On the heat impulse method for deducing sap flow

[摘要] Speed of sap flow in plants and trees is of interest to botanists and environmentalistsbecause of its connection with the rate of utilisation of nutrients in the soil. An established methoduses the transport of heat where an impulsive heat source is introduced along a radial line by aprobe in the trunk sapwood. The temperature is monitored, upstream and downstream, and, bysolving the heat flow equation in the moving fluid, the sap velocity may be deduced indirectlyunder some simplifying assumptions which chiefly render the method most useful when applied totrees of relatively large diameter. Transform methods are used to obtain the appropriate threedimensionaltime-dependent solution in explicit form and values for the resulting sap velocity arecompared with the existing two-dimensional theory.

[学科分类] 自然科学（综合）