Given a spanning forest on a large square lattice, we consider by Kirchhoff theorem a correlation function of $k$ paths ($k$ is odd) along branches of trees or, equivalently, $k$ loop–erased random walks. Starting and ending points of the paths are grouped such that they form a $k$–leg watermelon. For large distance $r$ between groups of starting and ending points, the ratio of the number of watermelon configurations to the total number of spanning trees behaves as $r^{-nu} log r$ with $nu = (k^2-1)/2$. Considering the spanning forest stretched along the meridian of this watermelon, we show that the two–dimensional $k$–leg loop–erased watermelon exponent $nu$ is converting into the scaling exponent for the reunion probability (at a given point) of $k$ (1+1)–dimensional vicious walkers, $tilde{nu} = k^2/2$.

LPTMS, Orsay