Production Of High Quality Timber Research Articles

Terrestrial laser scanning vs. manual methods for assessing complex forest stand structure: a comparative analysis on plenter forests

In continuous cover forestry, plenter silviculture is regarded as an elaborated system for optimizing the sustainable production of high-quality timber maintaining a constant but heterogeneous canopy. Its complexity necessitates high silvicultural expertise and a detailed assessment of forest stand structural variables. Terrestrial laser scanning (TLS) can offer reliable techniques for long-term tree mapping, volume calculation, and stand variables assessment in complex forest structures. We conducted surveys using both automated TLS and conventional manual methods (CMM) on two plots with contrasting silvicultural regimes within the Black Forest, Germany. Variations in automated tree detection and stand variables were greater between different TLS surveys than with CMM. TLS detected an average of 523 tree stems per hectare, while CMM counted 516. Approximately 9.6% of trees identified with TLS were commission errors, with 6.5% of CMM trees being omitted using TLS. Basal area per hectare was slightly higher in TLS (38.9 m3) than in CMM (38.2 m3). However, CMM recorded a greater standing volume (492.7 m3) than TLS (440.5 m3). The discrepancy in stand volume between methods was primarily due to TLS underestimating tree height, especially for taller trees. DBH bias was minor at 1 cm between methods. Repeated TLS inventories successfully matched an average of 424 tree positions per hectare. While TLS adequately characterizes complex plenter forest structures, we propose enhancing this methodology with personal laser scanning to optimize crown coverage and efficiency and direct volume measurements for increased accuracy of wood volume estimations. Additionally, utilizing 3D point cloud data-derived metrics, such as structural complexity indices, can further enhance plenter forest management.

Pruning revisited – effect of pruning season on wood discoloration and occlusion in four temperate broadleaved tree species

Abstract Pruning is a necessary part of tree management both in silvicultural systems and in urban forestry. For the wood industry’s production of high-quality timber, as well as for the urban forest’s risk reduction and ecosystem services enhancements, it is essential that the pruning is accurately implemented. This study aimed to determine the effect of pruning season on discoloration amount and occlusion rate in four broadleaved tree species. In 2014, 84 trees were pruned in January, May and September. Six years later, the 252 samples from the three pruning points per tree were collected and analysed. ‘Common oak (Quercus robur L.)’ and ‘small-leaved lime (Tilia cordata Mill.)’ showed least discoloration when pruned in January, ‘wild cherry (Prunus avium L.)’ showed least discoloration when pruned in September and ‘Norway maple (Acer platanoides L.)’ did not show any significant differences. All species occluded fastest when pruned in January, but at different rates. Common oak occluded 84 per cent of the samples, Norway maple 42 per cent, small-leaved lime 32 per cent and wild cherry 13 per cent. In summary, the pruning month affected discoloration amounts and occlusion rates of the tested tree species in varied ways. Our research suggests an important knowledge gap regarding optimal species-specific pruning times and underlying reasons for different reactions to pruning.

Large investment of stored nitrogen and phosphorus in female cones is consistent with infrequent reproduction events of Pinus koraiensis, a high value woody oil crop in Northeast Asia.

Pinus koraiensis is famous for its high-quality timber production all the way and is much more famous for its high value health-care nut oil production potential since 1990's, but the less understanding of its reproduction biology seriously hindered its nut productivity increase. Exploring the effects of reproduction on nutrient uptake, allocation and storage help to understand and modify reproduction patterns in masting species and high nut yield cultivar selection and breeding. Here, we compared seasonality in growth and in nitrogen ([N]) and phosphorus ([P]) concentrations in needles, branches and cones of reproductive (cone-bearing) and vegetative branches (having no cones) of P. koraiensis during a masting year. The growth of one- and two-year-old reproductive branches was significantly higher than that of vegetative branches. Needle, phloem and xylem [N] and [P] were lower in reproductive branches than in vegetative branches, although the extent and significance of the differences between branch types varied across dates. [N] and [P] in most tissues were high in spring, decreased during summer, and then recovered by the end of the growing season. Overall, [N] and [P] were highest in needles, lowest in the xylem and intermediate in the phloem. More than half of the N (73.5%) and P (51.6%) content in reproductive branches were allocated to cones. There was a positive correlation between cone number and N and P content in needles (R2 = 0.64, R2 = 0.73) and twigs (R2 = 0.65, R2 = 0.62) of two-year-old reproductive branches. High nutrient sink strength of cones and vegetative tissues of reproductive branches suggested that customized fertilization practices can help improve crop yield in Pinus koraiensis.

Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile

Chestnut (Castanea sativa Mill.) is an interesting species for high-quality timber production. It is well known that the species responds to early thinning, but there is no information on the impact of late interventions. The objective of this study was to assess the effect of a late thinning on the performance of unmanaged adult chestnut plantations in Chile. Future-tree selective thinning and control were compared in adult plantations using a randomized complete block design with three replicates at three sites, Minas, Pillo-Pillo and Pumillahue. Tree growth was evaluated periodically during the first 7 years after thinning in all plantations. Additionally, almost 20 years after the intervention, the Pumillahue plantation was measured for growth and tree shape variables. In this case study, the effect of thinning on tree growth decreased considerably after 5 years, with a maximum DBH increment in the third year after the intervention (45.8 %, 68.6 %, and 42.2 % in Minas, Pillo-Pillo and Pumillahue, respectively). In all plantations, basal area was smaller in the thinned plots in the first years after the intervention, but in Pumillahue, 19 years after thinning, no differences were found among treatments. Height was statistically greater under thinning seven years after the intervention; this effect was also found in Pumillahue plantation 19 years after thinning. Most trees showed high vigor, and were straight and healthy, even in control plots. Late effect of thinning was observed 19 years after thinning on tree shape, with a reduction in the proportion of bifurcated trees from 16 % to 8 %. The results suggest that late thinning is an effective silvicultural intervention to produce high-quality chestnut timber in unmanaged adult plantations. Progressive and frequent thinning should be used to increase growth and improve timber production in chestnut.

Mixed Castanea sativa plantations including arboreal companion species enhance chestnut growth and high-quality timber production

ContextChestnut (Castanea sativa Mill.) is an important tree species for its timber, which is widely used for multiple purposes, including the veneer industry. The species has an interesting productive potential in Chile and requires specific management strategies to produce valuable, high-quality logs. Although mixed plantations including companion species usually enhance timber quality of several trees, the performance of chestnut under different associations is not well known. AimsThe objective of this study was to assess growth, survival, health, and timber quality of chestnut trees in several plantation types, including monoculture and mixtures with other companion trees and/or shrub. MethodsGrowth and survival measurements were taken periodically in pure chestnut and mixed plantations established in southern Chile for a 20-year period after planting. The mixed plantations tested were: a main forest species mixture (Castanea sativa Mill., Quercus rubra L., Quercus robur L. and Prunus avium L.); three mixtures including main forest species plus one arboreal companion species (Alnus glutinosa L., Gevuina avellana Mol. or Embothrium coccineum J.R. Forst. & G. Forst.); one including main forest species plus one shrub nurse species (Fabiana imbricata Ruiz & Pav.); and three mixtures including one of the arboreal companion species and the shrub. Timber quality variables were assessed at age 20, and health status was recorded at ages 7 and 20 in all plantations. Growth variables were analyzed using linear mixed models to assess plantation effect over time. Kaplan-Meier survival analysis and Log Rank Test were used to compare chestnut tree survival among plantation types. Quality timber variables were analyzed with a χ2 test. ResultsChestnut trees associated with arboreal main species (P. avium, Q. rubra, Q. robur) (Mix1) showed the best performance, with 10.1 % and 8.3 % higher height than average values of the other mixtures and the monoculture, respectively, and 19.1 % and 12.8 % higher diameter growth than across plantation types and monoculture average values, respectively. Mix1 had the highest average volume per tree (0.34 m−3), at least 30 % higher than the average volume of pure and other mixed plantations. This mixture including only main species also exhibited the highest percentage of trees with high trunk length values of all plantation types. No pest or diseases were recorded on chestnut trees, and survival was high in all plantation types. ConclusionThe impact of mixed plantations on growth and timber quality was evidenced at age 20. In particular, the association including arboreal companion species enhanced chestnut tree performance.

