Structure of Isolated Acer grandidentatum Bigtooth Maple Communities and Potential Population ChangesReport as inadecuate




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Isolated, relic populations of Acer grandidentatum bigtooth maple, Sapindaceae were found in deep canyons in centralTexas. Associated with them on hilltops were communities of Juniperus ashei ash juniper. We determined the structure of relic A. grandidentatum populations and compared them to adjacent J. ashei populations. The overstory and understory densitywas counted and basal area was determined for all woody species in bothcommunities using the quadrat procedure. Acer grandidentatum was the highest density 788 ± 964 or 52% and basal area 29 ± 35 or52% overstory species in the canyon communities while J. ashei had the highest density 1589 ± 146 or 92% andbasal area 51 ± 13 or 88% in the hilltop communities. In the understory ofthe canyon communities, there were five juvenile tree species including A. grandidentatum which had the fourth highest density 13% or 176 ± 110 plants-ha. In thehilltop communities, J. ashei was the high density understory tree species 52%or 994 ± 400 plants-ha. There were no A. Grandidentatum overstory or understory plants in the hilltop Juniperus communities. Acer grandidentatum had an inverse quadratic size distribution with few juveniles. Althoughwe counted a number of seedlings, there was little recruitment over the last 16years and very little potential recruitment in the previous 20 years. Juniperus ashei had an inverse exponential size distribution withmany understory plants and considerable recruitment. Weibull age-sizedistributions showed one A. grandidentatum established in the 1670’s and 2 in the 1760’s, with peak establishment inthe 1970’s. Causes of the lack of recent recruitment are uncertain, but itcould be episodic due to changes in herbivory, management or otherenvironmental conditions.

KEYWORDS

Age structure, Community Structure, Dendrochronology, Diameter Structure, Population Dynamics, Weibull Analyses

Cite this paper

Auken, O. , Taylor, D. , Shen, C. and Bush, J. 2017 Structure of Isolated Acer grandidentatum Bigtooth Maple Communities and Potential Population Changes. American Journal of Plant Sciences, 8, 1368-1387. doi: 10.4236-ajps.2017.86093.





Author: Oscar W. Van Auken1, Donna L. Taylor2, Chen-chen Shen3, Janis K. Bush4

Source: http://www.scirp.org/



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