Total Timber Volume Research Articles

Enhancing Sustainability and Yield in Maritime Pine Forests: Evaluating Silvicultural Models for Natural Regeneration

The maritime pine (Pinus pinaster Ait.) forest is an essential element of the Portuguese forest landscape due to its social, economic, and environmental importance. The sustainability of these forests in the Mediterranean region faces challenges due to recurrent forest fires and the absence of or delayed management. The species has a high capacity for regeneration, but the perpetuation of pine forests in sustainable conditions depends on adequate management to achieve high biomass production and assure fire resilience. This study aimed to analyse four management scenarios (C1 to C4) for the natural regeneration of maritime pine in six areas with stand ages ranging from 6 to 16 years and densities varying from 15,000 to circa 93,000 trees per ha. The same four scenarios were implemented in each of the six areas. The scenarios considered the evolution of forest growth according to different management prescriptions and were simulated using Modispinaster and PiroPinus models. Scenario C1 considered no intervention, with only the final cut. Scenario C2 considered a thinning schedule to maintain the stand within the 50–60% range of the Stand Density Index (SDI). Scenario C3 followed the area’s Forest Management Plan (PGF), which typically includes two or three thinning operations throughout the cycle. Scenario C4 was adapted from the MS1 silvicultural model of the National Institute for Nature Conservation and Forests—ICNF, which involves opening strips at earlier ages (3 and 6 years), with the selection of trees to remain in the wooded area carried out between 4 and 10 years of age and performing thinning whenever the Wilson Spacing Factor (FW) reaches 0.21. The final cutting age was assumed to be 45 years but could be lowered to 35 years in Scenario 3 if defined in the plan. Based on the indicators generated by the simulators, the results showed variations in the total volume of timber produced at the time of harvest depending on the silvicultural guidelines. Scenario C4 was the most effective in generating the highest individual tree volume at the end of the cycle and the total volume of timber collected throughout the cycle. The ability of the forest to resist fire was evaluated before and after the first treatment for density reduction. The treatments performed did not decrease the resistance to fire control.

Optimizing species selection for the structural timbers of traditional farmhouses in a snowy rural area of northeastern Japan

AbstractVernacular houses constructed using local woods contain information about forest‐resource use. To clarify how timber was used to construct wooden farmhouses, we identified the timber species composition of 11 houses built between 1845 and about 1940 in Tadami, a snowy rural area in northeastern Japan, and interviewed 70 residents. We recorded 2004 timber parts (99–308 parts per house) and 171.2 m3(1828 parts) of known species (14 taxa).Cryptomeria japonica(cedar) andPinus parvifloravar.pentaphylla(white pine) were used for all essential structural parts and accounted for 44% and 39% of the total timber volume, respectively.Fagus crenata(beech) was the third most commonly used species (7%), for roof supports, beams, and girders. The interviews revealed that the timber was typically sourced from local private or common woodlands within 1 km and that local craftsmen selected and hauled the trees. Considering the region's unique and complex vegetation, as land‐cover distribution is strongly influenced by frequent avalanches, the timber was likely managed within local stands of tall trees, and the most available species would have been cedar (although whether native or planted is unknown), followed by native white pine on mountain ridges around settlements. In comparison, beech stands that could supply sufficient amounts of timber might have been limited. Based on the characteristics of the trees used as house timber in Tadami, we conclude that despite the surrounding harsh, snowy conditions, locally available species of tall trees were historically selected for timbers.

Genetic characterization of a group of commercial African timber species: From genomics to barcoding.

In the last decades, illegal logging has posed a serious threat for the integrity of forest ecosystems and for biodiversity conservation in tropical Africa. Although international treaties and regulatory plans have been implemented to reduce illegal logging, much of the total timber volume is harvested and traded illegally from tropical African forest regions. As a result, the development and the application of analytical tools to enhance the traceability and the identification of wood and related products is critical to enforce international regulations. Among available techniques, DNA barcoding is a promising approach for the molecular identification of plant species. However, although it has been used successfully for the discrimination of animal species, no set of genetic markers is available for the universal identification of plant species. In this work, we firstly characterized the genetic diversity of 17 highly-valuable African timber species from five genera (Afzelia, Guibourtia, Leplea, Milicia, Tieghemella) across their distribution ranges in West and Central Africa using the genome skimming approach in order to reconstruct their chloroplast genomes and nuclear ribosomal DNA. Next, we identified single-nucleotide polymorphisms (SNPs) for the discrimination of closely-related species. In this way, we successfully developed and tested novel species-specific genetic barcodes for species identification.

