Woody Plant Taxa Research Articles

Melaleuca (Myrtaceae): Biogeography of an important genus of trees and shrubs in a changing world

The number of naturalised and invasive woody plant species has increased rapidly in recent decades. Despite the increasing interest in tree and shrub invasions, little is known about the invasion ecology of most species. This paper explores the global movement of species in the genus Melaleuca (Myrtaceae; here including the genus Callistemon). We assess the global introduction history, distribution and biogeographic status of the genus. Various global species occurrence databases, citizen science (iNaturalist), and the literature were used.Seventy-two species [out of 386 Melaleuca species; 19%] have been introduced to at least 125 regions outside their native range. The main regions of global Melaleuca introductions are Southeast Asia, the southern parts of North America, south-eastern South America, southern Africa and Europe. The earliest record of a Melaleuca species outside of the native range of the genus is 1789. First records of Melaleuca species outside their native range were most commonly recorded in the 1960s, with records from all over the world. The main reasons for Melaleuca introductions were for use in the tea tree (pharmaceutical value) and ornamental horticulture industries. Melaleuca introductions, naturalizations and invasions are recent compared to many other woody plant taxa. Experiences in Florida and South Africa highlight the potential of Melaleuca species to spread rapidly and have significant ecological impacts. It is likely that the accumulating invasion debt will result in further naturalization and invasion of Melaleuca species in the future.

Effects of understory characteristics on browsing patterns of roe deer in central European mountain forests.

Selective browsing by deer on young trees may impede the management goal of increasing forest resilience against climate change and other disturbances. Deer population density is often considered the main driver of browsing impacts on young trees, however, a range of other variables such as food availability also affect this relationship. In this study, we use browsing survey data from 135 research plots to explore patterns of roe deer (Capreolus capreolus) browsing pressure on woody plants in mountainous forests in central Europe. We fitted species-specific generalised linear mixed models for eight woody taxa, assessing the potential effects of understory characteristics, roe deer abundance and lying deadwood on browsing intensity. Our study reveals conspecific and associational effects for woody taxa that are intermediately browsed by roe deer. Selective browsing pressure was mediated by preferences of plants, in that, browsing of strongly preferred woody taxa as for example mountain ash (Sorbus aucuparia) and of least preferred woody taxa, for example Norway spruce (Picea abies) was not affected by the surrounding understory vegetation, while browsing pressure on intermediately browsed species like for example silver fir (Abies alba) was affected by understory characteristics. Contrary to our expectations, roe deer abundance was only positively associated with browsing pressure on silver fir and bilberry (Vaccinium myrtillus), while all other plants were unaffected by deer abundance. Finally, we did not find an influence of lying deadwood volume on the browsing pressure on any woody-plant species. Overall, our results indicate that patterns in browsing preference and intensity are species-specific processes and are partly affected by the surrounding understory vegetation. Current management strategies that aim to reduce browsing pressure through culling may be inefficient as they do not address other drivers of browsing pressure. However, managers also need to consider the characteristics of the local understory vegetation in addition to deer abundance and design species-specific plans to reduce browsing on woody plant taxa.

Diversity of woody flora in Isparta Gölcük Nature Park and its relations with environmental variables

Ormancılıkta flora üzerine gerçekleştirilen çalışmalar sürdürülebilir ormancılık ve biyolojik çeşitlilik üzerine önemli bilgiler vermektedir. Bu çalışma Gölcük Tabiat Parkında odunsu flora çeşitliliğinin belirlenerek çevresel değişkenlerle ilişkilerini ortaya koymak amacıyla gerçekleştirilmiştir. Çalışmada arazi envanteri ile 20x20 metre boyutlarında 25 örnekleme alanı alınmıştır. Her bir örnekleme alanı için odunsu bitki taksonları ve yetişme ortamı özellikleri envanter defterine kaydedilmiştir. Kümeleme analizi ile kesme seviyelerinden elde edilen grupların en uygun olanını tespit edebilmek amacıyla çoklu permütasyon testi (MRPP) uygulanmış en etkili vejetasyon grup ayrımının gösterge bitki türlerini tespit edebilmek amacıyla gösterge bitki analizi uygulanmıştır. Alfa çeşitlilik indis değerleri ile çevresel faktörler arasındaki ilişkileri ortaya koyabilmek adına Pearson korelasyon analizi uygulanmıştır. Pinus nigra, Rosa canina, Populus nigra subsp. caudina ve Malus sylvestris subsp. sylvestris türlerinin çalışma alanın genelinde en sık rastlanan türler olduğu belirlenmiştir. Çalışmada en uygun odunsu grup ayrımı 3’lü grup ayrımında elde edilmiştir. İstatistiksel analizler neticesinde en uygun vejetasyon grup ayrımlarının oluşmasında bakı farklılıklarının önem arz ettiği belirlenmiştir. Bu sonuç tür çeşitliliğinin yörede güneyli bakılarda kuzeyli bakılara kıyasla daha fazla olduğunun tespit edilmesi ile desteklenmiştir.

