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•Cluster thinning and selective berry thinning significantly increased the accumulation of soluble solids in grapes.•Anthocyanin concentration was increased by both thinning ...treatments, and a shift in the profile was observed.•As compared to the control, only selective berry thinning promoted a significant reduction of the skin proanthocyanidins.•Both treatments resulted in a reduction of the proanthocyanidins galloylation in skins, but only berry thinning reduced the skin prodelphinidines.
‘Refosco dal peduncolo rosso’ is a late-ripening and low-yielding red grape variety, mainly cultivated in Northeastern Italy (Veneto and Friuli Venezia Giulia), and characterized by relatively high anthocyanins and average-to-low tannins concentrations. Under Friuli’s climatic conditions, it is often challenging to maintain the Refosco dal peduncolo rosso grapes hanging on the vines long enough to match complete berry maturation before the rain season starts. Therefore, winegrowers normally perform cluster thinning in order to enhance or accelerate ripening. This study compared the effects of selective berry thinning (cluster shoulders and tips removal) and classical cluster thinning on fruit technological maturity, anthocyanin profile, and skin and seed proanthocyanidins concentration. Our results revealed that both thinning treatments induced a significant increase in total soluble solids, as well as total anthocyanins through the specific enhancement of OH- and di-substituted monoglucosylated anthocyanins. Additionally, skin high molecular weight proanthocyanidins was reduced by selective berry thinning, while mean degree of polymerization and percentage of galloylation were significantly decreased by both thinning treatments. These results showed that the yield reduction obtained by both methods were profitable to improve the maturation of Refosco dal peduncolo rosso grapes. However, the application of selective berry thinning provided a significant reduction of both skin high molecular weight proanthocyanidins and percentage of prodelphinidins. Therefore, the first evidences on grapes composition favored the cluster thinning technique as less time consuming, but more research on wine and sensory effects is needed to confirm the potential of selective berry thinning.
•Selective pioneer removal was tested to enhance secondary tropical forest recovery.•Three thinning intensities were trialed in comparison to a no management control.•Stand composition shifted in ...favour of late-successional species.•Growth advantage was shifted from late to early successional with thinning intensity.•We highlight the need for greater investigation of this method for forest restoration.
Demand for tropical forest restoration has grown rapidly as the potential role of recovering secondary forests in sequestering carbon and enhancing biodiversity has been recognised. Active forest management is often prescribed to accelerate natural regeneration, but evidence for the efficacy of interventions is scarce for tropical forests. In this study we examine the hypothesis that the selective removal of abundant pioneers in the understory of recovering selectively logged forests can improve the composition of forest stands and accelerate succession. Four selective thinning treatments of increasing intensity were implemented in 8.75hacompartments and replicated six times. Within each compartment, three monitoring plots were established and measured immediately after thinning and one year later to assess implementation of thinning treatments, growth and survival of stems, and changes in stand composition. Canopy openness was measured using hemispherical photography. Thinning treatments substantially reduced the abundance of pioneers, but there was only a slight increase in canopy openness (3.7–4.3%) relative to the control (1.8%) 8monthsafter implementation. Canopy openness increased dramatically across all treatments in the follow year due to the 2015–16 El Niño event and increased more in thinning treatments. Large (>10cmdbh) and small (2–10cmdbh) late-successional stems showed enhanced growth only in the low intensity thinning treatment, whereas the growth of small pioneer stems increased across the thinning intensity gradient. The cost of implementing thinning treatments was $US80 per ha or approximately 10% of the cost of planting treatments in the same forest. Our findings suggest that selective thinning of understory pioneer stems is a practical option for manipulating stand composition and potentially accelerating natural regeneration. Continued monitoring of the experiment should reveal the long-term impact and cost-effectiveness of treatments.
•Radial growth was greater in thinned stands beginning three years post-treatment.•Glucose plus fructose was lower in treated stands suggesting use of carbon reserves.•Forb and graminoid abundance ...was associated with thinned stands.•Thinning increased vegetation associated with resilient open-pine systems.
An increasingly important goal of federal land managers in seasonally dry forests of the western US is restoring forest resilience. In this study, we quantified the degree to which a thinning treatment in a dry forest of eastern Oregon restored aspects of forest resilience by focusing on key functional attributes of our study system. First, we measured several physiological responses of overstory trees that are associated with resilience, including radial growth, resin production, abundance of non-structural carbohydrates (NSC), and leaf area. Second, we investigated understory vegetation responses including species diversity, composition, and cover by growth form that influence fire behavior and resilience to disturbance. We found that tree radial growth was greater in trees in thinned stands beginning three years post-treatment. The abundance of key chemical compounds found in trees, including resin, starch, total NSC and sucrose did not differ between treatments; however, abundance of glucose plus fructose was lower in treated stands, suggesting mobilization and use of carbon reserves for foliar and wood production following thinning. We observed an increase in species richness and diversity within thinned stands three to four years after thinning, primarily due to the release of forbs and reestablishment of graminoids following ground disturbance. Here, we demonstrate that elements of forest resilience can be restored in dry forest systems via selective thinning to promote historical forest structure. In forests where thinning reduces stand density, vigorous overstory trees and increased herbaceous cover can help facilitate the re-establishment of low intensity surface fire regimes that maintain stable and persistent vegetative states. Understanding the ecological effects of fuel reduction treatments allows land managers to assess potential forest resiliency and adapt future treatments based on the observed results of previous activities.
