Forest Management Methods Research Articles

Forest management and natural biocontrol of insect pests

Current silvicultural practices are under revision as result of changing demands and pressing environmental issues. We compared the monoculture clear-cut regime commonly used during the recent decades in Europe, especially in Fennoscandia, and in North America, with three alternative forest management methods, short rotation forestry, mixed forest stands and continuous cover forestry. We evaluate how these alternative management methods are Likely to affect the natural control of forest insect (regeneration pests, defoliators and bark beetles). Particular emphasis was placed on the effects of forest management on natural enemy pressure. We argue that changing forest management to any of the methods discussed will, in most cases, decrease the relative effects of bottom-up forces (resource quality and quantity) and increase the relative effects of top-down forces (natural enemy pressure) on forest pests. As population growth of the pest species presently causing most damage in European managed forests (i.e. pine weevil and spruce bark beetle) is mainly Limited by bottom-up forces (quantity of suitable breeding material), changes in forest management could increase the relative importance of top-down forces by modifying stand characteristics to actively support the natural enemies. However, it remains to be investigated to what extent such alterations will result in decreased damage to trees even though some evidence points in that direction.

Effect of salicylic acid on protease and urease activity in soils under Norway spruce pure stands

This study tested the hypothesis that soil protease and urease activity is inhibited by salicylic acid. This was tested in soils from spruce monocultures of different ages and treated by different forest management methods at the Rajec-Němcice Ecosystem Station. Surface organic H-horizons from three study plots were sampled: a mature spruce monoculture of 105 years and two young spruce monocultures of 33 years, one of which was thinned from above and the other thinned from below. Statistically significant differences between the measured values confirm that young stands are sensitive to the presence of 2-hydroxybenzoic acid as a phytotoxic substance. The results of this study do not conclusively show whether the effect of salicylic acid on protease activity inhibition increases when the protease activity itself is high. The impact of salicylic acid on soil urease activity was not clearly evident either.

A Phenology-Based Method for Monitoring Woody and Herbaceous Vegetation in Mediterranean Forests from NDVI Time Series

We present an efficient method for monitoring woody (i.e., evergreen) and herbaceous (i.e., ephemeral) vegetation in Mediterranean forests at a sub pixel scale from Normalized Difference Vegetation Index (NDVI) time series derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The method is based on the distinct development periods of those vegetation components. In the dry season, herbaceous vegetation is absent or completely dry in Mediterranean forests. Thus the mean NDVI in the dry season was attributed to the woody vegetation (NDVIW). A constant NDVI value was assumed for soil background during this period. In the wet season, changes in NDVI were attributed to the development of ephemeral herbaceous vegetation in the forest floor and its maximum value to the peak green cover (NDVIH). NDVIW and NDVIH agreed well with field estimates of leaf area index and fraction of vegetation cover in two differently structured Mediterranean forests. To further assess the method’s assumptions, understory NDVI was retrieved form MODIS Bidirectional Reflectance Distribution Function (BRDF) data and compared with NDVIH. After calibration, leaf area index and woody and herbaceous vegetation covers were assessed for those forests. Applicability for pre- and post-fire monitoring is presented as a potential use of this method for forest management in Mediterranean-climate regions.

Biotic homogenisation and differentiation along a habitat gradient resulting from the ageing of managed beech stands

Understanding the processes driving biodiversity changes in forest communities helps to better evaluate sustainable forest management methods and their effects on forest ecosystems. This, in turn, is crucial for the appropriate management of protected areas, in particular those covered under the European protection program Natura 2000. Two datasets from the Polish Eastern Carpathians collected in the 1970s and 2000s were compared to analyse the temporal and spatial changes in the species composition of beech forests in a habitat gradient of soil moisture, acidity and fertility. We found that species favouring fertile and alkaline soils, with low ability for vegetative propagation and without a persistent seed bank became less frequent, whilst frequency of good competitors tolerant to lower soil pH and fertility with a persistent seed bank and a capacity for dispersing seeds over long distances increased. Herb layer vegetation on poor and rich soils became less similar in the past 30years, though two opposite processes occurred. In poor habitats, the biotic differentiation of herb layer vegetation prevailed, whilst biotic homogenisation was more important in fertile habitats. It is suggested that the ageing of the managed beech stands might have contributed to these changes through the accumulation of litter, top soil acidification and the lowering of the concentration of nutrients as well as due to altered disturbance regimes in older stands. The observed relationships between biotic homogenisation/differentiation and the habitat gradient indicate that differences in soil conditions not only shape the spatial pattern of the forest vegetation, but also the spatial and temporal patterns of changes in vegetation composition resulting from the ageing of tree stands. Our results also suggest that in spite of continuous management the studied beech forests have only slightly changed in their specific species composition. Moreover, the ageing of tree stands did not necessarily generate better conditions for the conservation of the species richness of herbaceous plants, at least those species that are considered a measure of naturalness in beech forests.