Dendroflora of the Nataliivskyi Park (Kharkiv region, Ukraine): taxonomic diversity and monitoring of plantations

To develop measures for the restoration of historic plantations and landscapes of the Nataliivskyi Park (Kharkiv region, Ukraine), the investigations of taxonomic composition and distribution of woody plant taxa, as well as structure of different landscape areas, were carried out in 2018–2019. The recent studies were realized according to the same protocol applied in 1997 by Y. Klymenko, and taking into account previously published data.In 1939, the dendroflora of the Nataliivskyi Park comprised about 100 taxa. Later, the number of taxa significantly decreased, and in 1950 the park’s dendroflora comprised only about 40 taxa. In 1997 there were 74 taxa reported. Since 1997, the taxonomic composition of the park’s dendroflora has been enriched by ten taxa and is currently represented by 84 taxa. Simultaneously, the number of valuable plants in the plantations decreased (only one or two plants represent some such taxa). Due to a bark beetle attack on drought-weakened trees of Picea abies and P. pungens, most of them withered. The area of allotments with Pinus sylvestris and Quercus robur remained almost the same, which indicates their stability. The area of allotments with the domination of such naturalized introducers as Acer negundo and Robinia pseudoacacia and the area of allotments with the domination of neither taxa have increased. In the landscapes, the redistribution of the types of areas appeared. The forest type of landscape became predominant, while the meadow type of landscape has almost disappeared.Hence, to restore historical plantings and landscapes, it is necessary to re-cultivate taxa represented here during the park’s heyday and remove invasive tree species. Although cuttings in protected areas are currently prohibited, our investigations showed that they might help preserve such valuable territories as Nataliivskyi Park.

Modern assessment of natural dendroflora of the Crimea

The species composition of the indigenous woody plants of theCrimeawas studied. For the peninsula, 165 species of 58 genera and 31 families were recorded. 148 forms for 50 species of woody plants from 34 genera as well as 11 hybrids for 6 species of plants have been described. In total, there are 320 taxa of woody plants in theCrimea. Of them, 24 species are included in Red Data Book. Woody plants are distributed unevenly across the territory of the Crimea: Crimean Steppe (CS) - 1 species, Crimean Forest-Steppe (CFS) - 5, Mountanious Crimea (MC) - 37, Crimean Southern Coast (CSC) -7, CS+CFS+VC+ CSC - 26, CS+CFS+ CSC - 3, CS+ CSC - 2, CS+CFS+MC - 4, CS+CFS - 2, CS+MC+ CSC - 2, CS+MC -1, CFS+MC+ CSC - 30, CFS+ CSC - 5, CFS+MC - 14, MC+ CSC - 27 species. Dominating are the genera:Rosa- 16 species, Rubus - 21, Crataegus - 15. There are 101 species of shrubs and 64 species of trees; of them evergreen deciduous trees - 1, coniferous - 8, evergreen shrubs - 10, deciduous species - 146 species. Locally distributed are 19 species of the following genera: Arbutus, Betula, Daphne, Myricaria, Nitraria, Rubus, Ruscus, Vitex.

