Silvicultural Applications Research Articles

Genome-wide analysis of R2R3-MYB transcription factors in poplar and functional validation of PagMYB147 in defense against Melampsora magnusiana

Main conclusionTranscription of PagMYB147 was induced in poplar infected by Melampsora magnusiana, and a decline in its expression levels increases the host's susceptibility, whereas its overexpression promotes resistance to rust disease.Poplars are valuable tree species with diverse industrial and silvicultural applications. The R2R3-MYB subfamily of transcription factors plays a crucial role in response to biotic stresses. However, the functional studies on poplar R2R3-MYB genes in resistance to leaf rust disease are still insufficient. We identified 191 putative R2R3-MYB genes in the Populus trichocarpa genome. A phylogenetic analysis grouped poplar R2R3-MYBs and Arabidopsis R2R3-MYBs into 33 subgroups. We detected 12 tandem duplication events and 148 segmental duplication events, with the latter likely being the main contributor to the expansion of poplar R2R3-MYB genes. The promoter regions of these genes contained numerous cis-acting regulatory elements associated with response to stress and phytohormones. Analyses of RNA-Seq data identified a multiple R2R3-MYB genes response to Melampsora magnusiana (Mmag). Among them, PagMYB147 was significantly up-regulated under Mmag inoculation, salicylic acid (SA) and methyl jasmonate (MeJA) treatment, and its encoded product was primarily localized to the cell nucleus. Silencing of PagMYB147 exacerbated the severity of Mmag infection, likely because of decreased reactive oxygen species (ROS) production and phenylalanine ammonia-lyase (PAL) enzyme activity, and up-regulation of genes related to ROS scavenging and down-regulation of genes related to PAL, SA and JA signaling pathway. In contrast, plants overexpressing PagMYB147 showed the opposite ROS accumulation, PAL enzyme activity, SA and JA-related gene expressions, and improved Mmag resistance. Our findings suggest that PagMYB147 acts as a positive regulatory factor, affecting resistance in poplar to Mmag by its involvement in the regulation of ROS homeostasis, SA and JA signaling pathway.

In vitro cloning of Bambusa vulgaris Schrad. ex J. C. Wendl.: Effect of culture systems, sucrose and activated charcoal supplementation

Fast-growing forest species with multiple uses, like bamboo, have aroused interest for their silvicultural applications. Bamboo species are a valuable source of renewable raw material, and Bambusa vulgaris is an economically important species. However, there are limitations to large-scale cloning of adult-selected genotypes. This study aimed to evaluate the in vitro cloning of Bambusa vulgaris in different culture systems, sucrose and activated charcoal supplementation by the inter-simple-sequence repeat (ISSR) molecular markers. In vitro bud multiplication and shoot elongation were evaluated in three cultivation systems: semi-solid and liquid culture media, and temporary immersion bioreactor (TIB). The sucrose concentrations, 0 and 30 g L−1 were evaluated in the stages. Both the culture media were supplemented with 2.0 mg L−1 benzylaminopurine (BAP) and 0.5 mg L−1 α-naphthalene acetic acid (NAA). The absence and presence of activated charcoal (100 mg L−1) were evaluated in the in vitro rooting. MS culture medium was supplemented with 2 mg L−1 indole-3-butyric acid (IBA), 1.0 mg L−1 NAA, and 0.5 mg L−1 BAP. Semi-solid culture medium supplemented with 30 g L−1 of sucrose presented superior emission of bud per explant. Liquid culture medium supplemented with 30 g L−1 of sucrose presented the most elongated shoots. Activated charcoal in the culture medium did not influence the adventitious rooting. Micropropagated plants showed genetic fidelity and were clones of the adult selected plant.

Beyond the axe: Interdisciplinary approaches towards an urban silviculture

Forests in cities, from remnant woodlands to designed natural areas, are common and abundant. Ecologically similar to rural forests, these landscapes lend themselves to the principles of traditional forest management, such as silviculture. But the application of silviculture to forests in cities, at least in the United States, has long been met with resistance: as far back as Olmsted’s Central Park experiments with ‘planting thick and thinning quick’, public sentiment has been protective of trees, even when forest health would have benefitted from such treatments. Urban silviculture is a conceptual framework and a renewed call for a systematic approach to managing forests in cities that addresses cities’ socioecological context through adapted practices that integrate other disciplines, including design. Using emerging science and case studies, we explore how silviculture and landscape architecture, two allied yet often-alienated disciplines, can engage to create socially responsive evidence-based approaches that enhance the design, management and resilience of forested landscapes in cities.

