Picea Pungens Research Articles

Developing Integrated Strategies to Address Emerging Weed Management Challenges in Christmas Tree Production

Weed control is an important aspect during the first few years of Christmas tree establishment, as weed competition directly relates to the rate of Christmas tree growth during this time. The objectives of this study were to evaluate the weed control efficacy of organic mulch and herbicide combinations and to determine their phytotoxic effects on four different species of Christmas trees during the establishment stage: Fraser fir (Abies fraseri (Pursh) Poir), blue spruce (Picea pungens Engelm.), white pine (Pinus strobus L.), and Scotch pine (Pinus sylvestris L.). Twelve weed control treatments were established in a complete randomized block design with four replications in each of five fields. Weed control treatments included cypress bark organic mulch and herbicides applied alone and in combinations as well as an untreated control. Herbicides included clopyralid, oxyfluorfen, and glyphosate. All herbicides were applied at their highest labeled rate. Data collection included visual estimations of weed control and phytotoxicity to trees at 30, 60, and 90 days after treatment (DAT). Tree growth and foliar nitrogen concentration were also measured. Mulch combined with herbicide provided 60%–100% weed control in all cases; at two farms, mulch provided a significant increase in weed control when compared to the same treatments without mulch. Combinations of mulch + clopyralid + glyphosate and clopyralid + oxyfluorfen + glyphosate resulted in the highest phytotoxicity ratings. Tree growth was decreased due to some treatments at Gobles farm, and foliar N did not differ among any of the treatments.

Variation in metal concentration across tree organs and stands: implications for reference specimen development

Air pollution is a major environmental and public health issue in urban areas. Biomonitoring using trees has been widely used to determine atmospheric pollution due to its advantages of low cost, high spatial distribution, and accumulation of a wide range of air contaminants. However, challenges exist in applying the data obtained from biomonitoring trees, including differences in pollutant concentrations in samples of the same species from different locations, and the influence of biological and environmental parameters on metal accumulation. This study aims to inform the design of biomonitoring sampling for urban air quality studies and increase their applications to exposure assessment. Specifically, the study evaluates the variation in metal concentration in tree organs of two regionally relevant tree species (Picea pungens and Populus Alba), explores the implications of different aspects of field sampling, such as variation within tree stands, tree age, and develops a reference specimen to establish threshold values for differentiating between background levels and increased exposure. The results provide insight into the complexity of using biomonitoring trees for exposure assessment and the importance of considering multiple factors in study design.

Влияние препарата «Биостим» на рост и развитие семян и сеянцев древесных видов в засушливой зоне

The aim of the study was to study the effect of the biostimulator of growth «Biostim» on the germination and development of seeds and seedlings of woody species in order to develop a resource-saving technology of cultivation for nursery breeding in the Volgograd region. The objects of research were the woody species Quercusrobur L., Robiniapseudoacacia L., PopulusbolleanaLouche., Populusnigra var. italica Münchh., Catalpa bignonioides, Pinusnigra subsp. pallasiana (Lamb.), Platycladusorientalis (L.) Franco., Piceapungens Engelm. ofdifferentgeographicalorigin. As a result of the conducted studies, the best result was shown by poplars and catalpa with a concentration of «Biostim» at a dose of 2.5 l/ha (20 ml) for cuttings and 20 ml/l for seeds. The concentration of the preparation at a dose of 10 ml / kg (the consumption of the working solution is 1.5-2 l/kg) with soaking of seeds before sowing for 10-20 minutes, followed by drying, was suitable for Robiniapseudoacacia. The concentration of the preparation in a dose of 10 ml / l with soaking of the seeds before sowing for 10-20 minutes followed by drying was suitable for robiniapseudoactation. The worst result in the test of laboratory germination of seeds was shown by oak petiolate, due to the lack of reaction of seeds to processing and their mold formation. In coniferous species, the best result was shown by Crimean pine with a concentration of the preparation«Biostim» of 10 ml / l and 2.5 l / ha. The germination of spruce and thuja seeds was weak. According to the results of the test of the preparation «Biostim» on seedlings and seeds in a nursery on dark chestnut soils, the best result was shown by seedlings of poplar and catalpa species with a concentration of «Biostim» at a dose of 2.5 l/ha and 20 ml/l for seeds. Additional top dressing with poplar preparation proved to be effective, after which good growth, development and leafing of plants were observed. Seedlings and seeds of eastern thuja and blue spruce after additional processing grew and developed satisfactorily, subsequently their drying and loss was observed, which makes the topic of testing biostimulators of growth on conifers is promising for further research.