Sustainable management of metallurgical forest on Mont Lozère (France) during the Early Middle Ages

Mont Lozère, located in the French Massif Central region, provides an exceptional context in which to research the impact that charcoal production and metallurgy had on woodlands, along with the role that these activities played in changing the mountain landscape. This study provides an insight into the land use, forest management methods and metallurgical practices in the area during the Middle Ages (11th to 15th centuries). Medieval charcoal burning platforms, archaeological remains that have often been neglected in the past as a source of historical information, along with nearby smelting sites, were identified, sampled and analysed. In this paper, spatial analyses, radiocarbon dating and anthracological and dendro-anthracological studies have been combined in a unique manner. The results reveal that charcoal burners practiced beech coppicing, where the species and diameter of wood used remained the same over a period of four centuries. It is proposed that this form of metallurgical forest management be considered an early example of a sustainable utilisation of natural resources.

Situation und Anliegen der Waldeigentümer – einige Gedanken (Essay)

Situation and concerns of forest owners - some notions (essay) The swiss forest economy is expecting huge challenges due to major changes in national and international circumstances. The main task in future time will be to combine proven traditions and principles with new and probably massif changes in an optimized way. We must be aware of the fact that some existing methods of forest management and sylviculture will eventually have to be adapted in a quite extensive and fundamental way. Swiss forest land owners must be recognized again as the main actors and the most important stakeholder concerning forest matters. There has been a very long period of reducing forest owners property rights and liberty of action, this process has to be stopped now. The increasing demand for existing and new non-wood forest products and services and for further limitations in forest management must be satisfied increasingly on a voluntarely basis (product selling, service agreements), rather than by tightening up the forest and other forest-related laws. The well-known «wake theory» in Swiss forest economy doesn't work anymore in its traditional form.

A Review of Forestland Use and Management in China

In the past few decades, forestland management have changed in response to the improved patterns of resource use in rural China. Two main questions arise: what factors are to have an impacts on forestland use, and how does forestland management adapt to forestland use changes. Most researches mainly focus on forestland transfer for the forestland use, since forestland transfer has been the effective way of achieving intensive management. The forest tenure reform breeds new management modes and management methods for forestland change as the most basic driving force. However, there are some aspects need to be improved and further discussion is required, including constructing forestry credit system, perfecting mortgage system, and improving assets evaluation system and service mechanism. This paper summarizes the existing studies on forestland use and management from the reform of forestry system, forestland use change and forestland management.

Bryophyte species richness on retention aspens recovers in time but community structure does not.

Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer ‘lifeboats’ to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L.) retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 ‘retention aspens’ on 14 differently aged retention sites with 102 ‘conservation aspens’ on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered) and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20–30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20–30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old-growth forests.

Long-term responses of Scots pine and Norway spruce stands in Sweden to repeated fertilization and thinning

Recent investigations have shown that annual wood production in Sweden can be increased by 30millionm3 per year in a long-term perspective (>50years) by using new forest management methods such as new tree species or seedling materials. However, to meet the increased demands during the next 20years, Sweden will have to rely on silvicultural methods available today. Growth in boreal and cold temperate forest is with only few exceptions limited by nutrients availability, primarily nitrogen, and one way to satisfy the increased demands in a short-term perspective is nitrogen fertilization. A set of thinning and fertilization experiments were started in the 1960’s in Scots pine and Norway spruce stands over the whole of Sweden representing different soil, moisture and vegetation types. We used data from these experiments to examine the long-term effects of repeated fertilization in thinned stands on growth, stand development, and yield. The 34 Scots pine sites and 13 Norway spruce sites included in our analyses had at least four treatment plots (no thinning, repeated light thinnings, repeated light thinnings with repeated N fertilization, and repeated light thinnings with repeated N+P fertilization). In northern Sweden, 100kgNha−1 and 150kgNha−1 were applied at each fertilization event for Scots pine and Norway spruce stands, respectively. In southern Sweden, 150kgha−1 N was applied in Scots pine stands and 200kgha−1 N in Norway spruce stands. Phosphorus was applied at the rate of 100kgha−1. Several sites also included non-thinned fertilized plots. Pine stands but not spruce stands were responsive (up to 25% more growth depending of the attribute assessed) to repeated fertilization. Surprisingly, the non-thinned pine stands showed strong continuing response to fertilization throughout the 30+ year observation period resulting in higher cumulative volume response than the thinned stands. In thinned stands incremental volume response to fertilization continued but slowly diminished with time indicating that fertilization and thinning effects were less than additive. However, thinning and fertilization effects were additive for diameter growth. Fertilization accelerated stand development with significant shifts in diameter distributions to larger and potentially more valuable trees. Conclusively, repeated nitrogen fertilization is a silvicultural practice that will result in significant and sustained increases in Scots pine production.