The Influence of Slash Management Practices on Water and Nutrient Dynamics in Longleaf Pine Forests

(1) Silvicultural applications that manipulate woody debris loading and the structural composition of a forest can have both short and long-term effects on biogeochemical cycling. Longleaf pine forests have been the historically dominant community types throughout much of the Southeastern United States. Fire exclusion, hardwood encroachment, and resource exploitation have severely reduced the amount of remaining longleaf pine habitats, making ecological restoration necessary. The silvicultural treatments used to reestablish these communities have been widespread, leading to some skepticism regarding the sustainability of certain restoration practices. (2) This study aimed to understand how overstory manipulation and woody debris management affected soil water retention rates and nutrient availability. Using a randomized complete block design, abiotic responses to biomass harvesting, conventional harvesting, and mastication treatments were measured across a soil moisture gradient in the South Carolina sandhills. (3) Our findings indicate that mastication increased soil moisture retention rates by 37% and 41%, on average, compared to conventional harvesting and biomass harvesting, respectively. (4) Additionally, soil nutrient stocks did not decline following any management practice, indicating that both biomass harvesting and mastication treatments may not necessarily impact site productivity in a negative manner. These findings imply that mastication treatments keep moisture retention high and do not immediately change soil nutrient availability in longleaf pine forests. Long-term vegetation response studies should continue to document successional trends in conjunction with moisture retention rates and long-term nutrient pulsing.

Tree species composition and management influence short-term resilience to defoliation by Lymantria dispar L. in oak forests

The frequency and intensity of natural disturbances such as infestations by forest insect pests are expected to increase under a scenario of climate change. Thus, tools for monitoring the impact of these disturbance events at large spatial scales are required, together with appropriate management practices for enhancing the ability of forest ecosystems to overcome affectations by insect pests. Here, we used the Enhanced Vegetation Index (EVI) combined with ‘ground truth’ measurements to assess the effects of tree species diversity and forest management on the resistance, recovery and short-term (two years) resilience in mixed oak forests after a severe Lymantria dispar L. defoliation episode. Our results showed that, although neither diversity nor management influenced forest resistance to defoliation, both factors interacted and influenced EVI recovery after the disturbance event. This interaction revealed the complex role tree diversity plays in increasing (in managed forests) or decreasing (in unmanaged forests) resilience to defoliation, thereby suggesting that tree species composition may be more relevant than tree species diversity per se. Indeed, in the field we observed a variety of species-specific degrees of defoliation (e.g. higher in Quercus ilex L.), as well as the preference of L. dispar adults for ovipositing in unmanaged areas and on particular trees (Arbutus unedo L.) that were barely defoliated. In addition, we also found significant and positive effects of tree size (dbh) on avoiding defoliation damage. We thus make three management recommendations for increasing the resilience of oak forests to L. dispar defoliation: i) the application of continuous-cover silviculture (30% thinning intensity in basal areas), ii) the retention of larger trees, and iii) the maintenance of a preferential combination of tree species in mixed stands (e.g. Q. suber and Q. pubescens).

Detection and accumulation of environmentally-relevant glyphosate concentrations delivered via pulse- or continuous-delivery on passive samplers

