Black Pine Plantations Research Articles

Ecological Potential of Mediterranean Habitats for Black Pine (Pinus nigra J.F. Arnold) in Croatia

This study outlines research performed on experimental plots established in forest plantations and in natural black pine forests. The objective of the study was to determine the habitat factors that have the greatest impact on the growth and development of natural black pine forests and black pine forests plantations upon the return of climatozonal vegetation. Plots 625 m2 in size were selected and vegetation inventories made, and the structural elements of black pine plantations examined. Multivariate analysis found that elevation and slope were the two variables that had the highest positive correlation with the floristic composition of the vegetation. Furthermore, one of the goals was to determine the differences with regard to reforestation with black pine. The analysis of the isolated experimental plots showed a clear grouping of plots according to habitat factors. The differences in the synecological factors in the research area resulted in the presence of sub-Mediterranean, epi-Mediterranean and eu-Mediterranean elements within the black pine forest plantations. This also reduces the risk of the occurrence and development of large wildfires.

Woody species and taxonomic diversity of black pine plantations in the Inner Anatolian Region

Bu çalışmada, İç Anadolu Bölgesi’ndeki Anadolu karaçamı (Pinus nigra subsp. pallasiana) ağaçlandırmalarının yetişme ortamı özellikleri ve bonitet sınıfları ile odunsu bitki çeşitliliği (tür çeşitliliği, taksonomik çeşitliliği) arasındaki ilişkiler araştırılmıştır. Çalışmada 90 örnek alana ait yetişme ortamı faktörleri ile 38 bitki türü verileri kullanılmıştır. Örnek alanlar iyi bonitet (A) ve kötü bonitet (B) olmak üzere iki sınıfa ayrılmıştır. Tür çeşitliliği, Shannon indisi H ile belirlenmiştir. Taksonomik çeşitlik hesabında ağırlıklı ve ağırlıksız taksonomik çeşitlilik (To, uTo) ile taksonomik mesafe (To+, uTo+) indisleri kullanılmıştır. Shannon İndisi (H) ile bonitet sınıfı, eğim, yükselti, faydalanılabilir su kapasitesi, organik karbon ve yıllık yağış arasında pozitif; yıllık ortalama sıcaklık ve boylam arasında ise negatif ilişkiler belirlenmiştir. Taksonomik çeşitlilik, taksonomik mesafe ve tür çeşitliliği bakımından bonitet sınıfları arasında önemli farklılıklar belirlenmiştir. Taksonomik çeşitlilik ve tür çeşitliliği karaçamın verimli olduğu alanlarda daha yüksek bulunmuştur. Karaçam ağaçlandırma alanlarında en sık rastlanan taksonlar, az sayıda benzer cins ve familyaya bağlıdır. Bu durumun taksonomik çeşitlilikte azalma ve taksonomik mesafede daralmaya neden olabileceği düşünülmektedir.

Ecology, Population Density, and Translocation of the Snake-Eyed Skink (<i>Ablepharus kitaibelii</i>) in Westernmost Populations

Westernmost population of the Snake-eyed Skink is found in Papuk, Croatia, and is the closest to the population from Ilok, Croatia. So far, the ecology of any of them has not been studied, and here, we document the variation between them. Furthermore, we estimated population density in Papuk using line transects, and quantitatively assessed its viability, i.e., chances for its survival under different scenarios; under current situation, with increased habitat, and with the negative effect of catastrophic events (e.g., forest fires, habitat degradation). Our study suggests that the climate between the two populations differs significantly, while other general requirements of the species remain the same in both locations. In the Papuk area we estimated the total population size from 5036 to 5483 individuals, with a relative density of 97 individuals per hectare. The population viability results suggest that the extinction of the Papuk population is likely to happen due to the negative trend in the number of individuals over 100 years. This implies that the population is not stable and under current condition shows the need for urgent conservation measures. We modeled two measures, 1) restoration of habitat via the removal of black pine plantations, and 2) translocation of the Snake-eyed Skink into two new habitats. Both methods rely on the increase of available habitat, and both were implemented in the study area. In 2014 an area of 900 m2 of black pine forest was removed, and in 2014 and 2016 we translocated 100 individuals per year (altogether 200 individuals) into new habitats. Monitoring data confirmed that the newly established subpopulations are present at both sites, and are reproducing, which could imply that our translocation might be successful.

