Nachtvorst en microklimaat : in het bijzonder in jonge bosaanplant

In forestry frost may cause considerable damage. A purpose of this publication was to consider whether any of the many methods of preventing frost were suitable for forestry. Much of the research was devoted to a description of the microclimate and the relation between the physical phenomena occurring in the lowest air layers during inversion conditions.The different terms of energy balance were estimated or calculated with special attention to net long-wave radiation, the soil heat flux and the heat flux in the air. After an introduction on turbulence and convection, the turbulent transfer in neutral and thermally stratified conditions was discussed. The thermal stability indices and the transport coefficients for heat and momentum proved to be important parameters. Measured and calculated windspeeds and air temperatures were compared for different weather conditions.After a short review of recent literature on frost damage and frost resistance in plants, different methods of preventing frost were presented and explained. An application of passive methods was demonstrated by the measurements at different sites in the Netherlands and Tunisia.