Обоснование технологических процессов и систем машин для лесосечных работ

The work analyses the forest raw material resources of the Far Eastern Federal District. Corresponding to the conclusions, it is made an evaluation of a promising technology and systems of machinery for logging. It shows the significance of logging development for the rational exploitation of forest resources and the economic progress of the Far Eastern Federal District. It is performed an analysis of different technological procedures for timber harvesting. The study gives a mathematical model for the evaluation of forestry companies by economic efficiency, regarding the resolution “The Strategy for the Development of the Forest Complex of the Russian Federation Until 2030”. The examination of the region’s forest resources reveals that, currently, in coniferous forests, up to 60 % of industrial wood is available from the total volume of timber for harvesting. However, the sawlog of 1–2 classes contains only 30–35 % of this volume. Within the framework of the research conducted in the developed cutting areas are established territorial-technological plots, in which logging residues are produced and collected. In these plots, the types and the volumes of the abandoned wood are determined. It is estimated that approximately 40–50 % of the annual volume of the timber released for logging is left as a trunk lowvalue timber and forest residues at cutting areas and loading points. The article gives a proposal fоr the automation systems and technologies for harvesting in mixed stands with low-valued wood class, which allow to increase the degree of usable wood, reduce risks from littering and provide in the future various regional forestry companies with row materials. The represented mathematical model on determination of economic efficiency and cost-effectiveness of technological process allows to make rational decisions on the implementation of bucking program of forestry company. For citation: Ryabukhin P.B., Kunitskaya O.A., Grigoreva O.I. Substantiation of Technological Processes and Machinery Systems for Logging Operations. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 2, pp. 88–105. (In Russ.). https://doi.org/10.37482/0536-1036-2023-2-88-105

The Legal Roundwood Market in the Amazon and Its Impact on Deforestation in the Region between 2009–2015

Brazil is one of the largest producers of tropical wood in the world. Much of this wood is extracted from the Amazon region, especially in the state of Pará. Despite empirical knowledge, there is little information in the literature about the selectivity of trade and how this production has been behaving in recent years. Is there any relationship between this legal timber trade and deforestation? In this work, we compile data reports from control agencies and analyze the dynamics of the legal timber market in the state of Pará between 2009 and 2015 in terms of species, volume, and monetary value. We also correlate changes in volume m−3 and value m−3 with deforestation increase in the same period and region. We find that only ten groups of species represent almost 50% of the total timber volume marketed in the State, mainly from the Massaranduba (Manilkara) group. According to our models, the supply of a species of wood on the market is defined by its monetary value and not by its availability or characteristics, which hinders the insertion of new species and increases selectivity. Since 2011 the volume of legally traded logs has been decreasing sharply. Traditional forest regions in the state already demonstrate depletion in forested areas. While others, such as the lower Amazon region, have been increasing production, showing that new forestry operations areas are being used for harvesting in the function of the lower availability in traditional areas. Our models show that the legal reduced impact logging timber volume has an inverse relationship with the deforestation increase. Otherwise, preference for a small group of timber types still predominates, which may lead local woods to the danger of extinction.

Unrecorded volume of Norway spruce timber in cut-to-length harvesting

ABSTRACT Knowing credible records of harvested timber is in the interest of the forest owner, forest entrepreneur and timber-sector stakeholder. Therefore, the objective of the research was to determine the share of unrecorded Norway spruce timber volume in length allowance on the total timber volume produced by harvester technology in Czechia. We analyzed 176,980 merchantable logs (total volume of 10,333 m3) produced by 15 harvesters. Primary data were obtained from .stm files. Logs were categorized into five grades according to metric and qualitative requirements of the customers, also butt logs were distinguished. Statistical analysis were processed in the Statistica 13 package. Results showed that 1.99% of the volume of produced timber were excluded from the primary forestry records. Mean unrecorded volume of length allowance to assortments that contained both the cross-cut and cutting window allowances, varied from 2.99% up to 3.16%, while 0.27% to 0.46% of volume were unrecorded for those assortments that contained only the cutting window. In higher quality grades, we found shorter logs had a higher mean relative volume of length allowance than longer logs. The mean relative volumes of length allowances also varied between butt and other logs.

