Alternative Silvicultural Systems Research Articles

German-Ukrainian Efforts Towards Building Climate-Resilient Forests in Western Ukraine – First Results of Alternative Regeneration Systems

Due to the current changes in the socio-ecological system in Ukraine, forest adaptation is of high importance. Continuous-Cover Forestry (CCF) is seen to be promising for Ukraine to provide the Ukrainian society with various ecosystem services from forests and to increase the adaptive capacity of Ukrainian forests. First, basic features of Ukrainian forests and the forest sector are outlined, and the regeneration systems of the major tree species with economic value are described. Moreover, the need for forest conservation in order to safeguard the biodiversity of Ukrainian forests is highlighted. Based on a joint Ukrainian-German research project called 'Resilpine', the first scientific results on the regeneration of major tree species in Ukraine with alternative silvicultural systems to clearcut are illustrated. The data show that natural regeneration in group (or patch) selection systems is abundant and sufficient compared to clearcut. Especially Scots pine, but also intermediate species, are establishing. Group selection cutting can therefore be recommended as a promising alternative natural regeneration system to clearcutting in order to convert Ukrainian forests.

Silviculture in the function of sustainable development

Silviculture in the function of sustainable development

Assessing the externalities of timber production

Responsible forest policy promotes management that does not impair the multiple uses of forests or decrease their regulative effects and biological diversity. The most important regulative effect of boreal forests is their ability to remove carbon dioxide from the atmosphere. High biological diversity improves the resilience of forest ecosystems and forest-based economies, enhancing the long-term sustainability of forest production. This study developed a method for assessing the performance of forest management in terms of its effects on multiple uses, biodiversity, and carbon sequestration. These externalities were described with 11 indicator variables, which can be calculated for any Finnish forest stand from the current forest inventory data with currently available models and algorithms. The indicator variables were normalized based on the ranges of the indicator variables in Finnish forests on different sites. The forest-level averages of the normalized indicator variables were used to calculate a multiplicative externality score for the forest. The developed method for calculating the forest-wide externality score was used in two forest holdings for alternative silvicultural systems. The case study results suggested that continuous cover management enhances the positive externalities of timber production, as compared to even-aged rotation forestry. Green-tree retention improved the externality score in both silvicultural systems. Maximizing the net present value of timber production in rotation forestry decreased the externality score by about 50% compared to a non-managed forest. The decrease was about 30% smaller in continuous cover forestry.

Understory vegetation response to alternative silvicultural systems in coastal British Columbia montane forests

This study is one of several investigating the biological effects of silvicultural systems at the Montane Alternative Silvicultural Systems (MASS) project located on Vancouver Island in British Columbia (BC). We compared understory vegetation cover and diversity under four silvicultural systems (clearcutting, patch cutting, dispersed retention, and shelterwood) to an adjacent old-growth forest. Long-term plots were measured pre-harvest and at intervals up to 26 years post-harvest. We also compared vegetation response to fertilization and vegetation control treatments. All harvesting resulted in a short-term reduction in understory cover from logging debris and ground disturbance. Recovery from disturbance varied by species, life-form and system. Understory tree species returned to pre-harvest cover after 15 years and significantly exceeded initial cover after 26 years. Shrubs returned to pre-harvest cover after 5–10 years and continued to increase in most systems. Herb cover was low in the pre-harvest forest but increased rapidly in years three through 10 due to herbaceous colonizers; this was least pronounced in the shelterwood. Herbs have declined rapidly since year fifteen. Forest floor bryophytes were reduced to less than 5% cover in all systems except the shelterwood and they remain at one-third or less of their pre-harvest cover. The shelterwood retained more stand structure and plant species from the original old-growth forest than other systems immediately after logging, except for the retained patches. All the harvesting treatments increased species richness and diversity compared to the pre-harvest forest. The increase in total species and abundance was highest for year 15 when early-seral colonizers were still present, and many pre-harvest species had returned. By year 26, richness and diversity began to decrease as early-seral species were lost. For overall species diversity of vascular plants and forest floor bryophytes, silvicultural system did not have an effect after 26 years. All the late-seral herbs that occur at MASS were present after harvesting but several were locally eliminated or had reduced abundance in cut areas. We found no significant edge effects into retention patches, which had comparable species richness and diversity to the pre-harvest old growth—suggesting that aggregated retention can be effective for maintaining late-seral species. Silvicultural system had more significant long-term effects on shrubs and bryophytes than early vegetation control.

