Commercial Logging Operations Research Articles

Effects of harvester positioning errors on merchantable timber volume predicted and estimated from airborne laser scanner data in mature Norway spruce forests

Newly developed positioning systems in cut-to-length harvesters enable georeferencing of individual trees with submeter accuracy. Together with detailed tree measurements recorded during processing of the tree, georeferenced harvester data are emerging as a valuable tool for forest inventory. Previous studies have shown that harvester data can be linked to airborne laser scanner (ALS) data to estimate a range of forest attributes. However, there is little empirical evidence of the benefits of improved positioning accuracy of harvester data. The two objectives of this study were to (1) assess the accuracy of timber volume estimation using harvester data and ALS data acquired with different scanners over multiple years and (2) assess how harvester positioning errors affect merchantable timber volume predicted and estimated from ALS data. We used harvester data from 33 commercial logging operations, comprising 93 731 harvested stems georeferenced with sub-meter accuracy, as plot-level training data in an enhanced area-based inventory approach. By randomly altering the tree positions in Monte Carlo simulations, we assessed how prediction and estimation errors were influenced by different combinations of simulated positioning errors and grid cell sizes. We simulated positioning errors of 1, 2, …, 15 m and used grid cells of 100, 200, 300 and 400 m. Values of root mean square errors obtained for cell-level predictions of timber volume differed significantly for the different grid cell sizes. The use of larger grid cells resulted in a greater accuracy of timber volume predictions, which were also less affected by positioning errors. Accuracies of timber volume estimates at logging operation level decreased significantly with increasing levels of positioning error. The results highlight the benefit of accurate positioning of harvester data in forest inventory applications. Further, the results indicate that when estimating timber volume from ALS data and inaccurately positioned harvester data, larger grid cells are beneficial.2

Inspired by Harold Conklin

Harold C. Conklin (1926-2016) is without doubt one of the key figures in ethnobotany and environmental anthropology. His work is admired for, among other qualities, its precision and its level of « fine description ». In particular, his pioneering studies on shifting cultivation have changed the general perspective on this way of land use. His Ethnographic Atlas of Ifugao (1980) is still a landmark of ethnographic fieldwork, combining a wide range of methods, including sophisticated cartography. The focus of this atlas was on the culture of Ifugao farmers in their home area in the Cordillera Mountains on the island of Luzon in the Philippines. In recent decades, thousands of Ifugao farmers have left their home area and migrated eastwards to the Sierra Madre Mountains in the northeastern part of Luzon, across Cagayan Valley. They have done so for various reasons but land shortage is certainly one of them. In the foothills of the Sierra Madre, accessible arable land became available after large-scale commercial logging operations. In this article we will draw attention to the relevance of Conklin’s work before describing how the Ifugao farmers, with their extensive knowledge and experience, have been able to turn this new area into a highly productive environment, combining wet rice fields with upland agriculture. The research is based on fieldwork that was done over several years with Filipino, Dutch and other international students in the context of a long-standing cooperation project between Isabela State University in the Philippines and Leiden University (Netherlands).

Accuracy and Precision of Commercial Thinning to Achieve Wildlife Management Objectives in Production Forests

Tree stocking and the associated canopy closure in production forests is often greater than optimal for wildlife that require an open canopy and the associated understory plant community. Although mid-rotation treatments such as thinning can reduce canopy closure and return sunlight to the forest floor, stimulating understory vegetation, wildlife-focused thinning prescriptions often involve thinning stands to lower tree densities than are typically prescribed for commercial logging operations. Therefore, we quantified the accuracy and precision with which commercial logging crews thinned pre-marked and unmarked mid-rotation loblolly pine (Pinus taeda) stands to residual basal areas of 9 (low), 14 (medium), and 18 (high) m2/ha. Following harvest, observed basal areas were 3.36, 1.58, and 0.6 m2/ha below target basal areas for the high, medium, and low basal area treatments, respectively. Pre-marking stands increased precision, but not accuracy, of thinning operations. We believe the thinning outcomes we observed are sufficient to achieve wildlife objectives in production forests, and that the added expense associated with pre-marking stands to achieve wildlife objectives in production forests depends on focal wildlife species and management objectives.