Branch development in monoculture and mixed-species plantations of Betula alnoides, Erythrophleum fordii and Pinus kesiya var. langbianensis in southwestern China

The quantitative and morphological characteristics of branches are key factors influencing both tree growth and wood quality. The effects of stand density and artificial pruning on branch development have been widely studied in monoculture, while branch development in mixed forests has rarely been reported. In this study, branch development of Betula alnoides, Erythrophleum fordii and Pinus kesiya var. langbianensis were evaluated in a 6-year-old mixed-species trial plantation in Yunnan Province, China, which included five treatments: monocultures of B. alnoides, E. fordii and P. kesiya var. langbianensis, and mixtures of B. alnoides with E. fordii or P. kesiya var. langbianensis. Branch quantity (number, proportion, and density), morphology (diameter, length, and angle), and distribution (height and orientation) were measured from 63 dominant or codominant trees randomly sampled in the trial plantation. The results showed that the number of live and total branches of B. alnoides in the mixture was significantly higher than those in its monoculture, and the branch density of B. alnoides in the mixture with P. kesiya var. langbianensis was also higher than those in its monoculture and the mixture with E. fordii. Mixing with B. alnoides had no significant effect on the branch quantity of P. kesiya var. langbianensis, but significantly lowered the branch quantity of E. fordii. The branch angle was not significantly affected by the mixture for these species. More small branches (branch diameter < 15 mm) were observed in the mixed plantations than in the monocultures for the three species, while significantly lower branch diameter and length were seen in the mixture than in the monoculture only for B. alnoides. Significant differences were absent in the branch distribution of B. alnoides and E. fordii among the four cardinal orientations regardless of whether they were in the monoculture or in the mixture. The variations in branch quantity and morphology along the stem were much more determined by species-specific attributes and less affected by the mixture. It was concluded that a mixture of B. alnoides and E. fordii could significantly control the branch size of B. alnoides, reduce both the branch size and branch quantity of E. fordii, and thus be beneficial for high-quality timber production.

Genetic variability and predicted gain in progeny tests of native Atlantic Forest timber species: Cariniana legalis, Cordia trichotoma, and Zeyheria tuberculosa

Over the years, the Atlantic Forest has been one of the biomes most affected by fragmentation and despite the scarcity of studies related to their genetic and breeding aspects, native Atlantic Forest species can provide various high-quality timber products. In this context, the objectives of this work were to estimate genetic parameters and predict genetic gain with selection of provenance/progeny tests of Cordia trichotoma, Zeyheria tuberculosa, and Cariniana legalis, for diameter at breast height (DBH) and survival rate. Seed trees from different provenances were selected and measured, and their seeds were collected and tested in the areas of Porto Seguro - Bahia state, Brazil. All test individuals were evaluated for DBH (cm) survival rate (%) and stem straightness. The variance components and genetic parameters were estimated for DBH and survival rate. The narrow-sense individual heritability (h2i) for DBH of the three species ranged from 0.26 to 0.72, showing moderate to high genetic control. However, based on the likelihood ratio test (LRT) there is no genetic variability among genotypes of Z. tuberculosa. For survival rate, high genetic control (0.54) was observed only for C. trichotoma, while for C. legalis and Z. tuberculosa h2i value was 0.11 and 0.0, respectively. After genetic parameter analyses, the expected genetic gains were estimated for seed trees, potential genitors and potential clones. For seed trees, gains based on the additive genetic values (u+a) for DBH by selecting the top 10 individuals of each species per family ranged between 17.17 and 30.31%. In the case of potential genitors, by selecting the top ten individuals based on u + a value, are expected gains between 19.17 and 49.65%. The ranking of the top ten potential clones based on genotypic values (u +g) for each species showed gains between 32.43 and 56.53%. Conducting genetic breeding for C. trichotoma and C. legalis presents high potential of genetic gains and efforts should be taken into account for supporting breeding strategies for those species. In the case of Z. tuberculosa, the absence of genetic variability seems to be a result of the Atlantic Forest deforestation and genetic basis narrowing.