Endangered species account for 10% of Brazil’s documented timber trade

Federally listed endangered plant species have restrictions regulating their extraction and transit in Brazil. However, dozens of endangered species are important for the national timber trade. The present research addresses the question: What endangered tree species were legally traded as timber in Brazil between 2012–2016 and how significant is this trade with respect to the total volume of timber? To answer this question, we surveyed wood taxa and wood volume transported during this period as recorded by the National System for the Environment (SISNAMA). Under Brazil’s federal environmental law (L12651 Art. 35) Brazilian Institute of Environment and Renewable Natural Resources (IBAMA) is responsible for the registration of all commercial forest products. The law stipulates that products receive a Document of Forest Origin (DOF) indicating species, quantity, commercial use, origin, and destination. We correlated this data with the federal list of endangered plant species in Brazil to aggregate the number of endangered species transported from 2012 to 2016 and the total volume associated with each species. Among the 2214 species traded, we found 38 endangered species, comprising a volume of 6 million m3, representing approximately ten percent of the total traffic of 60.9 million m3. The endangered species Araucaria angustifolia (Bertol.) Kuntze and Mezilaurus itauba (Meisn.) Taub. Ex Mez were among the twenty species with greatest volume transported and traded, respectively 3.2 million m3 and 789,522 m3. The presence of these endangered species at the top of the list of woods transported within the national territory raises serious questions for conservation policy and practices in Brazil. Monitoring changes in deforestation rates inadequately assesses the impacts of timber harvesting on endangered native tree species. The information provided by this study should be of interest to national and international environmental agencies, international trade control agencies, conservation biologists, researchers and policymakers working to produce more effective control of harvest and trade of endangered species.

Forest Management Based on the Principles of Multifunctional Forest Use

ABSTRACT Effective forest management is based on the multipurpose use of existing forest resources and its ecological functions. The principle of multifunctionality is focused on sustainable forest management, taking into account environmental, economic, and social factors. The purpose of the research is to analyze development patterns of multifunctional forest management in order to identify the priorities in the forest sector development. The paper defines indicators affecting the level of forestry activities and designates territory zones depending on their qualitative and quantitative characteristics. The analysis of forest use for wood production showed that the annual underutilization of the allowable cut is due to a decrease in the total volume of timber cutting, depressed demand for hardwood of a low commercial quality, insufficient transport development of forests, and the lack of enterprises engaged in advanced processing of semi-subsistence deciduous forest stand. During the studies, it was found that areas, which location is economically advantageous, are more suitable for recreation purposes, as they are better provided with natural resources and are closer to waterbodies (rivers, lakes, reservoirs), possess unique forestland and are more attractive for investments. The paper identifies the problems and promising areas of multifunctional forest management.

Shade tree timber as a source of income diversification in agroforestry coffee plantations, Peru

Coffee is traditionally grown in agroforestry systems. Shade trees in coffee plantations provide important ecosystem services, and their timber may also be a good source of income for coffee growers. However, key information on the value of shade tree timber and its potential contribution to the income of coffee growers based on empirical data is lacking. The income that could be obtained from shade trees was estimated for three coffee plantations with different shade tree species. To estimate the marketable timber volume of standing trees, allometric equations were developed. Our results showed that the value of the shade tree timber varied significantly. It represented only 2-3% of the annual coffee farm income on the coffee plantation dominated by native Inga spp. On the other hand, the plantation predominantly shaded by Eucalyptus trees had high potential annual (50-68% of plantation income) and total (92-96% of plantation income) timber value, followed by the plantation shaded predominantly by Pinus (32-49% of plantation income for annual timber volume and 89-94% of plantation income for total timber volume). It is evident that shade trees may be a good economic reserve for coffee growers when exotic Eucalyptus or Pinus tree species are planted. However, using individual-tree data, it was found that the relatively rare native shade tree Retrophyllum rospigliosii, which was found in almost all plantations, has a high timber value and a large timber supply, making it a shade species with high potential for agroforestry.

