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Continuous cover forestry (CCF) is gaining popularity as an alternative to rotation forest management (RFM), especially in forests with multiple uses. The success of CCF depends on the amount and quality of remaining seedlings, but the effect of harvesting on their status is not well known. In the present study, the proportion and number of undamaged seedlings after harvesting (and soil scarification) in Scots-pine-dominated stands in Northern Finland were modelled by applying logistic binomial mixed-effects and negative binomial count data models. The treatments included both CCF (gap cutting and selection cutting) and RFM (clearcutting and seed tree cutting) harvesting methods. The clearcut areas and most seed tree areas were treated with disc trenching. In the clearcutting and seed tree cutting areas, 25–34% of the inventoried seedlings were damaged. In the gap cutting and selection cuttings, c. 7% and 12% of the seedlings were damaged respectively. Harvesting machinery traffic and soil scarification were the most important causal agents of seedling damage. An increase in slash coverage also significantly increased seedling damage. The average number of undamaged seedlings in the selection cutting areas was ca. 1500 pcs ha−1, indicating at least satisfactory regeneration potential in the experimental stands. [ABSTRACT FROM AUTHOR]

Abstract—Species diversity of the overstory, understory, undergrowth, ground vegetation layer, and the taxocene of ground beetles (Coleoptera: Carabidae) was assessed in forest ecosystems of Southern Primorye with different degrees of disturbance. Diversity estimates were obtained in 13 permanent test plots established in nominally primary forests and forests affected by selective logging and fires. The results of ANOVA showed that the corresponding groups of plots significantly differed from each other in the species composition of the overstory, understory, and undergrowth and in Shannon index values for the overstory, understory, and ground beetle taxocene. The Jaccard index of floristic similarity for species of the ground vegetation layer was below 0.1 in comparisons between test plots within the groups of Korean pine and oak forests and ranged from 0.3 to 0.5 in comparisons between these groups, indicating a radical change in the composition of herbaceous plants after pyrogenic forest transformation. The numbers of ground beetles were higher in oak forests, but Shannon index for their taxocene was higher in Korean pine forests. It is concluded that moderate selective logging does not lead to significant changes in the species composition of forests, whereas regular fires in forests are a hazard to their biological diversity. [ABSTRACT FROM AUTHOR]

This work aimed to verify the influence of the liberation technique on the growth of a young population of Cabralea canjerana, based on this to determine the best size for the plants to be liberated and to verify the differences in growth between emergent and dominate plants. The liberation consisted of the clear cutting of all species different from the species of interest, with 90 trees from the species being liberated and 73 being kept in competition (control). The variables total height and diameter at 10 cm from the soil were previously and annually, for four years after the liberation, measured. At the end of the experiment the crown diameter, crown length and branch insertion height were measured and the trees were classified according the treatment and sociological position (emergent or dominated). The data were submitted to means tests in the statistical package SISVAR. Liberated plants showed a higher increase in diameter or height than not liberated trees. However, the increase gain in diameter and height is higher when realized in plants up to 100 cm high, especially if the plants are able to become emergent. Not liberated emergent trees showed higher branch insertion height in the stem, which in practice shows a higher proportion of stem free from nodes. Thus, it is concluded that the liberation stimulates the growth of young trees of C. canjerana. [ABSTRACT FROM AUTHOR]

The abandonment of silvicultural activities can lead to changes in species richness and composition of biological communities, when compared to those found in managed forests. The aim of this study was to compare the multi-taxonomical diversity of two mature silver fir-beech-spruce forests in the southern Dolomites (Italy), corresponding to the European Union habitat type 9130. The two sites share similar ecological and structural characteristics, but differ in their recent management histories. In the last 50 years, one site underwent non-intensive management, while the other was left unmanaged and was included in a forest reserve. The species richness and composition of eight taxa were surveyed in the two sites between 2009 and 2011. The difference in mean species richness between the two forest management types was tested through permutation tests, while differences in species composition were tested by principal coordinates analysis and the permutational multivariate analysis of variance. Mean species richness of soil macrofungi, deadwood lichens, bark beetles, and longhorn beetles were significantly higher in the abandoned than in the non-intensively managed forests. Deadwood fungi and epiphytic lichens did not differ in mean species richness between the two study sites, while mean species richness of ground beetles and birds were higher in the non-intensively managed than in the abandoned forest. Significant differences in species composition between the two sites were found for all the taxa, except for longhorn beetles. These results indicate that improving forest landscape heterogeneity through the creation of a mosaic of abandoned and extensively managed forests should better fulfill the requirements of ecologically different taxa. [ABSTRACT FROM AUTHOR]

