PARENT SESSION
Poster Session #15: Vegetation Analysis.
Tuesday, August 7, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Spatial Analysis of a Maple/Basswood plot: fine scale regularity and large scale clustering.

Arenz, Brett¹, Fulton, Mark¹, ¹

ABSTRACT- We analyzed spatial patterns of adult stems in a 1 ha deciduous forest stand dominated by maple (Acer saccharum), with smaller numbers of basswood (Tilia americana), and some ironwood (Ostrya virginiana) and bur oak (Quercus macrocarpa) located on Star Island, Cass Lake in Northern Minnesota, USA. All stems >5 cm dbh were mapped, multiple-stem basswood clones were mapped to the location of the largest trunk. Spatial patterns were analyzed using Ripley-K statistics. The analysis revealed local regularity between trees on scales approximately corresponding to canopy radius. Stems larger than 20 cm dbh showed regularity at search radii from 2-10 meters. A striking transition was found in the spatial pattern of stems smaller than 20 cm dbh from avoidance at 2-4 meters to clustering from 6-11 meters. Clustering at this scale is indicative of regeneration in canopy gaps. Basswood showed clustering on the 1-3 meter scale even though only one stem from each field-identified clone was included in the data. This may indicate multiple episodes of stem dieback and re-sprouting, possibly reflecting long site occupancy by this species.

KEY WORDS: k-statistics, Acer saccharum, Tilia americana, spatial point patterns