STUDIES OF NATURAL- PRODUCTION ASPECTS OF MOUNTAIN LOGGING (ON THE EXAMPLE OF THE STATE ENTERPRISE "SLAVSKE FORESTRY")

The article presents the results of analytical studies of the natural-production conditions of management in the forests of a particular region. As initial data, the materials of the basic forest inventory of 2008 and reports on logging of the state enterprise Slavske forestry for 2010-2015 were used. Productive high-yielding tree stands of the I class and upper class of bonitet (79.1 %) is dominated in the enterprise. The third part of the forest is located on steep slopes. Medieval forest stands are predominate (42.2 %). The basis of the forest cover is formed by stand that includes spruce (73.6 %), where the average volume of ripe and overmature plantations consist 473 m3/ha. However, there is a low resistance of this specie to various pathogens of diseases and natural disasters. In recent years, there has been an increase in the volume of improvement thinning conducted on 84.0 % of all harvesting areas, where 68.6 % of the total volume of timber was harvested. The dynamics of the increase of the areas of sanitary felling is noted, which is associated with a large scale drying of spruce stands. The technological processes of logging operations at the enterprise are mainly based on ground aids of primary timber transportation, causing significant damage to the surface of the cutting area and the adjacent territories. Typically, a tractor trailing is used, with which 90.7 % of the total volume of harvesting is performed. The volumes of trailing by caterpillar and wheel tractors are almost identical. Less often, animal skidding (8.6 %) and cable yarding systems (0.7 %) are used. The distance of trailing of wood for all means of primary transportation exceeds the recommended values. The average distance of trailing by animal skidding on all type of cutting is 0.35-0.41 km. Caterpillar tractors on final cutting and improvement thinning have average distance of trailing, respectively, 1.48 km and 1.23 km. For wheeled tractors, the average distance of trailing on final cutting and improvement thinning is 1.26 km and 0.90 km, respectively. At the same time there are positive trends in reducing the distance of trailing on all types of cutting, connected with the construction of new forest roads. The main factor influencing the forest environment is the primary transportation of wood, the optimization of which is an urgent task for mountain logging.

Traditional plants in forest gardens of West Kutai, Indonesia: Production and financial sustainability

Apuy M, Lahjie AM, Simarangkir B.D.A.S, Ruslim Y, Kristiningrum R. 2017. Traditional plants in forest gardens of West Kutai, Indonesia: Production and financial sustainability. Biodiversitas 18: 1207-1217. Our research on the first generation forest gardens (munaan) in West Kutai District, Indonesia, aimed (i) investigating the cultivation and the financial profit of various plants grown by the residents in the first generation forest gardens (munaan); (ii) finding out the financial feasibility level of the first generation forest gardens (munaan) cultivation by the residents. The subject of this research included farmers or people who cultivated the old/ first generation forest gardens as well as several plant commodities namely durian (Durio zibethinus), rambutan (Nephelium lappaceum), cempedak (Artocarpus champeden), langsat (Lansium domesticum), ihau (Dimocarpus didyma) (i.e. native Borneo longan), meranti (Shorea sp.) and kapur (Dryobalanops aromatica) trees. Five villages/kampongs were sampled, with each plot sized 20 m x 20 m. Biomass analysis stocks growth of meranti and kapur trees are using volume formula. While the fruit production was calculated by weighing the weight of the fruit. In order to find out the relationships among variables, a polynomial regression equation was employed to obtain the regression coefficient of determination (R2). The bioeconomic analysis feasibility was done by using Pay Back Period (PP), Net Present Value (NPV), Net B/C ratio and IRR. The amount of revenue level for each variant of fruit (i.e. durian, rambutan, langsat, ihau, and cempedak was different depending on the volume of fruit production and the selling price. The total amount of revenue from the cultivation of kapur and meranti trees depended on the total volume of timber, which was based on their diameter and basal area multiplied by the price of the timber itself. These findings imply that the cultivation of first generation forest gardens (munaan) was feasible for the community. The calculated values of Pay Back Period, Net Present Value (NPV), Net B/C and IRR at the discount level factor of 5% were 19.3 years; IDR 30.004.000, 1.58 and 8.8% respectively.

