Cut/remove/thin forest plantations: freshwater marshes
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
This action includes clear cutting (felling and removing all trees) and thinning (removal of only some trees) to address the threat from forest plantations (i.e. areas where trees have been deliberately planted, usually after drainage). Large wetland areas have been drained and afforested in the Paraná River Delta, South America (Ceballos et al. 2013) and the Sanjiang Plain, China (Zhang et al. 2014). Removing trees may increase light intensity at the ground surface allowing herbaceous plants to grow (Aschehoug et al. 2015), and may allow the water table to rise somewhat, since water is no longer intercepted or taken up by the trees).
Related actions: Raise water level to restore degraded freshwater marshes; Raise water level to restore/create freshwater marshes from other land uses; Cut large trees/shrubs to maintain or restore disturbance; Use cutting to control problematic large trees/shrubs.
Aschehoug E.T., Sivakoff F.S., Cayton H.L., Morris W.F. & Haddad N.M. (2015) Habitat restoration affects immature stages of a wetland butterfly through indirect effects on predation. Ecology, 96, 1761–1767.
Ceballos D.S., Frangi J. & Jobbágy E.G. (2013) Soil volume and carbon storage shifts in drained and afforested wetlands of the Paraná River Delta. Biogeochemistry, 112, 359‒372.
Zhang B., Chang L., Ni Z., Callaham M.A., Sun X. & Wu D. (2014) Effects of land use changes on winter-active Collembola in Sanjiang Plain of China. Applied Soil Ecology, 83, 51‒58.
Supporting evidence from individual studies
A replicated, controlled study in 2002–2005 involving 24 pine plantations on a gradient of moist to dry soils in Ohio, USA (Abella et al. 2017) reported that some sites where trees were thinned or cleared contained more wetland-characteristic plant species than sites that remained afforested. Statistical significance was not assessed. After three growing seasons, six thinned or cleared sites developed wetter soils than the others and contained 4–18 wetland-characteristic plant species/0.05 ha. Nine thinned and cleared sites that retained drier soils contained 0–9 such species/0.05 ha. Nine sites that remained fully afforested, and also had drier soils, contained 1–3 such species/0.05 ha. Methods: In early 2002, pine Pinus spp. plantations (47–63 years old; 900 trees/ha) were thinned or cleared from 15 sites (50–100% of trees removed, but many of the remaining trees died). Nine other sites were left fully afforested. Soil moisture varied between sites: the driest, upland sites were not expected to develop wetland vegetation even if trees were removed. Understory vegetation (a mix of herbs and shrubs) was surveyed in summer 2004 in one 20 x 25 m plot in the centre of each site.Study and other actions tested