Measuring the social performance of forest management

Forests produce several types of benefits to both forest landowners and society. The social benefit of private forestry is equal to private benefit plus positive externalities minus negative externalities. This study developed alternative metrics for the evaluation of the social benefit of forest management. Forest management was assessed in terms of five criteria: economic, socio-cultural, environmental and ecological performance and the resilience of the forest ecosystem. Each criterion was described with three numerical indicators. Alternative performance indices were calculated from the indicator values using methods developed for multi-criteria decision making. It was concluded that indices based on the multiplicative Cobb–Douglas utility function might be the most recommendable when forestry should produce a balanced combination of different ecosystem services. When the indices were used to compare alternative silvicultural systems in terms of their social performance, continuous cover management was ranked better than even-aged management. The performance of even-aged management improved when it aimed at increasing the share of mixed stands and broadleaf species. Maximizing net present value (NPV) with a 1% discount rate led to better social performance than maximizing NPV with a 4% discount rate.

Short- and Long-Term Results of Alternative Silviculture in Peatland Black Spruce in Minnesota, USA

AbstractAcross the boreal forest in North America, the black spruce (Picea mariana) cover type is ecologically and economically important, occupying roughly 10 percent of Minnesota’s, USA 17.4 million acres (7.0 million hectares) of forestland. Traditionally managed through clearcut regeneration harvests, alternative silvicultural systems are being increasingly used in Canada. Here, we examine the 10- and 57-year effects of six silvicultural treatments (clearcut strips, clearcut patches, thinning, group selection, single-tree selection, shelterwood) on stand structure and dynamics in lowland black spruce. Treatments were installed in 1948 in northern Minnesota, and remeasured and re-treated 10 years later. A subset of the clearcut strips, clearcut patches, and shelterwood treatments were remeasured in 2017. After 10 years, diameter growth of residual stems varied by treatment, with the shelterwood experiencing the greatest growth, and basal area increased in all but the shelterwood treatment. Over the long term, the shelterwood exhibited larger diameters and heights and greater crown ratios, basal area, structural complexity, and compositional diversity than the clearcuts. Our results suggest that managers may consider using a shelterwood instead of traditional large clearcuts to achieve increased structural and compositional diversity, particularly when eastern spruce dwarf mistletoe (Arceuthobium pusillum) does not necessitate a traditional clearcut.

Silviculture in Forested Wetlands: Summary of Current Forest Operations, Potential Effects, and Long-Term Experiments

Bottomland hardwoods (BLH) and wet mineral flats (WMF) are common forested wetlands in the southeastern U.S. coastal plain (Virginia to Texas) that are often manipulated silviculturally, yet silvicultural forest operations are infrequently reported. This document summarizes forest operations in wetlands, consolidates reviews of silvicultural effects, and summarizes long-term research. BLH typically receive lower intensity management. Forest operations involve planning silvicultural operations and adapting harvest operations to wet site conditions. Clearcutting with natural regeneration is favored for BLH, but alternative silvicultural systems may be viable options, depending on stand characteristics and landowner objectives. WMF are frequently managed intensively as pine plantations. Following clearcut harvests, WMF may be mechanically and chemically site-prepared and planted. Intermediate silvicultural operations may include chemical competition control, fertilization, prescribed burning, and thinning operations. Reviews of effects in forested wetlands indicate wet-site harvesting can cause significant soil disturbances. Long-term research on effects of harvest disturbances on BLH and WMF are limited, but indicate effects of wet site harvests are ephemeral and sites recover due to natural factors and artificial amelioration. Overall, silvicultural operations in these forested wetlands are compatible with long-term sustainability when appropriate silvicultural systems, forest operations, and forestry best management practices (BMPs) are applied.