2. PENCEGAHAN PRAKTEK KEJAHATAN EKONOMI DALAM PERDAGANGAN BEBAS – ORIGIN FRAUD DALAM INDUSTRI MEBEL KAYU DI JEPARA

Indonesia has been known to have abundant natural resources and culture-based creative industries.The country is therefore vulnerable to the practice of fraud of origin. One of many industrial sectorssusceptible to that particular crime is the wooden furniture businesses. In many cases, it is apparent thatnatural products and raw materials of Indonesia are being exported without listing the country as the place oforigin. The most common Indonesian material falls within this illegal practice are timber products. In theprovince of Central Java, Jepara has been a prominent center of timber industry producing high quality timberproducts and wooden raw materials. From a unique standpoint, the timber industry in Jepara is deeply rootedto the culture and identity of the natives, making the attempt to separate the discussion between timber industryand the people of Jepara not only imprudent but virtually impossible. By looking at the statistic in whichJepara’s public education level is assessed to be still below the national standard, and as well bearing to thegeneral fact that the timber actors in Jepara are more focused on product sales rather than important technicalaspects such as certification of origin, it should be projected that crimes such as fraud of origin could be easilycommitted in Jepara. This study is using a comparative advantage theory and theories or models of H-O toinvestigate how the practice of fraud of origin in Jepara occurs and how to resolve such problem.

Silvicultural aspects of the sycamore (Acer pseudoplatanus L.) propagation &amp;ndash; Overview

The purpose of this study is to analyze existing silvicultural experience related to the sycamore using literary data in order to optimize future work with the species. The discussion looks into matters related to: ecological requirements, seed propagation, vegetative propagation via rooting of stem cuttings and grafting, natural regeneration specifications, creating and cultivation of forest plantations, growth and productivity of the stands, and silviculture activities dedicated to the production of high-quality timber.&amp;nbsp;

Comparison of Juvenile, Drought Tolerant Black Locust (Robinia pseudoacacia L.) Clones with Regard to Plant Physiology and Growth Characteristics in Eastern Hungary: Early Evaluation

(1) Background: The aim of our study is to present the results of initial growth and plant physiology studies of newly selected, vegetative propagated black locust clones, with a view to assess their suitability for the establishment of fast growing tree plantations for the production of high quality timber in marginal (semi-arid) sites. (2) Methods: In the spring (May) and autumn (November) of 2021, full inventories were carried out in the black locust industrial tree plantation. The Normalized Difference Vegetation Index (NDVI) values were observed monthly from May to September 2021. For measuring the assimilation parameters the net assimilation, transpiration, stomatal conductance, intercellular CO2 concentration, and other physiological parameters were recorded. (3) Results: Robinia pseudoacacia ‘NK2’ clone showed the highest assimilation rate and it produced the most height increment in the growing season, from May 2021 to November 2021. The discriminant analysis classified successfully the black locust clones, 86.7% of original grouped cases were correctly classified. (4) Conclusions: The study of industrial tree plantations is of great practical importance. As black locust can tolerate even marginal site conditions, the lack of timber can be reduced in the future by establishing black locust industrial tree plantations. To be able to produce good quality industrial wood on the plantations, it is essential to study the phytophysiological properties of the trees (biomass production, vegetation activity of plants, chlorophyll content, photosynthetic activity) in addition to the traditional stand full inventories.

COATING OF PLATHYMENIA RETICULATA BENTH SEEDS WITH DIFFERENT MATERIALS

Plathymenia reticulata Benth, popularly known as ‘vinhatico’, is a tree species with potential for the production of high-quality timber that is used in luxury furniture and construction. Seed coating ensures an adequate stand, vigorous plants, delayed onset of epidemics, and increased yield. The present study was carried out to investigate different types of seed-coating materials and their effects on the physical and physiological characteristics of Plathymenia reticulata Benth and define the best coating material. The coatings were made with sand, silicate, limestone, sand + silicate, sand + limestone and uncoated seeds as a control. The experiment was set up as a completely randomized design with six treatments tested in four replicates with 50 seeds each. Sand + limestone coating reduced GSI and ESI but did not influence the seedling germination or emergence rates. The best material for coating Plathymenia reticulata Benth was the sand + limestone mixture.