The wound healing rate (WHR) was investigated in 234 wounded trees in Iranian forests and was found to range from 6.4 to 24.0 mm·yr-1. Tree species, slope aspect, elevation, wound age and wound type had significant effects on the WHR. The mean of the WHR in the Fraxinus excelsior (24 mm·yr-1), Alnus subcordata (18.9 mm·yr-1) and in the Fagus orientalis (17.9 mm·yr-1) were significantly higher than in the Acer insigne (15.7 mm·yr-1), Acer cappadocicum (14.6 mm·yr-1), Carpinus betulus (13.7 mm·yr-1) and Tilia begonifolia (6.4 mm·yr-1). In addition, the mean of the WHR on northern slopes (17.5 mm·yr-1) was significantly higher than on southern slopes. Moreover, the parameters that positively influenced tree growth showed a similar effect on the wound healing rate. The WHRs of 5-, 10- and 15-year-old wounds were 19.3, 16.9 and 10 mm·yr-1, respectively. The WHR increased the higher the wound from ground level. The WHR for horizontal wounds (18.4 mm·yr-1) was significantly higher than for vertical wounds. The highest WHR was estimated in a stand with a canopy closure of 60-80%. The WHR decreased according to increasing wound width. Wounds affect future income, lowering the number of trees that potentially provide a higher quality of saw and veneer logs. [ABSTRACT FROM AUTHOR]

Selection cutting is a treatment that emulates tree-by-tree replacement for forests with uneven-age structures. It creates small openings in large areas and often generates a more homogenous forest structure (fewer large leaving trees and defective trees) that differs from old-growth forest. In this study, we evaluated whether this type of harvesting has an impact on genetic diversity of sugar maple ( Acer saccharum Marshall). Genetic diversity among seedlings, saplings, and mature trees was compared between selection cut and old-growth forest stands in Québec, Canada. We found higher observed heterozygosity and a lower inbreeding coefficient in mature trees than in younger regeneration cohorts of both forest types. We detected a recent bottleneck in all stands undergoing selection cutting. Other genetic indices of diversity (allelic richness, observed and expected heterozygosity, and rare alleles) were similar between forest types. We concluded that the effect of selection cutting on the genetic diversity of sugar maple was recent and no evidence of genetic erosion was detectable in Québec stands after one harvest. However, the cumulative effect of recurring applications of selection cutting in bottlenecked stands could lead to fixation of deleterious alleles, and this highlights the need for adopting better forest management practices. [ABSTRACT FROM AUTHOR]

Although selection cutting has many advantages, its potential for damage to residual trees is a major challenge of forest management. The present study evaluated damage to residual trees during manual felling and cable-skidder logging operations in 18 instances of selection cutting in the Caspian forests of Iran. Data was collected from 100 m × 100 m systematic sample plots (0.1 ha) at each logging site. Harvest intensity ranged from 3.8 to 11 trees ha −1 and it averaged 7.3 trees ha −1 . Damage to residual trees was 10.5–23.6% with an average of 16.9%. There was a positive and significant correlation between amount of damage and harvest intensity ( R 2 = 0.65, P < 0.01). The multiple regression analyses also indicated that there were statistically significant relation ( R 2 = 0.77, P < 0.01) between amounts of trees damage and independent variables (harvest intensity, ground slope and stand density). Injury to the bottoms of tree boles 100–200 cm 2 in size was the most common types of damage. Damage was concentrated in small diameter trees (DBH < 40 cm). Most logging damage occurred during winching. Results suggest adherence to two silvicultural practices: (1) limit harvest intensity to 6 trees ha −1 , (2) limit selection cutting in slopes, less than 50%. Additional operational suggestions are implementation of felling direction and avoid log extraction through dense stands. [ABSTRACT FROM AUTHOR]

The ecology and management of boreal forest ecosystems are drawing greater attention worldwide as their importance is being increasingly recognized for carbon sequestration or for harbouring the world's largest remaining intact forests. Selection cuts have been introduced as a more socially acceptable silvicultural method to improve the maintenance of habitat structure and functions as they mimic aspects of boreal forest succession dynamics. Many studies have shown that selection cutting helps maintaining arthropod communities in mature forests, but few have examined the increased risks of damage by bark- and wood-boring insects in boreal forests of eastern North America. We used multidirectional flight-interception traps to quantify the response of these beetles to 25 and 40% selection cutting in a balsam fir-white birch forest of Québec, Canada. The abundance and species number of both cerambycid and scolytid beetles were 5-6 times larger in selectively cut stands than in controls the year following treatments. Analyses revealed that bark- and wood-boring beetles' response was mostly associated with increased canopy openness in selectively cut stands (and sun-exposed locations within them) and residual tree injuries caused by harvesting operations. These conditions attracted beetles such as Trypodendron lineatum (Scolytinae) and Rhagium inquisitor (Cerambycidae), two species known for their ability to attack weakened, dying and dead hosts. Most species were more abundant in selection cuts, except for Evodinus m. monticola (Cerambycidae) whose abundance was strongly reduced after treatment. Some beetles can have detrimental effects on residual trees and thus could reduce timber value, but most species found in treated stands do not represent a high risk for healthy trees. Thus, selection cuts do not seem favourable to the establishment of tree-killing beetles. However, as they were found more active/abundant after selection cutting, it would be wise to further study their population dynamics over mid- and long-term periods, along with the ecological and economic implications associated with this silvicultural treatment. [ABSTRACT FROM AUTHOR]