Glyphosate is the most commonly used herbicide globally, which has contributed to its ubiquitous presence in the environment. Glyphosate application rates and delivery to surface water vary with land use. Streams in urban and agricultural catchments can experience continuous delivery of low concentrations of glyphosate and aminomethylphosphonic acid (AMPA), while their presence in forest streams occurs as an episodic pulse following silvicultural application. We assessed whether trace concentrations of glyphosate delivered as a 1-day pulse (mimic silvicultural applications) followed by flushing with deionized water would affect the detection of glyphosate or AMPA on novel passive samplers, Polar Organic Chemical Integrative Sampler with Molecular Imprinted Polymer (POCIS-MIP), compared with continuous delivery (mimic agricultural or urban applications). Within each delivery type, POCIS-MIP were exposed to seven treatment concentrations of Rodeo (equivalent to 0.0 to 1.84 μg glyphosate L−1). Experimental results demonstrate POCIS-MIP can detect differences in relative glyphosate concentrations above 0.115 μg L−1 (pulse-delivery) or 0.23 μg L−1 (continuous-delivery), but were unable to distinguish trace concentrations (i.e., < 0.115 or 0.23 μg L−1). Our results suggest POCIS-MIP may better retain glyphosate when delivered as a pulse than when delivered continuously, but both underestimated actual treatment concentrations by 46 to 56%. There is a need to demonstrate the field applicability of passive sampling methods to improve environmental monitoring of silvicultural herbicides, and our results demonstrate passive samplers were unable to distinguish lower concentrations, suggesting a limited utility for determining trace concentration levels such as those experienced during or immediately after silvicultural application.

Measuring tree growth using terrestrial laser scanning

Forests are dynamic ecosystems that are constantly changing. The most common natural reasons for change in forests are the growth and death of trees, as well as the damage occurring to them. Tree growth appears as an increment of its structural dimensions, such as stem diameter, height, and crown volume, which all affect the structure of a tree. Repeated measurements of tree characteristics enable observations of the respective increments indicating tree growth. According to current knowledge, the tree growth process follows the priority theory, where trees aim to achieve sufficient lightning conditions for the tree crown through primary growth, whereas increment in diameter results from the secondary growth. Tree growth is known to have an effect on the carbon sequestration potential of trees as well as on the quality of timber. To improve the understanding of the underlying cause–effect relations driving tree growth, methods to quantify structural changes in trees and forests are needed. The use of terrestrial laser scanning (TLS) has emerged during the recent decade as an effective tool to determine attributes of individual trees. However, the capacity of TLS point cloud-based methods to measure tree growth remains unexplored. This thesis aimed at developing new methods to measure tree growth in boreal forest conditions by utilizing two-date TLS point clouds. The point clouds were also used to investigate how trees allocate their growth and how the stem form of trees develops, to deepen the understanding of tree growth processes under different conditions and over the life cycle of a tree. The capability of the developed methods was examined during a five- to nine-year monitoring period with two separate datasets consisting of 1315 trees in total. Study I demonstrated the feasibility of TLS point clouds for measuring tree growth in boreal forests. In studies II and III, an automated point cloud-based method was further developed and tested for measuring tree growth. The used method could detect trees from two-date point clouds, with the detected trees representing 84.5% of total basal area. In general, statistically significant changes in the examined attributes, such as diameter at breast height, tree height, stem volume, and logwood volume, were detected during the monitoring periods. Tree growth and stem volume allocation seemed to be more similar for trees growing in similar structural conditions. The findings obtained in this thesis demonstrate the capabilities of repeatedly acquired TLS point clouds to be used for measuring the growth of trees and for characterizing the structural changes in forests. This thesis showed that TLS point cloud-based methods can be used for enhancing the knowledge of how trees allocate their growth, and thus help discover the underlying reasons for processes driving changes in forests, which could generate benefits for ecological or silvicultural applications where information on tree growth and forest structural changes is needed.

Regional Assessment of Carbon Pool Response to Intensive Silvicultural Practices in Loblolly Pine Plantations

