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BHSU Tree Inventory: taxonomic affinities, population structure, and health status of wild and cultivated trees on the 123-acre campus.

Black Hills State University is home to >1,500 trees that provide wildlife habitat, opportunities for student learning, and an attractive landscape enjoyed by the public.  Woody plants face challenges on campus, however, due to ongoing development projects and extreme weather.  2013’s Storm Atlas is an example of the latter -- an early October ice storm and blizzard that took down almost 25% of campus trees, and structurally weakened many others. Since 2014, the Ramseys have worked with students and BHSU Facilities to study trees on campus, with three primary goals: (1) evaluation of taxonomic affinities, size, and health; (2) creation of search-able and map-able databases that may be used by BHSU to prioritize tree upkeep activities and strategize new planting efforts; and (3) development of course exercises that use campus trees and the accumulated data set to instruct field methods and data analysis approaches. 

Below we report characteristics of BHSU trees inferred from comprehensive surveys (2014-2017) of permanently marked and geo-located individuals. (Our surveys have continued since 2017, and a more comprehensive analysis -- including estimates of species-specific survivorship and growth rates -- will be developed in 2020.)

Thirty-nine species were identified in total with three pest-prone taxa (apple, spruce, ash) representing 49% of individuals (Simpson's Diversity Index, 9.4).  Most species were spatially clustered (including several monoculture plantings) and exhibited modal size class distributions.  For example, ~75% of Green Ash trees were between 10 and 30 cm in trunk diameters while all Plains Cottonwood were >40 cm diameter.  Despite ongoing planting efforts, the campus lost >100 wild trees (especially Narrowleaf Cottonwood) to development during the sampling period.  Individuals unaffected by building and landscaping projects showed high health indices for trunk structure (94.4% of campus trees scored 3 or higher on a five-point scale) and foliage (98.1% of trees scored 3 or higher on five-point scale).  Several 'rare' species on the campus – including Box Elder, Honey Locust, Black Walnut, and Plains Cottonwood – scored highly in health assessments and are candidates for plantings that improve overall tree diversity and reduce susceptibility to the emerald ash borer, apple fire blight, and spruce cankers.

Photos of the Tree Inventory effort:

Additional  info about tree surveying can be found on our Photos & News page