Plant Collage (IMAGE) Penn State Caption Seven years of invasive shrub removal from the Hartley Wood in The Arboretum at Penn State promoted plant diversity and facilitated passive natural regeneration of native canopy tree seedlings, understory woody species and woodland herbaceous species. Among them (top left to right) Indianpipe, mayapple and hepatica, (bottom left to right) spotted geranium, waxflower shinleaf and mapleleaf viburnum. Credit Erynn Maynard-Bean Usage Restrictions non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.