Long-Term Empirical Studies Highlight Multiple Drivers of Temporal Change in Bird Fauna in the Wet Forests of Victoria, South-Eastern Australia

Birds are high profile elements of the vertebrate biota in almost all terrestrial ecosystems worldwide. Many studies have uncovered evidence of a decline in bird biodiversity, but temporal patterns of change vary among ecosystems and among bird species with different life history traits. Ecosystem-specific, long-term studies are critical for identifying patterns of temporal change in bird biodiversity and the drivers of that change. Here we present a case study of drivers of temporal change in the bird fauna of the Mountain Ash and Alpine Ash eucalypt forests of south-eastern Australia. Using insights from observational studies and experiments conducted over the past 18 years, we discuss the direct and interactive effects of fire and logging on birds. The extent and severity of wildfires have major negative effects on almost all bird species, and have persisted for more than a decade after the last major conflagration (in 2009). Logging has markedly different effects on birds than those quantified for fire, and may have resulted in elevated levels of site occupancy in remaining uncut areas in the landscape. Both fire and logging have led to marked losses in the extent of old growth forest in Mountain Ash and Alpine Ash ecosystems. This is a concern given the strong association of most species of birds with old forest relative to younger age cohorts. Based on an understanding of the effects of fire and logging as drivers of change, we propose a series of inter-related management actions designed to enhance the conservation of avifauna in Mountain Ash and Alpine Ash ecosystems. A particular focus of management must be on increasing the interval between fires and limiting the spatial extent of wildfires and, in turn, significantly expanding the extent of old growth forest. This is because old growth forest is where most bird species are most likely to occur, and in the event of future wildfires, where fire severity will be lowest. Expansion of the old growth estate will require commercial logging operations to be excluded from large parts of Mountain Ash and Alpine Ash forests.

A simple system for classifying sugar maple vigour and quality

In northern hardwood forests, treemarkers are responsible for selecting the trees to be harvested during commercial logging operations. They often select trees based on the presence and severity of defects, information that is used to assign trees to two or more vigour classes (reflecting the risk of dying or declining in growth) and two or more quality classes (reflecting the potential for recovering valuable sawlogs). Using these classes can simplify the tree selection process, but some classification systems may include superfluous classes beyond what is required to explain the variation in tree value. In this paper, we present a parsimonious classification system for sugar maple (Acer saccharum Marsh.) trees using formal classification analyses of empirical product recovery data. We also calculated the net value of trees in each class and assessed which defects affect tree value. Our results show that relatively few defects affect tree value, indicating that treemarkers should use a simpler classification system to describe the vigour and quality of trees. Specifically, we found that the best system contains just three classes: high vigour-high quality, low vigour-high quality, and low vigour-low quality. The use of this simple, easily implemented system would improve the ability of treemarkers to recognize the value of sugar maple trees when selecting the trees to be harvested during commercial logging operations.

Interaction between forest biodiversity and people’s use of forest resources in Roviana, Solomon Islands: implications for biocultural conservation under socioeconomic changes

BackgroundIn Solomon Islands, forests have provided people with ecological services while being affected by human use and protection. This study used a quantitative ethnobotanical analysis to explore the society–forest interaction and its transformation in Roviana, Solomon Islands. We compared local plant and land uses between a rural village and urbanized village. Special attention was paid to how local people depend on biodiversity and how traditional human modifications of forest contribute to biodiversity conservation.MethodsAfter defining locally recognized land-use classes, vegetation surveys were conducted in seven forest classes. For detailed observations of daily plant uses, 15 and 17 households were randomly selected in the rural and urban villages, respectively. We quantitatively documented the plant species that were used as food, medicine, building materials, and tools.ResultsThe vegetation survey revealed that each local forest class represented a different vegetative community with relatively low similarity between communities. Although commercial logging operations and agriculture were both prohibited in the customary nature reserve, local people were allowed to cut down trees for their personal use and to take several types of non-timber forest products. Useful trees were found at high frequencies in the barrier island’s primary forest (68.4%) and the main island’s reserve (68.3%). Various useful tree species were found only in the reserve forest and seldom available in the urban village. In the rural village, customary governance and control over the use of forest resources by the local people still functioned.ConclusionsHuman modifications of the forest created unique vegetation communities, thus increasing biodiversity overall. Each type of forest had different species that varied in their levels of importance to the local subsistence lifestyle, and the villagers’ behaviors, such as respect for forest reserves and the semidomestication of some species, contributed to conserving diversity. Urbanization threatened this human–forest interaction. Although the status of biodiversity in human-modified landscapes is not fully understood, this study suggested that traditional human modifications can positively affect biodiversity and that conservation programs should incorporate traditional uses of landscapes to be successful.