Tree plantations represent an important component of the global carbon (C) cycle and are expected to increase in prevalence during the 21st century. We examined how silvicultural approaches that optimize economic returns in loblolly pine (Pinus taeda L.) plantations affected the accumulation of C in pools of vegetation, detritus, and mineral soil up to 100 cm across the loblolly pine’s natural range in the southeastern United States. Comparisons of silvicultural treatments included competing vegetation or ‘weed’ control, fertilization, thinning, and varying intensities of silvicultural treatment for 106 experimental plantations and 322 plots. The average age of the sampled plantations was 17 years, and the C stored in vegetation (pine and understory) averaged 82.1 ± 3.0 (±std. error) Mg C ha−1, and 14.3 ± 0.6 Mg C ha−1 in detrital pools (soil organic layers, coarse-woody debris, and soil detritus). Mineral soil C (0–100 cm) averaged 79.8 ± 4.6 Mg C ha−1 across sites. For management effects, thinning reduced vegetation by 35.5 ± 1.2 Mg C ha−1 for all treatment combinations. Weed control and fertilization increased vegetation between 2.3 and 5.7 Mg C ha−1 across treatment combinations, with high intensity silvicultural applications producing greater vegetation C than low intensity (increase of 21.4 ± 1.7 Mg C ha−1). Detrital C pools were negatively affected by thinning where either fertilization or weed control were also applied, and were increased with management intensity. Mineral soil C did not respond to any silvicultural treatments. From these data, we constructed regression models that summarized the C accumulation in detritus and detritus + vegetation in response to independent variables commonly monitored by plantation managers (site index (SI), trees per hectare (TPH) and plantation age (AGE)). The C stored in detritus and vegetation increased on average with AGE and both models included SI and TPH. The detritus model explained less variance (adj. R2 = 0.29) than the detritus + vegetation model (adj. R2 = 0.87). A general recommendation for managers looking to maximize C storage would be to maintain a high TPH and increase SI, with SI manipulation having a greater relative effect. From the model, we predict that a plantation managed to achieve the average upper third SI (26.8) within our observations, and planted at 1500 TPH, could accumulate ~85 Mg C ha−1 by 12 years of age in detritus and vegetation, an amount greater than the region’s average mineral soil C pool. Notably, SI can be increased using both genetic and silviculture technologies.

Climate Adaptive Silviculture for the City: Practitioners and Researchers Co-create a Framework for Studying Urban Oak-Dominated Mixed Hardwood Forests

Urban forested natural areas are an important component of the forest and tree canopy in northeastern United States urban areas. Although similar to native forests in surrounding regions in structure, composition, and function, these natural areas are threatened by multiple, co-occurring biological and climate stressors that are exacerbated by the urban environment. Furthermore, forests in cities often lack application of formal silvicultural approaches reliant upon evidence-based applied ecological sciences. These include both urban- and climate-adapted silvicultural techniques to increase the resilience and sustainability of native forests in cities. With this in mind, we convened a group of urban forest practitioners and researchers from along a latitudinal gradient in the northeastern United States to participate in a workshop focused on co-developing long-term, replicated ecological studies that will underlie the basis for potential silvicultural applications to urban forests. In this article we review the process and outcomes of the workshop, including an assessment of forest vulnerability, and adaptive capacity across the region, as well as shared management goals and objectives. We discuss the social and ecological challenges of managing urban oak-dominated mixed hardwood forests relative to non-urban forests and identify potential examples of urban- and climate-adapted silviculture strategies created by practitioners and researchers. In doing so, we highlight the challenges and need for basic and long-term applied ecological research relevant to silvicultural applications in cities.

A Review on Bamboo Resource in the African Region: A Call for Special Focus and Action

The African region has untapped bamboo resource potential with immense socioeconomic, cultural, and ecological significances. Despite the long history of bamboo in the region, its contribution is at the infant stage. Therefore, the present study aimed at reviewing the existing literature supported by research experience on bamboo resource in the region. The review process mainly focused on four main specific objectives. These include (1) review extensively African countries that owned the resource and identify the species in each country, (2) identify and document species, generic, and taxonomic tribes of each bamboo species, (3) assess and report bamboo area coverage from available nations, and (4) highlight the existing experiences of special opportunities, challenges, and successful achievements on bamboo resource in representative African countries. The review process found out that a total of 4.56 million ha total bamboo area and 115 bamboo species are reported from 48 African countries. Hence, the African region shares 12.3% of the global bamboo resource and contributed 7.3% of the total bamboo species. Of this, 89.6% of the region is endowed with indigenous bamboo species. Among indigenous species, O. abyssinica is the most widely distributed in 38 African countries. Madagascar ranked first with 37 indigenous species, while Ethiopia led by 25 introduced bamboo species. Nowadays, Ethiopia has 1.44 million ha total indigenous bamboo area coverage, which accounted for 31.6% of the African region and 3.89% of the world total. Therefore, more detail and comprehensive research on species taxonomy, resource base inventory, silvicultural applications, and socioeconomic study is recommended.