Operational efficiency analysis of New Zealand timber harvesting contractors using data envelopment analysis

ABSTRACTData envelopment analysis (DEA), a non-parametric performance measurement approach, is used to measure the relative operational efficiency of logging contractors. An existing cost and productivity benchmarking dataset was used that contains system, stand and terrain factors with over 1000 unique entries on forest harvest operations in New Zealand from 2009 to 2015. Five input factors, number of harvest days, number of machines, total harvest area, number of log sorts, and total volume of timber accounted for 77.1% variation in the production output and are used in the DEA. Output-orientation under the assumption of constant, and variable returns to scale are used to estimate the performance of the logging contractors. The results indicate that the majority of the logging contractors are operating at or near scale efficiency level, and the main source of inefficiency in the industry is both technical and managerial. Analysis shows that if all inefficient contractors operate at optimal input and output levels, on an average, system productivity could increase by 52.2% from 28.7 to 52.2 tons/SMH. The DEA suggests that investment in technology and human capital could improve the overall efficiency of the logging industry.

Algorithm for solving the problem of optimal tracing of a timber road on a non-uniform terrain

The tracing of individual logging roads is part of a more general task - the development of a scheme for transport development of the enterprise's forest raw material base. As a result of its solution, the location of the main transport routes - highways and branches - is determined in the forest, taking into account the optimal distances between the branches. When establishing these distances, account is taken of the costs of forest management measures, referred to the total volume of timber, tending to the branch. The search for a variant of the track of a timber logging road close to the optimal for one of the criteria for the removal of the concentrated volume of timber is carried out in several stages. First, the optimal route variant is inscribed, inscribed in the grid of squares of the digital terrain model (the route passes along the sides and diagonals of squares). Then the found variant is smoothed with broken lines located in its vicinity. For each of the smoothed variants of the route, fourteen important technical and economic indicators are automatically calculated, allowing to make an informed decision when choosing the final version of the route of the future road. The accuracy of the construction of the digital relief model on a topographic map using the developed technique was estimated from the reference longitudinal profiles taken manually from the map in contours and built automatically using a digital terrain model. The results of the comparative analysis testify to the quite satisfactory accuracy of the developed method of manual digitization of maps. With the help of the same reference longitudinal profiles, it is possible to control the correctness of the results of digitization. To do this, it is sufficient to draw several rectilinear segments intersecting the simulated section in different directions and compare their longitudinal profiles constructed on the map with automatically calculated.

VALUASI EKONOMI KAWASAN ARBORETUM DIPTEROCARPACEAE UNIVERSITAS LANCANG KUNING

Arboretum as one example of ecosystems that have the diversity of flora and fauna requires good management, so as to provide benefits to the surrounding environment. Biological diversity (biodiversity) that exist in the Arboretum area is quite high. This is because the Arboretum has many species which are usually brought in from outside, then planted and maintained as a collection of plants for various purposes of academic activities, in addition to local species that live naturally in the Arboretum. Limited funds arboretum management and level of understanding about the functions and benefits of some of the arboretum, arboretum resulted in the existence of a very minimalist. This issue will greatly affect the existence of the arboretum in the future.The purpose of this study are aware of the economic value of the existing flora and fauna in the Dipterocarpaceae arboretum and get the benefits of environmental services for the around arboretum. Economic valuation of the timber is done by using the market price approach. To obtain economic value of wood made a simple calculation that the total timber volume multiplied by price per unit of wood. While the economic value of air services is divided into two parts namely the absorption of carbon dioxide by the market price method and coolness by using surrogate price method. Value of economic in Unilak dipterocarp arboretum of Rp. 15,538,672,849.13 consisting of timber economic value of Rp. 385,843,912.00 and the coolness of the economic value of Rp. 15,137,500,000.00 and carbon uptake value of Rp. 15,078,937.13. The economic value of benefits in the form of services (intangible) greater (97.52%) than the value in the form of objects (tangible) (2.48%).