Comparison of some wood properties of juvenile black pines of different origin planted in the same habitat

Black pine (Pinus nigra) is a significant raw material source for the forest products industry in Turkey. The purpose of this research was to study some chemical, anatomical, physical, and mechanical properties of wood obtained from juvenile black pines planted in Kavaklidere - Mugla, originating from five different locations: Mugla, Balikesir, Denizli, Bursa, and Kutahya. Although pines originating from Mugla and Balikesir were good in terms of wood properties, those from Denizli, Bursa, and Kutahya exhibited no remarkable features. Black pine of Mugla origin was recommended for planting in Kavaklidere and similar habitats, whereas pines of Denizli, Bursa, and Kutahya origins were not recommended. However, pine of Balikesir origin may be an alternative to that of Mugla origin for black pine plantations at Kavaklidere and similar sites

Increased Post-Drought Growth after Thinning in Pinus nigra Plantations

In Mediterranean seasonally dry regions, the rise in dieback and mortality episodes observed in pine afforestations has been related to higher drought intensity and lack of appropriate management, which enhance competition between trees for water and light. However, there is little understanding of the benefits of silviculture for plantations under seasonal drought stress. A combination of dendrochronology and wood C and O isotope analyses was used in three Black pine (Pinus nigra) plantations to work out the responses of radial growth (BAI, basal area increment) and water-use efficiency (WUEi) to thinning treatments (removal of 40% of the stand basal area). Thinning had a positive effect on BAI and WUEi, reduced drought sensitivity, and reduced the temporal dependence on the previous year’s growth. These results were significant even 13–14 years after thinning and coherent for the three study sites. Differences were found between the sites regarding the physiological mechanisms of adaptation. In two sites, we inferred the enhanced WUEi was due to increased photosynthetic rates (A) at constant stomatal conductance (gs). In the third site, which had higher tree density and therefore competition, we inferred increases in both A and gs, with the former being proportionally larger than the latter.

Covariation between plant biodiversity and soil systems in a European beech forest and a black pine plantation: the case of Mount Faito, (Campania, Southern Italy)

Both climate and land-use changes, including the introduction and spread of allochthonous species, are forecast to affect forest ecosystems. Accordingly, forests will be affected in terms of species composition as well as their soil chemical and biological characteristics. The possible changes in both tree cover and soil system might impact the amount of carbon that is stored in living plants and dead biomass and within the soil itself. Additionally, such alterations can have a strong impact on the detrital food web that is linked to litter decomposition. Although there are studies on the influence of plant diversity on soil physical and chemical characteristics, the effects on soil biological activity and carbon storage processes remain largely unknown. The aim of this study was to investigate and compare chemical and biological variables in covariation with plant communities in an autochthonous beech forest (Fagus sylvatica L.) and a black pine plantation (Pinus nigra J.F. Arnold subsp. nigra). Our results confirmed that the two communities were considerably different, with the old-growth beech community having a lower number of plant species and the pine community was in development as a consequence of anthropogenic activities. These aspects of the two communities were also reflected in the soil, with the beech soil having higher nitrogen levels and a more specialized microbial community compared to the pine soil, with most extracellular enzymes (such as peroxidase and chitinase) showing lower activity in the pine soil.