We studied the effects of different cutting intensities (0%, 5–10%, 15%, and 20% basal area removal) on stand growth, structure, and net carbon storage in spruce–fir (Picea jezoensis(Sieb. et Zucc.) Carr.–Abies nephrolepis(Trautv.) Maxim.) and broadleaf mixed forests on Changbai Mountain (Northeast China) over 19 years. At this site, inventory-based low-intensity selection cutting was used to maintain a continuous forest canopy. After two cutting events, results showed significant differences in growth, structure, and carbon storage among cutting intensities. When increasing cutting intensity, the growth rate of average diameter, basal area, and volume significantly increased, with the highest increment rates found in the plots with 20% basal area removal. Tree diameters for all plots showed a roughly inverse J-shaped distribution before cutting and a left-skewed unimodal distribution after two cuttings. Volume ratio (the relative amount of volume contained in different diameter classes) for small (6–14 cm), medium (14–26 cm), large (26–36 cm), and very large (>38 cm) diameters remained unchanged in the plots with 5 and 10% basal area removal, but the volume ratio of large and very large diameters increased in the plots with 15 and 20% basal area removal, reaching approximately a 1:2:3:4 ratio in the plots with 20% basal area removal after two selection cuttings. Net carbon storage increased when increasing cutting intensity, reaching maximum storage in the plots with 20% basal area removal (cutting intensity and net C storage increase: 0%, 7.21 Mg C ha−1, 5–10%: 11.68 Mg C ha−1, 15%: 21.41 Mg C ha−1, 20%: 26.47 Mg C ha−1). Therefore, our results show the potential of low-intensity selection cutting to meet demands of both timber production and maintenance of forest cover for biodiversity values. [ABSTRACT FROM AUTHOR]

Damage to 0.5-2.5 m saplings in selection cuttings in uneven-aged Norway spruce stands was studied in three stands in Finland. Harvest removals were 96-122 m3ha-1 or 32-41% of initial basal area. Harvesting was carried out with one-grip harvester and forwarder in March-April 2007. The strip road network had been established in previous cuttings. Before harvesting, trees higher than 2.5 m were measured and mapped with coordinates. Saplings 0.5-2.5 m were measured on circular sample plots of 10 m2 on a square grid, where line and plot intervals were 7.07 m. Trees to remove were selected with a computerized tree selection procedure and marked before cutting. Factors affecting the probability and severity of injury to an individual sapling were studied with logistic regression models. Percentage of injured saplings was 17.6, 29.8, and 61.0%, depending on study stand. Stem breakage was the most common type of injury. Distance of the sapling from the nearest strip road, sapling height, harvested basal area within 25 m of the sapling, and the distance to the nearest remaining tree were statistically significant factors in the model of the probability of injury. In the model for the severity of injury, only the distance from the nearest strip road and the sapling height were significant. Saplings near strip roads were vulnerable during both cutting and forwarding, and they often ended up under slash or logs. Development in working methods and machinery are potentially effective in reducing sapling damage in selection cuttings. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that the effect of overstorey density on height increment and mortality of seedlings and saplings is affected by the vertical structure of the overstorey. To test this, 28 plots, including four control plots, were studied at two sites, in northern and central Sweden. Norway spruce dominated all plots. The overstorey was thinned from "above", i.e. harvesting mainly large-diameter trees and maintaining a multilayered structure, or from "below", i.e. harvesting mainly smaller trees and creating a shelterwood. Three different densities were created for each structure, in the range 20-140 m[sup 3] ha[sup -1] at the northern site, and 40-200 m[sup 3] ha[sup -1] at the southern site. Seven years after treatment, seedling (0.1 m5 heightB 0.5 m) and sapling (0.5 m5 heightB 2.0 m) height increment tended to decrease with increasing overstorey density at both sites for plots thinned from below, but the effect was not statistically significant. Cutting regime had a significant effect on seedling height increment year 5 after treatment at the northern site, and cutting regimen and overstorey density combined had a significant effect on saplings in years 5 and 6 after treatment at the southern site. Annual mortality rates were 2-7% for seedlings and 0-4% for saplings. Ingrowth past 10 cm in height during the 7 yrs after treatment was less than 20 seedlings per hectare and year at the northern site, and less than three at the southern site. [ABSTRACT FROM AUTHOR]