Foliage influences forced convection heat transfer in conifer branches and buds
Article first published online: 25 JAN 2006
Volume 170, Issue 1, pages 87–98, March 2006
How to Cite
Michaletz, S. T. and Johnson, E. A. (2006), Foliage influences forced convection heat transfer in conifer branches and buds. New Phytologist, 170: 87–98. doi: 10.1111/j.1469-8137.2006.01661.x
- Issue published online: 25 JAN 2006
- Article first published online: 25 JAN 2006
- Received: 18 October 2005 Accepted: 30 November 2005
- boundary layer conductance;
- boundary layer resistance;
- heat budget;
- heat transfer coefficients;
- lodgepole pine (Pinus contorta);
- shelter effect;
- white spruce (Picea glauca)
- • Conifer foliage structures affect branch and bud temperature by altering the development and convective resistance of the thermal boundary layer. This paper examines foliage effects on forced convection in branches and buds of Picea glauca (Moench) Voss and Pinus contorta Dougl. Ex. Loud., two species that represent the range of variation in foliage structure among conifers.
- • Forced convection is characterized by a power law relating Nusselt (heat transfer) and Reynolds (boundary layer development) numbers. Data were collected in a laminar flow wind tunnel for free stream velocities of 0.16–6.95 m s−1. Scaling parameters were compared against literature values for silver cast branch replicas, a bed of real foliage, cylinders, and tube banks.
- • Foliage structures reduced Nusselt numbers (heat transfer) relative to cylinders, which are typically used to approximate leafless branches and buds. Significantly different scaling relationships were observed for all foliage structures considered.
- • Forced convection scaling relationships varied with foliage structure. The scaling relationships reported here account for variation within populations of branches and buds and can be used to characterize forced convection in a forest canopy.