Effects of afforestation with different species on carbon pools and soil and forest floor properties

Land use and land use change are factors that affect carbon and nutrient stocks in ecosystems. The aim of this research was to determine the effects of forest land use types on carbon pools and soil and forest floor features. This study was conducted in areas afforested with black pine (Pinus nigra Arn. subsp. pallasiana Lamb. Holmboe) and Scots pine (Pinus sylvestris L.) and on adjacent bare land within the Akdağ Nature Park, which is located in the West-Central Anatolia Region of Turkey. Three 20 × 20 m sample plots were selected within each forest land use, and the diameters at breast height and heights of all trees were measured. Tree biomass and carbon stocks in the unit areas were calculated using tree biomass equations, and carbon conversion factors were developed for two tree species. Within each sample plot, disturbed and core soil samples and forest floor samples were taken at three points at depths of 0–10, 10–20 and 20–30 cm. The physical and chemical properties of the soil and forest floor samples were determined in the laboratory and measurements were converted to a unit area using volume values. The data were evaluated using independent sample t-tests and analysis of variance. The results showed that the ecosystem carbon (C) stocks differed significantly with forest land use type; black pine plantations, Scots pine plantations and bare land accumulated 235.2 t C ha−1, 206.1 t C ha−1 and 37.4 t C ha−1, respectively. We found that in addition to the positive effect of afforestation on soil, black pine had a greater impact on some forest floor and soil characteristics in the region than Scots pine. Thus, we suggest that priority should be given to black pine in afforestation of the region and in other ecosystems with similar climates. Additionally, our results reveal the importance of afforestation on bare lands for reducing the impact of global climate change.

Ability of green cover from sainfoin (Onobrychis viciifolia Scop.) and dog rose (Rosa canina L.) to control erosion and improve soil organic carbon and nitrogen stocks in terraces of Northwest Turkey

The main aim of this study was to evaluate the impact of green cover and afforestation on soil properties, erosion susceptibility, as well as soil organic carbon (SOC) and soil total nitrogen (STN) contents and stock capacities. Mineral soil samples from two soil depths (0–10 cm and 10–20 cm) were obtained from a bare soil plot (BSP), a young forest plot (7-year-old juvenile cover; YFP), a mature forest plot (MFP) used as a reference control, a young forest plot with sainfoin green cover (YFP + S), and a young forest plot with dog rose green cover (YFP + R). The soil samples were analyzed for pH, water holding capacity (WHC), soil texture, dispersion ratio, bulk density, SOC, STN, and soil extractable P and K. Soil bulk density, soil volume, and the SOC and STN were used to calculate the mean SOC and STN stocks. Results showed that afforestation and green cover significantly influenced the chemical and physical properties of the soil, reduced its dispersion ratio, and increased its SOC and STN stock capacities (P < 0.05). The mean SOC stock was highest for MFP (39.7 t C ha−1), followed by YFP + R (37.1 t C ha−1), YFP + S (35.7 t C ha−1), YFP (22.1 t C ha−1), and BSP (10.9 t C ha−1). However, the mean STN stock was highest for YFP + S (2.40 t N ha−1), followed by MFP (2.25 t N ha−1), YFP + R (2.08 t N ha−1), YFP (1.88 t N ha−1), and BSP (0.55 t N ha−1). These results indicate that with proper care and management, natural or artificial leguminous and shrub species can provide year-round soil protection and minimize soil erosion in black pine plantation terraces. Growing these species could enhance soil productivity by increasing soil organic matter, improving the soil structure, and increasing the water holding capacity and nutrient retention of the soil.

Changes in carbon stocks of soil and forest floor in black pine plantations in Turkey

The objectives of this study were: (1) to determine carbon stock changes in the soil and forest floor of black pine (Pinus nigra subsp. pallasiana) plantations in Turkey; (2) to determine the effects of thinning on annual carbon accumulation in both; and, (3) to investigate relationships between annual carbon storage in soil and forest floor and stand characteristics of black pine. Samples were taken in 90 plots from stands at the pole (dbh = 11.0–19.9 cm) and sawlog (dbh = 20.0–35.9 cm) stages. Carbon analyses of soil and forest floor samples showed that in unthinned plantations significant organic carbon was sequestered an average of 1.47 Mg ha−1 a−1 in the soil and 0.20 Mg ha−1 a−1 in the forest floor. Organic carbon sequestered annually in the soil was significantly lower in thinned than in unthinned stands, while differences in the forest floor were insignificant. There were positive correlations between carbon sequestered in the soil and stand age, average DBH, mean stand height, basal area, and site index. Carbon sequestered the forest floor increased with basal area. As a result, carbon sequestered in the soil should not be ignored in greenhouse gas inventories because carbon stored belowground was approximately 70% of the aboveground pool.

