Timber Stock Research Articles

Geoinformation Exploration and Comparison of Computer Processing Processes of the Forestry of Ukraine

The main problems of forestry are considered in the article taking into account the current normative documents of Ukraine and developments of Ukrainian scientists. The period of forestry production is the longest of all known productions: 60-100 and more years. The total forest area of the forest fund of Ukraine is 10.4 million hectares, including the forest cover — 9.6 million hectares. The forested area of Ukraine is 15.9%. The stock of wood in forests is estimated at 2.1 billion m3. The total annual increase in the stock of timber reaches 35 million m3. Forests grow in different natural areas (Polissia, Forest-steppe, Steppe, Ukrainian Carpathians, and Mountain Crimea) and have differences in forest conditions. The forests are concentrated mainly in Polissia and the Carpathians. Afforestation in various natural zones varies from 3.7% in Zaporizhzhya to 51.4% in the Transcarpathian regions and does not reach a scientifically justified optimal level. Almost half of the forests have limited use, which does not contribute to the efficient use of forest resources.By means of which it is possible to solve the issues of collection, processing, control and document management in this field. Today, scientists and workers face a rather difficult task. In the short term, you need to create, implement in the industry, fill in archival data, learn how to use, maintain in working condition, implement updates in accordance with new laws and regulations, and update data. Today, several work programs have been developed that are in the process of being put into production. Comparative analysis of existing programs is presented in more detail and data on their implementation are given. UkrNILILA organized a joint Ukrainian-Czech project, TechInLis4, which implemented the use of a program-based system for collecting inventory of Field Map forests developed by the Institute of Forest Ecosystems Research (IFER, Czech Republic), which is based on a powerful database server, includes automated workplaces (ARMs) for specialists from all divisions and levels of the forestry industry and ozhlyvosti for the rapid exchange of data between entities. Such a system is the State Forests of Ukraine Information System (DIS). Also, the GIS — Lisproject software complex and 1C software product: Enterprise Forestry Management were considered. Given the unique combination of natural and socio-economic components in forestry, as well as a long period of forestry production, the overall objective of the program is to ensure a balanced development of forestry aimed at strengthening the environmental, social and economic functions of Ukrainian forests.

Структура ценопопуляций ключевых видов горно-таежных кедровников Восточного Саяна

Understanding of the key species coenopopulations structure of late-successional forest communities serve as a model of the forest ecosystems state and stability in the organization of sustainable forest management and conservation of biological diversity. The ontogenetic and age structures of cenopopulations of the key species, Pinus sibirica DuTour and Abies sibirica Ledeb., were studied in a climax S Siberian pine forest with Vaccinium myrtillus L. and green hypnum mosses (the most common forest type among taiga forests of the East Sayan mountains). The permanent sample plot (50×50 m) was located in the northeastern part of the Idarskoe Belogorye ridge of the East Sayan in the middle part of a westerly slope with a steepness of 2 degrees, at an elevation of 1000 m a.s.l. (54°44'N, 96°07'E). The forest stand had low productivity (quality class V), high closeness of crowns (about 1.0) and mixed composition with predominance of P. sibirica, which are characteristic of the mountain-taiga cedar forests of the Eastern Sayan (See Table.). We performed general geobotanical description, measurement of size and age, assessment of ontogenetic and sanitary states of each tree, as well as assessment of reforestation on the sample plot. P. sibirica coenopopopulation had a wide age amplitude (from 1 to 200 years) and absolutely uneven-aged structure, mass reforestation (more than 3000 ind./ha), large sizes of mature individuals (maximum diameter - 58 cm, height - 21.3 m), predominance of the number (70% of the total density of the forest stand) and timber stock (95%). The ontogenetic structure of P. sibirica cenopopulation was characterized by a normal state (See Fig. 1 and 2) with a sharp peak of the distribution and distinct left-handed skewness (coefficient of asymmetry - 2.0; kurtosis - 4.1). This corresponds with the concept of consistent self-reproduction and stability of forest ecosystems. A. sibirica was inferior in terms of the reforestation number (1575 ind./ha), life expectancy (up to 110 years) and the size of mature trees (maximum diameter - 22.7 cm, height - 16 m). The ontogenetic structure of A. sibirica cenopopulation (See Fig. 1 and 3) is characterized by a complete spectrum and more distinct left-handed skewness. Thus, P. sibirica had a clearly expressed competitive population strategy. A. sibirica showed indications of phytocenotic tolerance. It is obvious that sustainable forest ecosystems in the absence of anthropogenic pressure in the mountain-taiga forest belt conditions is formed in the process of continuous change of P. sibirica age generations.