Effects of standing culm density and fertilizer regimes on Dendrocalamus brandisii (Munro) Kurz shoot production at Simao District, southwestern China

Optimum shoot production in Dendrocalamus brandisii (Munro) Kurz depends on either standing culm density (SCD) or application of fertilizer. However, silvicultural application through the combined effect of SCD and fertilizer regimes is not fully understood. In this study, effects of SCD and fertilizer regimes, relationships between silvicultural treatments and growth parameters and model prediction on shoot production were conducted. A split-plot factorial design was applied in three blocks consisting of two main factors (SCD and fertilizer regimes). These were three SCD levels (2-1, 2-2 and control) and six fertilizer regimes (15 kg clump−1 compost; 0.25 kg clump−1 NPK mixed with 7.5 kg clump−1 compost; 0.5 kg clump−1 NPK; 0.75 kg clump−1 NPK; 1 kg clump−1 NPK; and control). Data collection on culms height, Diameter at breast height (DBH), soil properties and total number of shoots and shoot yield) was conducted from early July to mid-October. A total of 3,380 edible shoots ha−1 and 7.1 ton ha−1 shoot yield were harvested. Higher available nutrients (P and K) and total soil organic carbon (SOC) were associated by favorable soil pH, higher cation exchange capacity (CEC) and lower exchangeable acidity (EA) after fertilizer application. The largest shoot yield (12.04 ton ha−1) was recorded in 2-2 SCD responded to 0.75 kg clump−1 NPK. Shoot production further improved from 0.5 kg clump−1 NPK to 0.75 kg clump−1 and eventually declined to 1 kg. Linear mixed-effects model (LMM) showed that shoot yield had a positive and significant correlation (p<0.05) among D. brandisii silvicultural treatments and culm DBH classes. Our finding indicates that silvicultural application (SCD and fertilizer regimes) in relation to culm DBH classes could be a key factor for higher D. brandisii shoot production.

GIS-based determination of forest area changes: Case study in Çamsu Forest Sub-district

Bu çalışmada Coğrafi Bilgi Sistemi yardımıyla orman alanlarındaki değişimlerin belirlenmesi amaçlanmıştır. Denizli Orman Bölge Müdürlüğü, Uşak Orman İşletme Müdürlüğü’ne bağlı Çamsu Orman İşletme Şefliği olarak belirlenen çalışma alanındaki ormanlarda 1990-2019 yılları arasında meydana gelen değişimler  incelenmiştir. Çalışmada 1990 ve 2013 yıllarında yapılan orman amenajman planları ve meşcere haritalarından yararlanılmıştır. Basılı olarak elde edilen 1990 yılı meşcere haritaları sayısallaştırılmış ve raster-vektör dönüşümü işlemi uygulanmıştır. Coğrafi veri tabanında arazi örtüsü tipi öz nitelikleri düzenlendikten sonra 1990 ve 2013 yılı meşcere haritaları Coğrafi Bilgi Sistemi yazılımında bindirme analizi ile karşılaştırılmış ve değişim katmanı elde edilmiştir. Bu katmana ait coğrafi veri tabanı yardımıyla değişim matrisleri üretilmiş ve değişimler hesaplanmıştır. Ayrıca 2014-2019 yıllarında yapılan silvikültürel uygulamalar da coğrafi veri tabanına girilerek haritalanmıştır. Çalışmadan elde edilen sonuçlara göre, genel alanın %34’ünde çeşitli yön ve büyüklükte değişimler tespit edilmiştir. 2013 yılında orman alanlarının 484 hektar arttığı, kapalılığı %10’un altındaki meşcerelerin yaklaşık yarısının normal kapalılıktaki meşcerelere dönüştüğü ve tarım alanlarının yaklaşık %5 oranında azaldığı belirlenmiştir. 2014-2019 yılları arasındaki silvikültür uygulamalarda toplam 340 hektar karaçam meşceresinde tohumlama, ışık ve boşaltma kesimlerinin yapıldığı ortaya konulmuştur. Bu çalışmadan edinilen veriler, Coğrafi Bilgi Sisteminin orman alanlarındaki zamansal değişimlerin belirlenmesinde kullanılabilecek güçlü bir araç olduğunu göstermektedir. Ormancılık çalışmalarında uygulamacılara önemli bir karar desteği sağlayabilecek bu sistemler, coğrafi veri tabanına günübirlik aktarılan ormancılık aktivitelerine ait veriler ve insansız hava araçlarından alınan fotoğraflar, hava fotoğrafları ve uydu görüntüleri gibi uzaktan algılama verileri ile desteklenerek verimli bir orman bilgi sistemi haline dönüşebilecektir.