Shifting from even-aged management to less intensive forestry in varying proportions of forest land in Finland: impacts on carbon storage, harvest removals, and harvesting costs

Many studies have reported increased multi-functionality and financial profits due to a shift from even- to uneven-aged forest management. However, little is known (from long-term experiences or predictions) how alternative management systems could affect national-scale wood production and carbon storage, if adopted over very large areas. We analysed these effects using an area-based framework, in which multiple Markov chain models were used to simulate the development of forests according to different management systems. Classification of forests to wood availability categories was used to determine the system to be applied. We enhanced the framework to allow shifts between management systems that correspond to enforced or voluntary changes in forest use. Simulations of extensive shifts from conventional even-aged management to alternative silvicultural systems revealed interesting developmental patterns that cannot be directly deduced from studies that upscale from smaller areas. Our results show that the amount of carbon stored by Finnish forests can be increased by applying less intensive management systems, although this has trade-offs in terms of harvests and associated financial costs. The level of trade-offs differed depending on the type of forest that shifted between management systems and whether areas were also assumed to be completely set aside from forestry. These differences were further pronounced if the desired harvest levels and their allocation changed along with the management system. If the studied attributes were considered at the same relative scale and with equal weighting, the extensive shifts to alternative management systems exhibited the strongest impact on harvesting costs.

Building Resistance and Resilience: Regeneration Should Not be Left to Chance

Contemporary forest planning has tasked managers with developing goals associated with resistance and resilience. In practice, silviculturists use forest structure and tree species composition to characterize goals and desired future conditions, write prescriptions, and monitor outcomes associated with resistance and resilience. Although rarely discussed in the exploding literature relating to forest resistance and resilience, silvicultural regeneration methods are important and underutilized tools to meet these goals. We propose alternative silvicultural systems for building resistance and resilience to two common large-scale bark beetle disturbance agents in the Intermountain West, United States: mountain pine beetle (Dendroctonus ponderosae Hopkins) and spruce beetle (Dendroctonus rufipennis Kirby). Shelterwood, and shelterwood-with-reserves, silvicultural systems provide the desirable facilitative characteristics of a mature overstory on maintaining advance reproduction and the establishment of new cohorts of desirable tree species. These also allow the timely regeneration of large treatment areas necessary to rapidly promote desired future conditions in the face of inevitable disturbance. When implemented proactively, regeneration treatments allow silviculturists to take advantage of currently existing vegetation for the creation of age class and tree species diversity. In general, these examples illustrate the need for proactive planning for regeneration in response to any disturbance where desired future conditions include particular species. Furthermore, we argue that timely silvicultural interventions that focus on regenerating trees may be a key factor in achieving goals relating to resilience to specific disturbance types. Waiting until after the disturbance has occurred could result in the lost opportunity to establish desired species composition or stand structure—and may well result in a considerable restoration challenge.

Temporal changes of understory plant community in response to pre- and post-harvesting herbicide treatments and partial cutting in aspen-dominated boreal mixedwood stands

In response to concerns about the effects of traditional timber harvesting practices on biodiversity, we examined the effects of alternative silvicultural systems, including partial cutting and modified herbicide use on understory plant communities in an aspen-dominated mixedwood stand. These alternative silvicultural systems match disturbance rates that, based on the intermediate disturbance hypothesis, would support more diverse understory vegetation communities than uncut or clear-cut forests treated with a broadcast spray. Our results indicated that both understory vegetation cover and number of plant species increased at 5 and 10 years after timber harvesting in aspen-dominated boreal mixedwood stands. The highest amount of understory vegetation cover were found in the pre-harvesting herbicide spray treatment areas, likely because understory plants were not directly exposed to the herbicide, whereas the most species occurred in the partial cutting treatment, which represented the most diverse stand structure with both harvested and leave corridors. Understory composition by percent cover of individual species at 10 years post-harvesting was affected by all treatment attributes (i.e., level of harvesting removal, type and time of herbicide application, and mechanical site preparation); however, understory vegetation responded the most to harvesting level. Among treatments, the difference in understory composition was largely attributed to changes in understory species of different shade tolerance.

