In practical applications, flammable materials are often arranged in arrays of discrete objects whose combustion properties may be different as that of a homogeneous material. In this study, the influence of spacing between arrays of wooden dowels on the rate of upward flame spread through arrays has been studied. This configuration in some ways modelled physics that similar with flame spread through wildland fuels and cable trays. A single dowel was ignited at the base of an array of birch dowels with fixed spacings of 0.75, 0.875, 1.0 and 1.5 cm and allowed to spread upwards. Flame spread along the center columns, burning duration times and horizontal flame spread were plotted and compared with previous theory (Gollner et al., 2012 and Vogel and Williams, 1970). As a result of experimental results, it was shown that flame spread rates will decrease after a critical spacing is reached, most likely due to limited availability of oxygen. Experiments on horizontally-propagating flames through dowel arrays were performed to further show this effect.