Green Tree Retention in Fennoscandian Forestry

Vanha‐Majamaa, Ilkka; Jalonen, Jyrki

doi:10.1080/028275801300004433

Cited by 155 publications

(53 citation statements)

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“…Retained trees can provide direct benefits by ameliorating understory microclimate (Vanha-Majamaa and Jalonen 2001), increasing seed rain (Beach and Halpern 2001), or facilitating access to mycorrhizae (Luoma et al 2006). Conversely, they can inhibit regeneration by reducing light (Mitchell 2001), soil moisture, or nutrients (Boyden et al 2012).…”

Section: Introductionmentioning

confidence: 96%

Twelve-year responses of planted and naturally regenerating conifers to variable-retention harvest in the Pacific Northwest, USA

2013

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We studied patterns of conifer regeneration over 12 years as part of a regional-scale experiment in variable-retention harvest in the Pacific Northwest, the DEMO Study. We compared survival and height growth of planted conifers and density and seral composition of natural regeneration among treatments with differing retention levels (15% versus 40%) and patterns (dispersed versus aggregated) replicated across a range of latitudes and forest zones. We also assessed plot-scale relationships of natural regeneration with overstory density and basal area, competing vegetation, and slash accumulations. Early (1-to 2-year) survival of planted seedlings was greater in dispersed treatments (Pinus monticola Douglas ex D. Don, Abies spp.) or unaffected by retention level or pattern (Pseudotsuga menziesii (Mirb.) Franco). Later (5-to 12-year) survival did not differ (all species), but growth was distinctly reduced in dispersed treatments and (or) at higher levels of retention. Density of natural regeneration was 1.5-2.5 times greater in dispersed treatments than in the cleared areas of aggregated treatments. Low-level dispersed retention promoted Pseudotsuga, the early-seral dominant, presumably by enhancing seed rain within a relatively high-light environment. Dispersed retention favored late-seral conifers. The ability to manipulate retention pattern and level to influence regeneration density and composition provides managers with flexibility in developing structurally complex and compositionally diverse forests.Résumé : Nous avons étudié les patrons de régénération de conifères pendant 12 ans dans le cadre de l'étude DEMO, une expérience régionale sur les coupes à rétention variable dans la région du Nord-Ouest de l'Amérique du Nord. Nous avons comparé la survie et la croissance en hauteur de plants de conifères ainsi que la densité et la composition de la régénération naturelle entre des traitements se distinguant par le niveau (15% ou 40%) et le type (dispersée ou en bouquet) de rétention et qui ont été répétés sous une gamme de latitudes et dans une variété de zones forestières. Nous avons aussi établi des relations à l'échelle de la placette entre la régénération naturelle et la densité ainsi que la surface terrière du couvert dominant, la végétation concurrente et l'accumulation de débris de coupe. À court terme (1 à 2 ans), la survie des plants était meilleure dans les traitements à rétention dispersée (pour Pinus monticola Douglas ex D.Don et Abies spp.) ou n'était pas influencée par le niveau et le type de rétention (pour Pseudotsuga menziesii (Mirb.) Franco). À plus long terme (de 5 à 12 ans), la survie de toutes les espèces était la même, mais la croissance a été clairement réduite dans les traitements à rétention dispersée ou à niveau élevé de rétention. La densité de la régénération naturelle était de 1,5 à 2,5 fois plus forte dans les traitements à rétention dispersée que dans les aires coupées des traitements à rétention en bouquet. Les faibles niveaux de rétention dispersée ont favorisé Pseudotsuga, une es...

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Section: Introductionmentioning

confidence: 96%

Twelve-year responses of planted and naturally regenerating conifers to variable-retention harvest in the Pacific Northwest, USA

2013

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“…Studies of the distribution of fire refugia (e.g. Engelmark 1987) have been one basis for recommendations that retention patches preferably could be placed in wet and moist places (Vanha-Majamaa & Jalonen 2001). Buffer strips (retention of trees along watercourses) were initially used to protect aquatic values such as water quality and spawning sites for fish (Blinn & Kilgore 2001).…”

Section: Introductionmentioning

confidence: 99%

Do time‐lagged extinctions and colonizations change the interpretation of buffer strip effectiveness? – a study of riparian bryophytes in the first decade after logging