Le potentiel de la production forestière paysanne en Amazonie brésilienne

Dans l'État du Pará, 60 % des forêts destinées à l'aménagement sont des forêts paysannes. Les concessions forestières d'entreprise ne pourront fournir au mieux que la moitié de la consommation actuelle. À quelques exceptions près, les communautés traditionnelles et les familles paysannes n'ont ni l'expérience technique ni la capacité économique pour conduire l'exploitation commerciale des bois : l'aménagement est réalisé par le biais d'accords avec une entreprise, selon différentes modalités. Dans ce contexte, les contrats entre communautés et entreprise sont de nature très variée et aboutissent au contrôle total par les entreprises privées de toutes les opérations, du plan d'aménagement à l'exploitation. Les politiques publiques et la législation forestière cherchent aujourd'hui à améliorer les capacités des communautés locales à défendre leurs intérêts dans le cadre de tels partenariats. Cette étude analyse le cadre financier de l'entreprise par rapport à l'organisation paysanne pour son exécution, et les éléments clés qui permettent un meilleur contrôle : les inventaires pré- exploitation, la diversification de la production de bois d'oeuvre et de produits forestiers non ligneux, la commercialisation, le suivi et le contrôle des opérations d'exploitation. Il est proposé des pistes de politiques publiques qui doivent aider à la diffusion de l'aménagement paysan dans différentes contextes fonciers : unités de conservation et forêts de production, périmètres de colonisation agricole. L'article discute des modalités d'action et d'implantation d'un service public d'assistance technique et financière au profit des agriculteurs et des communautés. Le potentiel de l'intégration de la gestion forestière au sein des systèmes de production paysans est discuté dans le cadre du débat actuel de réforme du code forestier. (Résumé d'auteur)

Response of timber rattlesnakes to commercial logging operations

Forest management practices in the eastern United States directly impact large parcels of land that serve as habitat for timber rattlesnakes (Crotalus horridus). We assessed the behavioral response of timber rattlesnakes to commercial logging activities and the impact of such activities on a timber rattlesnake population in northcentral Pennsylvania. We radiotelemetrically monitored 67 individual snakes over periods of up to 4 years, marked and recaptured 306 snakes, and conducted search and survey efforts before, during, and after commercial logging operations on 3 timber sale parcels (totaling 154.2 ha). Location and timing of timber sales created the maximum opportunity for interaction of snakes with logging operations and with altered habitat. Observed logging-related mortality of snakes was low (<2% of the population/yr), but potential mortality could have reached 7%. Logging activity and resulting habitat changes did not alter behavior or movement patterns of telemetrically monitored snakes. Snakes with established activity ranges in timber sale areas continued to use these areas both during and after logging operations. Similarly, snakes with activity patterns that did not include timber sale areas did not alter their movement patterns to include such sites in the short-term. Timbering increased structural diversity of the habitat and, concurrently, diversity of habitat used by timber rattlesnakes increased. Our results suggest that the opportunity exists to develop forest management practices that provide timber products while limiting impacts on behavior and habitat use of timber rattlesnakes. To further reduce impacts to timber rattlesnake populations we recommend that management agencies require commercial logging contractors, sub-contractors, and field employees to adhere strictly to a policy that prohibits the intentional killing of rattlesnakes encountered during logging activities. © 2010 The Wildlife Society.

