Bark surface temperature measurements on the boles of wild cherry (<i>Prunus avium</i>) grown within an agroforestry system

Abstract

Bark surface temperature measurements on the boles of wild cherry (Prunus avium) grown within an agroforestry system Sheppard J., Morhart C., Spiecker H. (2016). Bark surface temperature measurements on the boles of wild cherry (Prunus avium) grown within an agroforestry system. Silva Fennica vol. 50 no. Highlights• Widely spaced trees within agroforestry systems are at risk of sun induced damages.• Bark surface temperature on the south western bole face reached nearly 50 °C in summer and experienced a maximum range of 38 °C within a 24 hour period in spring. • Maximum and minimum daily bark surface temperatures are modelled using climatic and solar position data. • The application of white paint to stems reduces the bark surface temperature. AbstractGrowing Prunus avium L. within an agroforestry system (AFS) may result in sun damage to cambial tissues on sun-exposed bole faces. There are two periods of risk of damage caused by insolation to exposed tree boles, the summer, when cambial temperatures become too high, or during winter, when the frozen dormant cambium tissue thaws and then rapidly re-freezes, a phenomenon commonly referred to as sunscald or southwest disease. Damage on the south western bole face was observed on a number of P. avium within an AFS. Five trees were sampled to assess the period in time that damage occurred. To retrospectively investigate such damage, bark surface temperature data were collected over a two year period for a further five P. avium and analysed. It was shown that bark surface temperature on the south western bole face reached nearly 50 °C during summer and experienced a maximum range of 38 °C within a 24 hour period in spring. A specially formulated white paint was applied to two trees, thus, testing a method to reduce the risk of sun damage. Two models were constructed to predict maximum and minimum daily bark surface temperature using maximum, minimum and mean daily air temperature, daily sum of sunshine hours, cloud cover, wind speed, relative humidity, maximum solar elevation and height on the tree bole as predictor variables. The damage occurred during winter 2009/2010. The models were used to identify maximum and minimum bark surface temperatures during that winter enabling the identification of possible damage events.

A Multi-Layer Model for Transpiration of Urban Trees Considering Vertical Structure

“…The highest surface temperature is in the upper layer, but that of the lower layer close to the ground is sometimes greater than that of the middle layer because of the high longwave radiation from the ground. This is similar to higher results, as with the surface temperature of the tree trunk near the surface [81]. The pattern is obvious in the 3H, north tree scenario, where the solar radiation is largely intercepted by the building, resulting in a small difference between the high and low layers.…”

“…The pattern is obvious in the 3H, north tree scenario, where the solar radiation is largely intercepted by the building, resulting in a small difference between the high and low layers. results, as with the surface temperature of the tree trunk near the surface [81]. The pattern is obvious in the 3H, north tree scenario, where the solar radiation is largely intercepted by the building, resulting in a small difference between the high and low layers.…”

Water relations in silver birch during springtime: How is sap pressurised?

“…In most other species, bark temperature can be substantially, even 20°C, higher than air temperature during the day due to warming by solar radiation (e.g. Sheppard et al 2016;Webster et al 2016). In addition, evaporation though the bark is further limited because birch bark is relatively impermeable to water vapour in comparison to other species (Geurten 1950).…”

Development of stem cracks in young hybrid aspen plantations

“…In these studies, notable differences in frequency of stem cracks as well as their length (reaching up to 2 m) were found (Christersson, 2006;Merdikes, 2015). Trees with thin and smooth bark, such as hybrid aspen, have low tolerance to rapid temperature fl uctuations (Nicolai, 1986); hence trees in orchards and urban areas are protected mainly by physical barriers and white paint on stems (Litzow & Pellett, 1983;Wagner & Kuhns, 2011;Sheppard et al, 2016). Up to now, there is no costeffi cient method to prevent stem cracks on trees in large scale plantations.…”