511 JOURNAL nl' l-ORESTRV 



ating surface than smooth bark and gives a higher temperature pro- 

 vided the angle of incidence is not great, (c) Structure; scaly bark 

 is a better non-conductor than bark of a uniform close texture and 

 therefore tends to hold down a subcortical temperature, (d) Thick- 

 ness ; this tends to increase insulation. 



4. Air movement tends to increase radiation from the log and there- 

 fore tends to reduce the temperature beneath the bark. 



5. Evaporation of water from the surface layers of the bark which 

 often takes place in early morning, or following a rain, tends to reduce 

 the log temperature. 



6. Close proximity to other radiating or absorbing surfaces tends 

 to stabilize the temperature beneath the bark. 



7. Conduction of heat around a log is slow but varies with different 

 species. This results in the concentration of heat in comparatively 

 limited areas. 