Ten Years of Provenance Trials and Application of Multivariate Random Forests Predicted the Most Preferable Seed Source for Silviculture of Abies sachalinensis in Hokkaido, Japan

Research highlights: Using 10-year tree height data obtained after planting from the range-wide provenance trials of Abies sachalinensis, we constructed multivariate random forests (MRF), a machine learning algorithm, with climatic variables. The constructed MRF enabled prediction of the optimum seed source to achieve good performance in terms of height growth at every planting site on a fine scale. Background and objectives: Because forest tree species are adapted to the local environment, local seeds are empirically considered as the best sources for planting. However, in some cases, local seed sources show lower performance in height growth than that showed by non-local seed sources. Tree improvement programs aim to identify seed sources for obtaining high-quality timber products by performing provenance trials. Materials and methods: Range-wide provenance trials for one of the most important silvicultural species, Abies sachalinensis, were established in 1980 at nine transplanting experimental sites. We constructed an MRF to estimate the responses of tree height at 10 years after planting at eight climatic variables at 1 km × 1 km resolution. The model was applied for prediction of tree height throughout Hokkaido Island. Results: Our model showed that four environmental variables were major factors affecting height growth—winter solar radiation, warmth index, maximum snow depth, and spring solar radiation. A tree height prediction map revealed that local seeds showed the best performance except in the southernmost region and several parts of northern regions. Moreover, the map of optimum seed provenance suggested that deployment of distant seed sources can outperform local sources in the southernmost and northern regions. Conclusions: We predicted that local seeds showed optimum growth, whereas non-local seeds had the potential to outperform local seeds in some regions. Several deployment options were proposed to improve tree growth.

Mixed Pyrus pyraster and Sorbus torminalis plantations including companion species enhance high-quality timber production

Wild pear (Pyrus pyraster (L.) Burgsd.) (P) and wild service tree (Sorbus torminalis (L.) Crantz) (S) are sporadic European tree species that are valued for their high-quality timber production. Although mixed plantations including companion species enhance timber quality of several trees, the performance of the association of P and S is not well known. The objective of this study was to assess growth and survival of P and S in pure plantations and in plantations mixed with other companion tree or shrub species in a non-native habitat. To answer the question of whether growth of these species is enhanced by mixtures, specific combinations of the main and companion species were established in central Chile and monitored for a 12-year period after planting. Besides each main species monoculture, five mixtures were tested: Mix1: P+S; Mix2: P+S+ the N-fixing tree Italian alder (Alnus cordata (Loisel.) Duby); and three associations of P and S including shrubs (Mix3: P+S+ Corylus avellana L., Mix4: P+S+ Sambucus ebulus L., and Mix5: P+S+ Sambucus nigra L.). Both P and S presented the highest height growth in Mix2, being 48.6% and 53.4% higher than in the monoculture, respectively. DBH growth was also enhanced in Mix2 for S. Wild service tree, which showed lower growth and survival than P, was more benefited from the mixture including Italian alder than P. Height growth, vigor and survival of the main species were highest in Mix2, even higher than in pure plantations and in Mix1 without companion species. Specific tree associations might increase the probability to obtain high-quality timber of noble species if a timely and adequate management of companion species is provided.

Pure and mixed plantations of Persian walnut (Juglans regia L.) for high quality timber production in Chile, South America

AbstractAimsPersian walnut (Juglans regia L.), an interesting forest species for the veneering industry, requires adequate management to produce valuable high-quality logs. Since species associations and management level can improve stand productivity, the novelty of this work was to assess Persian walnut performance in different planting mixtures and in pure plantations conditioned to management intensity.MethodsGrowth, straightness and survival measurements were taken annually for 7 years after planting pure and mixed plantations under two contrasting management scenarios. Diseases were recorded at Age 7 in all plantations. Under each management intensity, besides the monoculture, three mixtures were tested: a mixture of only main forest species, main forest species plus one arboreal companion species, Black alder (Alnus glutinosa L.) and main species plus the shrub Russian olive (Elaeagnus angustifolia L.) as nurse species. A test of interaction between plantation type and management scenario was conducted using repeated growth data.Important FindingsThe interaction was significant, indicating the presence of different mechanisms underlying plantation effects under high and low management level. Compared with pure plantations, Persian walnut associated with the nurse shrub exhibited 78% higher height and 53% higher diameter growth in plantations under low management. Health benefits (lower presence of walnut blight than in the monoculture) and better straightness were also found in the association including the shrub when the management intensity was not high. These beneficial effects in the presence of Russian olive were not present under high management intensity (irrigation, fertilization, tutoring and frequent pruning). Site-specific designs for Persian walnut plantations would depend on the foreseen management intensity.