Atmospheric pollen spectrum in Stone City, Mardin; the northern border of Mesopotamia/SE-Turkey

Airborne pollen distribution in Mardin city was measured volumetrically during three consecutive years, 2014-2016. Three thousand eight hundred fifty-seven pollen grains as a mean value belonging to 44 taxa were recorded annually during the study period, and pollen grains from woody plant taxa had the more substantial atmospheric contribution with 62.66% and with 23 taxa. Despite the differences between years, the highest pollen concentration was recorded in April. The main pollen producers of the pollen spectrum were Cupressaceae (27.79%), Poaceae (21.21%), Platanus (10.29%), Morus (6.19%), Olea europaea (5.01%), Quercus (4.91%), Pinus (3.84%), and Amaranthaceae (3.73%) and almost all dominant pollen types in the city atmosphere were previously stated to be allergic. The atmospheric sampling data was characterized by the high presence of woody plants in spring, as well as the high presentation of herbaceous plants in late spring to early winter. The main pollen season (MPS) and durations of dominated pollen types were analyzed and mostly found a little bit earlier or parallel with similar studies in Mediterranean basin, but found earlier than the east. Statistical analyses were performed to compare years with each other and for correlating daily pollen concentrations of dominated pollen types concurrent with the data of meteorological parameters; a number of significant correlations were found.

FLORISTIC CHARACTERISTICS OF ARBUTUS UNEDO L. AND ARBUTUS ANDRACHNE L. AS MEDICINAL PLANTS

633.88:582.688.3(560)
 Arbutus unedo L. and Arbutus andrachne L., belonging to Ericaceae family and being evergreen, are two important species having economic values in natural flora of Turkey. These species spread as enclave in the Black Sea Region, while they are found naturally in the Mediterranean and Aegean Region of Turkey. Arbutus unedo, whose fruits contain a high amount of sugar (42% - 52%), is widely preferred in the subbranchs of the food industry such as jam, marmalade and sweetener, especially in the beverage industry in Europe. Arbutus andrachne is a species that has an effect on the circulatory system and besides it has antihemorrhagic and urinal antiseptic properties. In this study, floristic characteristics of Arbutus unedo and A. andrachne, spreading in places where the Mediterranean climate is predominant in Turkey, being characteristic elements of maquis formation in coastal areas of Black Sea Region, are investigated. Within the scope of the study, sample plots were taken in Bartın, Kastamonu, Sinop, Samsun, Ordu and Trabzon regions. It was determined that the most common native species accompanying these species (only woody plant taxa) are different. These species are frequently spread together with Castanea sativa in Bartın, Quercus sp. + Carpinus betulus in Kastamonu, Castanea sativa + Pinus sylvestris + Fagus orientalis in Sinop, Pinus brutia in Samsun, Quercus sp. in Ordu and Quercus sp. + Carpinus betulus in Trabzon. In addition, shrub species such as Erica arborea, Laurus nobilis, Ruscus aculeatus, Smilax excelsa, Rubus sp. and Cistus sp. accompany to these species in all of these sample plots.

Improved Method of Enzyme Digestion for Root Tip Cytology

Chromosome numbers are an important botanical character for multiple fields of plant sciences, from plant breeding and genetics to systematics and taxonomy. Accurate chromosome counts in root tips of woody plants are often limited by their small, friable roots with numerous, small chromosomes. Current hydrolysis and enzyme digestion techniques require handling of roots before the root squash. However, optimum chromosome spread occurs when the cell walls have degraded past the point of easy handling. Here, we present a new enzyme digestion protocol that is fast, efficient, and flexible. This protocol reduces handling of the roots allowing for long-duration enzyme digestion. Digestions are performed on a microscope slide, eliminating the need for handling digested cells with forceps or pipettes. To illustrate the flexibility of this method across woody plant taxa, we performed chromosome counts on five angiosperms and one gymnosperm. Ploidy levels included diploids, triploids, and tetraploids with chromosome numbers ranging from 2n = 16 to 2n = 80. The range of holoploid 2C genome sizes spanned 1.54–24.71 pg. This protocol will provide a useful technique for plant cytologists working with taxa that exhibit a wide range of genome size and ploidy levels.

Seasonal and intradiurnal variation of airborne pollen concentrations in Bodrum, SW Turkey.