Spatial forest resource planning using a cultural algorithm with problem-specific information

A cultural algorithm (CA) is proposed for the spatial forest resource planning problem that aims at maximizing the total timber volume harvested over a harvest planning schedule, subject to constraints of minimum harvest age, minimum adjacency green-up age, and approximately even volume flow for each period of the schedule. To increase the solution-search ability, the CA extracts problem-specific information during the evolutionary solution search to update the belief space of each generation, which has cultural influences and guidance on the next generation. The key design of the proposed CA is to propose the cultural and evolutionary operators specifically for the problem. This work is of high value as a comprehensive experimental analysis shows that the proposed CA rooted from evolutionary algorithm (EA) obtains 0.44%–1.13% better fitness and performs more stably than the previous best-known simulated annealing (SA) approach, which was shown to perform better than the EA previously.

Determinação do volume de madeira em povoamento de eucalipto por escâner a laser aerotransportado

O objetivo deste trabalho foi avaliar a possibilidade de se estimar o diâmetro à altura do peito (DAP) com os dados de altura e de número de árvores derivados do escâner a laser aerotransportado (LiDAR, "light detection and ranging"), e determinar o volume de madeira de talhão de Eucalyptus sp. a partir dessas variáveis. O número total de árvores detectadas foi obtido com uso da filtragem de máxima local. A altura de plantas estimada pelo LiDAR apresentou tendência não significativa à subestimativa. A estimativa do DAP foi coerente com os valores encontrados no inventário florestal; porém, também mostrou tendência à subestimativa, em razão do comportamento observado quanto à altura. A variável número de fustes apresentou valores próximos aos observados nas parcelas do inventário. O LiDAR subestimou o volume total de madeira do talhão em 11,4%, em comparação ao volume posto na fábrica. A tendência de subestimação da altura das árvores (em média, cerca de 5%) impactou a estimativa do volume individual de árvores e, consequentemente, a do volume do talhão. No entanto, é possível gerar equações de regressão que estimam o DAP com boa precisão, a partir de dados de altura de plantas obtidos pelo LiDAR. O modelo parabólico é o que possibilita as melhores estimativas da produção volumétrica dos talhões de eucalipto.

Structural Dynamics of Romanian Forests after 1990

Abstract The Romanian forest area in 2010 was 6,515 million ha, which represents approx. 27.3 % of the national territory. At European level, Romania is ranked 13 in the areas occupied by forests, but below the average forest coverage of 32 %. After a decline in forested areas recorded between 1990 and 2000 there was a slight rebound in the last decade, with an FAO estimated growth of over 30 000 ha per year between 2005 and 2011. This growth is primarily attributed to natural regenerations. If the production function is intrinsically provided in different proportions by all the functional categories, the protective function has a special attention, having clear typological distinctions, based on well-established natural or social components. Only maintenance work is allowed in protection forests. The total volume of timber harvested in Romania in 2010 was about 17 million m3, according to NFA upon reading the regeneration cuts of an area of over 99 hectares, 5000 ha of which by cuttings Compared to 2000, when they harvested less than 14 million m3, one can see a substantial increase of approx. 20 %. In the same period, in 2010, the total area of artificial regenerations was about 10 000 ha, which represents a tenth of the cutting surface, the remaining land being regenerated naturally.

Sawn timber grade recovery from a planted coast redwood stand growing in New Zealand

