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Hakalau Forest NWR outplant growth


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Yelenik, S.G. and Rehm, E.M., 2020, Hakalau Forest NWR plant, soil, litter, and decomposition data 2015-2019: U.S. Geological Survey data release,


This data release includes data and metadata for native outplant growth rates for an experiment that added large quantities of woody litter to a restoration forest in an attempt to lower soil nitrogen and exotic grass biomass. All sites were within Hakalau Forest National Wildlife Refuge on Hawaii Island. Broadly, this study looked at the ability to alter soil nitrogen cycling, exotic grass biomass and native outplant survival and growth with large quantities of Metrosideros polymorpha litter in a forest dominated by Acacia koa.


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Outplant growth.csv 33.73 KB text/csv


Tree species can have large effects on soil nutrients in ways that alter succession, especially in the case of nitrogen (N) fixing trees, and it is not clear whether it is possible to reverse high soil N via management. In Hawaiʻi, forest restoration relies heavily on use of a native N-fixing tree, Acacia koa (koa), but this species increases soil available N and facilitates exotic pasture grasses. In contrast, Metrosideros polymorpha (‘ōhi‘a), the dominant native tree over most of the Hawaiian Islands, is rarely planted because it is slow growing yet it is associated with lower soil N and grass biomass, and greater native understory recruitment. We asked whether it is possible to reverse high soil N under koa by adding ‘ōhi‘a litter, and whether litter amendments could alter grass biomass and native understory survival and growth.

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