An aeropalynological study was performed in Bodrum, the famous tourism center in southwestern Turkey with a Hirst-type volumetric 7-day pollen and spore trap for 2 years (2007-2008). In Bodrum, 25,099 pollen grains as a mean value belonging to 41 taxa were recorded annually during the study period, and pollen grains from woody plant taxa had the largest atmospheric contribution of 86.99% and 24 taxa. However, 17 herbaceous plant taxa constituted 12.82% of the annual total pollen count, and 0.19% were unidentified. An average annual pollen index of 22.66% was recorded in March, despite differences from year to year. The highest pollen variability of 34 taxa was recorded in April and May. Predominant pollen types belonged to Cupressaceae/Taxaceae (42.73%), Quercus (15.95%), Pinus (9.78%), Olea europaea (9.04%), Poaceae (5.50%), Betula (1.82%), Pistacia (1.74%), Morus (1.72%), Urticaceae (1.46%), and Plantago (1.28%) and generated 91.03 of the annual total. In total, 32.59% of the mean annual total pollen index was recorded in the morning, and less pollen was recorded in the evening (18.71%). Maximum pollen concentration was recorded between 11:00 and 12:00 a.m.

Application of decision tree algorithms for discriminating among woody plant taxa based on the pollen season characteristics

The aim of this study was to verify whether and which parameters of the atmospheric pollen season can distinguish between pollen types, the ranges of parameter values that delineate classes of taxa, and finally which taxa are similar to others within the domain of these parameter ranges. Decision tree algorithms were applied and the best tree was chosen to describe the rules of pollen classification. The study material consisted of airborne pollen grains of the following eight taxa: Alnus, Betula, Carpinus, Corylus, Cupressaceae, Fraxinus, Populus and Ulmus. Research was conducted in Lublin in eastern Poland during 2001-2013. The following six atmospheric pollen season parameters were analyzed: season start and end, duration, maximum daily pollen concentration, date of maximum pollen concentration, and the Seasonal Pollen Index (SPI). Four algorithms were used in data analysis and the J4.8 algorithm was chosen as the best for taxa classification, date of the end of season and the SPI value belonging to characteristics that served most to discriminate between pollen types. Based on the classification tree, the following four groups of taxa were identified: (i) Ulmus; (ii) Corylus, Alnus, Populus; (iii) Betula; and (iv) Carpinus, Fraxinus, Cupressaceae.

Natural abundance (δ¹⁵N) indicates shifts in nitrogen relations of woody taxa along a savanna-woodland continental rainfall gradient.

Water and nitrogen (N) interact to influence soil N cycling and plant N acquisition. We studied indices of soil N availability and acquisition by woody plant taxa with distinct nutritional specialisations along a north Australian rainfall gradient from monsoonal savanna (1,600-1,300 mm annual rainfall) to semi-arid woodland (600-250 mm). Aridity resulted in increased 'openness' of N cycling, indicated by increasing δ(15)N(soil) and nitrate:ammonium ratios, as plant communities transitioned from N to water limitation. In this context, we tested the hypothesis that δ(15)N(root) xylem sap provides a more direct measure of plant N acquisition than δ(15)N(foliage). We found highly variable offsets between δ(15)N(foliage) and δ(15)N(root) xylem sap, both between taxa at a single site (1.3-3.4 ‰) and within taxa across sites (0.8-3.4 ‰). As a result, δ(15)N(foliage) overlapped between N-fixing Acacia and non-fixing Eucalyptus/Corymbia and could not be used to reliably identify biological N fixation (BNF). However, Acacia δ(15)N(root) xylem sap indicated a decline in BNF with aridity corroborated by absence of root nodules and increasing xylem sap nitrate concentrations and consistent with shifting resource limitation. Acacia dominance at arid sites may be attributed to flexibility in N acquisition rather than BNF capacity. δ(15)N(root) xylem sap showed no evidence of shifting N acquisition in non-mycorrhizal Hakea/Grevillea and indicated only minor shifts in Eucalyptus/Corymbia consistent with enrichment of δ(15)N(soil) and/or decreasing mycorrhizal colonisation with aridity. We propose that δ(15)N(root) xylem sap is a more direct indicator of N source than δ(15)N(foliage), with calibration required before it could be applied to quantify BNF.