Efficiency of alternative forest inventory methods in partially harvested stands

Forest inventory is vital to all aspects of forest management and inventory methods can vary greatly in their accuracy, precision, efficiency and cost. In Maine, much of the forestland base has been managed using partial harvesting methods over the past two decades. These partial harvesting methods generally produce highly heterogeneous stand structures and composition. Consequently, it is currently unclear which inventory methods are best given the distinct spatial and structural heterogeneity that is created. We compared efficiency and stand-level inventory estimates using horizontal point, fixed area and horizontal line sampling measurement methods in 16 partially harvested stands across northern and central Maine. Some stand-level variables were sensitive to measurement method (e.g., volume, quadratic mean diameter and small stem density and basal area), while others were less sensitive (e.g., overall basal area and stem density). Efficiency, defined as a combination of precision of volume estimates and measurement time, varied among measurement methods at lower stand basal area values but was similar at higher basal area, with the exception of the fixed area method. Overall, horizontal line sampling proved to be a viable method in post-partial harvest stand conditions. Our results illustrate the trade-offs between precision and time costs involved in several measurement methods under a range of heterogeneous stand conditions.

Corrigendum to: Wildland fire ash and particulate distribution in adjacent residential areas

In recent decades, the frequency of wildland fire incidents near residential areas has decreased but the number of acres burned has increased, in large part due to changes in forest management methods and further human encroachment in forested regions. There is much debate about whether the wood ash generated by these wildfires can significantly affect residential buildings outside the fire zone perimeter. This study investigates the distribution of ash, soot and char that are generated from wildfires and migrate into adjacent residential regions. For this purpose, a wildland fire in Bastrop, Texas, was studied with samples collected from a variety of locations within the fire site and in adjacent areas. The collected samples were assayed for pH, asbestos, heavy metals and polynuclear aromatic hydrocarbons. The results of this investigation showed that the magnitude of the deposition on residential buildings near wildfires is dependent on a variety of variables, in particular the distance from the centre of the fire.

Erdőművelés aljnövényzetre gyakorolt hatásainak vizsgálata zselici bükkösben

The studied beech forest is situated in south-west Hungary. This paper describe the surveyed forest stand and try to introducing the influence of applied forest management method. The analysis use phytosociological characters, flora elements, life forms and social behaviour types of plant spe-cies. The composition of herb layer was changed in the steps of regeneration cutting.

木材のカスケード利用に向けた可搬型３次元レーザスキャナによる木材資源量算定

Computerization and sharing of information regarding forest resources and timber distribution are important topics for sustainable forest management. Based on the example of Japanese cedars in Nagano prefecture this research study investigates precision and accuracy problems encountered when using portable 3D laser scanners for computerization of information on forests, therefore considering possible future forest management methods. The discrepancy between the scan-derived measurement and the manual measurement (by measuring each tree separately) as well as the technical aspect of both methods were evaluated. The scanner proved to be precise in measuring trunk diameter, tree height, and tree position. When all the parts of branches and leaves can be measured by a single 3D laser scanner, a significant correlation is seen between the number of reflection points from branches and leaves and their weight. The following regression equation was obtained for this case. However, the validity of the equation cannot be confirmed because of the small quantity of collected data (with only ten samples being investigated). It is assumed that more measurement data collected continuously in the future will enhance the accuracy and validity of the equation, which can be useful for accurate estimation of the amount of tree canopy.

SUSTAINABLE FOREST MANAGEMENT IN LOWER KINABATANGAN, SABAH: ISSUES AND CURRENT PRACTICES

Since 1992, when the first United Nations’ Earth Summit was held in Rio de Janeiro, sustainable forest management (SFM) has been increasingly used to maintain a balance between social, economic and environmental development. In line with this, the successful implementation of SFM depends in large measure on the involvement of all the stakeholders. However, in the Lower Kinabatangan area, not all the stakeholders, especially the local community, are involved in the decision making process when it comes to forest management. The primary objective of this research is to explore the views of the three major stakeholders (Government, Private Sector and Local Community) with regard to issues concerning the environment, the current methods of forest management and the factors that are having an impact on SFM in Lower Kinabatangan. The quantitative method was used in this research and the data was obtained through questionnaires which were distributed to a stratified sample of the target population of stakeholders. Of the 160 questionnaires that were distributed, 115 or 56% of them were returned. The data analysis revealed some similarities and differences in the viewpoints of the stakeholders. It was found from this research that the majority of the respondents were in favour of improving forest management as a way to solve the environmental issues that have arisen in Lower Kinabatangan.