Effects of alternative silvicultural systems on litter decomposition and nutrients dynamics in sub-Antarctic forests

Forest harvesting is one of the main economic practices in South Patagonia. The impacts produced by forest harvesting have been studied by numerous investigations. And it is known that forest harvesting affects the decomposition of soil organic matter. However, there is no data about how the harvesting by variable-retentions affect this decomposition. Our objective was to determine how impact variable-retention upon decomposition and nutrient release in Nothofagus pumilio forest soils. We hypothesized that variable-retention accelerate decomposition and nutrient release. We compared primary and harvested forests with two types of retentions (aggregated and dispersed) and two times [1 and 5 years after harvesting (YAH)]. To measure litter decomposition, we used bag technique for to determine organic matter loss. We determined carbon; nitrogen; calcium; potassium; magnesium and lignin concentrations in decomposing material. We analysed the data using linear mixed models ANOVA. Decomposition rates were estimated as derivate of the linear mixed model for the logarithm of the remaining leaf litter weight. We found that dispersed retentions treatment had the highest decomposition rates. Primary forest and aggregated retentions had the smaller slopes of the decomposition model. Dispersed and aggregated retention 5 YAH retained more nitrogen compared to primary forest. Dispersed retention 5 YAH had the lowest C/N ratio. Primary forest had higher Lignin/N ratio at 540 incubation days. Dispersed retention 5 YAH released more phosphorus compared to primary forest. Dispersed and aggregated retention 1 YAH had higher C/P ratio. Dispersed retention 5 YAH presented the most mineralization of potassium in the initial time of decomposition. We conclude that the harvesting by variable-retentions had an immediate negative effect on litter decomposition and the nutrients dynamics.

The influence of forest management on the abundance and diversity of hoverflies in commercial plantations of Sitka spruce: the importance of sampling in the canopy

Abstract The majority of Sitka spruce plantations in the UK are managed by clear-cutting and replanting, which leads to the formation of relatively large blocks (5–30 ha) of even-aged, closely spaced trees. These stands are considered to be poor in terms of general biodiversity and vulnerable to outbreaks of insect pests and diseases. In contrast, stands managed using alternative silvicultural systems, such as shelterwood or group selection systems, contain a wider range of tree ages and sizes and have the potential to support greater numbers of other species. If this includes the natural enemies (predators, parasitoids) of pest species, then adopting alternative silvicultural systems might help to reduce current and future pest impacts. To determine whether the greater structural complexity of stands managed using alternative silvicultural systems is associated with an increase in insect diversity and an increase in the abundance of predatory species, we sampled hoverflies (Diptera: Syrphidae) in 5 shelterwood stands, 6 group selection stands and 13 even-aged stands of Sitka spruce at 4 forest sites in mid and north Wales. The larvae of aphidophagous hoverflies are important invertebrate predators in spruce plantations, and hoverfly species richness is often used as an indicator of general invertebrate diversity. Hoverflies were sampled at ground level and in the canopy using yellow pan traps and flight interception traps. 7323 adult hoverflies of 74 species were captured, the majority of these in traps in the canopy. Total hoverfly abundance and the abundance of aphidophagous species were significantly higher ( P

The irregular shelterwood system as an alternative to clearcutting to achieve compositional and structural objectives in temperate mixedwood stands