Creation of Methods for Automated Determination of Forest Parameters Based on Data from UAVS

The article presents a scientific study on the use of aerial photographs obtained by unmanned aerial vehicle (UAV), for the automated collection of data on forest resources in the taiga forests of the European North of Russia. On the example of the trial plot, a technique is described for automated allocation of crown contours, calculation of the trunk diameter and timber stock in the forest area. The methodology used morphological methods for processing digital images, geographic information tools for representing and processing spatial information, as well as the results of statistical observations of leading scientists in the field of forestry. The results have been verified in the field in several plots. The technique is applicable to automate the process of thematic interpretation of orthorectified aerial photographs with a spatial resolution of five to ten centimeters per pixel. The experiments presented in the article were carried out on images of forests in the north of the European part of Russia. The research results are used for regular automated updating of information on forest resources.

Silvicultural treatment effects on commercial timber volume and functional composition of a selectively logged Australian tropical forest over 48 years

Post-logging silvicultural treatments involving thinning are commonly recommended to increase the commercial timber production under polycyclic harvesting regimes in tropical forests. However, thinning practices intentionally designed to improve commercial timber production may alter species composition and functional composition. Low, medium, and high intensity thinning following logging plus a logged only control was applied in an Australian tropical forest in 1969 to assess the long-term liberation thinning impacts on the commercial timber volume and the functional composition of the regenerating forest. Over 46 years following thinning, only medium- and high-intensity thinning promoted recruitment of commercial trees into the >10 cm diameter class. All three thinning treatments enhanced the standing volume of most desirable commercial species, mainly driven by the growth of remaining non-harvested trees in the 10–20 cm diameter class. The merchantable timber volume of other less desirable species was also promoted in the four treatments. Over the first 28 years after treatment (1969–1997), the average annual timber volume accumulation rate was highest in the medium-intensity thinning (1.97 m3 ha−1 year−1). The positive impacts of medium- and high-intensity thinning on commercial timber volume growth lasted longer than the low-intensity thinning. From 1997 to 2015, average annual volume increments increased in the medium- and high-intensity thinning, changed little in the low-intensity thinning, and decreased in the untreated control. Moreover, the medium- and high-intensity thinning led the community functional composition to shift towards early-successional species, which reduced community-weighted mean wood densities. The changes induced by intensive thinning treatments may affect the recovery of forest biomass and biodiversity. Hence, the trade-off between enhancing timber stocks and maintaining functional composition should be considered during planning and implementation of tropical forest management.

Quantification of material stocks in existing buildings using secondary data—A case study for timber in a London Borough

The existing building stock represents a huge accumulation of physical resources: a material ‘reserve’ that could be mined in the future to improve resource efficiency. However, in the absence of systematically collected information about materials deposited in the built environment, the ability to manage and exploit them is limited. An approach to quantification of material stocks based on the use of secondary data from external research bodies, national statistics and a housing stock management database is used to estimate the timber stock in residential buildings constructed in the London Borough of Tower Hamlets before 1992. Results show a total timber accumulation of almost 67,000 tonnes across 68,000 dwellings, with a material intensity for timber between 20−34 kg/m2 of building floorspace (6.8–11.2 kg/m3 of gross building volume) for terraced houses and 5.4−11 kg/m2 (1.8–3.6 kg/m3) for flats and maisonettes. Generally, there is more timber in floors and roofs, and in older buildings. This method appears to be robust, as it results in comparable timber intensities to those determined using other methods in previous studies. It can be used for other materials and may be useful in other contexts where data is available (i.e., other scales, building types and materials), and capable of contributing to the growing understand of existing buildings as material banks.