Optimizing Somatic Embryogenesis Initiation, Maturation and Preculturing for Cryopreservation in Picea pungens

Picea pungens (Engelm.), known for its blue-green needles, has become a likable ornamental species in northeast China since 2000. Nonetheless, a lack of propagation methods that can maintain genetic fidelity and develop seedlings at a large scale prevents the further expansion of the species. Somatic embryogenesis (SE), paired with cryopreservation technologies, may provide a valid alternative. Picea pungens SE is not new, but its practical application has been limited due to low efficiencies in SE initiation and maturation as well as a lack of effective cryopreservation technology. In this study, experiments were carried out to overcome the limitations by modifying culture media. For initiation, the efficiency was enhanced by adjusting concentrations of 2.4-dichlorophenoxy acetic acid (2,4-D), 6-benzyl amino–purine (6-BA) or sucrose supplemented to the induction medium. The concentrations of 4.0 mg/L 2,4-D, 2 mg/L 6-BA, and 5 to 10 g/L sucrose were found optimal in maximizing initiation efficiency. For maturation, the efficiency, expressed as the number of mature somatic embryos per gram of fresh mass cultured (E/gFM), varied greatly with the choices of the basal medium and concentration of abscisic acid (ABA) of the maturation medium. Based on our results, the judicial choices were using the DCR medium as the basal medium and 10 mg/L ABA. The maturation efficiency could also be improved by adjusting the maturation medium’s osmotic pressure by manipulating the concentrations of carbohydrate and Gelrite and culture density. While the maturation medium, using sucrose as carbohydrate source or supplemented with a low (<8 g/L) Gelrite concentration, facilitated maturation, optimal selections were truly genotype-dependent. Our results also suggest that, while the optimal culture density varied with genotype, in general it is needless to culture more than 100 mg embryogenesis tissues per dish (size: 10 × 1.5 cm). Based on this study, the optimum pretreatment for embryogenesis tissue cryopreservation was culturing the tissues on the proliferation medium with 0.4 mol/L sorbitol for 24 h, followed by treatment with 5% Dimethyl sulfoxide. This study significantly improved the initiation (achieved a frequency of 0.56) and embryo maturation efficiencies (achieved 1030 E/gFM) and established an effective preculturing protocol for cryopreservation (recovered 1354 E/gFM) for the species. The protocols developed here, paired with the available ones for other SE steps in the literature, form a well-refined SE technology intended for commercial application to Picea pungens.

Assessment of Cr and Zn deposition on Picea pungens Engelm. in urban air of Ankara, Türkiye

Assessment of Cr and Zn deposition on Picea pungens Engelm. in urban air of Ankara, Türkiye

