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Retention Trees (retention + tree)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

The effects of green tree retention and subsequent prescribed burning on ground beetles (Coleoptera: Carabidae) in boreal pine-dominated forests

ECOGRAPHY, Issue 5 2006
Petri Martikainen
We studied how two methods to promote biodiversity in managed forests, i.e. green tree retention and prescribed fire, affect the assemblages of carabid beetles. Our experiment consisted of 24 study sites, each 3,5 ha in size, which had been prepared according to factorial design. Each of the eight treatment combinations determined by the two factors explored , tree retention level (0, 10, 50 m3/ha,1 and uncut controls) and prescribed use of fire (yes/no) , was replicated three times. We sampled carabids using pitfall traps one year after the treatments. Significantly more individuals were caught in most of the burned sites, but this difference was partially reflective of the trap-catches of Pterostichus adstrictus. The fire did not increase no. of P. adstrictus in the uncut sites as much as in the other sites. Species richness was significantly affected by both factors, being higher in the burned than in the unburned sites and in the harvested than in the unharvested sites. Many species were concentrated in the groups of retention trees in the burned sites, but only a few were in the unburned sites. The species turnover was greater in the burned than in the unburned sites, as indicated by the NMDS ordinations. Greater numbers of smaller sized species and proportion of brachypterous species were present in the burned sites. Fire-favored species, and also the majority of other species that prefer open habitats were more abundantly caught in the burned sites than in the unburned sites. Dead wood or logging waste around the traps did not correlate with the occurrence of species. We conclude that carabids are well adapted to disturbances, and that frequent use of prescribed fire is essential for the maintenance of natural assemblages of carabid beetles in the boreal forest. Small retention tree groups can not maintain assemblages of uncut forest, but they can be important by providing food, shelter and breeding sites for many species, particularly in the burned sites. [source]

Lichen acclimatization on retention trees: a conservation physiology lesson

JOURNAL OF APPLIED ECOLOGY, Issue 4 2009
Kadi Jairus
Summary 1.,Green-tree retention (GTR) has been suggested as a means to effectively support epiphytic lichen species in managed forests, given the low lichen mortality on retention trees in the short term. However, a long-term perspective requires a physiological understanding of lichen responses to logging. This study compares anatomical, morphological and physiological traits of lichens on retention trees and on intact forest trees. 2.,Thalli of nine taxa (Buellia griseovirens, Cladonia digitata, Hypogymnia physodes, Lecanora allophana, Lecanora pulicaris, Lepraria spp., Peltigera praetextata, Pertusaria amara and Phlyctis argena) were sampled from birch Betula spp. and aspen Populus tremula in GTR cuts, where they had previously been reported to survive well, and in adjacent managed forests. In the laboratory, chlorophyll fluorescence parameter Fv/Fm, thickness of the upper cortex, photobiont to mycobiont ratio and (in Lecanora species) the relative area of the apothecia were measured. 3.,All the lichen samples collected from GTR cuts appeared alive, but their Fv/Fm was significantly lower, relative areas of the apothecia were larger and the upper cortices of thalli were thicker compared with the samples from adjacent forests. No difference in photobiont to mycobiont ratio was found. These patterns were broadly consistent among species, indicating a common mechanism: while suffering from photoinhibition, the lichens had acclimatized to the open conditions and increased their investment to sexual reproduction in a few years. 4.,Synthesis and applications. The study highlights the value of a morpho-physiological framework for conservation management by pointing out that, in GTR areas, lichen survival is high-irradiation limited and heavily dependent on phenotypic plasticity. A thin upper cortex may be a common feature of the most sensitive species. To sustain epiphyte populations in managed forests, precautionary harvesting strategies (gradual felling; group-retention; extended rotations) should be preferred and large-enough populations should be preserved, even though short-term studies suggest a high survival of lichens in cut areas. [source]

Tree regeneration before and after restoration treatments in managed boreal Picea abies stands

APPLIED VEGETATION SCIENCE, Issue 2 2009
M. De Chantal
Abstract Questions: What are the short-term effects of restoration treatments, including fire and/or partial cutting with dead wood creation, on seedling density and distribution among microsites, and do they differ between upland and paludified biotopes? Location: Mature managed Picea abies -dominated stands in southern Finland. Methods: The restoration treatments consisted of four levels of cutting, with and without fire: uncut, low-CWD (partial cutting leaving 50 m3 ha,1 of standing retention trees and 5 m3 ha,1 of down retention trees, DRT), intermediate-CWD (as previous but with 30 m3 ha,1 of DRT), and high-CWD (as previous but with 60 m3 ha,1 of DRT). Results: The cutting treatment alone did not affect seedling density. Fire had an immediate effect, both by itself in upland biotopes (decreasing effect on P. abies density) and in combination with cutting in paludified biotopes (increasing effect on Betula spp. density). The density of other deciduous species (Sorbus aucuparia, Populus tremula, and Salix spp.) was not affected. Before treatments, seedlings grew predominantly on level ground and mounds. After treatments, more Betula, but fewer P. abies and other deciduous species, grew on these microsites. More Betula and other deciduous species grew next to CWD and under a fallen crown; more P. abies grew under a fallen crown in unburned stands. Conclusion: The post-treatment tree seedling density and distribution among microsites can be affected by restoration treatments. However, knowledge of local site characteristics and their interaction with different restoration treatments is needed to achieve the goals set for restoration at the stand and landscape levels. [source]