Dynamique des populations d'azobé, Lophira alata Banks ex C. F. Gaertn., et implications pour sa gestion durable au Cameroun

L'impact de l'exploitation forestière sur le renouvellement du stock de bois d'œuvre reste largement méconnu en Afrique centrale du fait du manque de données sur la dynamique des populations d’arbres exploités. C’est en particulier le cas pour l’azobé, Lophira alata, un bois d’œuvre de grande valeur commerciale. L'objectif de cette étude était double : quantifier l'effet du type forestier et de l’exploitation sur la croissance de l’azobé et simuler l'évolution du stock exploitable et du taux de reconstitution après exploitation. Nous avons effectué pendant trois ans un suivi annuel de la croissance et de la mortalité dans trois types forestiers au Cameroun : en forêt sempervirente, en forêt mixte et en forêt semi-caducifoliée. Le recrutement a été étudié uniquement en forêt mixte, sous deux conditions : en milieu exploité et non exploité. Nous avons calibré, avec ces données, un modèle matriciel de Usher. Douze scénarios d’exploitation ont été simulés en faisant varier le diamètre minimum d’exploitation de 60, 70 et 80 cm, et l’intensité de prélèvement des arbres de 100, 80, 60 et 40 %. La croissance de l’azobé est influencée à la fois par le type forestier et l'exploitation. Les arbres de forêt sempervirente ont une croissance plus faible jusqu’à 50 cm de diamètre, alors que la croissance maximale prédite pour ce type forestier est la plus élevée. L'exploitation a par ailleurs stimulé la croissance. Enfin, l’exploitation de l'azobé ne respecte pas le principe du rendement soutenu : ses taux de croissance à long terme varient entre 0,54 et 0,83. Pour garantir la durabilité de son exploitation au Cameroun, une sylviculture dynamisant la croissance des futurs arbres exploitables, ainsi que leur régénération, s’avère indispensable.

Volume recovery and estimation of commercial volumes of Okan (Cylicodiscus gabunensis Harms) in southern Cameroon

The objective of this study was to quantify the volume of residues and develop volume equations for estimation of commercial outside-bark volumes of Okan (Cylicodiscus gabunensis) at different logging stages. Two hundred and five stems with diameter at breast height (DBH) varying between 65 and 167 cm were cut and scaled (by successive logs) and followed at forest management unit 09 004b in South Cameroon. The relationships between the scaled volumes and the measured dendrometric variables were established using weighted regressions. The largest proportion (>63%) of the total volume of discarded waste was observed at the stump. Modelling the proportion of stem residues, although resulting in a low R2 value, was best described by considering log length and quality class. Commercial volumes were estimated using DBH, the proportion of waste, grade quality and commercial length. Although difficult to estimate, commercial length offers better results compared with the use of grade quality. These results can contribute to better management of Okan’s commercial timber stocks in South Cameroon.

ANALISIS FINANSIAL REHABILITASI AREAL EKS IUPHHK-HA PT KALANG MURNI DI PROVINSI KALIMANTAN TENGAH

ABSTRACK Production forest management in Indonesia had been developed using a pattern of forest concessions (IUPHHK) since 1970s. In the development portion has ended a period of concession for 20 years. Forest areas that are not burdened the forest concessions or other rights, then the management is partly handed back to the goverment, and some management handed over by other appliances as Timber Utilization Permit (IPK). In connection with that carried a 0,3% timber cruising activities in the work areas of PT. ? Kalang Murni to obtain details about the condition of the standing stock. According on the analysis results, the standing stock of commercial trees in the group of diameter ? 20 cm contain average number of 25.5 stems/ha and average volume of 15.69 m3/ha, and the standing stock of other timber in the group of diameter ? 20 cm contain average number of 27.3 m3/ha, and average volume of 20.57 m3/ha. With the result that the total standing stock of the tress at the secondary forest of PT. Kalang Murni contain average number of 52.8 stems/ha and and average volume of 36,26 m3 / ha. According to the financial analysis, the Indonesia Strip Cutting and Planting (TJTI) system is suitable applied at the site when the interest rate in the position of 18%, whereas the Clear Cutting and Artificial Regeneration (THPB) system is not suitable at the same of interest rate.
 Keyword: Financial, forest concession, secondary forest, standing stock

Can timber provision from Amazonian production forests be sustainable?

Around 30 Mm3 of sawlogs are extracted annually by selective logging of natural production forests in Amazonia, Earth’s most extensive tropical forest. Decisions concerning the management of these production forests will be of major importance for Amazonian forests’ fate. To date, no regional assessment of selective logging sustainability supports decision-making. Based on data from 3500 ha of forest inventory plots, our modelling results show that the average periodic harvests of 20 m3 ha−1 will not recover by the end of a standard 30 year cutting cycle. Timber recovery within a cutting cycle is enhanced by commercial acceptance of more species and with the adoption of longer cutting cycles and lower logging intensities. Recovery rates are faster in Western Amazonia than on the Guiana Shield. Our simulations suggest that regardless of cutting cycle duration and logging intensities, selectively logged forests are unlikely to meet timber demands over the long term as timber stocks are predicted to steadily decline. There is thus an urgent need to develop an integrated forest resource management policy that combines active management of production forests with the restoration of degraded and secondary forests for timber production. Without better management, reduced timber harvests and continued timber production declines are unavoidable.