КОМПЛЕКСНА ОЦІНКА СКВЕРУ ІМ. І. ЧЕРНЯХОВСЬКОГО М. УМАНЬ ЧЕРКАСЬКОЇ ОБЛАСТІ ТА ПРОПОЗИЦІЇ ЩОДО ЙОГО ВІДНОВЛЕННЯ

The article presents an analysis of the dendrological composition, spatial and phytocenotic structure of the plantations of I. Chernyakhovsky park in Uman, Cherkasy region. During plantation inventory in the park were found 18 taxa of trees, 2 species of shrubs and 3 species of perennial flowering plants. The dendrological structure of the park is mainly represented by the genera Aceraceae (17,1 %), Tiliaceae (17,6 %), Rosaceae (4,8 %), Hippocastanaceae (1,7 %), the share of other genera is insignificant. The main tree species in the groups are Aesculus hippocastanum L. The accompanying species are Styphnolobium japonicum L., Robinia pseudoacacia L., Tilia cordata L. and others. The composition of the park is dominated by simple groups. Green plantations make up 76.2% and occupy a significant part of the park's territory, 36.4% belong to artificial coverings. The project of reconstruction of the territory envisages increase of species composition and improvement of decorative qualities of the park plantations. For this purpose we suggest using the most ornamental plants (Picea pungens f. "Glauca", Larix decidua f. "Pendul", Picea omorika L., Picea abies f. "Ohlendorffii", Catalpa bignonioides L., Platanus occidentalis L., Prunus serrulata f. "Kiku shidare", Stachys lanata, Juniperus communis f. "Repanda", Buxus microphylla f. "Folker", Rhododendron impeditum L., etc.).

Outbreak of Pityogenes chalcographus and Pityophthorus pityographus on Spruce Seedlings Resulting from Inappropriate Management in a Forest Nursery

In this report, we describe a local outbreak of small bark beetles on 4-year-old seedlings of Picea abies in a forest nursery in Central Europe in 2021. In March 2022, 10–50% of the seedlings were “dry” (i.e., with dry and easily broken twigs and with easily peeled bark) in each 4-row bed in the nursery. Half of the dry plants were completely covered by galleries of bark beetles and another 35% of the seedlings were with one or two bark beetle galleries. Almost 90% of the beetles found on the affected seedlings were Pityogenes chalcographus, and only 10% were Pityophthorus pityographus (we studied 100 seedlings in the second bed). The chipping of Picea pungens in previous years had left many felled trunks, branches, and other logging residues in the area. These residues are covered by galleries of both bark beetles. We suggest that, after multiplying on the logging residues, the beetles could not find suitable material for reproduction and were lured to the nursery seedlings, which had been weakened by location (a location that provided inadequate shade and no wind protection) and by repeated replanting.

Forest structure determines nest box use by Central European boreal owls

Nest boxes represent a popular tool to support secondary cavity-nesting species. Surprisingly, the benefits and limitations of nest boxes for target species in different environments are poorly understood. We performed a 3-years experimental study in two different Central European forests to evaluate nest box use and breeding performance of boreal owl (Aegolius funereus) — a species well known for its readiness to occupy nest boxes. Based on territorial vocalisation, two boreal owl populations 200 km apart were similarly abundant in their environments. However, only the boreal owl population in young restored Norway (Picea abies) and blue (Picea pungens) spruce-dominated forests on mountain plateaus readily occupied nest boxes with the occupancy reaching 8–15%. Nest boxes lost their supporting function for the boreal owl in mature Scots pine (Pinus sylvestris)-dominated forests in the lowland, where the nest box occupancy reached 0–1%. As a result, the population of boreal owls that used nest boxes in the young restored forests produced 10 times more fledglings than the population inhabiting mature Scots pine forests. We explain the differences by the contrasting availability of natural tree cavities between the two study areas being much higher in mature Scots pine forests. For the first time, this study documents differences in nest box use despite similar food availability and population size of the target species. The study provides the findings-related recommendations for deploying nest boxes for boreal owls and points out a general lack of practical guides.

Dendrochronological analysis of the influence of climate on autochthonous and introduced coniferous tree species in the city park “Prostor”, Kardzhali

The study focuses on the response to climate change of indigenous and introduced coniferous tree species – Austrian black pine (Pinus nigra Arn.) and Colorado spruce (Picea pungens Engelm.) situated in the urban city park “Prostor” in the town of Kardzhali. A multifactor regression analysis was used in the frame of the dendrochronological studies to establish the functional dependence “climate – radial growth”. The model was tested in a climate window with a segment of 16 years – from 2005 to 2020. The data for air temperature and monthly precipitation amounts for Hydro-meteorological station (HMS) Kardzhali were used as predictors for the radial growth. = Both species’s indifference to the temperatures and rainfalls during the months August and September, crucial for the ring formation, leads to the absence of significant growth depressions in tree-rings chronologies and justifies the good condition of the studied trees.