Effect of root competition and shade on survival and growth of nine woody plant taxa within a pecan [Carya illinoinensis (Wangenh.) C. Koch] alley cropping system

Suitability for production of woody floral stems in a pecan [Carya illinoinensis (Wangenh.) C. Koch] alley cropping was determined for nine shrub species in northwest Florida. Treatments included partial shade without root competition, partial shade with root competition, and full sun. Only three species had high rates of survival for all treatments throughout both years of the study: Callicarpa americana L. (American beautyberry), C. americana var. Lactea (white American beautyberry), and Crataegus marshallii Eggl. (parsley haw). For C. americana, plant growth index increased through time and was similar among the three treatments, indicating that this species grew equally well in sun or shade irrespective of root competition from the tree crop. C. americana var. Lactea had similarly high rates of survival and grew largest in partial shade without root competition (81.7 cm) compared to partial shade with root competition (67.2 cm) and full sun (57.0 cm). C. marshallii had 100 % survival in partial shade without root competition, with one mortality in partial shade with root competition (91.7 % survival) and one in full sun (91.7 % survival). Growth index did not increase over time and was similar among all three treatments. Other species tested had low rates of survival in all treatments throughout both years of the study and included: Ilex glabra L. (inkberry), Ilex myrtifolia Walt. (myrtle-leaf holly), Hydrangea paniculata Seibold var. ‘Tardiva’ (panicle hydrangea), Hydrangea quercifolia Bart. (oakleaf hydrangea), Lyonia lucida (Lam.) K. Koch, and Salix matsudana Koidz. F. tortuosa Rehd. (corkscrew willow). No species produced sufficient flowers, fruits or ornamental stems during this establishment period to allow a florist evaluation of the stems for use as woody floral stems.

Patterns from the past: modeling Public Land Survey witness tree distributions with weights-of-evidence

The Public Land Survey (PLS) witness tree data provide one of the few quantitative data sets of pre-and early-European settlement composition and structure of the forests and woodlands in the western United States. However, quantifying the areal extent of individual woody species from PLS records has proven difficult due to the coarse sampling structure of the data. Several attempts have been made to convert the discrete PLS witness tree data into continuous distributions through the use of various interpolation techniques. While these methods may adequately represent the spatial patterns of individual species over large areas, they fail to consider the numerous environmental covariates that can influence the distribution of individual tree species at finer scales. A more statistically rigorous method calls for combining species–environment relationships to estimate the areal extent of individual species from point data. In this study, we utilize weights-of-evidence (WofE), a discrete multivariate method, to estimate the probable historical distribution of six important woody plant taxa of the cross timbers of south-central Oklahoma. We successfully created posterior probability distribution maps for Quercus stellata, Q. marilandica, Q. velutina, Carya texana, C. illinoinensis, and Juniperus spp. Each posterior probability map was classified into four predictive categories, thereby enabling better estimations of the historical distribution of individual taxon from coarse-resolution PLS data. Model validation indicated that the WofE method effectively estimated the posterior probabilities of all taxa under consideration.

Foliar‐Nitrogen and Phosphorus Resorption Patterns Differ among Nitrogen‐Fixing and Nonfixing Temperate‐Deciduous Trees and Shrubs

Nutrient resorption from senescing leaves enables plants to conserve nutrients. Low foliar‐nitrogen (N) resorption levels have been estimated in past studies for some N‐fixing woody plant taxa. To determine whether this trait is characteristic of N‐fixing temperate species, N‐resorption proficiency estimates were derived for several species during two seasons in central Illinois, United States. Nutrient‐resorption proficiencies were measured for 24 species of temperate‐deciduous woody plants. Thirteen actinorhizal species and three non‐N‐fixing species in families with actinorhizal species were sampled. One N‐fixing woody legume, four non‐N‐fixing legumes, and two species lacking N‐fixing capabilities and unrelated to these groups were also sampled. Nitrogen resorption, based on resorption proficiency values, was less in N‐fixing species (1.78% N retained in abscised leaves) than in non‐N‐fixing species (1.01% N). Phosphorus (P) resorption, however, was greater in N‐fixing species (0.06% P retained in abscised leaves) than in non‐N‐fixing species (0.26% P). Resorption of P may have been low in a group supporting ectomycorrhizal symbionts. Results indicate a consistent pattern in which N‐fixing species are less proficient at N resorption than other temperate‐deciduous woody species.