ENERGY WOOD STORES IN UNDERGROWTH OF FORESTS IN LATVIA

INTRODUCTION
 Forest resources are the most significant natural asset of the state of Latvia. According to data of the 2nd stage of forest resource monitoring for 2014, Latvia has 3575 thousand hectares of forest land comprising 55.3 percent of the total territory of Latvia, while the total timber stock is estimated at 668 million cubic meters (Bumanis et al., 2014).
 However, from the available data on forest resources it is only possible to theoretically and hypothetically state what proportion of these resources would be useful and economically justified as an energy supply. Each forest stand has a certain amount of undergrowth and understorey – small woody plants (shrubs) which have not been researched much until now. A precise determination of the amount of energy wood in Latvian forests would be of great benefit to the Latvian economy.
 MATERIAL AND METHODS
 Research data were collected in forests at the Jelgava Forest District “Forest Research Station”. The research was carried out in two forest subquarters of forest site type Myrtillosa mel. Eight circle-shaped sample plots were established. The area of each single plot was 25 m2.
 In the sample plots, the understorey and undergrowth trees were cut at the root neck. A sample was prepared from each tree harvested which was then sent for drying.
 The wood samples were transferred to "Forest and wood products research and development institute Ltd” for moisture determination. Total moisture content of the wood sample was determined according to standard LVS EN ISO 18134-2: 2016.
 RESULTS
 In the forest subquarter with a stand composition of 10Pine (66 years old) the sum biomass of undergrowth and understorey was 177.91 kg per sample plot. In the forest subquarter with a stand composition of 9Pine1Birch (88 years old) there was a total understorey tree mass of 180.9 kg but 16.17 kg of undergrowth per plot. This means there was more biomass in understorey than undergrowth in the site investigated.
 DISCUSSION
 When the tree stand was 10Pine (66 years old) the amount of dry matter to be extracted from all sample plots was 12.37 t ha-1 on average. In the forest subquarter with a stand composition of 9Pine1Birch (88 years old) the amount of dry mass is 10.24 t ha-1 on average.
 According to previous research, 7-20 t ha-1 of dry mass was obtained in Sweden, 7 to 12 t ha-1 in Poland, 6 to 14 t ha-1 in Germany and 8 to 12 t ha-1 in Latvia (Lazdina et al., 2010). There are also several researches papers which describe biomass from young hardwood stands on abandoned agricultural land in Canada: the values vary from 0,6 t ha-1 to 82,6 t ha-1 (Lupi et al., 2017). Consequently, a sufficient amount of biomass was obtained in the forest subquarters investigated in our research, which fits with the results of other studies carried out.
 CONCLUSION
 The volume of potential energy wood in undergrowth and understorey in Myrtillosa mel. forest site types is significant and it is advisable to use it as a raw material for energy production together with felling residues. However, it is necessary to evaluate the technical and technological capabilities from an economic perspective in each particular case.

Growth determinants of timber species Triplochiton scleroxylon and implications for forest management in central Africa

The sustainability of the polycyclic logging system in tropical forests has been increasingly questioned for a variety of reasons, and particularly in central Africa as commercial species, mostly light-demanding long-lived pioneer species, usually fail to recover a stable number of large trees after exploitation. Several factors are known to affect tropical tree demographic processes, like tree growth, survival and recruitment. Tree growth has particularly been showed to depend on ecological conditions, tree genetics, and competition with surrounding vegetation, as well as tree size or ontogeny. Yet, due to the paucity of available data, the importance of such factors is unclear and usually ignored when estimating future timber yields. To fill this gap, we chose to evaluate the variability in growth of one African long-lived pioneer and commercially very important species: Triplochiton scleroxylon K. Schum, gathering a broad dataset composed of tree ring data recorded in one site in Cameroon and periodic field inventory data recorded in seven sites across central Africa. In total, we analyzed 13,225 records of annual tree diameter increments recorded over 920 trees from seven sites in Cameroon, Republic of the Congo and Central African Republic. We evaluated (i) to what extent the average growth of trees that reach harvestable dimensions differs from population average and (ii) to what extent past perturbations influence the growth of remaining trees. We found the diameter growth of T. scleroxylon to be remarkably variable and this study provided an unprecedented quantification of the magnitude of some key growth determinants. In unlogged forests, the diameter increment of T. scleroxylon ranged between 0.40 cm year−1 in Southern Cameroon and 0.83 cm year−1 in South-Eastern Cameroon. The diameter increment was weakly related to tree size but increased twofold from unlogged to logged forests. Perturbation caused by logging stimulates growth of T. scleroxylon for at least 10–15 years. Finally, harvestable timber stock of large-sized T. scleroxylon was found to be constituted by trees that grew in average twice faster than trees of the entire extant population. As more and more inventory data become available, quantifying these effects could be replicated for other timber species and in other sites, to improve the accuracy of future timber resource estimates and improve forest management guidelines.