Hylander

Weibull²

2012

Journal of Applied Ecology

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Summary1. There is a risk that short-term studies either underestimate disturbance effects because of time-lagged responses, including both time-lagged extinctions and colonizations, or overestimate them because of fast recovery. 2. To evaluate the conservation effectiveness of tree group retention (in this case, buffer strips along streams), we studied the bryophyte community once prior to, and twice after logging, comparing one buffer and one clear-cut plot (0Á1 ha) in each of 13 riparian sites. We asked whether time-lagged responses or recovery processes had dominated the period between two re-inventories, 2Á5 and 10Á5 years after logging, focusing both on the whole community and on species of conservation concern. 3. Although there were examples of recovering species in both clear-cuts and buffer strips, the similarity in species composition to predisturbance conditions had decreased in the second re-inventory. Even if the buffer strips displayed more time-lagged colonizations and local extinctions over the later period compared to the clear-cuts, the overall species composition in the buffer strips was still significantly more similar to the prelogging conditions than the clear-cuts. 4. The red-listed species had mostly declined during the first period, and the number of redlist species per plot (mostly species growing on dead wood) was rather stable at <20% of predisturbance levels in clear-cuts and <60% in buffer strips in the last re-inventory. 5. Synthesis and applications. We show that most extinctions of red-list species occurred soon after disturbance and that the conclusions drawn from a study carried out 2Á5 years after the disturbance did not change profoundly 8 years later. Although the species composition in the buffer strips continued to change over time, sensitive species survived much better in buffer strips than in clear-cuts, which supports the practice of retaining buffer strips for terrestrial species too. This knowledge should encourage managers to find ways of increasing the efficacy of this practice. One obvious measure could be to retain wider strips or implement other management practices that make the buffer strips less sensitive to wind, which will lead to higher tree retention to support a prelogging species composition.

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“…Many specialized oldgrowth species are assumed to be confined to small, remaining areas in a matrix of younger stands, but the knowledge of the extent to which species can thrive in the matrix of managed forests is, however, still scarce (e.g., Gustafsson 2002). Many authors have proposed that retention groups, remnant trees, woodland key habitats, and nature reserves will function as refugia for organisms that subsequently can recolonize surrounding areas when a hospitable environment has returned (e.g., Vanha-Majamaa andJalonen 2001, Fenton andFrego 2005). It is self-evident that the propagules for recolonization (if it happens) must come from somewhere, but Manuscript received 9 January 2008; revised 12 May 2008; accepted 29 May 2008.…”

Section: Introductionmentioning

confidence: 99%

No increase in colonization rate of boreal bryophytes close to propagule sources

Hylander

2009

Ecology

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Knowledge of the process of recolonization, and which temporal and spatial scale it operates on, is central to our understanding of species distributions, metapopulation dynamics, regional extinction risks, and ecosystem resilience. In this study the recolonization pattern of boreal forest bryophytes was investigated in stands that had been clear-cut approximately 50 years ago. Species known to be sensitive to clear-cutting were inventoried in 23 mature forest stands and in adjacent young stands at 10, 20, 40, and 80 m from the former forest-clear-cut edge. Based on previous studies showing that bryophytes tend to be dispersal limited at local population levels, it was hypothesized that the recolonizaton of many bryophyte species should be higher closer to the mature forest edge. It was also hypothesized that some species would show full recovery, while for others the young stands would still be inhospitable. All these patterns were found for individual species, but the main pattern was, however, quite different. Most species had started to recolonize the young stands (i.e., little or much, depending on species), but without any tendency of a higher colonization rate close to the mature stands. Possible explanations for the limited signs of positive influence of local propagule sources might be microsite limitation or that the local propagule availability displays a rapid decline from its sources and is masked by a higher regional propagule rain. For organisms with light propagules able to build up a regional background level, the role of mature forest stands in the recolonization process of the matrix may rather be to contribute to the regional background level of spores in the landscape than to affect the adjacent stands directly.

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Green Tree Retention in Fennoscandian Forestry

Cited by 155 publications

References 0 publications

Twelve-year responses of planted and naturally regenerating conifers to variable-retention harvest in the Pacific Northwest, USA

Twelve-year responses of planted and naturally regenerating conifers to variable-retention harvest in the Pacific Northwest, USA

Do time‐lagged extinctions and colonizations change the interpretation of buffer strip effectiveness? – a study of riparian bryophytes in the first decade after logging

No increase in colonization rate of boreal bryophytes close to propagule sources

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