The Long-term Impact of Timber Harvesting on the Resource Base of Chimpanzees in Kibale National Park, Uganda

Commercial timber harvesting results in the loss of critical habitat for tropical forest fauna, and large-bodied frugivores (including chimpanzees and most other apes) may experience particularly detrimental effects. Few quantitative data, however, are available to evaluate the long-term impact of harvesting on chimpanzees and other apes. In particular, few data are available to compare population demographics and/or forest composition before and after timber harvesting at the same site. Utilizing detailed forestry department records of logging operations conducted in the late 1960s, present-day botanical surveys, and long-term data on the feeding ecology of chimpanzees in Kibale National Park (KNP), Uganda, I examined the impact that logging has had on KNP chimpanzee communities of known size and demography. Although some important chimpanzee food resources were harvested in high abundance during commercial logging operations, the overall impact on the most predominant dietary items (those making up roughly 75% of the chimpanzees’ diet) and on presumably critical subsistence resources was limited. Furthermore, the low density of chimpanzees inhabiting the logged region of KNP is apparently not attributable to the impact of logging at the site: comparisons of resource densities at this ‘low-chimpanzee-density’ site with that of an unlogged and ‘high-chimpanzee-density’ KNP site did not differ when logging concessions at the low-chimpanzeedensity site were excluded from the analysis. This study suggests that low-intensity logging can be compatible with the conservation of large-bodied frugivores, provided that dietary data are taken into account in forest management planning.

Selection of Nest Trees by Cavity-nesting Birds in the Neotropical Atlantic Forest

One of the five most important global biodiversity hotspots, the Neotropical Atlantic forest supports a diverse community of birds that nest in tree cavities. Cavitynesting birds may be particularly sensitive to forestry and agricultural practices that remove potential nest trees; however, there have been few efforts to determine what constitutes a potential nest tree in Neotropical forests. We aimed to determine the characteristics of trees and cavities used in nesting by excavators (species that excavate their own nest cavity) and secondary cavity-nesters (species that rely on existing cavities), and to identify the characteristics of trees most likely to contain suitable cavities in the Atlantic forest of Argentina. We used univariate analyses and conditional logistic regression models to compare characteristics of nest trees paired with unused trees found over three breeding seasons (2006‐2008). Excavators selected dead or unhealthy trees. Secondary cavity-nesters primarily selected cavities that were deep and high on the tree, using live and dead cavity-bearing trees in proportion to their availability. Nonexcavated cavities suitable for birds occurred primarily in live trees. They were most likely to develop in large-diameter trees, especially grapiaApuleia leiocarpaand trees in co-dominant or suppressed crown classes. To conserve cavity-nesting birds of the Atlantic forest, we recommend a combination of policies, economic assistance, environmental education, and technical support for forest managers and small-scale farmers, to maintain large healthy and unhealthy trees in commercial logging operations and on farms.

Assessment of logging efficiency and development of allometric models for predicting stumpage volume of some commercial tree species in Ghana

SUMMARY The need to develop instruments to capture the realistic stumpage volume and influence loggers to improve on their logging efficiency has been a topic of interest in recent times. This study assessed the logging efficiency in Ghana and developed allometric models to predict stumpage volume. A total of 135 trees from nine timber species were sampled from three logging sites during commercial logging operations. The average logging recovery for all sampled trees was about 75 %. The small-end diameter of the merchantable residues averaged between 31 cm and 60 cm while their length values varied from 3.0 m to 8.5 m. In general, species-specific models exhibited better predictive power than mixed-species models. Models that predicted total merchantable volume from the volume of the extracted logs had the best fits, with Furnival index values ranging from 0.590 to 1.727. Results of the models' validation indicated that mixed species models could predict merchantable volume better for relatively small tr...