Динаміка активності супероксиддисмутази та каталази у листках Аilanthus altissima за аеротехногенного забруднення

У листках айланту найвищого (Ailanthus altissima Swingle), особини якого зроста-ють на територіях з хронічним аеротехногенним навантаженням, визначено актив-ність основних оксидоредуктаз: супероксиддисмутази (СОД) (ЕС 1.15.1.1) і каталази(ЕС 1.11.1.6). Зміни сезонної динаміки активності антиоксидантних ферментів, що зне-шкоджують активні форми кисню, вказують на їх участь в реалізації виду Ailanthusaltissima Swingle стратегії адаптації до комбінованого впливу полютантів. Встановлено,що рослини айланту найвищого впродовж вегетації пристосовуються до несприятливихумов існування за рахунок підвищення активності супероксиддимутази та каталази.

The economic consequences of future climate change in the forest sector of Russia

A prediction estimate of the economic consequences of climate change for forestry in the subjects of the Russian Federation at the end of the 21st century was made. The estimate is based on mass ensemble calculations of climate changes with high spatial resolution. Due to the expected growth in productivity, stock of coniferous and hardwood timber will increase, which may lead to an increase in the economic evaluation of forests. As a result of climate-related fire risk changes in the subjects of Russia, an increase in the total amount of forest fires extinguishing costs by the end of the century is expected. An economic evaluation of possible damage shows that, on average in Russia, the amount of forest fires extinguishing costs can increase with the realization of radiation exposure scenarios RCP 4.5 and RCP 8.5, respectively, with an accumulated amount of 211.114 thousand rubles and 248.956 thousand rubles.

Timber stock inventory in Amazon: simulations of cross-malt conglomerates sampling intensities

A high diversity of tree species and a fact that only a few they have commercial value makes it difficult to establish appropriate sampling to characterize the timber stocks of tropical forests. In contrast, large inventories are needed to subsidize the identification, description, and bidding of public forests for concession. The aim of this study was to evaluate the effectiveness of the cross-malt conglomerate in different sampling intensities to estimate the commercial volume of tree species and their susceptible to exploitation in an Amazon forest under concession. For this, a sampling process in cross-malt conglomerates was simulated with intensities of 20 (0.5%), 40 (1%), 60 (1.5%), 80 (2%), and 100 (2,5%) sampling units from a forest census. The intensity of 100 sampling units was adequate to sampling the timber stock in natural forests, since it generated sampling errors close to or less than 10% established by law. The detection of species susceptible for exploration and the characterization of floristic composition of the tree stratum were other advantages observed. Thus, sampling by cross-malt conglomerates with first random stage is recommended for inventories of production forests in Amazon.

Ecuaciones de volumen para Prosopis articulata S. Watson y Lysiloma divaricata (Jacq.) J. F. Macbr. en el noroeste de México

