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Fig. 5 | Fire Ecology

Fig. 5

From: Understory community shifts in response to repeated fire and fire surrogate treatments in the southern Appalachian Mountains, USA

Fig. 5

A dendrogram of clustered plots (n = 120) derived from the agglomerative hierarchical cluster analysis (AHCA) for shrubs shows four distinct clusters (labeled 1 through 4) in response to treatments (control = C, burned four times = B, mechanical removal two times of stems <10 cm dbh = M, and combination of M and B = MB). Data from 2016 were used in this study (2001 to 2016) of plant community change in response to fuel treatments in Green River Game Land, North Carolina, USA. A Bray-Curtis approach was used as the distance metric and a flexible beta linkage was used as the fusion strategy to determine the appropriate number of clusters. The cluster number was determined from fusion height, a visualization method that shows natural breaks in the data, indicating the highest number of plot similarities. Each line on the dendrogram is denoted by orange (burned four times; B), black (control; C), purple (mechanical treatment two times; M), and blue (mechanical treatment two times plus burned four times; MB) dots that indicate which treatment was applied to that plot. Cluster 1 had six plots in B, three in C, one in M, and seven in MB, categorizing it as having a different response from C (category 2; Cat. 2). Cluster 2 had ten plots in B, six in C, four in M, and nine in MB, falling under category 2. Cluster 3 had eight plots in B, 15 in C, 23 in M, and nine in MB, falling under category 2. Cluster 4 had six plots in B, six in C, two in M, and five in MB, categorizing it as having a similar response to C (category 1; Cat. 1). The horizontal axis at the bottom of the dendrogram represents the distance or dissimilarity between clusters

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