Forestry and the aquatic environment: studies in an Irish context

Abstract

Research on the interaction between plantation forestry and aquatic environments is essential to develop environmentally compatible and sustainable management further. Given, in Ireland, the generally low levels of atmospheric pollution, its geology and maritime climate, and the unique fauna and flora due to its island history, such studies are important not only in the regional context, but also internationally, as they provide an opportunity to examine the effect of forestry and forest management practices on aquatic systems per se, without the complications of acidification. Here, some of the major findings of forestry and water research in Ireland have been reviewed and compared with those from the UK and elsewhere. Plantation forests do not exacerbate acidification in the south of Ireland (Munster) as a whole so that the influence of forestry on water chemistry is far less important than in other parts of the country (such as Wicklow and Mayo). The main forestry influence on streams in Munster is more likely through physical factors, but their nature is unclear. In a few catchments some negative effects are evident, but in many others apparently positive forest effects occur. In this context, smaller scale catchment-level effects appear to be more important in explaining the various relationships between plantation forests and stream ecology than larger scale regional factors. The management of riparian zones, particularly in forested catchments, is of major importance for the structure and functioning of aquatic communities and further work is needed on best management practices. It is suggested that it is unreasonable to base forest management on national Forest-Fisheries guidelines since regions vary too much and the signal from local conditions is too strong. The approach for environmentally benign, scientifically sound forestry management has to be at the catchment scale. Trees in the right places may be beneficial ecologically but further work is needed to identify these locations. The introduction of new forest management practices such as adoption of new species mixes and continuous forest cover are at an early stage in Ireland and their influence on aquatic systems is unknown.

Input, retention, and invertebrate colonization of allochthonous litter in streams bordered by deciduous broadleaved forest, a conifer plantation, and a clear-cut site in southwestern Japan

“…In particular, study streams in northern Europe often suffer from stream acidification (Ormerod et al 1993;Friberg 1997;Friberg et al 1998;Murphy and Giller 2000a;Riipinen et al 2010), probably due to atmospheric pollution and the low acidbuffering capacity of the surface soils of the study areas. Because such acidification can be induced by establishing a conifer plantation (Ormerod et al 1993;Friberg et al 1998), it is often difficult to separate the effects of the presence of a conifer forest per se from those mediated by acidification in those European streams (see Giller and O'Halloran 2004;Riipinen et al 2010). Therefore, information from other geographical regions is necessary to gain a general understanding of conifer-plantation effects, given the global growth in plantation forestry (Winjum and Schroeder 1997).…”

“…Conifers are often used for commercial forestry, and such conifer plantations are characterized as monotonic, even-aged stands. Most regions where conifer plantations dominate are located in biomes of deciduous or evergreen broadleaved forests (e.g., northern Europe : Friberg 1997;Kerr 1999;Giller and O'Halloran 2004;New Zealand: Hicks et al 2004; Japan: Inoue and Nakamura 2004). The conversion of broadleaved forests to conifer plantations has raised concerns about their impacts on stream ecosystems (e.g., Friberg 1997;Riipinen et al 2010).…”

“…In many regions of the world, plantation forestry is a major cause of extensive changes in forest vegetation (Friberg 1997;Kerr 1999;Giller and O'Halloran 2004;Hicks et al 2004;Nagaike et al 2006). Conifers are often used for commercial forestry, and such conifer plantations are characterized as monotonic, even-aged stands.…”

Effects of riparian forest management on Chilean mountain in-stream characteristics

“…These activities have 21 altered the natural riparian vegetation of most Chile's 22 aquatic systems, but their effects have not been totally 23 addressed by scientific studies. 24 Forest management activities in headwater areas can 25 potentially degrade water quality and the physical habitats 26 within streams (Carroll et al, 2004), affecting woody 27 debris, leaf litter and sediment supplies (Webster et al, 28 1990;Gurnell et al, 1995;Giller and O'Halloran, 2004), 29 modifying physicochemical conditions and invertebrate 30 diversity (Danger and Robson, 2004;Davies et al, 2005), 31 and altering hydrology, nutrient fluxes and productivity 32 (Campbell and Doeg, 1989;Lockaby et al, 2004;Lin and 33 Wei, 2008). Therefore, proper forestry best management 34 practices (BMPs, sensu Aust and Blinn (2004)) should be 35…”

Sustainability of UK forestry: contemporary issues for the protection of freshwaters, a conclusion

“…The research patterns followed in the UK have provided a benchmark for developments elsewhere such as Ireland where echoes of the situation in Britain have been combined with new lessons (Giller and OHalloran, 2004). Over the last 20 years, information has grown about the physical, chemical and energy effects of forests particularly on upland British streams.…”