Una herramienta de gran importancia en el manejo forestal son los modelos alométricos, con los cuales se puede estimar de forma confiable el volumen en árboles individuales y masas forestales, además de construirse tablas de volumen que faciliten la cuantificación de existencias maderables. En el presente trabajo se ajustaron datos de 160 árboles; para ello, se derribaron 80 individuos de cada especie que incluyeron todas las categorías diamétricas. Se midieron las variables: diámetro normal (D), diámetro de la base (DB) altura total (H) y diámetro de copa (DC), así como los diámetros y longitudes de cada una de las ramas mayores a 6 cm de diámetro en su base. Se probaron modelos de regresión lineal simple, múltiple y no-lineal con una y dos variables independientes, para estimar el volumen fustal total con corteza. La selección del mejor modelo se hizo con base en la RCME, R2 ajustado y el nivel de significancia de los parámetros. Para la predicción del volumen total en función del diámetro normal, el modelo alométrico de Berkhout presentó mejores ajustes, con R2 de 0.9053 y RCME de 0.0432 para Prosopis articulata; y R2 de 0.8178, RCME de 0.1048 para Lysiloma divaricata. A partir del diámetro normal y altura total, los mejores ajustes se obtuvieron con el modelo de Schumacher-Hall, con valores de 0.9139 en R2 y RCME de 0.0411 para Prosopis articulata; para Lysiloma divaricata el modelo de mejor ajuste fue el Spurr Potencial con R2 de 0.7936 y un valor de RCME de 0.1118.

Ріст і формування дубових деревостанів за участю липи дрібнолистої в умовах свіжої грабової діброви Західного Поділля

Досліджено лісівничо-таксаційні показники та санітарний стан дубових деревостанів різного віку за участю у їх складі липи дрібнолистої. Встановлено, що тут формуються складні деревостани за участю дуба звичайного, ясена звичайного, граба звичайного, липи дрібнолистої, в’яза голого, кленів гостролистого і явора та інших деревних видів. Частка липи у їх складі становить від поодиноких дерев до 6-8 одиниць. Серед них переважають деревостани, в яких частка липи становить 2-4 одиниці. Дуб звичайний росте за ІІ-Іb бонітетом та досягає максимальної продуктивності (Іа-Іb бонітет) у деревостанах, де частка липи у складі змінюється в межах 2-8 одиниць і відстає в рості від дуба за висотою на 10,0-46,1%. Найгіршим ростом дуб звичайний характеризується в деревостанах, де відмінності за висотою між ним і липою становлять до 7%.
 Повнота деревостанів і запас стовбурової деревини відзначаються високою варіабельністю навіть у межах вікових груп. У середньовікових деревостанах абсолютна повнота становить 21,4-34,0 м2/га, а запас деревини – 172-374 м3/га. У пристигаючих деревостанах ці показники, відповідно, становлять 24,6-34,9 м2/га і 263-409 м3/га, а в стиглих – 26,6-40,3 м2/га і 330-487 м3/га. Найбільшого запасу (409-487 м3/га) досягають дубові деревостани, де частка липи у їх складі становить 3-6 одиниці. Водяні пагони у дерев дуба не виявлено на 20% дослідних ділянок. В інших деревостанах різної повноти і продуктивності кількість дерев дуба з водяними пагонами становить 5,3-53,3%. У деревостанах переважають дерева І і ІІ категорій санітарного стану. Сухі дерева трапляються на 70% дослідних ділянок в кількості 1,2-7,2%. Індекс санітарного стану дуба змінюється в межах 1,36-2,65.

PILOT STUDY ON THE RETRIEVAL OF DBH AND DIAMETER DISTRIBUTION OF DECIDUOUS FOREST STANDS USING CAST SHADOWS IN UAV-BASED ORTHOMOSAICS

Abstract. One fundamental metric to characterize trees and forest stands is the diameter at breast height (DBH). However, the vertical geometry of tree stems hampers a direct measurement by means of orthographic aerial imagery. Nevertheless, the DBH in deciduous forest stands could be measured from UAV-based imagery using the width of a stem´s cast shadow projected on the ground. Here, we compare in-situ measured DBH of 100 trees with the DBH visually interpreted from cast-shadows derived in UAV-based aerial imagery. Then, based on simulated datasets, we determine suitable DBH sampling sizes for a robust and efficient retrieval of stand diameter distributions. The UAV-based DBH estimation resulted in an r2 of 0.74, RMSE of 7.61 cm, NRMSE of 12.8 % and approximately unbiased results. According to our simulations it can be assumed that a sample size of 25–50 individual DBH measurements per forest stand allows estimating reliable diameter distributions. The presented pilot study gives a first insight on the potential of such an approach for operational assessments of diameter distribution in deciduous forest stands and might be particularly interesting for stands in difficult terrain situations. The presented approach can be extended to estimate the basal area, timber stock or biomass.

