The beauty of marking uneven-aged stands

Silvicultural treatments are often conducted in uneven-aged stands to achieve ecological sustainability; however, they can also fulfill the public's desire for stands that appear "natural." Marking guidelines for uneven-aged stands have most often been based on stand density goals and tree spacing requirements, with little regard to spatial pattern. Determination of spatial patterns of naturally occurring uneven-aged stands may provide a basis for developing marking guidelines to maintain visual appearances within traditional marking frameworks. Fourteen pure, uneven-aged ponderosa pine stands in eastern Montana were stem-mapped on plots ranging from 0.5- to 1.0- acre in size. Spatial attributes of the data were analyzed using Ripley's K statistic. Results indicate that small-diameter trees are most often clustered in their spatial distributions, while mid- to large-sized individuals tend to be randomly distributed. In no instances were trees uniformly spaced at any scale in any of the 14 stands examined. In order to maintain the spatial point pattern of uneven-aged stands during treatment, small diameter trees should be allowed to remain clustered within stocking constraints, while larger diameter trees should never be spaced uniformly. Stand aesthetics may be maintained during treatment through quantification and perpetuation of spatial attributes.