Silviculture and tree breeding for planted forests

One of the main issues facing the forestry sector is balancing the demand for forest products and the sustainable management of forest ecosystems. Efficient plantation management and intensive silviculture practices are needed to grow timber in forest tree plantations. Due to the tangible impact on wood production, the plantations area in the world has constantly increased during the last several decades. The annual increase of plantation was 3.3 million ha in the period of 1990-2015. Over the past decades, tree improvement programs have progressed to the second, third, and fourth cycles to provide genetically improved planting stock to plantations. Substantial genetic gain has been realized from major tree improvement programs around the world. The effect of tree breeding on wood and fiber production per unit area has further increased by the modern plantation silvicultural applications, such as soil preparation, fertilization and thinning. Combination of tree breeding and silvicultural applications shortened the rotation ages of plantations, increasing the wood and fiber output per unit time. In this study, the importance of silvicultural treatments and plantation management has been reviewed and how such practices could enhance sustainable management of natural forests.

Survival, Height Growth, and Phytoextraction Potential of Hybrid Poplar and Russian Olive (Elaeagnus Angustifolia L.) Established on Soils Varying in Salinity in North Dakota, USA

Salt-affected soils in the Northern Great Plains, USA, can impact the long-term survival and growth of trees recommended for agroforestry systems, with Russian olive (Elaeagnus angustifolia L.) being one of few options that survives on these sites. Similarly, hybrid poplars have been used for phytotechnologies on high-salinity soils throughout the world. The objective of this study was to test the survival, height growth, and phytoextraction potential of eight hybrid poplar clones (Populus deltoides Bartr. ex Marsh. × P. nigra L. ‘Robusta’, ‘DN17’, ‘DN182’, ‘DN5’; P. deltoides × P. maximowiczii A. Henry ‘NC14104’, ‘NC14106’; P. nigra × P. maximowiczii ‘NM2’, ‘NM6’) versus Russian olive grown on soils categorized according to initial salinity levels: low (0.1 to 3.9 dS m−1), medium (4.0 to 5.9 dS m−1), and high (6.0 to 10.0 dS m−1). Seven trees per genotype were grown in each salinity treatment at a spacing of 3 × 3 m for four years in Burleigh County, North Dakota. Survival and height were determined following the first four growing seasons, and leaf phytoextraction potential of Al, Ca, Cd, Fe, K, Mg, Mn, Na, and Zn was measured for one-year-old trees. Soil salinity decreased over time, reflecting the phytoextraction potential of the trees. Russian olive did not survive as well as expected, having lower overall survival than three of the hybrid poplar clones (‘DN17’, ‘DN5’, ‘NM6’). At the end of three years when trees were removed per a landowner maintenance agreement, 86%, 71%, and 43% of the Russian olive trees were alive in the low-, medium-, and high-salinity soils, respectively. At this time, ‘NM2’ was the only hybrid poplar clone with similar survival to Russian olive in the high-salinity soils. Russian olive had greater Na, Cd, and Fe leaf concentrations than the hybrid poplar clones, but it also had the worst uptake of Ca and Mg of all genotypes. For hybrid poplar, the P. deltoides × P. nigra genomic group had the broadest clonal variability among all traits, with ‘Robusta’ and ‘DN182’ exhibiting great potential for establishment on high-salinity soils. ‘Robusta’ and ‘DN17’ are the same genotype but they came from different nursery sources (i.e., hence their different nomenclature), and they did not differ for height nor leaf phytoextraction. Populus deltoides × P. maximowiczii clones were not suitable for the soil conditions and silvicultural applications (e.g., tree shelters) of the current study, while P. nigra × P. maximowiczii clones exhibited the most stable performance across all years and salinity treatments. Both ‘NM2’ and ‘NM6’ had superior fourth-year survival and height, as well as average or above average phytoextraction of all elements tested.