Determining the nutrient stocks in black pine plantation areas in Turkey

Bu çalışma, karaçam (Pinus nigra subsp. pallasina) ağaçlandırma alanlarındaki besin stoklarını belirlemek amacıyla yapılmıştır. Örneklemeler Eskişehir, Afyonkarahisar, Kastamonu, Çanakkale, Balıkesir ve Kütahya illerinde verim sınıfı, gelişim çağı ve kapalılık bakımından farklılık gösteren toplam 46 alanda yapılmıştır. Araştırmada, ESK-10(6303) numaralı araştırma projesi kapsamında araziden alınan toprak, ölü örtü, diri örtü ve ağaç bileşenlerine ait örnekler kullanılmıştır. Laboratuvarda, araziden alınan toprak ve bitki örneklerinde N, P, K, Ca, Mg, S, Na, Fe, Zn, Mn ve Cu analizleri yapılmıştır. Ekosistemin farklı bileşenlerine ait besin yoğunluklarının ve besin stoklarının meşcere tiplerine göre değişimi varyans analizi ile değerlendirilmiştir. Ağaç bileşenlerine ait besin yoğunlukları, genel olarak meşcere yaşına bağlı olarak azalmıştır. N, P, K, Mg, S, Zn ve Mn yoğunluğu ibrelerde, Na ve Fe yoğunluğu kuru dalda, Ca yoğunluğu ise kuru dal ve kabukta en yüksek düzeyde bulunmuştur. Meşcerede ağaçlardaki besin stokları, gelişim çağının ve kapalılığın artmasına bağlı olarak artmıştır. Makro besin elementleri ağaçlarda en fazla ibre ve kabukta depolanmaktadır. Karaçam ağaçlandırma alanlarında, S ve Fe dışındaki besin stoklarının en önemli kısmını toprak oluşturmaktadır. Kükürt stoğu c meşcerelerinde (d1,3=20,0-35,9 cm) ağaçlarda, Fe stoğu ise b (d1,3=8,0-19,9 cm) ve c meşcerelerinde ölü örtüde en yüksek düzeyde bulunmuştur. Fe stoğunun önemli bileşeni olması sebebiyle ölü örtünün korunmasına önem verilmelidir. Besin kaybını en az düzeye indirmek amacıyla ekonomik değeri olmayan ibre, kuru dal, kabuk ve kökün ormanda bırakılmasına azami özen gösterilmelidir.

The Effect of Non-Native Black Pine (Pinus nigra J. F. Arnold) Plantations on Environmental Conditions and Undergrowth Diversity

The cover of introduced tree species in Europe has recently increased, due to several factors. Attempts to understand the impact of non-native edificator trees on the environmental conditions and diversity of undergrowth have so far been limited to a few studies. In this paper, we analyse the effect of one of the most commonly planted non-native tree species–black pine (Pinus nigra J. F. Arnold) in the Carpathian-Pannonian region, north of the border of its native occurrence. The objectives of our study were to determine the following: (i) How does black pine, as a non-native edificator, change the forest structure and environmental conditions in comparison to those of native communities? (ii) How does black pine change the species composition of undergrowth in comparison to that of native communities? (iii) Which factors are associated with the impact of black pine on diversity? To answer these questions, we used the twin plot method, sampling two neighbouring plots with the same environmental conditions in which one plot of the pair is in a forest with native tree species composition and the second plot is in a planted non-native Pinus nigra plantation. We found that in forests dominated by the non-native black pine, (a) the tree canopy is significantly more open; (b) the cover of the shrub layer is significantly higher; (c) the needles of black pine form a significantly thicker litter layer and (d) the cover of the herb layer is significantly lower than that in the native forest. (e) Black pine plays a vital role in modifying local climate by altering air temperature and humidity; (f) there were no significant differences in the soil pH between black pine plantations and native forests; (g) the plantations of black pine cause changes in diversity at both the species and the community level and (h) the dissimilarity between black pine plantations and neighbouring native forests decreases at higher altitudes.

