= Solution
For complete wetting, the meniscus has curvature radius equal to the capillary radius $r=d/2$. The <Young–Laplace equation> gives the supporting <pressure> difference $\Delta p=2\gamma/r=4\gamma/d$. Balance it against the <hydrostatic pressure> $\rho gh$. Taking the sap's <mass density> to be water-like, $\rho\simeq10^3\ \mathrm{kg\,m^{-3}}$, gives
$$
\boxed{h_{\max}=\frac{4\gamma}{\rho gd}=\frac{4(0.072)}{(10^3)(9.81)(10^{-6})}\simeq29\ \mathrm m.}
$$
This is the height supported by the stipulated capillary-pressure model. The density assumption is needed because the <surface tension> and capillary diameter alone do not determine a height.
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