Teak (Tectona grandis) silviculture and research: applications for smallholders in Lao PDR

ABSTRACTTeak is an important forest plantation species in Lao PDR (Laos), that has been planted extensively by smallholders, supplying domestic industries and international markets. There have been significant advances in the intensive silvicultural management of teak focused on the production of high-quality timber. Laos is not an exception. With support from the Australian Centre for International Agricultural Research, there have been advances in the understanding and knowledge of appropriate management practices for smallholder teak, as well as development of supporting technologies (i.e. ex situ conservation, genetic improvement, growth models, thinning and pruning prescriptions, and agroforestry systems). This paper summarises published information on the silviculture and management of teak, including improvement of genetic resources, stocking rate, thinning and agroforestry systems used in Asia, Africa, Latin America and Oceania, and relates this to the current situation in northern Laos. The challenge is to now transfer this knowledge to the teak smallholders, professionals, educators and policy decision makers of Laos.

Estructura y dinámica de bosques de palo santo en el Chaco Seco

Knowledge on the structure and dynamics of Bulnesia sarmientoi (“palo santo”) populations is necessary for forest management aimed at the conservation and high-quality timber production by this species and the preservation of the ecosystem services of its forests. We characterized forest structure and dynamics in stands with palo santo presence in the Nothern Argentinian Dry Chaco. We sampled 21 forest sampling clusters. Each forest sampling cluster includes four sets of concentric circular plots of 1000 m² (diameter &gt;20 cm) and 500 m² (diameter &gt;10 cm), located at the vertices of a square of 100 m side. Forest clusters were measured in 2007 and 2012. We calculated the importance value index (IVI) of each species in each conglomerate. We identified three typical structures with palo santo: a) palosantales in regularly flooded soils, b) palo cruz con palo santo, and c) Chaco mixed forest with the presence of palo santo. Periodic annual increment in diameter was 1.14 mm for all diameter classes. Taking as a reference the structure of a conglomerate with palo santo that was selective logged, we simulated alternative interventions (80% removal of all diameter classes or a diameter restriction of &gt;40 cm) on stand dynamics. Cutting of 80% of the trees was a very severe intervention, suggesting that the removal of the smallest sizes for rural construction could compromise the recovery of the stand. A minimum size restriction could warrant recovery in 50 years. We suggest that the harvest of palo santo trees should be focused on large individuals with the highest added value potential.https://doi.org/10.25260/EA.18.28.1.0.615

Do Common Silvicultural Treatments Affect Wood Density of Mediterranean Montane Pines?

Wood density is one of the most important and well documented wood quality attributes. However, studies focusing on the effects of thinning combined with pruning on wood density in Mediterranean areas are scarce, even though both are recommended practices in forests managed for the production of high-quality timber. We assess the effects of both silvicultural interventions on wood density traits (tree-ring, earlywood, and latewood) and on the percentage of latewood, on an annual scale, for the main timber species Pinus sylvestris L. and Pinus nigra Arnold (subsp. nigra and subsp. salzmannii) in Mediterranean mountains. To this end, three trials (one species per trial) were established in monospecific reforestations in the 1990s. Three silvicultural treatments were applied: thinning, thinning combined with pruning, and a control. At the time of installation, stand ages ranged from 26 to 37 years. Small differences were found among treatments in regard to the wood density attributes, with no significant effects of thinning and pruning on the studied wood traits in either timber species. The two subspecies of P. nigra presented comparatively denser wood than P. sylvestris. Our results suggest that thinning and pruning treatments can be applied without causing unfavourable changes to wood density.