The main problem with the utilization of untended stands for energy use is that small-diameter trees are expensive to harvest, and the value of the harvest fails to exceed the harvesting cost. Until ...now, the equation has appeared difficult to solve, but a wood harvesting innovation - the Risupeto II accumulating felling head - which works on a continuous basis, could provide a solution to the harvesting cost problem of young stands with a dense undergrowth. The novel accumulating felling head is attached to the boom of the crawler excavator, and trees are harvested at full-tree length. The crosscutting is done later during loading by a forwarder equipped with a grapple saw. The objectives of the present study were: 1) to define the productivity; 2) produce time consumption models for the Risupeto II harvesting unit in selective thinnings and 3) to determine the harvesting cost of whole trees from the early thinnings based on the above described two-machine configuration. Time study data from the 16 study plots consisted of 3,099 whole trees where the average tree volume varied between 14.2 and 52.0 dm
3
resulting in 73 m
3
of whole trees. The productivity varied between 11.2 and 26.6 m
3
/PMh on the time study plots indicating that felling-bunching productivity was relatively high compared to the latest studies with the Nordic harvesting technology in early thinning. According to the profitability analysis, the harvesting costs could be covered by the revenue from energy wood sales.
•We put forward a continuous cover forestry management model—BFM.•SBFM pays high attention to the spatial structure and health of forest.•Improving spatial structure of forest by single-tree ...selection is the key issue of SBFM.•The spatial structure of timber harvested according to SBFM is quite diverse.•The spatial structure of harvest wood is helpful to quick selection of thinning.
The selection of harvested trees is key to the success of near-natural forest management, yet few people have focused on the structural characteristics of harvested woods. Here, we examined the structural characteristics of harvested trees in Korean pine-broadleaf forest and pine–oak mixed forest in China using bivariate distributions of spatial structure parameters and the distribution of diameter classes. The stands were strictly managed according to the principles of structure-based forest management. We found that trees cut from both types of forest had wide structural diversity: they were widely distributed across vertical levels of the forest stand, including dominant, medium, and suppressed trees. Most trees from the Korean pine-broadleaf forest were of small–medium size and were highly mixed and randomly distributed in relation to their neighbors. In contrast, trees cut from pine–oak mixed forest tended to be clumped in relation to their neighbors. The majority were dominant trees surrounded by other species or distributed randomly, and were generally evenly distributed across stem diameters. In both forest types, most individuals were highly mixed and distributed in a random pattern, and trees in a clumped or regular distribution were more likely to be retained. In addition, the distribution of diameter at breast height size classes retained a reversed-J-shaped curve before and after management. These structural features closely matched the prior conditions of both forests and the purpose of management. They may also be conducive to quick selection of trees cut from the same forest type in the future, and can aid the recognition and interpretation of forest structure.
•SIMREG is a stochastic tree-level distance-independent forest model.•Model the impact of silviculture and management on forest development.•Calibrated with widely available national forest inventory ...data.•Generic growth, thinning and recruitment models for 17 species groups.•Current management of Walloon spruce forests is unsustainable.
SIMREG is a non-deterministic tree-level distance independent forest model that can simulate forest growth, yield and management on a regional scale while representing the wide diversity of composition, structure and management found in forest stands. It is composed of several sub-models to represent the main forest dynamics (growth, recruitment, removal, clearcut and reforestation) and to account for species composition, stand density, tree size and social status, forest ownership type and some sites characteristics. We used the data collected by the permanent forest inventory of Wallonia (IPRFW) between 1994 and 2015 to calibrate SIMREG and forecast the development of Wallonia's 479 500 ha of productive forest (465 million simulated trees) until 2050. According to our simulation, the harvesting rate of Norway spruce (the main production species) is currently unsustainable and it is gradually being replaced by other species such as Douglas-fir, larch and various hardwoods. It appears that in terms of total softwood volume production, the higher production level of Douglas-fir and larch should eventually compensate for the decline in spruce. In contrast, the harvest rate in hardwood stands is around 75% of the annual yield, resulting in a steady increase in the total hardwood stock of about 600 000 m³ per year. Our methodology is easily replicable and the data required for sub-model calibration are consistent with those measured by most permanent NFIs, so our forest simulation model could be adapted to other regions and countries.
•Fuel treatments and patch cuts may promote invasion and shrub expansion.•Introduced species richness and cover in fuel treatments were lower than patch cuts.•Fuel treatments increased shrub richness ...and cover 12–13 years post-treatment.•Higher canopy cover can help reduce introduced species and native shrub recruitment.