A value-added forest management policy reduces the impact of fire on timber production in Canadian boreal forests

When fire rates are sufficiently high, fire disturbances can have negative impacts on industrial timber supplies. One can mitigate such problems at the strategic level by accounting for potential fire losses in the timber supply planning process by reducing harvest levels to maintain a buffer stock of timber. With a forest planning model based on a timber volume maximizing policy, reducing the harvest level will lead to a reduction in the harvested timber volume and likely, of revenues. One possible solution is to change the policy to increase the value of the wood that is harvested so as to minimize such reductions with less risk. We have evaluated alternative policies for three commercially-managed forests that have different burn rates in northeastern Canada. When compared with a volume-maximization policy, a revenue-maximization policy that considers sustained production and the sale of sawmilling wood products (lumber, chips and sawdust) increased mean revenues by 130% (36–770%) with >0.90 probability and substantially decreased the area and volume harvested by 27% (11–38%) and 28% (14–36%), respectively. By reducing the harvest volume, the total number of jobs associated with forest operations decreased by 20% (10–27%) but the number of jobs per unit area harvested and volume increased. The policy also increased the harvest age and thereby enhanced the retention of a greater proportion of old-growth stands. Our study indicated that a tighter link between strategic planning and wood product processing helped identify better compromises between harvesting activities and revenues, despite the occurrence of natural disturbances.

Theory-of-Change Development for the Evaluation of Forest Stewardship Council Certification of Sustained Timber Yields from Natural Forests in Indonesia

To illustrate the importance of theories-of-change (ToCs) for evaluation of conservation interventions, we consider the global ToC from the Forest Stewardship Council (FSC) and then develop a more explicit ToC focused on the sustained timber yield (STY) aspiration for natural forest management in Indonesia. We use these ToCs to consider certification implementation processes vis-à-vis indicators for STY extracted from FSC’s Indonesian Stewardship Standard that mentions STY explicitly in 45 and implicitly in 21 of 237 indicators. Analysis of 38 audit reports about 23 enterprises (2001–2017) revealed that only 77 of 504 major non-conformities assigned by auditors addressed STY. This apparent lack of attention to STY is surprising given the exhaustion of timber stocks in many production forests and the closure of many forest enterprises over the past two decades, but our ToC reveals numerous unsatisfied and unsatisfiable assumptions in certification that preclude detection of unsustainable harvests. Furthermore, compliance with governmental regulations on harvest intensities does not allow full timber recovery. To sustain yields, logging intensities need to be reduced and/or silvicultural treatments applied to increase yields, both of which reduce short-term profits. Declining yields might be accepted if the capacity of logged forests to grow timber is not impaired, but forest abandonment due to timber stock depletion is worrisome if it fosters illegal forest conversion.

Actively restoring resilience in selectively logged tropical forests

Abstract Huge tracts of tropical forest are selectively logged. Meanwhile, emerging global agendas are providing unprecedented incentives for large‐scale restoration within human‐impacted tropical forest landscapes. Whilst logged forests have high conservation value, their adoption within these agendas remains controversial. We review the value of restoring logged tropical forests for boosting economic and environmental resilience. Targeted interventions can recover depleted timber stocks, increase saleable carbon stores, and deliver employment and non‐timber forest products (NTFPs) to local communities. Restoration has mixed outcomes for biodiversity but if it improves relogging practices and protects forests from conversion to agricultural plantations may have major positive impacts. We also examine socio‐economic and political pathways for upscaling logged forest restoration and their incorporation into sustainable forestry, given political and commercial malaise on post‐logging interventions. Spurring these transitions will require strong institutions, executed by policies that enable long‐term concession licences and community land tenure, that leverage commercial involvement and payments for ecosystem services, and that optimise existing interventions. Research frontiers include: (a) validating the economic and technical feasibility of different interventions; (b) understanding how these interventions impact on synergies and trade‐offs between ecosystem services, NTFPs, and biodiversity; and (c) identifying when to restore a logged forest. This requires establishing long‐term experimental trials that jointly track environmental and socioeconomic outcomes. Synthesis and applications. Post‐logging interventions can deliver various timber, carbon, socioeconomic and potentially biodiversity benefits but are underemployed and undervalued pantropically. Opportunities exist to optimise interventions by tailoring incentives, policies, and management to ecological and social circumstances. Governments, conservation bodies and the private sector must underscore restoration of production forests as a major future objective, including via greater adoption in global initiatives, including forest and landscape restoration under the Bonn Challenge and the Reducing Emissions from Deforestation and Forest Degradation (REDD+) agenda.