Even-aged systems including clearcutting and its variants have been used for decades in North America for managing conifer-dominated stands with the goal to achieve sustainable wood production. Although clearcutting has been successfully applied in conifer-dominated stands of the boreal forest, it has proved maladapted in the temperate mixedwood forest where hardwood and shrub competition is more intense. Over time, regulated even-aged management has simplified the structure and composition of the temperate mixedwood forest which used to be dominated by late-successional stands with high conifer proportions. This study assesses alternative silvicultural systems inspired by natural dynamics for balsam fir (Abies balsamea [L.] Mill.) – yellow birch (Betula alleghaniensis Britton) stands growing in Québec, Eastern Canada. In absence of stand-replacing disturbances, spruce budworm outbreaks (Choristoneura fumiferana [Clem.]) and windthrow trigger regeneration phases through gap dynamics that result in multi-cohort, irregular stand structures. Here, we assess irregular shelterwood systems aiming at regenerating red spruce (Picea rubens Sarg.), balsam fir and yellow birch. In 2009, we established an experiment made of four randomized blocks comparing a gradient of treatments of increased cutting intensity: (i) uncut control (0% removal, 30m2/ha); (ii) continuous cover irregular shelterwood (19m2/ha of residual basal area [RBA] at the first cut, 25–30years intervals without final cut), (iii) extended irregular shelterwood (RBA 17m2/ha, final cut at year 30), (iv) uniform regular shelterwood (RBA 15m2/ha, final cut at year 10) and (v) clearcut (harvest of merchantable trees >9cmDBH). We monitored light transmission, seedbed quality and lower vegetation (<3m) during the first 5years postcut. Shelterwood treatments diversified both understory light and seedbed conditions, thereby increasing the array of available regeneration niches. Shade-tolerant red spruce and balsam fir established more successfully in the less intense irregular shelterwood treatment (continuous cover) and with a higher spruce: fir proportion. All cutting treatments increased seedling density >30cm of mid-tolerant yellow birch. Interspecific competition dominated by pin cherry (Prunus pensylvanica L.f.) and red maple (Acer rubrum L.) was the main factor limiting conifer establishment and was more abundant in the clearcut. Maintaining a partial cover in shelterwood treatments successfully limited competition expansion while regenerating target species. Even if relatively short term, results show that irregular shelterwood systems could be a sound alternative to clearcutting for regenerating and maintaining the structure of late-successional balsam fir-yellow birch stands.

Endurance and Adaptation of Community Forest Management in Quintana Roo, Mexico

Despite regional deforestation threats, the state of Quintana Roo has maintained over 80% of its territory in forests. Community forest management (CFM) has played a pivotal role in forest cover and biodiversity conservation in the region. In this article, we present the institutional, socioeconomic and environmental conditions under which community-based forest management has been consolidated in the tropical state of Quintana Roo, which occupies the eastern half of Mexico’s Yucatan Peninsula. With a focus on management for timber and other market-based development strategies, we then examine the institutional and socioeconomic factors, as well as biophysical shocks, that have constrained community forestry development in the past 25 years, challenging its persistence. Following, we discuss how forest communities and institutions have responded and adapted to changing forest policies and markets as well as major environmental shocks from hurricanes and fires. CFM in Quintana Roo has shown resiliency since its institutionalization 30 years ago. Future challenges and opportunities include biodiversity conservation, carbon management through Reducing Emissions from Deforestation and Forest Degradation (REDD+) initiatives, market strengthening, business management training as well as the implementation of alternative silvicultural systems, particularly to manage sustainable populations of commercial timber species.

Silvicultural alternatives to conventional even-aged forest management - what limits global adoption?

Background: The development of forestry as a scientific and management discipline over the last two centuries has mainly emphasized intensive management operations focused on increased commodity production, mostly wood. This “conventional” forest management approach has typically favored production of even-aged, single-species stands. While alternative management regimes have generally received less attention, this has been changing over the last three decades, especially in countries with developed economies. Reasons for this change include a combination of new information and concerns about the ecological consequences of intensive forestry practices and a willingness on the part of many forest owners and society to embrace a wider set of management objectives. Alternative silvicultural approaches are characterized by a set of fundamental principles, including avoidance of clearcutting, an emphasis on structural diversity and small-scale variability, deployment of mixed species with natural regeneration, and avoidance of intensive site-preparation methods. Methods: Our compilation of the authors’ experiences and perspectives from various parts of the world aims to initiate a larger discussion concerning the constraints to and the potential of adopting alternative silvicultural practices. Results: The results suggest that a wider adoption of alternative silvicultural practices is currently hindered by a suite of ecological, economic, logistical, informational, cultural, and historical constraints. Individual contexts display their own unique combinations and relative significance of these constraints, and accordingly, targeted efforts, such as regulations and incentives, may help to overcome specific challenges. Conclusions: In a broader context, we propose that less emphases on strict applications of principles and on stand structures might provide additional flexibility and facilitate the adoption of alternative silvicultural regimes in a broader set of circumstances. At the same time, the acceptance of alternative silvicultural systems as the “preferred or default mode of management” will necessitate and benefit from the continued development of the scientific basis and valuation of a variety of ecosystem goods and services. This publication is aimed to further the discussion in this context.