Identification of Alternative Hosts of Xylella Fastidiosa in the Washington, D.C., Area Using Nested Polymerase Chain Reaction (PCR)

A survey of 27 herbaceous and woody plant taxa was conducted to identify possible alternative hosts of the xylem-limited bacterium, Xylellafastidiosa. Samples were collected from wild and cultivated plants inhabiting and surrounding the National Park Service Daingerfield Island Nursery in Alexandria, Virginia, and from national parks in Washington, D.C. These samples were analyzed using up to 3 different bacterial extraction methods and a 2-step, nested polymerase chain reaction (PCR) amplification using oligonucleotide primers specific to X. fastidiosa. Six out of the 27 sampled plant taxa tested positive. Acer negundo, Aesculus x hybrid, Cdastrus orbiculata, Cornus florida, and Hedera helix have not been previously confirmed as hosts, while Vitis species have been described as wild and cultivated hosts in numerous studies. Eleven of the 27 taxa could not be tested due to failure to amplify X. fastidiosa DNA in the positive controls, regardless of the extraction method.

Seasonal Cold Hardiness Differences of Three Woody Plant Taxa during the Production Stage and as Established Landscape Plants

Abstract Seasonal cold hardiness levels of Crape myrtle (Lagerstroemia L. ‘Natchez’), Leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks.] ‘Haggerston Gray’ and Lacebark elm (Ulmus parvifolia Jacq. Allee™) were determined for nursery production and established landscape plants grown at the same location. Differences in cold hardiness between the growth treatments were taxon specific. During October, November and December, nursery-grown crape myrtle plants were up to 11°C (20°F) less cold hardy than those established in the landscape. Differences in Leyland cypress cold hardiness were detected, but were not as great as in crape myrtle. During October, November and December newly transplanted Leyland cypresses were from 3 to 6°C (5 to 11°F) less cold hardy compared to established landscape plants. Differences occurred between nursery production and established landscape plants of lacebark elm in January and February.

Selecting Trees for Cold Climates

Lack of sufficient tolerance to low temperatures is often a limiting factor for successful use of many woody plant taxa in cold climates. Trees capable of acclimating to withstand the lowest midwinter temperatures may still perish if they do not acclimate early enough to withstand severe freezing temperatures in early winter. The University of Minnesota has introduced several tree cultivars selected for their winter hardiness. Merits of these introductions and other plants that have shown potential for use in Minnesota and other northern areas are described in this paper. The goals and activities of the Center for Development of Hardy Landscape Plants are also briefly discussed.

ENDOGENOUS PRODUCTION OF RAFFINOSE FAMILY OLIGOSACCHARIDES INCREASES DURING THE FIRST STAGES OF COLD ACCLIMATION IN SEVERAL WOODY PLANTS

Woody plants can be induced to cold-acclimate by exposure to sublethal low temperatures, but only after the onset of vegetative maturity. We monitored seven woody plant taxa, at monthly intervals, to determine the date of vegetative maturity, freeze-killing temperature, cell membrane electrolyte leakage, and the quantity and diversity of endogenous oligosaccharides. The freeze-killing temperature changed from -5 to -7C before vegetative maturity to -15 to -20C after vegetative maturity. There was a 10-fold increase in raffinose and about a 3-fold increase in endogenous stachyose in samples that were cold-acclimated under controlled conditions. In field samples, endogenous raffinose increased from <0.02% in August to 2% to 11% in cortical stem tissues of all cold-acclimated taxa. The tetrasaccharide stachyose increased from <0.02% to 0.25% to 2.5% for similar comparisons. None of the other sugars or polyols showed similar, consistent patterns during the onset of cold acclimation. In response to low temperature, raffinose family oligosaccharides (RFOs) have previously been shown to increase substantially in cabbage, soybean, kidney bean, and Chlorella. RFOs also possess high water-binding characteristics and tend to enhance aqueous glass transitions. Accordingly, we hypothesize that the endogenous production of these oligosaccharides may play an important role in metabolic events associated with cryoprotection of critical cellular functions during low-temperature stress.