La selvicoltura delle pinete artificiali di pino nero: analisi delle legislazioni regionali italiane

Abstract: During the last century, afforestation programmes were planned in most of the Italian regions and black pine plantations have represented one of the main public policy effort in mountain areas. The afforestation tecniques has been generally similar throughout Italy, producing nowadays artificial back pine forests showing similar age and structures. Nevertheless, contrasting forestry legislations and decision making both theoretically and technically are adopted at regional scale specifically on black pine forest management. Because of these heterogeneity of laws and regulation, a reference knowledge base can standardise and harmonise the different terms and technical-management aspects often involved in the forestry sector. The aim of this work is to provide a legislative history concerning afforestation at the National level, with a synoptic framework of the current regional forest legislation on the treatment of black pine forests.

Teamwork makes the dream work: Disentangling cross-taxon congruence across soil biota in black pine plantations

Soil plays a fundamental role in many ecological processes, throughout a complex network of above- and below-ground interactions. This has aroused increasing interest in the use of correlates for biodiversity assessment and has demonstrated their reliability with respect to proxies based on environmental data alone. Although co-variation of species richness and composition in forests has been discussed in the literature, only a few studies have explored these elements in forest plantations, which are generally thought to be poor in biodiversity, being aimed at timber production. Based on this premise our aims were 1) to test if cross-taxon congruence across different groups of organisms (bacteria, vascular plants, mushrooms, ectomycorrhizae, mycelium, carabids, microarthropods, nematodes) is consistent in artificial stands; 2) to evaluate the strength of relationships due to the existing environmental gradients as expressed by abiotic and biotic factors (soil, spatial-topographic, dendrometric variables). Correlations between groups were studied with Mantel and partial Mantel tests, while variance partition analysis was applied to assess the relative effect of environmental variables on the robustness of observed relationships. Significant cross-taxon congruence was observed across almost all taxonomic groups pairs. However, only bacteria/mycelium and mushrooms/mycelium correlations remained significant after removing the environmental effect, suggesting that a strong abiotic influence drives species composition. Considering variation partitioning, the results highlighted the importance of bacteria as a potential indicator: bacteria were the taxonomic group with the highest compositional variance explained by the predictors used; furthermore, they proved to be involved in the only cases where the variance attributed solely to the pure effect of biotic or abiotic predictors was significant. Remarkably, the co-dependent effect of all predictors always explained the highest portion of total variation in all dependent taxa, testifying the intricate and dynamic interplay of environmental factors and biotic interactions in explaining cross-taxon congruence in forest plantations.

Exploring visitors' perceptions of silvicultural treatments to increase the destination attractiveness of peri-urban forests: A case study in Tuscany Region (Italy)

Peri-urban forests are characterized by multiple-use and various kinds of recreation activities. Public forest services have to take into account ecological, economic and social issues to provide a sustainable management of peri-urban forests, able to improve their attractiveness. Understanding visitors' demands and perceptions on peri-urban forests is a key element to support decision-makers and ensure proper management of these forests. This study is aimed at investigating visitors' perceptions and preferences regarding the characteristics of the peri-urban forests and the role of silvicultural treatments. The investigation was implemented in the Monte Morello peri-urban forest located near the metropolitan area of Florence (Italy). The forest is a dominant black pine and Calabrian pine plantation, established in the sixties for protection purpose but largely abandoned. Recently, silvicultural treatments have been applied to restore the ecological stability and enhance the resistance and resilience of forest. An innovative selective thinning was applied to compare its effects (economical, ecological and social) with the traditional thinning and with unmanaged areas. Visitors' perceptions and preferences were collected through the administration of a face-to-face interview to 201 respondents. The survey investigated three aspects: recreational use of peri-urban forests; benefits of peri-urban forest vegetation; preferences towards the characteristics of the peri-urban forest. The visitors assessed from the aesthetic point of view three images of the Monte Morello forest after different silvicultural treatments (traditional thinning, selective thinning and unmanaged forest). The results show that the preferred type of peri-urban forest is a mixed forest of coniferous and deciduous with a random arrangement of trees in space. The tourist facilities (i.e. waste baskets, picnicking and sport areas) are perceived in a positive way by visitors. With regard to the forest management alternatives, the results show that the visitors prefer the managed forest through a selective thinning.