Herbicides Registered for Pine Management in Florida – 2005 Update

This publication presents a list of herbicides registered for forestry use in Florida (Table 1) and provides information on their basic weed control characteristics and silvicultural applications (Table 2). All herbicide active ingredients important in pine management in Florida are included. Others, that are registered in Florida, but are rather marginally used for pine plantations, like 2,4-D, atrazine, dicamba, paraquat, and simazine, are also listed. Since an increasing number of private and public owners manage their forestlands for non-commodity purposes, herbicides that are intended mostly for turf and/or landscape maintenance, but also labeled for forestry, have been included as well. This document is CIR1475, one of a series of the School of Forest Resources and Conservation, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published in April 2005.

Türkiye’nin kuzeydoğusundaki yüksek dağ ormanlarında meşcere kuruluşları: Kavron Vadisi örneği

Aim of the study: In this study, cohort structures of the high mountain forests in northeast Turkey were investigated.Material and Methods: Eighteen plots were selected in six sampling units. Treeline, timberline and sub-timberline stands were sampled in each unit. Main results: Structures varied from single-cohort to multi-cohort stands in the research area. The incidence of multiple cohort structures increased towards the timberline and treeline from the sub-timberline. Tree ages ranged from 10 to 150 years in the treeline, 15 to 270 years in the timberline and 13 to 105 years in the sub-timberline. 8 sampled stands were pure and 10 stands were mixed stands. Mixed stands were composed by Sorbus aucuparia, Populus tremula, Fagus orientalis, Picea orientalis and Abies nordmanniana in the treeline. Picea orientalis, Fagus orientalis and Abies nordmanniana were tree species in mixed stands in the timberline and sub-timberline. However, Picea orientalis was dominant in all zones. Numbers of trees in the tree collectives ranged from 2 to 17 in the treeline, 3 to 9 in the timberline and 2 to 3 in the sub-timberline stands. Mean areas per tree in the collectives were 1.77 m2 in the treeline, 2.56 m2 in the timberline and 2.51 m2 in the sub-timberline. Numbers of tree collectives ranged from 6 to 7 in the treeline, 2 to 5 in the timberline and 2 to 3 in the sub-timberline stands. Research highlights: Multi-cohort structures and tree collectives are key factors in silvicultural applications in high mountain forests. Silvicultural treatment such as single-tree selection method, patch and group selection method can be provided because of being suitable for multi-cohort structure.

Potential risks to freshwater aquatic organisms following a silvicultural application of herbicides in Oregon's Coast Range.

Glyphosate, aminomethylphosphonic acid (AMPA), imazapyr, sulfometuron methyl (SMM), and metsulfuron methyl (MSM) were measured in streamwater collected during and after a routine application of herbicides to a forestry site in Oregon's Coast Range. Samples were collected at 3 stations: HIGH at the fish-no-fish interface in the middle of the harvest and spray unit, MID at the bottom of the unit, and LOW downstream of the unit. All herbicides were applied by helicopter in a single tank mix. AMPA, imazapyr, SMM, and MSM were not detected (ND) in any sample at 15, 600, 500, and 1000 ng/L, respectively. A pulse of glyphosate peaking at approximately equal to 62 ng/L manifested at HIGH during the application. Glyphosate pulses peaking at 115 ng/L (MID) and 42 ng/L (HIGH) were found during the first 2 postapplication storm events 8 and 10 days after treatment (DAT), respectively: glyphosate was less than 20 ng/L (ND) at all stations during all subsequent storm events. All glyphosate pulses were short-lived (4-12 h). Glyphosate in baseflow was approximately equal to 25 ng/L at all stations 3 DAT and was still approximately equal to 25 ng/L at HIGH, but ND at the other stations, 8 DAT: subsequently, glyphosate was ND in baseflow at all stations. Aquatic organisms were subjected to multiple short-duration, low-concentration glyphosate pulses corresponding to a cumulative time-weighted average (TWA) exposure of 6634 ng/L × h. Comparisons to TWA exposures associated with a range of toxicological endpoints for sensitive aquatic organisms suggests a margin of safety exceeding 100 at the experimental site, with the only potential exception resulting from the ability of fish to detect glyphosate via olfaction. For imazapyr, SMM, and MSM the NDs were at concentrations low enough to rule out effects on all organisms other than aquatic plants, and the low concentration and (assumed) pulsed nature of any exposure should mitigate this potential. Integr Environ Assess Manag 2017;13:396-409. © 2016 SETAC.