Small-mammal response to group-selection silvicultural systems in Engelmann spruce – subalpine fir forests 14 years postharvest

Concerns about the impacts of clear-cut harvesting on ecosystem components in subalpine forests have generated a variety of alternative silvicultural systems in high-elevation forests in western North America. We examined responses of forest-floor small mammals, 14 years posttreatment, in four replicate units, uncut forest, a 1.0 ha group-selection cut, a large (&gt;30 ha) clearcut, and the edge between the group-selection cut and uncut forest, in the Engelmann Spruce ( Picea engelmannii Parry ex Engelm.) – Subalpine Fir ( Abies lasiocarpa (Hook.) Nutt.) biogeoclimatic zone in south-central British Columbia, Canada. Populations of small mammals were livetrapped during five sessions from June to September 2006. The mean abundance of southern red-backed voles ( Myodes gapperi Vigors) was significantly lower on large clearcuts than in uncut old-growth forests, with intermediate numbers in 1 ha cuts. The opposite trend was found for dusky shrews ( Sorex monticolus Merriam), while there was no significant difference in mean abundance of deer mice ( Peromyscus maniculatus Wagner) among treatments. Trappability, proportion of adult females breeding, and rate of survival of red-backed voles and deer mice were similar among treatments. Our results suggest that group-selection silviculture conducted in subalpine forests may have fewer negative impacts on the small-mammal community than large clearcuts.

Short-rotation woody crops for bioenergy and biofuels applications

Purpose-grown trees will be part of the bioenergy solution in the United States, especially in the Southeast where plantation forestry is prevalent and economically important. Trees provide a “living biomass inventory” with existing end-use markets and associated infrastructure, unlike other biomass species such as perennial grasses. The economic feasibility of utilizing tree biomass is improved by increasing productivity through alternative silvicultural systems, improved breeding and biotechnology. Traditional breeding and selection, as well as the introduction of genes for improved growth and stress tolerance, have enabled high growth rates and improved site adaptability in trees grown for industrial applications. An example is the biotechnology-aided improvement of a highly productive tropical Eucalyptus hybrid, Eucalyptus grandis × Eucalyptus urophylla. This tree has acquired freeze tolerance by the introduction of a plant transcription factor that up-regulates the cold-response pathways and makes possible commercial plantings in the Southeastern United States. Transgenic trees with reduced lignin, modified lignin, or increased cellulose and hemicellulose will improve the efficiency of feedstock conversion into biofuels. Reduced lignin trees have been shown to improve efficiency in the pre-treatment step utilized in fermentation systems for biofuels production from lignocellulosics. For systems in which thermochemical or gasification approaches are utilized, increased density will be an important trait, while increased lignin might be a desired trait for direct firing or co-firing of wood for energy. Trees developed through biotechnology, like all transgenic plants, need to go through the regulatory process, which involves biosafety and risk assessment analyses prior to commercialization.

Short-term responses of ground-active beetles to alternative silvicultural systems in the Warra Silvicultural Systems Trial, Tasmania, Australia

The Warra Silvicultural Systems Trial (SST) in Tasmania, Australia provides a framework for investigating the responses of beetles (Order: Coleoptera) to three alternative systems in lowland wet eucalypt forest: aggregated retention; dispersed retention; and understorey islands retained in clearfelled areas. Beetles from three families known to be sensitive to forest management, the families Carabidae (ground-beetles), Curculionidae (weevils) and Leiodidae (fungus-beetles), were collected with pitfall traps prior to harvest, and in the first and third years post-harvest. The retained aggregates in the aggregated retention system maintained beetle assemblages reasonably typical of mature forests, at least in these early years following harvesting. These aggregates appear to provide a stable habitat, with similar species composition in the first and third years post-harvest. In contrast, the harvested areas of the aggregated retention system contained low numbers of beetle species affiliated with mature forest, as did the understorey islands and the dispersed retention system. Relative to clearfelling, all alternative silvicultural systems appeared to be of some benefit to beetles affiliated with mature forest, but aggregated retention retained far greater numbers of these beetles compared to the other systems in Tasmanian wet eucalypt forest.

