Action: Log/remove trees within forests: effects on non-vascular plants
- Two of three studies (including one replicated, paired sites study) in Australia, Norway and Sweden found logging trees in forests decreased epiphytic plant abundance and fern fertility. One found mixed effects depending on species.
Here logging is defined as the selective removal of trees with the aim of removing tree biomass. This helps to restore natural open woodland by creating gaps and increasing light availability within the forest, which may increase the growth of the remaining vegetation. Interventions where trees are removed to enhance the future condition of a forest and the development of remaining trees are discussed under ‘Thin trees within forests’. Studies comparing the effects of partial logging with clearcutting are discussed in ‘Use partial retention harvesting instead of clearcutting'.
Supporting evidence from individual studies
A site comparison study in 1991-1994 in wet eucalyptus forest in Victoria, Australia (Ough & Murphey 1996) found that logging trees decreased the percentage of fertile tree ferns and the number of living leaves, but not the number of leaves produced. The percentage of fertile ferns (thinned: 30-31%; control: 86-89%) and the number of living leaves/fern (thinned: 2-11; control: 22-29) was higher in control sites, while the annual number of leaves/fern produced was similar between sites (thinned: 10; control: 14-18). Two tree ferns, soft tree fern Dicksonia antarctica and rough tree fern Cyathea australis,were monitored in five 30 × 30 m plots in a 12 ha thinned site (logged in 1991-1992). An additional 51 soft tree fern and nine rough tree fern individuals were monitored in unlogged sites. Data were collected two years after thinning.
A controlled study in 1995-2001 in boreal forest in Norway (Hilmo, Hytteborn & Holien 2005) found that logging decreased cover and abundance of lichens. For Cavernularia hultenii, cover and abundance (number of lichen branches/m branch length) were lower in sites that were thinned by cutting few relatively large gaps (cover: 2.4%; abundance: 2.6) than in sites that were thinned by cutting a large number of relatively small gaps (cover: 4.2%; abundance: 5.5). Cover and abundance were the highest in unthinned sites (cover: 6.2%; abundance: 8.4). For Platismatia glauca cover (large gaps: 22.6%; small gaps: 30.4%; unthinned: 29.1%) and abundance (large gaps: 9.1; small gaps: 13.3; unthinned: 13.8) were lower in large gaps sites than in small gaps and unthinned sites. For Norwegian ragged lichen Platismatia norvegica cover (3.0-3.7%) and abundance (0.6-0.9) were similar between treatments. A 100 ha area was divided into large gaps (three clearcuts of 150 × 150 m), small gaps (23 clearcuts of 50 × 50 m) and unthinned sections. Logging was applied in 1995-1996. Lichens were monitored in 2001 on 110 trees (>40 cm diameter at breast height): 45 in each logging treatment and 20 in the unlogged section.
A replicated, paired sites study in 1997-2001 in boreal forest in Sweden (Dynesius & Hylander 2007) found that loggingt decreased the number of liverwort and increased the number of moss species. Numbers of liverwort species/plot (0.1 ha) was lower in thinned plots than in uncut, both in the short-term (cut: 25; uncut: 33) and long-term (cut: 27; uncut: 32). Numbers of moss species/plot was higher in cut than in uncut plots in the short-term (cut: 53; uncut: 47) and similar in the long-term (48). Total number of bryophytes species/plot was similar in both short-term (cut: 78; uncut: 80) and long-term (cut: 75; uncut: 80). Liverworts and mosses were monitored in 2001 in 15 short-term (cut in 1998) and 18 long-term (cut in 1950-1970) pairs of cut and uncut 20 × 50 m plots.
- Ough K. & Murphy A. (1996) The effect of clearfell logging on tree-ferns in Victorian wet forest. Australian Forestry, 59, 178-188
- Hilmo O., HYTTEBORN H. & HOLIEN H. (2005) Do different logging strategies influence the abundance of epiphytic chlorolichens? The Lichenologist, 37, 543-553
- Dynesius M. & Hylander K. (2007) Resilience of bryophyte communities to clear-cutting of boreal stream-side forests. Biological Conservation, 135, 423-434