SUSTAINABLE FOREST MANAGEMENT IN LOWER KINABATANGAN, SABAH: ISSUES AND CURRENT PRACTICES

Since 1992, when the first United Nations’ Earth Summit was held in Rio de Janeiro, sustainable forest management (SFM) has been increasingly used to maintain a balance between social, economic and environmental development. In line with this, the successful implementation of SFM depends in large measure on the involvement of all the stakeholders. However, in the Lower Kinabatangan area, not all the stakeholders, especially the local community, are involved in the decision making process when it comes to forest management. The primary objective of this research is to explore the views of the three major stakeholders (Government, Private Sector and Local Community) with regard to issues concerning the environment, the current methods of forest management and the factors that are having an impact on SFM in Lower Kinabatangan. The quantitative method was used in this research and the data was obtained through questionnaires which were distributed to a stratified sample of the target population of stakeholders. Of the 160 questionnaires that were distributed, 115 or 56% of them were returned. The data analysis revealed some similarities and differences in the viewpoints of the stakeholders. It was found from this research that the majority of the respondents were in favour of improving forest management as a way to solve the environmental issues that have arisen in Lower Kinabatangan.

Nitrogen, Phosphorus, Carbon, and Suspended Solids Loads from Forest Clear-Cutting and Site Preparation: Long-Term Paired Catchment Studies from Eastern Finland

The long-term impacts of current forest management methods on surface water quality in Fennoscandia are largely unexplored. We studied the long-term effects of clear-cutting and site preparation on runoff and the export of total nitrogen (total N), total organic nitrogen (TON), ammonium (NH(4)-N), nitrate (NO(3)-N), total phosphorus (total P), phosphate (PO(4)-P), total organic carbon, and suspended solids (SS) in three paired-catchments in Eastern Finland. Clear-cutting and soil preparation were carried out on 34 % (C34), 11 % (C11), and 8 % (C8) of the area of the treated catchments and wide buffer zones were left along the streams. Clear-cutting and soil preparation increased annual runoff and total N, TON, NO(3)-N, PO(4)-P, and SS loads, except for SS, only in C34. Runoff increased by 16 % and the annual exports of total N, TON, NO(3)-N, and PO(4)-P by 18, 12, 270, and 12 %, respectively, during the 14-year period after clear-cutting. SS export increased by 291 % in C34, 134 % in C11, and 16 % in C8 during the 14, 6, and 11-year periods after clear-cutting. In the C11 catchment, NO(3)-N export decreased by 12 %. The results indicate that while current forest management practices can increase the export of N, P and SS from boreal catchments for many years (>10 years), the increases are only significant when the area of clear cutting exceeds 30 % of catchment area.

Forest lepidopteran communities are more resilient to shelterwood harvests compared to more intensive logging regimes

A common measure of ecosystem resilience is the time course to recovery for a system that has been previously disturbed. The goal of this study was to assess whether forest lepidopteran communities displayed three different forms of resilience following experimental timber harvest. Specifically, I examined whether moth species assemblages returned to pre-logging composition (compositional resilience), species richness (structural resilience), and guild diversity (functional resilience) after forest management. Lepidoptera were sampled from 16 forest stands managed with one of four harvest treatments: no logging, clear-cutting, shelterwood harvests, and group selection harvests. Moths were sampled from all forest stands one year prior to harvest in 2007 and immediately postharvest in 2009-2011. Moth community composition only appeared to be resilient to timber harvest in stands managed with shelterwood methods (15% biomass removed) or in the unlogged stands within managed concession units. Both total species richness and species richness of Quercus-feeding moths also appeared to recover to a near original condition three years post-shelterwood logging. In contrast, moth assemblages in clear-cut stands and group selection stands (80% biomass removed) remained impoverished. Tests of functional resilience suggested that richness of species known to be pollinators was largely unaffected by timber management, and the number of moth species known to feed on herbaceous vegetation doubled in stands logged using group selection methods. Dietary specialists were disproportionately abundant in the unlogged stands postharvest, suggesting that species with more narrow dietary niches have the lowest resilience to timber management. These results suggest that most methods of forest management have short-term negative impacts on woody-plant-feeding Lepidoptera, but that the effects are limited to a few years when the harvest method involves shelterwood cuts. Herbaceous-feeding Lepidoptera appear to quickly colonize stands managed with group selection or clear-cutting, so loss of species richness in stands managed with either of these treatments may be less than predicted based on level of timber being removed. Recovery of moth assemblages in more highly disturbed stands will require longer time periods and techniques such as group selection harvests, where upwards of 80% of the standing bole is removed, may not be consistent with conservation goals.