Зимостойкость хвойных растений в условиях северной лесостепи юга Тюменской области

We have studied 4 species of the genus fir, 3 species of the genus spruce (including (hereinafter) 14 varieties of Norway spruce and 12 varieties of blue spruce), 2 species of the genus larch (3 varieties of Western European larch), 7 species of the genus pine (7 varieties of mountain pine and 12 varieties of northern white cedar), 6 species of the genus juniper (3 varieties of common juniper, 5 varieties of savin juniper, a variety of Rocky Mountain juniper, 3 varieties of flaky juniper, 2 varieties of Virginian juniper and 3 varieties of Juniperus pfitzeriana) and a species of Siberian carpet cypress. All the studied plants were divided into three groups: highly promising, less promising and unpromising for this region. Most plants from the first group have large habitats indicating a wide range of their ecological potential. It has been found that the use of plants from the second group requires a careful selection of suitable locations and great attention to care measures. Plants from the third group are unpromising. It is impractical to use them actively in landscaping. The analysis also resulted in the development of a method for selecting coniferous plants for landscaping in the northern forest steppe of the south of the Tyumen region, based on their size parameters, species, varieties and needle colour. There are also 4 groups based on height: procumbent, scrubby, medium-grown, and tall-grown. Each group is divided into 3 subgroups based on the color of the needles: green, yellowish and caesious. The size of the plant has to be taken into account when creating ornamental plantations. Thus, fastgrowing varieties are useful for short-term decorative effects or in places where wind or noise protection is required fairly quickly. Medium-grown species are suitable for landscaping any territories and, with the use of restrictive pruning, even for small gardens or topiary art. Scrubby plants are suitable for landscaping small gardens, rockeries, small compositions. Depending on their growth rate, groundcover plants can be used as a lawn replacement, to stabilize slopes and create a carpet effect. For citation: Lyasheva L.V., Lyashev A.A., Steinberg Yu.S. Winter Hardiness of Conifers in the Northern Forest Steppe Conditions of the South of the Tyumen Region. Lesnoy Zhurnal [Russian Forestry Journal], 2022, no. 1, pp. 49–61. DOI: 10.37482/0536-1036-2022-1-49-61

СРАВНИТЕЛЬНЫЙ АНАЛИЗ НАКОПЛЕНИЯ ТЯЖЕЛЫХ МЕТАЛЛОВ В ХВОЕ ИНТРОДУЦЕНТОВ В ЗЕЛЕНОЙ ЗОНЕ Г. НУР-СУЛТАН

Comparative analysis of heavy metal accumulation in the needles of introduced species in the green zone of Nur-Sultan has been carried out. 10-year-old forest plantations created from introduced conifers of the genus Spruce (Picea), Fir (Abies) and Larch (Larix) have been investigated in the green zone of Nur-Sultan. Siberian spruce (Picea obovata Ledeb.) has the greatest ability to absorb heavy metals, then (in decreasing order): black spruce (Picea mariana Mill.), Engelmann spruce (Picea engelmannii Parry ex Engelm.), Siberian fir (Abies sibirica Ledeb.), Siberian larch (Larix sibirica Ledeb.), Colorado spruce (Picea pungens Engelm.). The needles of introduced species were found to exceed the MPCs for lead (Pb), cobalt (Co), and manganese (Mn). High concentration of manganese led to a decrease in the concentration of active iron (Fe), the manganese-iron ratio in trees of the Spruce genus was 1.6-2.9: 1 in all the studied conifers. The content of this element in Siberian larch was the highest (34.9 mg/kg) one, but iron was also present in a fairly large amount (19.7 mg/kg), so the manganese-iron ratio was 1.8:1. Gas resistance and a tendency to accumulate heavy metals in needles, decorativeness and high preservation have been shown by spruce Siberian, which can be recommended for planting in the green zone. Black spruce and Engelman spruce are also resistant to unfavorable environmental factors and decorative. The accumulation capacity and safety of Siberian larch, as well as Siberian fir, is very low, so these species should not be recommended for growing in the green zone of Nur-Sultan