A spatial dataset of forest mensuration collected in black pine plantations in central Italy

The dataset provides an exhaustive tree inventory with forest mensuration and spatial location carried out in 54 plots sampled in 45- to 55-year-old black pine plantations, located in two areas of Tuscany (central Italy). Forest mensuration includes horizontal and vertical structure measurements and a total of 4171 trees were geo-referenced. The most abundant species was the black pine, Pinus nigra spp. laricio , for which a total of 3631 trees were observed. The dataset was collected as part of the SelPiBio LIFE project (LIFE13 BIO/IT/000282). Dataset access at . Associated metadata available at . The main aim of the SelPiBio LIFE project ( www.selpibio.eu ) is to demonstrate the effects of two thinning regimes, selective and from below, on soil biodiversity in young black pine stands. The spatial structure of forests and the relationships between trees are a good proxy of overall biodiversity level. Spatial datasets with geo referenced trees and related mensurational data represent the highest level of information for forest inventories and research activities. This dataset has been developed during the A2 Action (Assessment of structural and mensurational parameters of the forest stands and the dead wood) of the project, to record the main mensurational parameters of the studied black pine stands. A tree-level database was compiled to describe the vertical and horizontal structure of 54 monitoring plots before the application of the silvicultural treatment. In addition to classical in-field measurements (e.g. diameters at breast height, total height of the tree, crown depth etc.), all trees were georeferenced by means of polar coordinates collected from the centre of each monitoring plot, including crown projection on the ground, described with eight points. Then, a polynomial spline function was fitted across the recorded data to obtain a convex polygon and to calculate crown area and crown perimeter of each measured tree in GIS environment. A polygonal ESRI shapefile in ETRS89/UTM32N reference system (EPSG: 25832) with 4171 records representing the crown projections on the ground of each measured tree with all the mensurational parameters included into the attribute table. The database is freely available under the Creative Commons Attribution-NonCommercial 4. 182 0 License. With this database, a wide range of forestry-related indices could be easily calculated, including geostatistical analysis and autocorrelation functions, to compare Italian artificial black pine stands with other studied forests.

Assessing the mechanical stability of trees in artificial plantations of Pinus nigra J. F. Arnold using the LWN tool under different site indexes

In young black pine plantations, the most valuable and interesting thinning scheme is mainly based on the positive selection of dominant and well-shaped trees to be candidates for carbon sequestration, timber production and natural regeneration. The mechanical stability of candidate trees is here a fundamental skill that must be taken into account and the slenderness ratio (HD) is one of the main indicators. HD has been recently proved to be correlated to the living whorl number (LWN) by Cantiani & Chiavetta (2015). In this study, the statistical model was re-calibrated in order to study the influence of soil fertility on the HD - Living whorls number (LWN) relationship. The fertility-balanced models estimated a different LWN threshold. The model for the highest fertility class (Site index 24) estimated 12 LWN (RMSE of 20%). Similarly, a lower value were detected for the other two fertility classes, SI20 and SI16, where 10 LWN were considered enough with an associated RMSE of 16% and 17% respectively. Compared to the general model provided by Cantiani & Chiavetta (11 LWN with 18% of RMSE) the site index approach improved the accuracy and reliability.