Inter-household variations in subsistence strategies within a rural society of Roviana, Solomon Islands: An analysis of agricultural production and cash income in relation to socio-demographic factors

Since several decades ago, rural societies in Solomon Islands have experienced rapid socioeconomic changes due to the direct and indirect influences of commercial logging operations by foreign companies on their customary lands. This study aims to explore household level subsistence patterns and their variations within a rural society that was subjected to the logging operation in the recent past, in Roviana, Western Province. Crop yield (MJ) and cash income (SBD: Solomon Islands Dollar) were compared among households and adjusted for the consumer unit (CU) and producer unit (PU), respectively. The results indicated large inter-household variations for both of these variables. Multiple regression analyses showed that the variation in crop yield was primarily explained by the available labor force (PU), while that in cash income was determined by the householders’ par ticipation in SDC, a local enterprise founded using a portion of royalty money, as well as the labor force. It is suggested that an individual’s experience in generating and increasing cash income in local environments increases his/her household’s economic level.

Bird responses to partial retention timber harvesting in central interior British Columbia

Current legislation in British Columbia, Canada, requires patches of forest to be left uncut within timber harvest blocks during commercial logging operations, to maintain wildlife diversity in the post-harvest stand. To test the effectiveness of this practice, we compared bird content in (i) conventional clearcuts (all trees removed), (ii) clearcuts with partial forest retention (15–22% of the stand), and (iii) mature uncut stands in sub-boreal conifer forest in central interior British Columbia. The forest and the partial retention sites had similar numbers of species and similar numbers of birds in total (per transect km) in all three years. The clearcuts had fewest. The partial retention sites contained species from the forest, species from the clearcuts, and species found at neither of the other two site types. Some forest-dwelling species were missing from the partial retention sites, and some were less abundant, but others were more abundant at the partial retention sites. Within sites, species distributed themselves among habitat structure-types by nesting/foraging ‘guild’. Tree-containing habitat types (uncut forest patches, riparian strips) were preferred by most species (occupancy versus extent), but some preferred open ground or remnants of the former understorey. Subject to the question of sustainable breeding, these findings suggest that partial retention harvesting (i) succeeded in maintaining most of the forest bird community, and (ii) increased the total bird diversity. These results were obtained at higher cut:leave ratios than have been reported hitherto.

A spreadsheet (lotus 1-2-3) based technique for analysing storm suspended sediment data with particular reference to logging disturbance in tropical forests

The procedure describes a simple and functional method using a commercial spreadsheet (Lotus 1-2-3) to calculate water and sediment yields from measured or given data sets. Suspended sediment concentrations are located on a storm hydrograph and concentrations for unsampled points on the hydrograph are estimated using the principle that the change in concentration between two sampled points will be proportional to the change in discharge between the same two points. The relationships are then solved by a cross-correlation equation using simple formulae in the form of triangle-square equations to calculate water and sediment yields between each sample time. The technique is applied to a 51 month data set from a long-term monitoring programme assessing the impacts of commercial logging operations in Sabah, East Malaysia. Yields for the monitoring period derived by the spreadsheet technique are compared with results from the application of more traditional discharge-sediment rating techniques. In the undisturbed catchment, yields derived from some rating equations compare favourably with the spreadsheet technique. However, in the disturbed catchment, rating techniques proved less applicable because of the continuously changing nature of the catchment in relation to vegetation recovery, exacerbating variation and scatter in the data set. The application of the spreadsheet technique provides detailed information at an individual storm level; however, working with the method on long-term discharge records requires a significant commitment of time as compared to the straightforward application of rating equations. (C) 1998 John Wiley Bi Sons, Ltd.

Spotted Owls and Old Growth Logging in the Pacific Northwest

Northern Spotted Owls, Strix occidentalis caurina, require large tracts of old-growth conifer forest to survive and reproduce. Much of this forest has been or is being cut by commercial logging operations, with uncertain consequences for the owls. In this paper I present simulation models of owl population change over the next 100 years, as summing a variety of scenarios for habitat destruction and fragmentation. My analysis differs from previous models by incorporating patchy territory distribution and random environmental fluctuations. Fragmented and patchy habitat distributions are common problems for endangered organisms, but they have received little attention from modelers. My results indicate that yearly fluctuations in breeding success have little impact on owl populations, but that spatial structure is quite important and should be considered in planning forest preservation. The simulations suggest that for all reasonable parameter values the proposed US. Forest Service logging plans will lead to the demise of the owls.