Gemmamyces piceae Bud Blight Damage in Norway Spruce (Picea abies) and Colorado Blue Spruce (Picea pungens) Forest Stands

Since 2008, spruce bud blight (Gemmamyces piceae (Borthw.) Casagr.) has been spreading epidemically in forest stands of the Czech Republic’s Ore Mountains. This fungus, with a disjunct Holarctic range, injures buds, especially of Colorado blue spruce (Picea pungens Engelm.). Damaged buds do not sprout, and, in case of a stronger attack, the tree does not recover its assimilation apparatus and may die. Within the past few years, there has been a huge spread of this fungus throughout the mountain range. This paper summarizes the biology of G. piceae, its host plants, and presents the first findings from the massive outbreak of G. piceae. In 2015, an increase in damage was detected on Norway spruce (Picea abies (L.) Karst). The course of the G. piceae epidemic had been monitored in 25 permanent research plots over the course of 11 years. In the case of Colorado blue spruce, stands aged 10–60 years were attacked, with 60% of buds damaged on average. The intensity of damage to Norway spruce buds was around 25%. Norway spruce infestation varied significantly depending upon the age of the stand (GLMM: p < 0.01). In the age class of 31–60 years, on average 80% of individuals were infested. In older stands, only 42% of trees were infested, and no infestation was found in individuals younger than 15 years. In Colorado blue spruce, the distribution of the pathogen was continuous, whereby all individuals in the research plots were affected, and, with the exception of a few trees, the infestation was lethal or resulted in a significant reduction of the assimilation apparatus. The development of damage on Colorado blue spruce can be characterized as continuous growth.

Picea pungens (blue spruce)

Picea pungens (blue spruce)

СОСТОЯНИЕ ХВОЙНЫХ ИНТРОДУЦЕНТОВ В Г. НУР-СУЛТАНА

The article presents observational data on the survival, preservation and growth of introduced tree species created in the interstrip spaces of the green zone of the city of Nur-Sultan. The greatest preservation is characterized by Siberian spruce (Piceaobovata Ledeb.) (76.8%) and blue spruce (Piceapungens Engelm.) (58,9%). Black spruce (Piceamariana Mill.) and Siberian larch (Larixsibirica Ledeb.) have a preservation rate of an average of 44.5%. The lowest survival rate and preservation (16.4%) is distinguished by Siberian fi r (Abiessibirica Ledeb.). When comparing the method of planting forest crops with planting the material with an open and closed root system, it was revealed that the survival ability and preservation of seedlings with ORS was slightly higher than that of seedlings with CRS. The average survival ability of seedlings with ORS was 58.1%, for seedlings with CRS – 53.7%. Plants height corresponds to the biological characteristics of woody species. The highest average height was for Piceamariana Mill (184.1 cm), the smallest average height was for Piceaengelmannii Parry ex Engelm (143.4 cm). The most acclimatized species of woody plants – Piceaobovata Ledeb., Piceapungens Engelm. and Piceamariana Mill – have been identifi ed. These trees have a high capacity for survival, stable growth and decorative effect. These coniferous plants can be used to create green areas of settlements in Kazakhstan, similar in soil and climatic conditions to the city of Nur-Sultan.

Influence of biologically active substances, chemicals and growth regulators on diseases of conifers in urban conditions

The objects of study were coniferous plants aged from 6 to 10 years. The study involved such plants as Siberian spruce (Pícea obováta), prickly spruce Hoopsi (Picea pungens Hoopsii), western thuja Smaragd (Thuja occidentalis Smaragd), thuja western Brabant (Thuja occidentalis Brabant). The subject of the study was the pathological symptoms manifested on the aboveground plant organs. The plants were planted in 2015 at the age from 6 (thuja Smaragd and thuja Brabant) to 10 (prickly spruce and Siberian spruce) years. The studies were conducted from May 2016 to September 2018 inclusive. During the initial examination, which was carried out on May 28, 2016, on all conifers, there was a loss of decorativeness, partial premature drying of shoots and falling of needles. When using biological products, a persistent stimulating effect is very noticeable — the general condition of conifers improves, this makes it possible to recommend tank mixtures for use, the composition of which is less toxic. Thuja Brabant turned out to be the most unresponsive to drug treatment.

