Theor Appl Climatol (2012) 110:373–384 DOI 10.1007/s00704-012-0631-0