Effects of alternative silviculture on stump sprouting in the southern Appalachians

Stump sprouts are an important form of regeneration for a number of species in the southern Appalachians, especially the oaks ( Quercus spp.). Alternative regeneration systems to clearcutting such as shelterwood and leave-tree systems are being implemented in many hardwood stands in the Appalachians. However, the effects of these alternative silvicultural systems on stump sprouts are not known. Therefore, we evaluated the impact of three silvicultural systems: a clearcut, leave-tree, and shelterwood on stump sprouting. These treatments were implemented in seven stands in Virginia and West Virginia in the Appalachian Plateau (AP) and Ridge and Valley (RV) physiographic provinces. The stands were even-aged oak dominated Appalachian hardwood stands with ages ranging from 62 to 100 years. Species were placed into six groups: (1) red oak ( Quercus spp.), (2) chestnut oak ( Q. prinus L.), (3) white oak ( Q. alba L.) and hickory ( Carya spp.), (4) red maple ( Acer rubrum L.), (5) mixed mesic, and (6) midstory groups. Partial harvesting also reduced the number of sprouts per stump for the red oak group and red maple. Sprouting probabilities were generally less in the Appalachian Plateau than the Ridge and Valley, particularly for the oaks ( Quercus spp.). Partial harvesting systems decreased sprouting in both physiographic provinces. However, the sprouting in specific species groups varied between the two physiographic provinces. In the Ridge and Valley, the highest sprouting rates were in the clearcut for the red oak (60%), chestnut oak (77%), white oak–hickory (26%), and midstory (33%) species groups. Red maple sprouting was highest in the leave-tree (67%) in the Ridge and Valley. The mixed mesic and midstory groups were only reduced in the Ridge and Valley. Sprouting was negatively correlated with residual basal area for the red oak group, chestnut oak, and red maple. For the all oak species except white oak, sprouting was reduced by about 2% for every 1m 2/ha increase in residual basal area.

Are nest boxes a viable alternative source of cavities for hollow-dependent animals? Long-term monitoring of nest box occupancy, pest use and attrition

Nest box programs have often been established to conserve hollow-dependent fauna but their effectiveness is unknown in many jurisdictions. We examined nest box effectiveness in a 10-year experimental study in the Mountain Ash ( Eucalyptus regnans) forests of Victoria (south-eastern Australia) where the paucity of hollow-bearing trees is a significant conservation issue. We quantified occupancy by arboreal marsupials, infestation by pest invertebrates, and nest box attrition. We found a large proportion of nest boxes (68.8%) were never used, including by the endangered target species, Leadbeater’s Possum ( Gymnobelideus leadbeateri). Nest boxes were more often occupied in younger forests (58.3% cf 4.1% for old forest) but these sites were also where infestations by the introduced European Honeybee ( Apis mellifera) were greatest and where the probability of nest boxes collapsing was highest. Our data suggest that it is important to carefully target the locations where nest boxes should be established, but these same places are also those where most effort is required to maintain them, either by removing pest invertebrates and/or by re-attaching them to trees after they have fallen down. We recorded reasonable levels of occupancy by arboreal marsupials in young forest ∼2–3 years after box establishment, but then high levels of nest box attrition (>51%) occurred after 8–10 years. This suggests an “effective occupancy time” for arboreal marsupials of only ∼5 years. A key consideration must be to weigh the ecological and economic effectiveness of nest boxes against other strategies such as implementing alternative silvicultural systems that result in the creation and retention of more hollow-bearing trees within logged areas.