Evaluation of predictive models for Douglas-fir bark thickness at breast height following 12 biomass harvest treatments

Foresters often require an estimation of bark thickness from a reference height (typically breast height) to accurately estimate the bark or wood volume of a tree. Various models for estimating the bark thickness of interior Douglas-fir (Pseudotsuga menziesii var. glauca) from measured dbh (diameter at breast height) were evaluated. Sample trees were from northern Rocky Mountain mixed conifer stands that had been subjected to four levels of experimental woody biomass harvesting. Among simple linear, nonlinear, and segmented linear mixed effects models, the segmented linear model performed best. A join point (where the linear equations are linked) for the segmentation was statistically detected at approximately 19.0 cm dbh. The join point seems to indicate the size at which juvenile Douglas-fir trees boost the production of bark tissue, perhaps as those trees express dominance over competing understory vegetation. Woody biomass utilization level had no impact on bark thickness, indicating that the bark:dbh relationship does not depend on biomass utilization intensity. The study results enable accurate bark thickness estimation for interior Douglas-fir in this region, and suggest several silvicultural applications for juvenile Douglas-fir stand management.

Depression and growth recovery of silver fir in uneven-aged Dinaric forests in Croatia from 1901 to 2001

The causes of the decline of silver fir across Europe in the 1960s and 1970s and its subsequent recovery remain open to debate. We studied the radial growth of silver fir and possible influential factors on growth decline in uneven-aged silver fir-Norway spruce- European beech forests in the Dinaric Mountains of Croatia (180 000 ha) since 1900 using dendrochronological methods. Data on the radial growth of large firs (diameter at breast height >50 cm) sampled in 2002 across the region (151 plots, 491 m(2) each), regional climatic data (temperature, precipitation and drought) and SO2 emissions were used in both statistical and dynamic factor analyses. Two main growth patterns of fir trees were identified: the first features a sharp decline in radial growth in the period 1966-1983, followed by a dramatic recovery, while the second is characterized by a relatively constant increase in radial growth. The most influential climatic factors were mean monthly temperatures in February, July and August ; mean precipitation in May and September ; and summer drought. However, SO2 emissions explained a larger part of the total variability of radial growth than climatic factors (46-60 per cent and 0-42 per cent, respectively). The growth recovery of silver fir supports further application of uneven-aged silviculture in the region.

The simulated effects of timber harvest on suitable habitat for Indiana and northern long‐eared bats

Bat conservation in the eastern United States following the onset of white‐nose syndrome necessitates the conservation and production of important summer habitat required by bats for both diurnal roosting and nocturnal foraging and commuting. Forest management via silvicultural applications can purposely direct forest succession so important habitat features are retained and developed. The effects of timber harvest on habitat at large spatiotemporal scales for a species are not always readily apparent but can be investigated with spatially explicit forest dynamic modeling. Here we used a forest succession model (LANDIS‐II) to simulate future forest conditions under different harvest regimes. We simulated nine harvest scenarios on Indiana State Forests that ranged from a complete cessation of timber harvest to intensive timber extraction. We then applied previously created models of nocturnal and diurnal habitat occupancy for both Indiana and northern long‐eared bats. We found that suitable nocturnal habitat was maximized for Indiana bats but minimized for northern long‐eared bats under low intensity timber harvest scenarios. Among moderate intensity timber harvest scenarios, both species exhibited the greatest amount of suitable nocturnal habitat when timber harvest applications focused on regenerative openings. The quantity of suitable diurnal habitat trended in the opposite direction of nocturnal habitat with selection harvests favoring suitable roosting habitat. Finally, both species displayed a trend in which overall suitable habitat was primarily driven by the degree of suitable diurnal habitat rather than nocturnal habitat. These results highlight the complex nature of managing multiple habitat needs for more than one species. Furthermore, our research illustrates the importance of understanding the distinct habitat requirements associated with different life history needs that can occur within a single species. Despite such complexities, our results can help guide forest management to preserve and encourage suitable habitat for multiple imperiled bat species.