Plasticity of tree architecture through interspecific and intraspecific competition in a young experimental plantation

It is acknowledged that trees behave remarkably plastic in response to environmental conditions. Even so, knowledge of how tree architecture in pure and mixed stands compare is largely underexplored. Such information is relevant from a fundamental ecological and an applied silvicultural perspective, given the increased attention for mixed species silviculture and the close linkages between tree architecture and high-quality timber production. The main objective of this work was to test the effects of competition, diversity and species identity of neighboring trees on the architecture of five important European tree species (Quercus robur, Betula pendula, Fagus sylvatica, Pinus sylvestris and Tilia cordata) in a temperate plantation before and during canopy closure.Data were collected in FORBIO-Zedelgem, a five-year old tree diversity experiment in Belgium. For 396 trees we measured architectural properties including branchiness, tree height-to-diameter (HD) ratio, branch diameter and branch insertion angle, and we investigated how these properties were shaped in different competitive neighborhoods using mixed regression models.Species showed contrasting architectural responses to neighborhood competition, in line with species life-history strategies. In more competitive environments, trees of Q. robur (slow growing and light-demanding) increased HD ratio and branch insertion angle to optimize light foraging in the upper canopy; trees of B. pendula (fast growing and light-demanding) increased HD ratio and decreased branching following the branch autonomy principle; trees of F. sylvatica (slow growing and shade tolerant) increased branching to improve light uptake under shading and finally, trees of P. sylvestris (fast growing and light-demanding) and T. cordata (slow growing and shade tolerant) were not shaped in response to competition. Diversity and identity of species in a trees’ neighborhood did not contribute to the architectural plasticity, although competitive differences between pure and mixed stands underpinned such effects for B. pendula, with lower branching in the highly competitive monocultures.We conclude that competition between trees, but not diversity, influences the architecture of young plantation trees before and during canopy closure in mixtures. To guide tree architectural development towards high-quality timber, management may have to pay considerable attention to competitive processes already in the juvenile forest stages.

Large-Scale Variations in Lumber Value Recovery of Yellow Birch and Sugar Maple in Quebec, Canada.

Silvicultural restoration measures have been implemented in the northern hardwoods forests of southern Quebec, Canada, but their financial applicability is often hampered by the depleted state of the resource. To help identify sites most suited for the production of high quality timber, where the potential return on silvicultural investments should be the highest, this study assessed the impact of stand and site characteristics on timber quality in sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.). For this purpose, lumber value recovery (LVR), an estimate of the summed value of boards contained in a unit volume of round wood, was used as an indicator of timber quality. Predictions of LVR were made for yellow birch and sugar maple trees contained in a network of more than 22000 temporary sample plots across the Province. Next, stand-level variables were selected and models to predict LVR were built using the boosted regression trees method. Finally, the occurrence of spatial clusters was verified by a hotspot analysis. Results showed that in both species LVR was positively correlated with the stand age and structural diversity index, and negatively correlated with the number of merchantable stems. Yellow birch had higher LVR in areas with shallower soils, whereas sugar maple had higher LVR in regions with deeper soils. The hotspot analysis indicated that clusters of high and low LVR exist across the province for both species. Although it remains uncertain to what extent the variability of LVR may result from variations in past management practices or in inherent site quality, we argue that efforts to produce high quality timber should be prioritized in sites where LVR is predicted to be the highest.

Bark Beetles in Pine Tree Plantations in Uruguay: First Record ofOrthotomicus erosusWollaston (Coleoptera: Curculionidae: Scolytinae)

Forestry in Uruguay has grown exponentially for the last 20 years. Even though plantations of Eucalyptus L’Her. account for about 80% of the total forested area in the country, pine tree plantations are relevant in the production of high quality timber. Following the introduction of pine in 1810, large scale production of pine tree plantations started in 1940, mainly with Pinus radiata Don (Pinaceae) (Porcile 2007). In 1950, seeds of Pinus taeda L. and Pinus elliottii Engelm., among others, were brought from the United States. To date, pine tree plantations occupy 20% of the forested area in the country (250,000 ha mainly in the northern part of the country), mostly with P. taeda and P. elliottii (MGAP 2012).