Forests in the western United States are actively managed to increase resilience to fire and extract timber resources. Disturbance from these management activities, however, may reduce forest resilience to invasion and promote shrub expansion, which could compromise treatment efficacy in the long-term. To assess mid- and long-term impacts of forest management practices, we coupled a field experiment with a chronosequence of patch cuts (~0.5 ha cuts) located at Blodgett Forest Research Station in the north-central Sierra Nevada. The field experiment, which was part of the national Fire and Fire Surrogate (FFS) study, compared three fuel treatments to control plots 12–13 years post-treatment. Fuel treatments included mechanical thinning, prescribed fire (that burned twice), and mechanical thinning plus fire. In contrast, the chronosequence assessed the impacts of patch cuts on vegetation across 33 years. The FFS fuel treatments led to increases in introduced species richness initially and in the mid-term. Introduced species richness and cover in the fuel treatments, however, were considerably lower than in patch cuts, which reached over 100% cover six years post-harvesting. In addition, while fuel treatments initially reduced shrub cover and richness, shrubs increased significantly in all fuel treatments in the mid-term. Understory vegetation dynamics in the fuel treatments were influenced by pretreatment flora richness and cover. In contrast, overstory removal was likely the strongest driver of high invasion in patch cuts within the first ten years, suggesting that severe disturbance (e.g., 100% removal of the overstory) may overwhelm biological legacies. Finally, overstory canopy was significantly and negatively associated with introduced species in the fuel treatments and the patch cuts, highlighting that canopy gap dynamics likely influenced invasion in this system. Our study underscored that while pretreatment species composition was a strong determinant of invasion in fuel treatments, management strategies that sustain overstory canopy cover may reduce growth and recruitment of introduced species and native shrubs.
•The knowledge regarding thinning effects on the decomposer in forest ecosystem is needed.•We studied the community of saprotrophic macrofungi pre- and post-thinning in tropical area.•Thinning ...decreased species richness of saprotrophic macrofungi and altered their community.•Saprotrophic macrofungi are very sensitive to thinning disturbances.•Population dynamics of Scytinopogon sp. could reflect influences of thinning.
Forest thinning is an important method for managing forests, changing forest structure, biological diversity and community. This study examined forest thinning effects on macrofungal diversity and the environmental factors affecting fruiting and community structure. Field surveys were conducted from 2006 to 2010 in 35-year-old Cryptomeria japonica plantations in central Taiwan. Thinning was completed in October 2007 and included control, 25% thinning, and 50% thinning treatments. Each treatment had four replications. Forest thinning and time affected macrofungal species richness observed but not abundance. Thinning influenced macrofungal community compositions; however, the difference between the two thinning intensities was not significant. The macrofungal community showed significant differences between communities of eastern and northern aspect. A redundancy analysis indicated that macrofungal communities in the C. japonica plantations were significantly affected by relative humidity, light, canopy cover, soil water content, soil temperature, soil pH value and soil texture. The fruiting of a dominant coral fungal species, Scytinopogon sp., was affected by thinning and light. The fruiting bodies of this species decreased in the 25% thinning plots and disappeared in 50% thinning plots in the first two years post-thinning, but were recorded in the third year post-thinning. After thinning, macrofungal species richness observed decreased, the community changed, and changes were associated with environmental conditions. Forest thinning decreased observable macrofungal diversity and changed the community structure, and these changes were associated with environmental variation after thinning.
Many studies have outlined the benefits for growth and reproduction resulting from thinning extremely crowded young forests regenerating after stand replacing wildfires (“thickets”). However, scarce ...information is available on how thinning may influence fire severity and vegetation regeneration in case a new fire occurs. We investigated the relationship between thinning and fire severity in P. halepensis thickets, and the effects on the establishment of pine seedlings and resprouting vigour in resprouter species the year after the fire. Our results show a positive relationship between forest basal area and fire severity, and thus reserved pines in thinned stands suffered less fire damage than those in un‐thinned sites (respectively, 2.02 ± 0.13 vs. 2.93 ± 0.15 in a scale from 0 to 4). Ultimately, differences in fire severity influenced post‐fire regeneration. Resprouting vigour varied depending on the species and the size of individuals but it was consistently higher in thinned stands. Concerning P. halepensis, the proportion of cones surviving the fire decreased with fire severity. However, this could not compensate the much lower pine density in thinned stands and thus the overall seed crop was higher in un‐thinned areas. Establishment of pine seedlings was negatively affected by the slope and positively driven by the number of cones and thus it was higher in un‐thinned than in thinned stands (respectively, 2581 ± 649 vs. 898 ± 325 seedlings∙ha-1). Thinning decreases fire intensity, and thus it may facilitate fire suppression tasks, but retaining a higher density of pines would be necessary to ensure P. halepensis regeneration after a new fire event.
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