Timber from old-growth stands of coast redwood (Sequoia sempervirens (D.Don) Endl.) is dimensionally stable, resistant to surface checking and splitting, and has been widely used for outdoor purposes such as decking and cladding. Restrictions on the supply of redwood timber from Californian stands have increased the focus on timber from plantations grown elsewhere in comparatively short rotations. Little is known about the quality of timber produced from plantations of redwood in New Zealand. In this study trees from a 38-year-old pruned stand in Mangatu Forest near Gisborne, New Zealand, selected to cover the range of stem diameters present, were cross-cut into logs. Each log was then sawn into boards and each board was graded according to a simplified United States redwood grading system. Total timber volume (50 logs) was 16.2 m3, valued at USD 7,835 (2008 prices). This was less than might be expected in a well-managed stand. The 13 pruned logs accounted for 38% of the total volume recovered and 50% the total financial value of the timber. Pruned log quality assessed according to a pruned log index (PLI) was low, due to untimely pruning and the presence of epicormic shoots. Only 12% of the timber was graded clear and 32% of this came from pruned logs. Despite low PLI scores, the relationships between PLI, proportion of clear timber and pruned log value were reasonably strong. Recoveries from individual stems were variable. The most important determinants of log value were log size, which affected timber recovery; pruning quality, which governed the volume of clear wood; the proportion of heartwood, (valued for durability and appearance); and to a lesser extent, mid-stem branch vitality. High incidence of dead (bark-encased) knots in most of the unpruned logs contributed to the poor timber grade recovery results. Other defects (insect tunnels, rot and traumatic resin pockets) were associated with a 7% reduction in financial value. Accurate prediction of the pattern of distribution of heartwood inside a redwood log could play a major role in maximising the value of recovered timber.

Potentials and limits of the k-nearest-neighbour method for regionalising sample-based data in forestry

The k-nearest-neighbour (knn) method is known as a robust nonparametric method. It is used to estimate unknown values of data sets by means of similarity to reference data sets with known values. The spectral information of satellite remote sensing data can be used to provide the common characteristics in the knn estimation process. In forest sciences, the knn method is studied for its application potential. Some application examples are: (1) the estimation of parameters such as basal area, stem volume, number of trees per diameter class and tree species; (2) the estimation of forest debris and non-wood goods and services; (3) the production of wall-to-wall information for modelling, risk management and logistics. On the other hand, different limitations with respect to methodological characteristics as well as the selection of suitable parameters must be taken into consideration. The scope of this article concentrates on the discussion of the application potential and limits of the knn method in forestry with particular emphasis on management planning needs. The study is based on data taken from a forest inventory (FI) covering a test site near Rottenburg, in southwest Germany. Analysis results are compared with the traditional outcome of inventory data analysis and partly presented in thematic maps, which show identical spatial distribution patterns. For the map of six tree species, a map accuracy of 52.2% was found. The user’s accuracy for the prevailing tree species was between 52.6% for Picea abies and 69.4% for Quercus sp. A timber volume map for Quercus sp. clearly visualises the bias at the extreme ends of the volume distribution. The root mean square error (RMSE) for the total timber volume estimate was 30.9% for k = 5 and could be reduced to 22.6% for k = 20. For Quercus sp., however, the respective RMSE values were between 106.5 and 84.8%. Significant differences between FI and knn estimates were mainly found for rare classes with minor representation in the reference data.

Beyond Reaping the First Harvest: Management Objectives for Timber Production in the Brazilian Amazon

Millions of hectares of future timber concessions are slated to be implemented within large public forests under the forest law passed in 2006 by the Brazilian Congress. Additional millions of hectares of large, privately owned forests and smaller areas of community forests are certified as well managed by the Forest Stewardship Council, based on certification standards that will be reviewed in 2007. Forest size and ownership are two key factors that influence management objectives and the capacity of forest managers to achieve them. Current best ecological practices for timber production from Brazil's native Amazon forests are limited to reduced-impact logging (RIL) systems that minimize the environmental impacts of harvest operations and that obey legal restrictions regarding minimum diameters, rare species, retention of seed trees, maximum logging intensity, preservation of riparian buffers, fire protection, and wildlife conservation. Compared with conventional, predatory harvesting that constitutes >90% of the region's timber production, RIL dramatically reduces logging damage and helps maintain forest cover and the presence of rare tree species, but current RIL guidelines do not assure that the volume of timber removed can be sustained in future harvests. We believe it is counterproductive to expect smallholders to subscribe to additional harvest limitations beyond RIL, that larger private forested landholdings managed for timber production should be sustainable with respect to the total volume of timber harvested per unit area per cutting cycle, and that large public forests should sustain volume production of individual harvested species. These additional requirements would improve the ecological sustainability of forest management and help create a stable forest-based sector of the region's economy, but would involve costs associated with lengthened cutting cycles, reduced harvest intensities, and/or postharvest silviculture to promote adequate growth and regeneration.