Chronology of the use of woody plants in landscaping of Kryvyi Rih

Aim. Analysis of the chronological sequence of involvement of woody plants in landscaping of the city of Kryvyi Rih to develop conceptual foundations for their more effective use. Methods. Chronology of species implementation of woody plants in landscaping of the city were studied until the year 2000 on the basis of archival documents, scientific publications, as well as studies of the dendroflora of Kryvyi Rih. Results. In total, 185 species and forms of woody plants belonging to 82 genera were used in the landscaping of the city until the year 2000. In the period between 1870–1910, only 26 species were involved. In the postwar period (1945–1950), the number of species planted in the city was already 38 species, it increased significantly up to 78 species in the 1960s, and the maximum number of species - 90 was used in the landscaping of the city in the 1970s. In the first half of the twentieth century the most common species were members of the genus Acer L., among them A. negundo L., as well as Robinia pseudoacacia L.; species of the genera Ulmus L. and Fraxinus L. 1970–1980 years can be called the era of species of the genus Populus L. Conifers were solitarily planted in the city in the 1950s and 1960s, these are species of the genus Thuja L.and Juniperus L. In the late 1970s and 1980s, species of the genera Picea A. Dietr., Pinus L. and Taxus L. were massively introduced in the city. Today, such species as Picea pungens Engelm., as well as forms of P. pungens f. coerulea and P. pungens f. glauca is most represented among conifers in plantations, slightly less – Pinus pallasiana D. Don and P. sylvestris L. At this time and in the following years, Juniperus sabina L. is widespread in the city. Conclusions. In the urban environment of the XX century, the species, with a high level of vitality, primarily among deciduous Acer, Betula L., Catalpa Scop., Crataegus L., Fraxinus, Gleditsia L., Malus Mill., Morus L., Padellus Vass., Populus, Prunus L., Pyrus L., Quercus L., Rhus L., Sophora L., Tilia L., Ulmus proved to be stable and among coniferous — species of the genera Picea, Pinus, Taxus, Juniperus and Thuja, which are promising for further use.

Рост и продуктивность инорайонных древесных видов в условиях Среднего Урала

Climate warming has been recorded over the last decades. The air temperature in Yekaterinburg has been rising since the 1930s. Temperatures dropped sharply in 1940–1949, then rose sharply and fell again, especially in 1967–1968, when many large introduced species considered to be adapted died: Phellodendron amurense Rupr. and Pseudotsuga taxifolia (Lindl.) Britt. Due to the cyclical nature of weather conditions, it was necessary to assess the features of adaptation and state of the introduced plants in recent years. Snowless autumn and winter, temperatures above zero in early spring are unfavourable for many species, especially or conifers. Thus, in 2014 much snow fell on October 16 and melted in 2 weeks, temperatures below zero did not afford plants to prepare for the winter; in March 2015 the temperature rose up to +10 °C while the ground temperature was below zero for a long time. As a result of physiological dryness 100 % of specimens of variegated forms of northern white cedar Thuja occidentalis L. `Ellwangeriana Aurea`, `Ericoides` died. In other forms the leafage died to the snow cover level and recovered after abundant rains: `Aurea spicata`, `Gold Pearl`, `Golden Globe`, `Lutescens`, `Semperaurea` and `Wareana Lutescens`. Due to a steady increase in the sum of positive temperatures and reaching a certain age, many conifer species entered the fruiting stage and gave self-seeding: Pinus peuce Grieseb, Pinus strobus L., Picea canadensis (Mill.) Britt. et al., Picea pungens Engelm., Pseudotsuga taxifolia (Lindl.) Britt., and Abies sachalinensis (F. Schmidt) Mast. In the warmest year of 2016, the latter gave an abundant yield – red-brown cones with protruding seed scales; a strong wind dropped them all. They remained under the snow for the winter and did not crumble (probably, the fruits were unripe), so Abies sachalinensis was mistaken for Keteleeria fortunei (A. Murray bis) Carrière), which has cones that do not crumble. Unusual flowering was observed in Crataegus oxyacantha L. `Rosea Plena`, Mespilus germanica L., Syringa reflexa C.K.Schneid, Hamamelis virginiana L. With the rise in average annual temperatures, the number of years with abnormal weather conditions increased and the condition of some plants deteriorated. For citation: Semkina L.A., Tishkina E.A. Growth and Productivity of Non-Indigenous Woody Species in the Middle Urals. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 100–109. DOI: 10.37482/0536-1036-2021-6-100-109