Estimating the mechanical stability of Pinus nigra Arn. using an alternative approach across several plantations in central Italy

Black pine has been used often in central and southern Italy to reforest mountainous areas depleted by the intensive use of natural resources. The main purpose of establishing pine forests in Italy was to protect the soil from excessive erosion, and also to facilitate the natural succession toward mixed forests with deciduous species. The most common silvicultural treatments in Europe currently aim at maximizing the stability of the stands and facilitating the transition from pure to mixed stands comprising a larger component of native tree species. In this work, we investigated the relationships between the living whorls number and four indexes of individual tree stability: the slenderness ratio, the crown depth, the crown projection, and an eccentricity index of the canopy. The data set used was composed of 1098 trees from ten black pine plantations located in central Italy. Our results demonstrate that the living whorls number can be handily used to predict the slenderness ratio with an error of 18%. A non-parametric model based on a reduced number of field measures was obtained as a support for thinning operations aimed at improving single tree stability.

Height curve as a new aspect of black pine (Pinus nigra) plantations in the Sumadija region

Both ecological aspects i.e. biotic and biotic factors were analyzed and studied in black pine plantations in the Sumadija region. The black pine plantations analyzed within 5 experimental fields are 30, 40 and 55-60 years old, and are found in: good quality habitats medium quality habitats and low quality habitats. The same-aged plantations were studied in different habitats. All dendrometric measurements were performed, including diameter, height and tree volume, along with tree analysis and complete growth calculation. Stand structure, thickness, height, structure by basal area and volume structure are also presented. Height growth proved to be a new significant indicator. Conclusions were drawn, and tending practices for each experimental field and growing recommendations were suggested. .

Comparing growth patterns of jack pine and black spruce in mixed natural stands and plantations

This study examined changes in individual tree height and diameter at breast height and stand-level gross total volume over time, comparing plantation-grown jack pine (Pinus banksiana) and black spruce (Picea mariana) to wildfire-origin, mixed conifer stands. Mensurational data were collected from fixed-area plots in 32 plantations (15 jack pine; 17 black spruce; age 6–64 y) and 21 fire-origin conifer-dominated stands (jack pine/black spruce mixtures; age 4–91 y). Using a generalized three-parameter modified-Weibull function, we described relationships for individual tree and standlevel measures of growth and age for managed and natural origin stands, separately, and then compared the functions to assess growth pattern differences between managed and natural stands. Both the black spruce and jack pine plantations consistently outperformed the natural stands based on all measured individual and stand-level parameters, and significantly lowered the age to operability of the trees. For example, the modeled gross total volume at age 50 resulted in “improved” volumes over the natural stands of 35% and 50% for plantation-grown jack pine and black spruce, respectively. The results from this study suggest that establishing and maintaining desired species at moderate and relatively uniform densities on productive boreal sites can significantly increase yields and shorten the age to operability by nearly 15 y.

Mesures de gestion favorisant les coléoptères du bois dans une réserve forestière

Measures favouring saproxylic beetles in a forest reserve The goal of this study is to propose conservation measures aiming at favouring saproxylic beetle populations, considering the general management of a forest reserve. The study site is a periurban forest above the city of Neuchâtel in the Swiss Jura. The studied habitats are oak and beech forests alternating with dry meadow patches and black pine (Pinus nigra) plantations. The general management goal of this forest reserve is to conserve rare plant associations and to preserve characteristical fauna and flora. In order to achieve these goals, the following management actions were undertaken: preserve open habitats, reduce black pine occurrence, restore and enhance oak forest and preserve islands of old growth. An inventory of four beetle families (Cerambycidae, Buprestidae, Lucanidae and Cetoniidae) was made by means of direct collection. Between 2004 and 2009, twenty-five collecting tours lasting for an average of 1 hour 45 minutes were performed from the beginning of May to the beginning of July. Fifty-two beetle species were caught and grouped in six categories based on their larval ecology. For each of them, enhancing actions were proposed, potential conflicts between saproxylic beetle conservation and general management actions were discussed. In order to find a balance between sometimes contradictory actions, the best solution to promote an optimal biodiversity is a patchwork of forest and open biotopes. As far as saproxylic beetles are concerned, tree diversity should be enhanced and old trees preserved. In the open areas, old bushes growing in the edges should not be removed.