Wildland fire ash and particulate distribution in adjacent residential areas

In recent decades, the frequency of wildland fire incidents near residential areas has decreased but the number of acres burned has increased, in large part due to changes in forest management methods and further human encroachment in forested regions. There is much debate about whether the wood ash generated by these wildfires can significantly affect residential buildings outside the fire zone perimeter. This study investigates the distribution of ash, soot and char that are generated from wildfires and migrate into adjacent residential regions. For this purpose, a wildland fire in Bastrop, Texas, was studied with samples collected from a variety of locations within the fire site and in adjacent areas. The collected samples were assayed for pH, asbestos, heavy metals and polynuclear aromatic hydrocarbons. The results of this investigation showed that the magnitude of the deposition on residential buildings near wildfires is dependent on a variety of variables, in particular the distance from the centre of the fire.

Changes in diversity of the mountain beech forest herb layer as a function of the forest management method

Development of more sustainable forest management methods is heavily reliant on the profound understanding of interactions between management methods and the forest vegetation. This study presents an analysis of changes in the interactions between the diversity of the tree and herb layers over the past 50years in the previously over-exploited Eastern Carpathian beech forests. After the anthropogenic pressure related to large scale forest clearings, intense forestry and agricultural use ceased, the regeneration processes accompanied two distinct routes (1) implementation of more sustainable forest management (shelterwood system) and (2) complete cessation of land use. The vegetation diversity and its dependence on the biotic and abiotic factors has been examined based on the data collected from 62 semi-permanent plots during two sampling periods: 1955–1962 and 2005–2009. The plots were located within the polish part of the “Eastern Carpathian” International Biosphere Reserve. The analysis included forest management methods, diversity indicators specific to different vegetation layers, indicator species groups, individual tree species, canopy density and the height of the forest stand.The main direction in changes indicates an increase in strength of the correlation between the diversity of tree and herb layers, caused by a change in the factor differentiating the diversity of the tree layer from a historical one related to general use of the land by the autochthonous people to an environmental one. Sycamore has been identified as a highly important species responsible for maintaining the stability and diversity of the herb layer structure. It has also been verified that analysis conducted using general diversity indicators does not truly reflect the interrelations between the tree and herb layer vegetation. A better representation of these interactions is provided by an analysis incorporating individual tree species and indicator species groups. Three distinct diversity patterns of the tree and herb layers have been distinguished, depending on the developmental stage of the forest and the management method implemented. First one, specific to heavily disturbed, overexploited maturing forests from the period between 1955 and 1962 is characterised by a weak relationship between the diversity of the tree and herb layer vegetation and a major role of sycamore in development of the herb layer structure. The second pattern was identified in mature forest stands, where more sustainable management methods were implemented. The second pattern is characterised by a strong relationship between the diversity of the tree and herb layer with a concomitant decrease in the importance of sycamore and an increase in the negative effects of beech exerted on the herb layer structure, which consequently undergoes homogenisation due to a decrease in habitat heterogeneity. The third pattern was described for unmanaged, mature forests, in which an emerging relationship between the diversity of tree and herb layers accompanied by a more diverse structure of the herb layer maintained by the presence of sycamore within the forest stand as well as the presence of large quantity of coarse woody debris has been identified.

Evaluation of harvesting methods for Sustainable Forest Management (SFM) using the Analytical Network Process (ANP)

Forest harvesting is a basic component of Sustainable Forest Management (SFM). Consideration of all aspects of harvesting operations in an effort to improve forest practices requires an approach that first addresses multiple criteria and incorporates a wide range of data. Second, the approach should provide a framework to evaluate both quantitative and qualitative criteria. In this study, the Analytical Network Process (ANP) is utilized to evaluate three existing harvesting methods by integrating the main components of the FAO Model Code of Harvesting Practice as an international mechanism for local management. The ANP framework helps forest managers to prioritize all alternatives and criteria with respect to each other and to develop their corresponding preferences. This study is an analysis of the environmental, economic, and social context of harvesting operations with the goal of making forest practices more sustainable and leading forest utilization to SFM. Although the criteria are calibrated for Caspian forests (northern Iran), the key principles applied here can be used or developed in other countries or regions.