Somatic embryogenesis in mature zygotic embryos of Picea pungens

This study developed somatic embryogenesis protocols for Picea pungens (Engelm), an important ornamental species, including initiation, proliferation, maturation, germination, and acclimation. Somatic embryogenic tissues were induced from mature zygotic embryos of five families, with a frequency of ge 22% for each. Embryogenic tissues (ET) from 13 clones of three families were proliferated for one week, achieving an average rate of 179.1%. The ET of 38 clones of three families were cultured in maturation medium for six weeks; 188 mature embryos on average were counted per gram ET cultured, of which ge 81.1% appeared normal, and each clone developed at least 28 normally matured embryos. A total of 69.9% or more of cotyledonary somatic embryos germinated normally and developed into normal emblings. The experiment of transplanting the emblings into a greenhouse had an average survival rate of 68.5%. Considerable variation among and within families during initiation and proliferation was observed, but this variation decreased in the maturation and germination. Changing the concentration of plant growth regulator of the initiation medium did not significantly change the initiation frequency. We recommend incorporating these protocols into the current Picea pungens practical programs, although further research is essential to increase efficiencies and reduce cost.

Adaptation and validation of a voxel based energy transport model for conifer species

A spatially explicit energy balance model previously developed for deciduous trees was extended to account for physical differences in conifer species. These differences include the emission and scattering of radiation in needles compared to leaves as well as the boundary-layer conductance for needles. To validate the model, an array of sensors was placed in and around two separate isolated Picea pungens trees in a heterogeneous urban environment. Model validation examined components of the local-volume averaged needle energy budget utilizing radiative and turbulent fluxes as the forcing inputs. Analysis focused on the model's ability to reproduce integrated upward shortwave and longwave radiation, local radiation attenuation through the tree crown, and local needle surface temperature. The model performed quite well with R2 values above 0.9 for calculated versus measured integrated upward longwave and shortwave radiation and above 0.87 for needle surface temperature. The high level of agreement with experimental measurements was only possible with the modifications made to the boundary layer conductance for needles.

High-Performance Solar Steam Generator Based on Polypyrrole-Coated Fabric via 3D Macro- and Microstructure Design.

Due to the abundance and easy availability of solar energy resources, solar-driven water evaporation provides a sustainable way to obtain clean water from wastewater and seawater. However, achieving a high evaporation rate with excellent light absorption remains a critical challenge in the structural regulation of evaporators. Herein, inspired by the natural transpiration process in plants (blue spruce), we designed a three-dimensional (3D) cone-shaped solar steam generator based on vertical polypyrrole nanowires-coated fabric (VPPyNWs-fabric). The microstructure design of polypyrrole (PPy) increases the solar energy absorption of the incident light through multiple reflections between the VPPyNWs, while the macrostructure design of the 3D evaporator possesses an enlarged surface area for energy harvesting, wide path for water supply, and open structure for vapor diffusion. As a proof of concept, the as-obtained 3D VPPyNWs-fabric-based solar steam generator demonstrates a fast water evaporation rate of 2.32 kg m-2 h-1 with high solar absorption of 97% and solar-to-vapor conversion efficiency of 98.56% at 1 kW m-2 energy density. In addition, the solar steam generator can be steadily applied in various water conditions, e.g., seawater, dye wastewater, and acidic and alkaline wastewater. This high-performance evaporator via 3D macro- and microstructure design offers a new avenue for better utilization of solar energy.